## Total Maximum Daily Loads

For Toxic Pollutants San Diego Creek and Ne wport Bay, California

U.S. Environmental Protection Agency Region 9

Established June 14, 2002

Alexis Strauss Director Water Division EPA Region 9Newport Bay Toxic Pollutant TMDLs



### Table of Contents

Summary TMDL Document

I. Introduction ........................................................................

.... 2
II. Overview of TMDLs and Available Data .......................................... 12
III. Organophosphate (OP) Pesticide TMDLs .......................................... 24
IV. Selenium TMDLs...................................................................... 32
V. Metals TMDLs........................................................................ 40
VI. Organchlorine Compound TMDLs.................................................

.. 51
VII. Chromium and Mercury TMDLs .................................................... 63
VIII. Arsenic Analysis......................................................................

.. 69
IX. Implementation Recommendations................................................... 71
X. References............................................................................

.. 77
XI. Glossary/Abbreviations................................................................ 82

Technical Support Documents
A. Relevant Maps
B. Freshwater Flow a nd Seasonal Variations
C. Organophosphate Pesticides
D. Selenium
E. Metals
F. Organochlorine Compounds
G. Chromium and Mercury
H. Decision Document
I. Responsiveness Summary

summary document 1Newport Bay Toxic Pollutant TMDLs



## I. Introduction

What Is the Purpose of This Action?

This document describes Total Maximum Da ily Loads (TMDLs) being established for several toxic pollutants by U.S. Environmental Protection Agency (EPA) to help protect and restore the water quality of Ne wport Bay, San Diego Creek, and their tributaries. A TMDL identifies the maximum amount of a pollutant th at may be discharged to a water body without causing exceedences of water quality standards and impairment of the uses made of these waters. The federal Clean Water Act requires development of TMDLs for polluted waters to assist in identifying pollutant control needs and opportu nities. EPA is establishing these TMDLs pursuant to a 1997 consent decree in which EPA committed to ensure that these TMDLs would
be established in 2002. EPA has worked closel y with the California Regional Water Quality Control Board, Santa Ana Region (Regional Boar d) in the development of these TMDLs. Although the State has primary responsibility fo r developing TMDLs under the Clean Water Act, the State was unable to complete its formal adoption of these TMDLs by the consent decree deadline; hence EPA is required to establish the TMDLs at this time.



### What Is A TMDL?

Section 303(d)(1)(A) of the Clean Water Act (CWA) requires that "Each State shall identify those waters within its boundaries for which the effluent limitations...are not stringent enough to implement any water quality standard a pplicable to such waters.” The CWA also requires states to establish a prio rity ranking for waters on the 303(d) list of impaired waters and establish Total Maximum Daily Loads (TMDLs) fo r such waters. As part of California’s 1996 and 1998 Section 303(d) lists, the Regional Board identified Newport Ba y and San Diego Creek as water quality limited due to several toxic pollutants (in addition to other pollutants not addressed in these TMDLs) and designated th is watershed as a hi gh priority for TMDL development.

The elements of a TMDL are described in 40 CFR 130.2 and 130.7 and Section 303(d) of the CWA, as well as in EPA guidance docum ents (e.g., EPA 1991 and EPA 2001). A TMDL is
defined as “the sum of the individual waste load allocations for point sources and load allocations for nonpoint sources and natural b ackground” (40 CFR 130.2) such that the capacity of the water body to assimilate pollutant loadings (the Loadin g Capacity) is not exceeded. A TMDL is also required to be developed with seas onal variations and include a margin of safety to address uncertainty in the analysis. In a ddition, pursuant to the regulations at 40 CFR 130.6, states must develop water quality management plans which incorporate approved TMDLs and implementation measures necessary to implement the TMDLs.

Upon establishment of TMDLs by EPA or the St ate, the State is requ ired to incorporate the TMDLs along with appropriate implementati on measures into the State Water Quality Management Plan (40 CFR 130.6(c)(1), 130.7). Th e Regional Board Basin Plan, and applicable state-wide plans, serve as the State Water Qu ality Management Plan governing the Newport Bay
watershed. If the State subs equently adopts and submits fo r EPA approval TMDLs which are different from the TMDLs established by EPA, EPA will review the State-submitted TMDLs to

summary document 2Newport Bay Toxic Pollutant TMDLs

determine if they meet all TMDL requirements. If EPA approves the State TMDLs, they will supercede the TMDLs being established now by EPA.



### Why Is EPA Establishi ng These TMDLs?

The Environmental Protection Agency (EPA ) has oversight authority for the 303(d) program and is required to review and either approve or disapprove the TMDLs submitted by states. If the EPA disapproves a TMDL submitted by a state, the EPA is required to establish a TMDL for that water body.

On October 31, 1997, EPA entered into a consent decree (decree), Defend the Bay, Inc.

v. Marcus , (N.D. Cal. No. C 97-3997 MMC), which esta blished a schedule for development of TMDLs in San Diego Creek and Newport Bay. The decree required development of TMDLs for several toxic pollutants by January 15, 2002. Th e agreement also provided that EPA would establish the required TMDLs within ninety (90) da ys, if the State failed to establish an approved TMDL by the deadline. In early April 2002, the decree was modified to extend the deadline for EPA establishment of these TMDLs to June 15, 2002.

Pursuant to the decree, EPA Region 9 and th e Regional Board have already established sediment and nutrient TMDLs for San Diego Cr eek and Newport Bay. EPA has also approved state-adopted TMDLs for fecal coliform in Newport Bay.

The RWQCB has conducted extensive analys is in support of these toxic pollutant TMDLs and has proposed to adopt TMDLs and associated implementation plans for two pesticides and selenium. However, the State of California has not yet ad opted TMDLs for any of the toxic pollutants covered by the decree. Ther efore, in compliance with the terms of the decree, EPA is establishing the TMDLs for th ese toxic pollutants in order to meet the requirements of the decree. On April 12, 2002, EPA published a public notice seeking comment on the proposed toxic pollutant TMDLs for San Diego Creek and Newport Bay. EPA carefully considered comments received during the comment period and made some changes in the final TMDL decisions. EPA also completed a responsiveness summary that describes how EPA
considered each comment received.



### What TMDLs Are Being Established?

EPA is establishing TMDLs for several toxi c pollutants which are exceeding applicable State water quality standards: selenium; severa l heavy metals; and several organic chemicals including modern pesticides (i.e., diazinon and chlorpyrifos) and legacy pesticides (DDT, Chlordane etc.) and polychlorinated biphenyls (PCBs). The pesticide diazinon is being addressed by these TMDLs because the State found that it is associated with significant water toxicity in San Diego Creek and concluded that it should be addressed by EPA concurrent with the similar pesticide chlorpyrifos, which is addr essed by the consent decree. These TMDLs are being developed for specific water bodies in the Newport Bay wate rshed for which available data indicate that water quality is impa ired. Table 1-1 lists the specif ic water bodies and associated pollutants for which TMDLs are being established.

summary document 3Newport Bay Toxic Pollutant TMDLs

Table 1-1. Toxic Pollutants per waterbody requiring TMDL Development WaterBody (Type) Element/ Metal Organic compound San Diego Creek (freshwater) Cd, Cu, Pb, Se, Zn Chlorpyrifos, Diazinon, Chlordane, Dieldrin, DDT, PCBs,Toxaphene Upper Newport Bay (saltwater) Cd, Cu, Pb, Se, Zn Chlor pyrifos, Chlordane, DDT,
PCBs Lower Newport Bay (saltwater) Cu, Pb, Se, Zn Chlordane, Dieldrin, DDT, PCBs

Rhine Channel, within Lower Newport Bay (saltwater) Cu, Pb, Se, Zn, Cr, Hg Chlordane, Dieldrin, DDT, PCBs

Table 1-1 Toxic pollutants per waterbody requiring TMDL development.

California’s Section 303(d) list of impaired waters does not specifically name each of these water body-pollutant combinations. The 1996 Section 303(d) list identified Newport Bay and San Diego Creek as impaired due to metals , pesticides and priority organics. The 1998 Section 303 (d) list added “unknown toxicity” to one specific part of San Diego Creek—Reach 2. During the negotiation of the consent decree, Regi onal Board staff provided a more specific list of pollutants covered by these gene ral pollutant categories used in the listing decisions, and the consent decree refers to this more specific pol lutant list. In 2001-02, EPA and Regional Board staff carefully evaluated more recent water qualit y data to help determine whether TMDLs were needed for each of the toxic pollutants identified in the decree. As described in EPA Region 9’s assessment of water quality in San Diego Creek and Newport Bay ( Decision Document 2002), and in this summary TMDL document below, EPA and the State determined that the list of water body-pollutant combinations warranting TMDL deve lopment should be fine-tuned to reflect the best current information concerning water body imp airment. Based on our assessment of the most current local data and national EPA guidan ce concerning arsenic, EPA has concluded that
TMDLs are not needed for arsenic for wa ters in the Newport Bay watershed.



### Why Are These Pollutants Of Co ncern to EPA and the State?

By definition, toxic substances are poisonous through chemical action that may result in adverse impacts to humans or othe r living organisms. Adverse im pacts may include, but are not limited to, cellular injury, mutagenic impair ment, reduced reproductive success, and carcinogenic responses. The impacts of greatest potential concern in these water bodies are: a) chemical bioaccumulation through the aquatic f ood chain at levels which could harm human health when we consume fish or shellfish and b) chemical concentrations in water, sediment or
biota that cause adverse effect s in aquatic life or aquatic-depe ndent species. Available data indicate that the pollutants addressed in these TMDLs were found in water column, bottom sediments, or fish tissue at potentially unsafe levels which exceed applicable water quality
standards. There is no current evidence of adve rse effects on human health due to consumption
of contaminated fish or direct exposure to toxic pollutants. Evidence of adverse impacts to aquatic life as a result of direct or indirect exposures to th ese toxic pollutants is limited. However, because the pollutants addressed in these TMDLs have the potential to cause short term adverse impacts to aquatic life or long term human health a nd aquatic life impacts due to pollutant bioaccumulation, actions to reduce disc harges of these pollutants to the aquatic environment are warranted. The TMDLs are designe d to assist in targeting pollutant reduction
activities.

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### How Are the TMDL Documents Organized?

This document provides summary informa tion about the Toxic Pollutant TMDLs, including a description of th e environmental problems, water body goals, source analysis, loading capacity (i.e., TMDL), and loading al locations for each toxic pollutant TMDL. The document also describes how other federally-requ ired TMDL components (i.e., margin of safety to account of analytical uncertain ty, and critical conditions and seasonal variations associated with water body flow and pollutant loadings) ar e addressed. Individual pollutants have been grouped together based on chemical characteristics as follows:

Organophosphate (OP) Pesticides —diazinon and chlorpyrifos are two organophosphate pesticides with similar sources and impairm ent primarily limited to San Diego Creek. Selenium —is a toxic bioaccumulative metal, with significant groundwater sources
Metals —cadmium, copper, lead and zinc have simila r aqueous behavior a nd affect nearly all
water bodies Organochlorinated compounds —PCBs, DDT, chlordane, dieldrin and toxaphene have similar fate (bioaccumulation) and transport mechanisms (primarily from watershed soils to freshwater and saltwater sediments) for all waterbodies. Mercury and Chromium —are two metals with very small geographical areas of impairment.

The State and EPA initially found that arsenic was present at levels of concern in Upper and Lower Newport Bay; however, based on more recent data and new information concerning arsenic risk in saltwater bodies, EPA has now c oncluded that Newport Bay and its tributaries are not impaired due to arsenic pollution. This su mmary document includes a section describing the basis for this conclusion in greater detail. The consent decree governing development of these TMDLs contains provisions that authorize EPA to make a determination that TMDLs are not
needed for individual waters and/ or pollutants if available data and information support those determinations. Pursuant to these decree pr ovisions, EPA is making the determination that
arsenic TMDLs are not needed for wate rs in the Newport Bay watershed.

EPA has prepared several Technical Suppor t Documents (TSDs) to accompany this summary TMDL document. The TSDs provide cons iderably more detailed information relevant to each pollutant (grouped together as desc ribed above). The TSDs describe chemical characteristics of each toxicant, the basis for num eric targets, a complete source analysis, an explanation of how we calculated the loading capacity and TMDL s, and related information. A TSD is also provided that disc usses EPA’s analysis of freshw ater flows in San Diego Creek, which was used to identify the appropriate num eric targets for certain pollutants, address
seasonal variations and critical conditions in fl ows and pollutant loads, and evaluate the best approaches for calculating pollutant loading capacities and allocations. Another TSD provides more maps of the San Diego Creek, Santa Ana-Delhi Channel and Newport Bay watersheds and analysis concerning water residence times in Upper and Lower Bay. A summary of public comments and EPA’s responses to those co mments is provided in another TSD.

summary document 5Newport Bay Toxic Pollutant TMDLs



### What Happens After The TMDLs Are Established?

TMDLs are not self-implementing – they must be implemented by the State and the entities that are discharging pollu tants of concern. Federal regul ations require states to adopt TMDLs and associated implementation measures in the State Water Quality Management Plan (i.e., the Basin Plan) (40 CFR 130.6). The Stat e of California’s proce dure for adopting TMDLs and associated implementation measures is thro ugh amendments to the Basin Plans. These amendments are developed by the Regional Board staff, then approved by the Regional Board, State Water Resources Control Board, and State Office of Admini strative Law. The amendments are then submitted to EPA for appr oval. (If the TMDLs adopted by the State are different from the TMDLs established by EPA then the TMDLs must be resubmitted to EPA for approval.)

EPA does not establish implementation pl ans as part of TMDLs under currently applicable federal regulations. However, we have included several implementation recommendations (see Section IX) which are intende d to assist the State and local stakeholders in devising appropriate pollutant control and mon itoring plans to address these toxic pollutants.

Three general categories of pollutant s ources are identified in these TMDLs:

• Nonpoint sources , which discharge pollutants th rough diffuse runoff from the land, primarily in response to rainfall runoff, and which are addressed by the State through a combination of voluntary and regulatory measures outlined in California’s State Nonpoint Source Management Plan.

• Point sources , which discharge pollutants throug h discrete pipes or conveyances and which are addressed through regulatory provisions of the National Pollutant Discharge Elimination System (NPDES) permit program. Several sources of pollutant runoff from roads and urban ar eas in the Newport Bay watershed are addressed through NPDES stormwater perm its. There are a small number of additional permitted point source discharges in the watershed which are addressed in the TMDLs, including several groundwater dewatering operations.

• Pollutants already in water body sediments , which are usually associated with contaminated sediments discharged to wa ter bodies in the past, but which retain and release significant quantities of pollutants to the ecosystem. These contaminated sediments may be concentrat ed to the point where remediation or removal action is warranted to remove the contaminated material, or they may be
so diffuse that remedial action would be ineffective.

The federal Clean Water Act creates federa l regulatory jurisdiction only over point sources. When NPDES permits for point source discharges addressed in the TMDLs are revised, their provisions must be consis tent with the requirements and assumptions of any wasteload allocations contained in these TMDLs (see 40 CFR 122.44(d)(1)(vii)(B)). Permit modification may occur when the permits are reopened or reissued. The State has some discretion in determining the appropriate permit pr ovisions to ensure consistency.

Although the TMDLs include allocations which address nonpoint source and contaminated sediments, implementation of th ese allocations is usually based on the TMDL

summary document 6Newport Bay Toxic Pollutant TMDLs

implementation plan developed by the State as part of its Basin Plan amendment process
described above. The State of California has br oad authority under State law to apply voluntary or regulatory approaches to addressing these so urce categories. Past TMDL implementation plans in California have provi ded for State-issued “Waste Discharge Requirements” for some nonpoint sources, remedial action plans to address contaminated sediment sites, and opportunities for voluntary action to comply with load allocations. The Regional Board is currently in the process of deve loping implementation plans for several of the toxic pollutant TMDLs and will address the remaining toxic pollutant TMDLs in the near future.



### Environmental Setting

(see Figure 1-1 in TSD--Part A)

The Newport Bay/San Diego Creek watershed is located in Central Orange County in the southwest corner of the Santa Ana River Basin, about 35 miles southeast of Los Angeles and 70 miles north of San Diego (see Figure 1-1 in TSD—Part A). The watershed encompasses 154 square miles and includes portions of the Cities of Newport Beach, Irvine, Laguna Hills, Lake Forest, Tustin, Orange, Santa Ana, and Costa Mesa. Mountains on three sides encircle the watershed; runoff from these mountains drains ac ross the Tustin Plain a nd enters Upper Newport Bay via San Diego Creek. Newport Bay is a co mbination of two distinct water bodies - Lower and Upper Newport Bay, divided by the Pacific Coast Highway (PCH) Bridge. The Lower Bay, where the majority of commerce and recreational boating exists, is highly developed. The Upper Bay contains both a diverse mix of developm ent in its lower reach and an undeveloped ecological reserve to the north.

San Diego Creek flows into Upper Newport Bay and is divided into two reaches. Reach 1 is located downstream of Jeffrey Road and Reach 2 lies upstream of Jeffrey Road to the headwaters. The San Diego Creek watershed (ca. 105 square miles) is divided into two main
tributaries:

• Peters Canyon Wash, which drains Peters Canyon, Rattlesnake Canyon, and Hicks Canyon Washes that have their headwaters in the foothills of the Santa Ana Mountains,
and

• San Diego Creek itself, which receives flow s from Peters Canyon Wash in Reach 1 and includes Bee Canyon, Round Canyon, Marshburn Ch annel, Agua Chinon Wash, Borrego Canyon Wash and Serrano Creek

Important freshwater drainages to Upper Newport Bay, together covering 49 square miles, include the San Diego Creek, Santa Ana-Delhi Channel, Big Canyon Wash, Costa Mesa Channel and other local drainages.

San Diego Creek is the largest contributor (9 5%) of freshwater flow into Upper Newport Bay, followed by Santa Ana-Delhi Channel (

∼ 5%) (ACOE 2000). Table 1-2 summarizes the drainage areas of the major tributaries.

summary document 7Newport Bay Toxic Pollutant TMDLs

Table 1-2 Drainage Areas of the Newport Bay Watershed

Tributary Drainage Area (acres) Drainage Area (%) San Diego Creek 47,300 48 Peters Canyon Wash 28,200 29
Santa Ana-Delhi 11,000 11 Other Drainage Areas 12,000 12
Total 98,500 100

Upper Newport Bay contains one of the hi ghest quality remaining wetland areas in Southern California. The Upper Bay estuary contains a State Ecol ogical reserve in the upper half with habitat designated for sensi tive species. Sediment capture ba sins exist in the Upper Bay and have been dredged periodically by Army Corp s of Engineers (ACOE). Another sediment removal/ecological restoration project has been proposed and is currently being evaluated (ACOE 2000). Newport Dunes R ecreation area—a small public beach—is in the lower portion of Upper Bay (outside of the Ecological Reserv e) along with more small boat marinas down near Pacific Coast Highway Bridge. Historical water uses for Upper Bay included water skiing, commercial and sport fishing although it is now used mainly for wildlife habitat, preservation of rare species, marine habitat, recreation and shellfish harves ting. In Lower Bay, surrounding shores and two islands are highly urba nized with nine boatyards and many (

∼ 10,000) small boats. Rhine Channel, a dead-end reach in western side of Lower Bay, is an isolated area with poor tidal flushing and minimal storm drain input. The Regi onal Board has identified Rhine Channel as a toxic hotspot based on previous in vestigations (BPTCP 1997). The entire Newport Bay up to the mouth of San Diego Creek is subject to tidal influence.

Climate is characterized by short, mild wint ers, and warm dry summers. Average rainfall is approximately 13 inches per ye ar. Ninety percent of annual rainfall occurs between November and April, with minor precipitation during summer months. In the past six years, San Diego Creek has a mean base flow rate of approximate ly 12 cubic feet per seco nd (cfs) (for all flows <20 cfs). Storm events, depending on their magn itude, intensity, and ante cedent conditions, can increase this daily mean flow to over 9000 cfs (Dec. 7, 1997). San Diego Creek is freshwater with wide range of hardness and small influences by the slightly saline water table (less than 1 or 2% salinity). Upper Bay is an estuary with sa line water conditions dur ing dry weather and yet there is heavy freshwater influx (from San Di ego Creek and Santa Ana-Delhi Channel) during major storms. Lower Bay waters are dominated by twice-daily ocean tides via the jetty entrance,
thus saline waters exist at 30 to 35 parts per thousand (ppt).



### Watershed History

The description below is taken largely from Regional Board staff report prepared for its draft Newport Bay TMDLs (RWQCB 2000).

The nature of the Newport Bay watershed has changed dramatically over the last 150 years, both in terms of land use and drainage pattern s. In the late 19th and early 20th centuries, land use changed from ranching and grazing to op en farming. During this time the Santa Ana River flowed into Newport Bay, while San Dieg o Creek and the small tributaries from the

summary document 8Newport Bay Toxic Pollutant TMDLs

Santiago Hills drained into an ephemeral lake an d the neighboring area call ed “La Cienega de las Ranas” (Swamp of the Frogs) and then into th e River. To accommodate rural farming, the ephemeral lake and Swamp of the Frogs were dr ained and vegetation cleared. Channels were constructed (but often did not follow natural dr ainage patterns) to c onvey runoff to San Diego Creek and then Newport Bay. After a major fl ood event in 1920’s, the Santa Ana River was permanently diverted into the current flood contro l channel which now discharges to the Pacific
Ocean. As a result of these land use and drai nage changes, surface and groundwater hydrology have been substantially altered from natural conditions. Followi ng World War II, land use again began to change from grazing and open farming to residential and commercial development. As urban development in the watershed proceeded (a nd continues), drainages were further modified through removal of riparian vegeta tion and lining of str eam banks to expand their capacity and to provide flood protection. These changes culminated in the channe lization of San Diego Creek in the early 1960s by the Orange County Flood Control Department. The channelization isolated the San Joaquin Marsh, the last remaining porti ons of the historic ma rsh upstream of Upper Newport Bay, from San Diego Creek (Trimble 1987).

Conversion of rural farmland to residential, commercial and light i ndustrial use has been
constant in the watershed. Land use statistics supplied by Orange County demonstrate this urban development (ACOE 2000). In 1983, agriculture account ed for 22% and urban uses for 48% of the Newport Bay watershed. In 1993, agricultural uses accounted for 12% and urban uses for over 64% of the area. As of 2000, agriculture had dropped to approximately 7% (<7,500 acres), including row crops (primarily strawberries a nd green beans), lemons, avocados and commercial nurseries. Currently, San Diego Creek watershed is greater than 90% urbanized whereas Santa Ana-Delhi is approximately 95% urbanized. Pr ojected land use suggests 81% urban land use, 11% open, 8% rural and no agriculture (ACOE 2000).

Land use and drainage modifications cha nged the nature and magnitude of toxic substance discharges to the Bay. Converting from grazing type agriculture to orchards and row crops has increased the amount of pesticide use in the watershe d, resulting in discharges of pesticides from these areas. The commercial nurse ries drain to Peters Canyon Wash via Central Irvine Channel and to San Diego Creek via Ma rshburn Channel and Serrano Creek. Tustin and El Toro military bases exist within the watershed and have historically used various toxic substances during operations. Both military sites are involved with base closure procedures and may ultimately be converted to more urban/subu rban areas. Urban development introduced new sources of toxic substances, including different pesticides and metals associated with human habitation (e.g., buildings, landscapi ng, and motor vehicles). In addition, land use activities which cause erosion may contribute to the delivery of pesticides and other pollutants that adhere to sediments or normally remain in solid form.

summary document 9Newport Bay Toxic Pollutant TMDLs

Table 1-3 Land Use types in watersheds of Newport Bay Land use type San Diego Creek Santa Ana Delhi Newport Bay
Acres % total Acres % total Acres % total Agricultural/ 5092 6.6 0 0 5147 5.2

Residential 11,668 5285 19420 19.7 15.2 18.2
Commercial 6381 8.3 2397 8.3 9641 9.8
Industrial 3965 5.2 1102 3.8 5263 5.4 Education/Religion/ 15,811 20.6 825 2.8 17,393 17.7 Recreation

Roads 10,295 13.4 3446 11.9 15,774 16.0 Transportation 1177 1.5 99 0.3 1326 1.3

No assigned land 440 0.6 339 1.1 936 0.9
code Vacant 21,910 28.5 1 060 3.7 23,462 23.9

Total 76,739 99.9 29003 100 98,362 99.9 Source: OCPFRD land use data defined by sub-watersheds to compose each watershed. (see TSD Part A) Most accurate and recent land use data prov ided by OCPFRD GIS De pt., March 1, 2002.



### Public Participation

The State and EPA have provided for public participation through se veral mechanisms. The Regional Board staff has conducted numerous technical workshops (e.g., quarterly meetings since April 2000) on its assessment of toxic pol lutant TMDL needs and the specific toxic pollutant TMDLs being developed by the Stat e. The Regional Board held several public workshops as part of their regular meetings to discuss staff TMDL proposals (January 15, September 26, and October 26, 2001). EPA staf f provided updates on its TMDL development
activities at several of these Regional Board meetings. On October 26, 2001, the State’s draft organophosphate (OP) pesticide and Selenium TMDL s were presented before the public as part of a Regional Board meeting. These draft Stat e TMDLs were also available via the Regional
Board website after that date.

On April 12, 2002, EPA publicly noticed the avai lability of the proposed Toxic Pollutant TMDLs and gave the public until May 28, 2002, to provide written comments. The EPA notice of availability was published in the Orange County Register, mailed to the Basin Plan distribution list provided by th e Regional Board, and posted on the EPA Region 9 TMDL website. Two public meetings were held dur ing the public comment period – a meeting to discuss the TMDLs in general in Newport Beach on April 16, 2002, and a meeting to discuss specific technical issues in Irvine on May 9, 2002. Copies of the TMDLs and TSDs were available at the public meetings, in EPA and Regional Board offices, and on the EPA Region 9
TMDL website.

summary document 10Newport Bay Toxic Pollutant TMDLs


### Changes in the Final TMDL Documents

Several changes were made in the final TM DLs in response to comments received during the comment period:

• The numeric targets for some pollutants were modified to follow California screening guidelines or to reflect the most recent screening value studies. The organophosphate pesticide TMDL targets are based on values calculated by the California Department
of Fish and Game. The California Office of Environmental Health Hazard Assessment guidelines were applied for organochlorine pollutant fish tissue targets. More recent literature values were applied for the freshwater or ganochlorine sediment targets.

• The flow records used to calculate flow tiers for several pollutant TMDLs were changed to reflect a longer pe riod of record and to incorporate more recent flow data.

• The selenium TMDLs for the highest flow tier are based on acute water quality standards because, based on analysis of the longer flow record, flow patterns necessary to apply chronic standards were not expected to oc cur under the highest
flow tier.

• The metals TMDLs for San Diego Creek are concentration-based; the metals TMDLs for Newport Bay are both concen tration-based and mass-based.

• The organochlorine pollutant TMDLs were revised based on additional modeling analysis and consideration of more recent data. The flow tier approach applied for San Diego Creek organochlorine pollutant TMDLs was slightly modified. The description of analy tical methods used for the orga nochlorine pollutant, chromium, and mercury TMDLs was revised to more clearly explain the analytical methods.

• The allocation methods used for each TMDL were clarified.

• A new section of implementation and m onitoring recommendations was added to assist the State in preparing to adopt and implement TMDLs for these pollutants.

summary document 11Newport Bay Toxic Pollutant TMDLs



## II. Overview of TMDLs and Available Data

TMDL Components

This section describes the components of a TMDL and discusses the analytical approaches used in the Newport Bay wate rshed TMDLs to address each component.

The goal of the TMDL process is to attain water quality standa rds and protect the beneficial uses of water bodies, including aquatic habitat, fishi ng, and recreation. A TMDL is a written, quantitative assessment of water quality pr oblems and contributing pollutant sources. It identifies one or more numeric targets (endpoints) based on applicable wa ter quality standards, specifies the maximum amount of a pollutant that can be discharged (or the amount of a pollutant that needs to be reduced) to meet water qual ity standards, allocates pollutant loads among sources in the watershed, and provides a basis for taking actions needed to meet the numeric target(s) and implement water quality standards.

For federally established TMDLs, seven components are included:

‹ Problem Statement —a description of the water body setting, beneficial use impairment of concern, and pollutants causing the impairment. ‹ Numeric Targets— for each pollutant addressed in the TMDL, appropriate measurable
indicators and associated nu meric target(s) based on numeric and/or narrative water quality standards which express the target or desired condition for the water body which will result in protection of the designated beneficial uses of water. ‹ Source Analysis —an assessment of relativ e contributions of pollu tant sources or causes to the use impairment. ‹ Loading Capacity/Linkage Analysis —a connection between the numeric targets and pollutant sources which yields calculations of the assimilative capacity of the water body for each pollutant. ‹ TMDL and Allocations — an expression of the total allowable pollutant loads as divided between pollutant sources through load allo cations for nonpoint sources and wasteload allocations for point sources. The TMDL is defined as the sum of the allocations and cannot exceed the loading capacity for each pollutant. ‹ Margin of Safety —an explicit and/or implicit margin of safety must be specified to
account for technical uncertainti es in the TMDL analysis. ‹ Seasonal Variation/Critical Conditions— an account of how the TMDL addresses
various flows and/or seasonal variatio ns in pollutant loads and effects.



### Problem Statement

EPA includes problems statements in TM DL documents to assist readers in understanding the context for TMDL developmen t and describe the water quality standards issue(s) which prompted development of the TMDL. The problem statements identify:

• name(s) and location(s) of waterbody segments for which the TMDL is being developed,

• the pollutant(s) for which the TMDL is bei ng developed and information about why the pollutant(s) are being addressed,

summary document 12Newport Bay Toxic Pollutant TMDLs

• a description of the water quality impairment or thre at which necessitated TMDL development, and

• adequate background information about the wate rshed setting for the TMDL to help the reader understand the key water quality, pollu tant discharge, land use, and resource protection issues in the watershed.

As discussed above, California’s Section 303( d) listing decisions only identified general pollutant categories for toxic pollutants impairing waters in the Newport Bay watershed. The consent decree identified suspected individual pollutants of concern, but the decree provides that
TMDLs need not be established fo r individual pollutants and/or wa ters if subsequent analysis indicates TMDLs are not necessary at this time. To help define the scope of these TMDL studies, EPA Region 9, with assistance from the Regiona l Board, completed an assessment of available monitoring data for San Diego Creek and Newpor t Bay to determine which chemicals warrant TMDL development. In our assessment, we revi ewed available toxicity and chemical data in three critical water quality categories: water column quality, sediment quality, and fish and shellfish tissue levels. We applied a two-tier ed approach whereby all available data were analyzed to determine whether there is clear evidence of impa irment with probable adverse effects (Tier 1) or incomplete evidence and/or ev idence of possible adverse effects (Tier 2) (EPA Region 9, 2002). If a chemical exceeded the screen ing criteria in Tier 1 with respect to any one of the water quality categories, then it was determined a TMDL is necessary. If a chemical exceeded the screening criteria in Tier 2 with respect to two or more categories then a TMDL is necessary. EPA also considered whether TMDL s might be necessary based on evaluation of water quality trends and conditions in water segments adjacent to a segment in question. We examined monitoring data for the past fifteen ye ars; however, to maximize the relevance of our assessment to present-day water quality, we focuse d on the most recent re sults (since 1995). Our
assessment evaluated each chemical identified in the decree for four separate water bodies: SanDiego Creek, Upper Newport Bay, Lower Newport Bay and Rhine Channel. The water bodypollutant combinations for which EPA determined TMDLs are needed at this time are listed in
Table 1-1.

The introduction to this document provides a ba sic discussion of the problems associated with exposures to toxic pollutants addressed in these TMDLs and background information on the watershed setting.



### Numeric Targets and Applicabl e Water Quality Standards

Numeric targets identify the specific wate r column, sediment, a nd/or tissue goals or endpoints for the TMDL which equate to attainment of the water qual ity standards (see EPA Region 9, 2000). In some cases, multiple indicators and associated numeric target values may be needed to interpret applicable water quality standards (e.g. wher e there is uncertainty that a single indicator is sufficient to measure protection of designate d uses). In addition, some TMDLs may incorporate multiple numeric target s to account for differences in acceptable pollutant levels in a particular water body at different time scales (e.g., short term acute toxicity effects versus long term ch ronic exposure effects).

Water quality standards are comprised of th e designated beneficial uses made of water bodies, narrative and numeric water quality criteri a (known as “water quality objectives” in California), and anti-degradation policies. Appl icable standards of concern for these toxic

summary document 13Newport Bay Toxic Pollutant TMDLs

pollutant TMDLs include the designated uses and both narrative and numeric water quality criteria, which are applied in a manner which is expected to result in pr otection of the designated
beneficial uses.

The Regional Board Basin Plan (1995) desi gnates the beneficial uses for Newport Bay, San Diego Creek and its tributaries. All water bo dies are designated as wi ldlife habitat, with San Diego Creek identified as warm freshwater habitat and Upper and Lower Bay identified as estuarine and marine habitat, re spectively. The recreation beneficial uses are designated for all of Newport Bay and San Diego Creek. Upper and Lo wer Bay are also designated for commercial and sport fishing, preservation of biological habitats—spawning, reproduction, development, rare, threatened and endangered species, recr eation, and shellfish harvesting. The specific beneficial uses of San Diego Creek and Newpor t Bay are identified in Appendix A-1 at the end of this summary document.

These toxic pollutant TMDLs focus on two of the most sensitive designated aquatic life
and wildlife beneficial uses of concern in the watershed—RARE and WILD. One primary objective is to protect the special biological a nd wildlife habitat of the Newport Bay Nature Preserve and Ecological Reserve, in the upper part of Upper Newport Bay. The Nature Preserve is considered a critical estuary of Southern Ca lifornia. The Upper Newport Bay Nature Preserve consists of approximately 1,000 acres of open space and is home to seven rare or endangered bird species: Light-footed clapper rail, Beldi ng's savannah sparrow, le ast tern, brown pelican, peregrine falcon, black rail, and California gnatc atcher. Two endangered plants, the salt marsh birds-beak and the rare Laguna liv e-forever, are also found at the reserve. The second objective is to reduce build up of toxicants in fish and sh ellfish within all water bodies, thereby minimizing the potential for adverse impacts associated with wildlife and hu man consumption of contaminated food. Seventy-eight species of fish inhabit the Upper Newport Bay waters, including the California ha libut and barred sand bass—t wo popular sport fishes.

Narrative water quality objectives consider ed for each TMDL are specified by the 1995 Regional Board Basin Plan:

• Toxic substances shall not be discharged at levels that will bioaccumulate in aquatic resources to levels which are harmful to human health;

• The concentrations of toxic substances in th e water column, sediments or biota shall not adversely affect beneficial uses.

Numeric water quality objectives for severa l pollutants addressed in these TMDLs were promulgated by EPA in 2000 in the California Toxi cs Rule (CTR). Pollutants covered by CTR objectives include seleni um, cadmium, copper, lead, zinc, ch romium, chlordane, dieldrin, DDT, toxaphene and PCBs. Chlorpyrifos and diazinon are not listed as toxic pollutants pursuant to Section 307(a)(1) of the Clean Water Act (see 40 CFR 401.15), and the CTR did not establish numeric objectives for those pollu tants. Additionally, the CTR did not establish aquatic life objectives for mercury and the selenium and cadm ium objectives were esta blished contingent on an EPA commitment to revise the objectives promptly to better protect wildlife.

In many cases where applicable standard s are expressed in numeric terms, it is appropriate to set the numeric ta rget equal to the numeric wate r quality standard. For most metals addressed in these TMDLs, the numeric ta rgets are equal to the numeric objectives in the CTR. For selenium (Se) the freshwater and saltwater water quality standards are defined by

summary document 14Newport Bay Toxic Pollutant TMDLs

CTR. However, EPA acknowledged in its consultati ons with the U.S. Fish and Wildlife Service (USFWS) that the freshwater standards for Se ma y not be fully protective of wildlife, and EPA committed to revisit and, if necessary, revise the Se criteria in the near future. In its draft TMDL for Se, the Regional Board proposed to apply more protective Se targets based on USFWS
recommendations. In the draft TMDL doc ument, EPA proposed TMDLs based on the promulgated CTR standards, but invited comment on the alternative approach of basing the Se TMDLs on the more protective targets proposed by the Regional Board. The final TMDLs are based on the promulgated CTR standards. (See se ction IV—Se TMDL for further discussion.)

In some cases, it is necessary to interpret a numeric standard in terms other than the method through which the standard is expressed as long as the target(s) ca n be shown to relate back to achieving the water quality standard(s ). For some pollutants (e.g., bioaccumulative toxins) or receiving water setti ngs (e.g. embayments), it often makes more sense from the standpoint of source control a nd impact assessment to focus the TMDL on reductions of pollutant mass loads than solely on avoidance of exceedences of concentration-based standards. Moreover, use of sediment and/or fish tissu e endpoints may provide more discriminating indicators of the beneficial use impacts of con cern in a TMDL (e.g., pollutant bioaccumulation in
the food chain and resultant human health or aquatic life impacts from consumption of contaminated organisms). Moreover, selection of targets based on these media enabled EPA to more completely utilize site specific data for several pollutants for which water column data were limited, consistent with the pr ovisions of 40 CFR 130.7(c)(1)(i).

For several pollutants addressed in these TMDLs for which numeric objectives are in place (mercury, chromium, chlordane, dieldrin, DDT, toxaphene, and PCBs), the numeric targets are expressed in terms of protective sediment or fish/shellfish tissue levels. EPA’s analysis of the relationship between the levels of these pollutants found in the water column, sediment, and fish/shellfish tissue found that a ttainment of the sediment and fish /shellfish tissue numeric targets will result in attainment of the water column numeric objectives. The sediment and tissue numeric targets are probably more protective than the numeric obj ectives for these pollutants. The use of sediment and tissue targ ets is appropriate in these cases in order to provide an implicit margin of safety to account for uncertainties in the relationship between pollutant loadings and beneficial use effects, and to ensure that bot h numeric and narrative standards are attained as required by 40 CFR 130.7(c)(1). In addition, EPA’s decision to use sediment quality and fish tissue values as numeric targets for these polluta nts is based in part on the fact that these substances are much more likely to be associated with particulate matter than to remain in the dissolved phase; that is, these compounds are either sorbed to bottom sediments or associated with extremely fine suspended sediments. Als o, there are technological challenges accompanied with sampling and accurately detecting these compounds in water column samples. Therefore, these pollutants are unlikely to be detected in the water column in dissolved form even in waters where they may be present at levels of concern.

In situations where applicab le water quality standards are expressed in narrative terms, it is necessary to develop a quantitative interpre tation of narrative standards (EPA Region 9 2000). Since a TMDL is an inherently quantitative analysis, it is necessary to determine appropriate quantitative indicators of the wate r quality problem of concern in order to calculate a TMDL. It is sometimes possible to supplement water column indicators (i.e., polluta nt concentrations in water) with measures in sediment or tissue medi a since these alternativ e indicators are more directly associated with the po llutant effects of concern.

summary document 15Newport Bay Toxic Pollutant TMDLs

Where sediment indicators are used in these TMDLs, they are based on sediment quality guidelines developed by several studies (Long et al. 1995, Smith et al.1996, MacDonald et al. 1996) and compiled by Long and MacDonald in the biological effects data base system (BEDS) synthesizing many, many samples throughout North America. These sediment quality guidelines (equivalent to threshold effect levels) have been endorsed by NOAA in the screening quick reference tables (SQuiRTs) for contaminants in sediments (Buchman 1999). Where fish or shellfish tissue indicators are used, they are ba sed on tissue screening values established by the
California Office of Environmental Health Ha zard Assessment (OEHHA 1999). The specific basis for these target indicators is discu ssed in the individual TMDL descriptions.

For the organophosphate (OP) pesticides, chlorpyrifos and diazinon, there are no promulgated water quality criteria established by EP A or the State of California. Several entities including EPA (USEPA 1986 and 2000c) and Califor nia Department of Fish and Game (CDFG 2000a) have recommended criteria values for thes e pollutants. To be protective of aquatic resources and to meet beneficial uses, EPA has selected the CDFG values for chlorpyrifos and
diazinon at the recommendati on of the Regional Board.



### Source Analysis

An understanding of pollutant loading sources and the amounts and timing of pollutant discharges is vital to the development of eff ective TMDLs. These TMDLs provide estimates of the amounts of pollutants entering the receiving wa ter of concern or, in some cases, the amount of pollutant that is bioavailable based on historic loadings stored in the aquatic environment. These pollutant source estimates are documente d based on data analysis and modeling studies
described in the individual TMDLs and associ ated TSDs. Source loading estimates can be categorized in many ways, including but not limited to discharge source, land use category, ownership, pollutant production process (e.g. se dimentation processes) , and/or tributary
watershed areas.

The source analysis for these TMDLs indicate d that historical disc harges of PCBs and chlorinated pesticides, all of wh ich are no longer authorized to be used, are believed to be primarily responsible for the po llutant levels measured in Newport Bay. Metals loading is associated with historical and ongoing discharges of urban runoff. Selenium loadings are estimated to come primarily from erosion and ru noff, and discharges of shallow groundwater. Discharges of OP pesticides ar e associated with past and ongoi ng uses of these pesticides for household and agriculture pest cont rol. Some pollutant loads are also estimated to come from seawater and atmospheric deposition.

The individually permitted point sources listed below discharge into waters in the Newport Bay watershed. These TMDLs include wasteload allocations for some of these facilities. A general permit is in place to regulate discharges asso ciated with groundwater cleanup, which affects 21 permittees and focuses principally upon total suspended sediment, petroleum hydrocarbons and chlorinated solvents . Another general permit is in place which regulates groundwater dewatering operations of 12 permittees and focuses principally on suspended sediment discharges. Finally, the st atewide general permit for industrial stormwater discharges covers several facil ities that may discharge in the Newport Bay watershed, including John Wayne Airport. Runoff from state highways is regulated through the statewide CalTrans NPDES permit.

summary document 16Newport Bay Toxic Pollutant TMDLs

Six boatyards are located around Newport Bay; all are regulated for indirect metals discharges to the sewer system. Discharges from these boatyards do not flow to the Bay. Instead, wastewater flows into sumps or into connections to the Orange County Sanitation District pre-treatment system.

Table 2-1: NPDES Permits In Sa n Diego Creek/Newport Bay Watershed NPDES permits in San Diego Creek
watershed Comments

Orange County Stormwater MS4 Permit; In cludes many cities as co-permittees Tustin Marine Base/GW general At presen t this is general permit, although RWQCB is currently drafting an individual permit Silverado Constructors/GW cleanup Genera l permit, discharges under emergency conditions only
Irvine Ranch Water District Individual permit, discharg es tertiary treated water into Sand Canyon Reservoir and permit regulates stormwater overflows from Sand Canyon Reservior
Serrano Water Treatment Plant Individual permit for a drinking water filtering plant City of Tustin groundwater desalter Indi vidual permit, irre gular discharges Great Lakes Chemical/GW cleanup Indivi dual permit, no longer discharges
CalTrans Stormwater Statewide permit for CalTrans facilities
Industrial Stormwater Statewide gene ral permit for industrial stormwater discharges

The Regional Board currently regulates three commercial nurseries through waste discharge requirements (WDRs): Bordier’s, Hine s and El Modeno Gardens. These nurseries are located in the upper reaches of the watershed, and their discharge (normally only during storm events) flows into Peter’s Canyon Wash (for Hi nes and El Modeno) and Marshburn Channel (for Bordier’s) before reaching the main stem of Sa n Diego Creek. The Regional Board is currently evaluating whether WDRs are needed for tw o other nurseries (Nakase Nursery and AKI nursery). There are some unpermitted nurseries that are smaller in size than the permitted nurseries. Runoff from other ag ricultural operations in the wa tershed, including row crops, orchards, and vineyards, is not currently regulated.



### Loading Capacity/ Linkage Analysis

The loading capacity is the cr itical quantitative link betwee n the applicable water quality standards (as interpreted through numeric targets) and the TMDL. The loading capacity reflects the maximum amount of a pollutant that may be delivered to the water body and still achieve water quality standards. The li nkage analysis investigates the relationship between pollutant loadings and water quality effect s in order to calculate loadin g capacities for each pollutant and water body. The loading capacity sections discuss the methods and data used to estimate loading capacity. A range of methods were used to derive the loading cap acities for the various pollutants, including predictive water quality mo dels and linkage methods based principally on data analysis. The individual TMDLs and associ ated TSDs describe the linkage analysis in
detail.

summary document 17Newport Bay Toxic Pollutant TMDLs



### TMDLs and Allocations

For each pollutant and water body, this documen t identifies the necessary TMDL (total allowed pollutant amount) and its components: appropriate wasteload allocations for point sources and load allocations for nonpoint sour ces and natural background. The TMDLs and
associated wasteload and load allocations are expressed in quantitative terms as required by federal regulations.

TMDL calculation methods are summarized in this document and described in greater detail in the TSDs. Separate wasteload and load allocations ar e identified for point and nonpoint sources, respectively. In cases where it is f easible, individual wast eload allocations are established for each existing point source discharg e, including permitted stormwater discharges. For several pollutants, insufficient information was available to support delineation of individual WLAs for each NPDES-permitted discharge. Therefore, the TMDLs include wasteload allocations for a category of “other NPDES pe rmittees.” This wasteload allocation category covers discharges under the following permits:

• Tustin Marine Base groundwater

• Silverado Constructors

• Irvine Ranch Water District

• Serrano Water Treatment Plant

• City of Tustin desalter

• Great Lakes Chemical

• Statewide Industrial Stormwater

• Statewide Construction Stormwater

EPA is establishing the grouped allocations for the “other NPDE S permittees” category based on the following assumptions, which are discusse d here to provide information to assist in implementing the allocations through the NPDES pe rmitting process. The State, in consultation with the permittee(s) where appropriate, should gather data and information necessary to characterize the discharge flows and, if feasible, the loads of the specific pollutants for which
allocations are established. The State should c onsider this new data and information when it considers adoption of the TMDLs and associated im plementation plans for these toxic pollutants. If this categorical wasteload allocation is not subdivided when the State adopts the TMDLs, we assume that when any permit in this category is considered for revision or reissuance, the State should prepare an analysis as part of the perm it fact sheet that (1) identifies the specific proportion or amount of the categor ical wasteload allocation that can be discharged by the individual discharger, and (2) shows that the su m of all discharges covered by these permits will not exceed the total categorical wasteload allocation and is ot herwise consistent with the TMDLs. Several alternative approaches are ava ilable to the State to apportion available loading amounts among the facilities covered in this wasteload allocation category (see Technical Support Document for Water Based Toxics Control , (EPA-505-2-9-001), March, 1991, pp. 68-69 for guidance on allocation criteria).

In the absence of additional analysis by the State in support of individual permitting actions consistent with the assumptions discus sed above, we assume that available loading capacity identified in the categor ical wasteload allocation is to be divided equally among the 8 permitted discharges. We expect that the foll owup State analysis in support of TMDL adoption

summary document 18Newport Bay Toxic Pollutant TMDLs

or permit reissuance may result in different di visions of allocation capacity depending upon the combination of discharge flows, loads, and timi ng associated with each permitted discharge.

Load allocations for nonpoint sources may be expressed as specific allocations for specific dischargers or as “gross allotments” to nonpoint source discharg er categories (40 CFR 130.2). TMDLs usually provide sepa rate load allocations for natu ral background loads. Separate load allocations for background loads are calculated for the Newport Bay metals TMDLs; however, insufficient information is available to support a conclusion that these loads are completely natural. Separate natural background allocations are inappropriate for pesticides and organochlorine compounds because they of anth ropogenic origin and because all known loading sources are accounted for in the TMDL analysis. Separate background allo cations could not be calculated for selenium, chromium and mercury because insufficient information was available to support these calculations. Background levels of selenium a ssociated with groundwater inputs to surface water may be significant; however, th e physical and hydrological structure of the watershed has been highly altered as a resu lt of hydrologic modifica tions, groundwater pumping, irrigation practices, and water imports to the waters hed. As a result, it would be very difficult to estimate “naturally occurring” selenium discha rge levels. Background levels of chromium and mercury are not expected to be substantial.

Allocations may be based on a variety fact ors. Federal regulations do not establish specific criteria which must be considered in dividing and allocating any available loading capacity between contributing sources. Criteria applied to determine the division of available pollutant loading capacity include:

• Organophosphate Pesticides: All allocations are concentration-based and are applied equally to all discharge sources.

• Selenium: Allocations were divided in proporti on to land use areas of the different allocation categories for nonpoint sources and in proportion to discharge flow rates for point source categories. Cons ideration of flow rates in freshwater bodies, directly linked to precipitation events, is included.

• Metals: Load allocations and the stormwater wasteload allocation for San Diego Creek were generally divided in proportion to land ar eas associated with ea ch source category. In defining the wasteload allocations for Sa n Diego Creek, we considered the relative discharge flows associated w ith the different dischargers. We also included an undefined sources load allocation as a gross allotment to account for apparent loadings
that could not be associated w ith other source categories.

• Organochlorine Compounds: Allocations to terrestrial wa tershed sources were generally divided in proportion to land us e areas of different alloca tion categories, with some
consideration of the feasibil ity of reducing loads for DDT. Newport Bay allocations are expressed as net available loads, taking into account as background loads loadings already allocated for “upstr eam” segments. For this r eason, the allowable loads as expressed in the allocation tables in th e TMDL document do not increase cumulatively
in a downstream direction. The division of available loading capacity between terrestrial and in-Bay sediment sources was done in proportion to the percentage of total
loads associated with watershed versus in-Bay sediment sources.

• Mercury and Chromium: Allocations to watershed sources were generally divided in proportion to land use areas of different al location categories. Allocations between

summary document 19Newport Bay Toxic Pollutant TMDLs

watershed sources and in-Bay sediment s ources were divided in proportion to the percentage of estimated contributions from new sources and resuspended sediments.

TMDLs (and thus, load allocations and wa steload allocations) can be expressed as “mass per time, toxicity, or other appropriate measure” , depending on the type of waterbody and the sources that contribute to impairment. The TMDLs for all pollutant s except diazinon and chlorpyrifos are expressed in terms of mass loads per time, and the TMDLs for the pesticides diazinon and chlorpyrifos are ex pressed in terms of water column concentrations. It is appropriate to express these pest icide TMDLs in terms of water column concentrations because these pollutants cause adverse e ffects on aquatic life through rela tively short term exposures. These pollutants are relatively short-lived in th e environment before they break down into less toxic forms, and they do not bioaccumulate thro ugh the food chain in th e same way several of the other pollutants addressed in these TMDLs do. Therefore, th e water column concentrations of these pesticides are of greatest concer n in preventing adverse ecosystem effects.



### Margin of Safety

A margin of safety is incorporated in each TMDL analysis in order to account for uncertainty in the relationship between po llutant loads and wate r quality effects.

The margin of safety can be implicit (i.e., incorporated into the TMDL analysis through conservative assumptions) or explicit (i.e., expres sed in the TMDL as a portion of the loadings) or a combination of both. The TMDLs described in this document include a margin of safety discussion for each pollutant that describes the ba sis for the provided margin of safety and shows why it is adequate to account fo r uncertainty in the TMDL. Th e document discusses sources of uncertainty in the analysis and how individual analytical assumptions or other provisions adequately account for these spec ific sources of uncertainty.

For all pollutants except metals, a 10% explic it margin of safety was applied to account for uncertainties in the analysis. An explicit ma rgin of safety is appropriate for each TMDL because there is significant uncertainty in the an alysis of pollutant eff ects, loads, fate (i.e. chemical transformations and degradation followi ng discharge), and transport in the watershed. The data supporting the TMDLs were somewhat lim ited. For metals, a 20% explicit margin of safety was applied to account for (1) these analytical uncertainties and (2) the consideration that the metals TMDLs are expressed in terms of di ssolved metals although it is likely that total metals loading levels are somewhat higher than dissolved metals loads, and that total metals loads may be of concern as a cause of sediment toxicity.

For all pollutants, the TMDLs also incorpor ate an implicit margin of safety because numerous conservative assumptions were made to ensure that the analytical methods applied are environmentally protective. Each TMDL section de scribes sources of uncertainty in the analysis and the assumptions made which provide an implicit margin of safety.

summary document 20Newport Bay Toxic Pollutant TMDLs



### Seasonal Variations and Critical Conditions

TMDL must describe the methods used to account for seasonal variations and critical conditions (e.g., stream flows, pollutant loadings , and other water quality parameters) in the TMDL(s) [40 CFR 130.7 (c)]. In the semi-arid climate of Southern California there are two seasons—dry weather during most of the year and intermittent wet weather events typically
between November and March. This two-season climate creates significant differences in flow through the creeks and streams. In general, 90% of the water flow occurs during less than 10% of the time; that is, most significant storm even ts and associated high flows usually occur during the months of December, January and February.

EPA has utilized two different approaches to seasonal variations and critical conditions in developing these TMDLs. One approach varies TMDLs on a seasonal basis. For example, the OP pesticide TMDLs (chlorpyrifos and diazinon) show there is considerable increase in pesticides applied during the dry season (whe n pests grow and create problems); however, aquatic impairment occurs during wet weather events as surface runoff pollutes the freshwater tributaries. OP pesticide critical conditions are explained more in section III below.

The other approach to addressing seasonal vari ations and critical conditions is to define critical conditions solely based on freshwater flow rates due to pr ecipitation regardle ss of season. This flow based approach is applied to freshw ater loading to metals , Se, and organochlorine (OC) compounds. Unlike the OP pesticides, th e water quality effects as sociated with these pollutants are not expected to vary on a seasona l basis. In this flow-based approach, the continuous range of stream flows (measured as daily flow rates) that occur in San Diego Creek is broken down into several flow tiers. The loading cap acity for each breakpoint in the flow tiers is established, and the sum of allowable loads unde r all tiers equals th e total annual loading capacity for freshwater bodies. Thus the a pplicable allocation for a given source does not depend on the time of year, but on the actual stream flow (or associated sediment deposition rate for OC compounds) at the time of discharge. This flow approach is partially used for chromium and mercury TMDLs for Rhine Channel, wher e freshwater has little influence (6%) on deposition within that dead -end reach of Newport Bay.

To estimate the loading capacity of freshwat er systems, EPA has utilized daily flow records at San Diego Creek at Campus Drive wh ich were collected by USGS from 1977 - 79 and 1983 – 85 and Orange County Public Facilities and Resource Division (OCPFRD) from 1985 to present. EPA and Regional Board staff reviewed the entire daily mean flow record set from USGS and OCPFRD. The analysis was performed on a water year basis (e.g., July 1977 to June 1978). Incomplete USGS data for the period 1979/80 to 1982/83 were not used because only partial records were available for each year. Thus, the USGS and OCPFRD records yielded 19 water years of daily mean flow records for Sa n Diego Creek. This time span covered water years: 1977-78, 1984/85 – 2000/01. EPA used thes e records for calculating the flow based approach to Se, dissolved metals, organochlorin e, mercury and chromium TMDLs. EPA used annual flow records for water year 1 996, 1997, 1998, 1999, 2000, 2001 to determine flow inputs from Santa Ana Delhi Channel. This time sp an covers a reasonable diversity of rainfall conditions based on precipitation measurements from 1958 to 2001. It includes the exceptionally wet El Nino year, 1998, as well as relatively drier years, 1999 and 2000. Table 2-2 shows

summary document 21Newport Bay Toxic Pollutant TMDLs

rainfall recorded at Tustin/Irvine Ranch gage st ation for each year within the time span utilized by EPA, as well as historical high and low rainfall records. These data illustrate that the data years used by EPA for this approach are reasona bly representative of th e entire time period. Technical Support Document—Part B gives more e xplanation of freshwat er flows and seasonal
variations.

Table 2-2. Annual Precip itation Records at Tustin-Irvine Ranch Station
Water Rainfall Water Rainfall Water Rainfall Water Rainfall
Year * (inches) Year (inches) Year (inches) Year (inches)
1958-59 5.03 1971-72 5.02 1983-84 10.47 1995-96 11.17
1959-60 9.6 1972-73 14.9 1984-85 10.25 1996-97 16.19
1960-61 4.13 1973-74 9.81 1985-86 14.42 1997-98 34.72
1961-62 13.07 1974-75 12.36 1986-87 8.79 1998-99 8.6
1962-63 5.76 1975-76 5.11 1987-88 11.14 1999-00 8.8
1963-64 9.38 1976-77 10.2 1988-89 8.17 2000-01 14.6
1964-65 10.28 1977-78 27.96 1989-90 5.93 Summary
1965-66 12.68 1978-79 18.59 1990-91 11.23 Min: 4.13
1966-67 14.22 1979-80 20.75 1991-92 17.18 Max: 34.7
1967-68 8.58 1980-81 8.47 1992-93 27.09 Mean: 13.03
1968-69 19.91 1981-82 13.22 1993-94 10.23 Median: 10.8
1969-70 8.48 1982-83 25.92 1994-95 24.65 Count: 42

Source: OCPFRD; *Water years run from July 1 to June 30 of the following year.
Rainfall data for water year 1970-71 not available



### Available Data

Monitoring data used in these TMDLs came from numerous sources. Much of the analysis has been summarized in a Regional Bo ard staff report describing the monitoring results in relation to water quality objectives, sediment guidelines and fish ti ssue screening values (SARWQCB 2000). EPA has included data from a few more recent studies and focused on monitoring results compiled over the past five years to assess present day water quality
conditions. EPA has also reviewed ten years of sediment data a nd nearly twenty years of fish tissue results to determine long- term trends. Finally, the Regi onal Board has several projects currently in progress with the Southern California Coastal Res earch Water Project (SCCWRP).
The studies relevant to these to xics pollutant TMDLs address sedi ment toxicity in Newport Bay (2001a), fish bioaccumulation in Newport Bay ( 2001b) and freshwater toxicity in San Diego Creek at Campus Dr. (2001c). Preliminary resu lts for two studies (2001a, 2001b) were available as of Dec 1, 2001 and (where feasib le) some data were included in these TMDLs. A summary of all monitoring data, the waterbodi es sampled, measured parameters and citation/abbreviation is provided in Table 2-3.

Table 2-3 Overview of monitoring data Organization

Lee & Taylor (2001a) 319(h) report (for SA RWQCB) Period of
record
Winters 1999;
2000 Geographic Scope San Diego Creek Watershed Measured
Features
stormwater runoff Measured
Parameters and comments Se; metals and OP pesticides in watershed,
Draft report provided May 2001

summary document 22Newport Bay Toxic Pollutant TMDLs

Hibbs & Lee Se Study 1999 San Diego Creek;
Groundwater Surface and groundwater Se in groundwater and SDCreek

Lee & Taylor (2001b) 205(j) report (for SA RWQCB) 1997-‘99 San Diego Creek Watershed Surface water toxicity Toxicity and pesticides in watershed

CDPR Red Imported Fire Ant (RIFA) study 1999

- present San Diego Creek
Watershed Surface water Toxicity and pesticides Insecticides and OP pesticides in watershed; toxicity and chemical
concentrations
IRWD (1999)
Database Fall 1997
--March
1999 San Diego Creek; Upper and Lower Bay (10 sites) Surface water;
sediments metals and organics using appropriate sampling and analytical techniques, one day composites, year round, no storm events
OCPFRD (2000) (NPDES annual report) 1996

- 2000 All freshwater tributaries, San Diego Creek; Upper and Lower Bay,
Rhine Channel Surface water;
sediments 7 metals, some organics, dry and wet weather events; some four consecutive day sampling; semi

annual sediment data

Orange County Coastkeeper (1999) Oct. 1999 Rhine Channel (2 sites); Lower Bay (1 site) Sediments Metals, sediment core in Rhine

Ogden Env. (1999, for City of Newport Beach) June 1999 Lower Bay (12 sites) Sediment Metals; few priority organics in dredge studies

BPTCP (1997) (for SWRCB/ NOAA/EPA) 1994; ‘96 Upper and Lower Bay (18 sites total) Sediment triad study Metals; many organics; toxicity; benthic comm. Index

Bight ’98 (coordinated by SCCWRP) 1998 Lower Bay (11 sites; not Rhine). Sediment triad study chemistry; toxicity; benthic comm. index; interstitial porewater data
for AVS & SEM Cal. Dept. Fish & Game 1999

- 2000 San Diego Creek watershed Sediment; Fish
tissue OP Pesticides; insecticides in sediment and fish tissue as part of Red Imported Fire Ant project
Calif. Fish Contamin. Study (CFCS) (for SWRCB/ OEHHA) 1999–
2000 Upper and Lower Bay (sport) Fish tissue Preliminary results for three metals; many organics in fish fillets with skin off

State Mussel Watch (SMW) (for SWCRB) 1980

- 2000 mostly Upper and Lower Bay Shellfish
tissue Metals; organics in resident or transplanted mussels, no recent
data in SDC
Toxic Substance Monitoring (TSM) (for SWRCB) 1983– 1998 all Newport Bay waterbodies Fish
tissue Total metals; organics in whole fish with skin on

SCCWRP (2001a) Sediment Toxicity Study (for SA RWQCB) On-going Upper and Lower Bay; including
Rhine Channel (10 sites) Sediment; Water Toxicity chemistry; toxicity; benthic comm. index, some preliminary results
available

SCCWRP (2001b) Fish Study (for SA RWQCB) On-going Upper and Lower Newport Bay Fish tissue Four metals; priority organics, sportfish samples in 2001; ecological risk samples in 2002
SCCWRP (2001c) Freshwater Study (for SA RWQCB) On-going San Diego Creek (1 site) Freshwater Toxicity TIEs for metals in Winter 2002; Se bioaccumulation study

summary document 23Newport Bay Toxic Pollutant TMDLs



## III. Organophosphate (OP) Pesticide TMDLs

TMDLs are required for chlorpyrifos and di azinon for San Diego Creek. To address impairment specified in the 1998 Section 303(d) list, the TMDLs for San Diego Creek address both Reach 1 and Reach 2, unless otherwise explicitly indicated. A TMDL is also required for chlorpyrifos in the Upper Newport Bay. TMDL s are required despite recent re-registration agreements to phase out certain uses of th ese two OP pesticides by 2006 (EPA 2001b, 2000b). A large portion of information presented here and in the Technical Support Document – Part C is
based on the OP Pesticide draft TMDLs written by Regional Board st aff (SARWQCB 2001a).



### Problem Statement

San Diego Creek

Water column acute and chronic toxicity to aquatic life in San Diego Creek and its tributaries has
been identified and attributed la rgely to diazinon and chlorpyrifos through toxicity identification evaluation (TIE) studies. Over 300 toxicity te sts have been performed on 123 water samples collected from the Newport Bay watershed. Toxicity occurred during virtually all monitored storm events and is viewed primarily as a we t weather problem. Dry weather toxicity was generally confined to up per reaches of the watershed (near the foothills) and diluted or otherwise remediated in downstream locations (Lee and Tayl or 2001a, b). These TMDLs are structured to prevent toxicity under all flow conditions.

Average diazinon concentrati ons in San Diego Creek duri ng baseflow (200 ng/L) and stormflow (445 ng/L) have exceeded the chronic numeric target of 50 ng/L. Ninety-five percent
of the observed concentrations were also above the acute numeric target of 80 ng/L. Average chlorpyrifos concentrations in San Diego Creek during baseflow (111 ng/ L) and stormflow (87 ng/L) have exceeded the chronic numeric targ et (14 ng/L). At leas t 59% of the observed concentrations also exceeded the acute numeric target of 20 ng/L.

Upper Newport Bay

Evidence exists indicating water column toxicity due to chlorpyrifos in Upper Newport Bay.
This is restricted to storm events when fres hwater inputs from San Di ego Creek and Santa Ana Delhi linger in the Upper Bay (Lee and Taylor 2001a, b). Average chlorpyrifos concentrations observed in Upper Newport Bay (43.3 ng/L) have exceeded the saltwater chronic numeric target of 9 ng/L during stormflow conditions, and 80% of the concentrations exceeded the acute numeric target (20 ng/L). Toxicity attributed to chlorpyrif os does not extend into Lower Bay. Diazinon does not appear to cause toxicity in sa ltwater bodies such as Upper or Lower Newport Bay.

Bioaccumulation

In San Diego Creek watershed, fish tissue concentrations of chlorpyrifos have consistently remained orders-of-magnitude be low the OEHHA screening value (10,000 ppb) for fish consumption. Diazinon fish tissue concen trations have exceeded the OEHHA screening value of 300 ug/kg only once (440 ug/kg), accordi ng to Toxic Substances Monitoring data.

summary document 24Newport Bay Toxic Pollutant TMDLs

Mussel tissue concentrations of both OP pestic ides have never exceede d the OEHHA screening values. Therefore, there is no compelling eviden ce of bioaccumulation of these substances to levels of concern, an observation consistent with monitoring from other studies (CDFG 2000, EXTOXNET).

In short, there is conclusive evidence that diazinon and chlorpyrifos are causing acute and chronic toxicity in San Diego Creek and that chlorpyrifos causes t oxicity in Upper Bay. Toxicity predominantly occurs during storm events and cer tainly affects lower level aquatic organisms
such as Ceriodaphnia (Lee and Taylor 2001a, b).



### Numeric Targets

At present, there are no promulgated water qua lity criteria for chlorpyrifos and diazinon. For these TMDLs, EPA has selected the numeric targets from recommended acute and chronic criteria derived by the California Dept. of Fish and Game for chlorpyrifos and diazinon in freshwater and saltwater (CDF G 2000a). These numeric targets serve as the quantitative interpretation of the narrative water-column quality objective as specified in the Basin Plan (1995). These numeric targets will be protective of aquatic life in San Diego Creek and Upper Newport Bay and sufficient to remove impairme nt caused by OP pesticide toxicity. Target concentrations are shown in Table 3-1; saltwater chronic and acute targets for diazinon are not applicable since TMDLs are not required for this pollutant in any of the saltwater bodies covered by these TMDLs.

Table 3-1 Selected Numeric Targets

Pesticide Criterion Concentration (ng/L)

Freshwater Saltwater

Diazinon Chronic 50 N/a
Diazinon Acute 80 N/a

Chlorpyrifos Chronic 14 9 Chlorpyrifos Acute 20 20

from Calif. Fish & Game (2000a) chronic means 4-consecutive day average



### Source Analysis

This section of the TMDL presents a synops is of the major sources of diazinon and chlorpyrifos to San Diego Creek and chlorpyrifos to Upper New port Bay. This synopsis focuses
on water column concentrations from several studies conducted in th e watershed targeting aquatic life toxicity a ssociated with pesticides (Lee and Taylor 2001a; 2001b; DPR studies). These studies were not detailed enough to iden tify discrete sources, but it appears that diazinon and chlorpyrifos are problems attributed to agricu ltural and residential us e. Investigations of DPR pesticide use reports provide some estimates of pesticide applications by land use within the watershed; however this does not comprehens ively depict all sources in San Diego Creek. Additional analysis via land use information indi cates that residential contributions are also

summary document 25Newport Bay Toxic Pollutant TMDLs

significant. The synopsis is presented below, whereas the reader will find a more complete source analysis in the Technica l Support Document – Part C.

Diazinon

Within freshwater bodies of San Diego Cr eek, monitoring results show extremely high detection frequency (>98%) of di azinon during storm events. This detection frequency decreases slightly (89%) during dry weather or base fl ow conditions. Maximum concentrations were observed in Hines Channel (which drains into Peters Canyon Cha nnel, and is tributary to San Diego Creek Reach 1).

At virtually all the locations, the median stor mflow concentration is significantly higher
than the median baseflow concentration. Since stormwater runoff constitutes about 80% of the volume of water discharged to Newport Bay on an annual basis, this would indicate that the overwhelming majority of the pest icide load would derive from stor mflow rather than baseflow. The average concentration is actually higher for baseflow, but this is biased by a few very high detections from 1998 near nurseries. These result s have not been observe d in later sampling and the nurseries have subsequently instituted measures targeted at reducing pesticide runoff.

Chlorpyrifos

Chlorpyrifos was detected less frequently (in 45% of samples) than diazinon. This is due in part, to the lower solubility of chlorpyrifos, and its greater affinity for sediment. The lower mobility of chlorpyrifos results in lower concentr ations in the drainage channels. According to DPR Pesticide use database, over twice as much ch lorpyrifos is applied as compared to diazinon (per pound of active ingredient).

Sample locations monitoring residential areas tended to have lower chlorpyrifos concentrations. Chlorpyrifos was not detected at three of the reside ntial locations under both
baseflow and stormflow conditi ons. The detection frequency, and maximum concentrations detected at another partly resi dential location (Santa Ana Delhi Channel) were low. The only residential site with relatively high chlorpyrifos concentrations was Westcliff Park (stormflow),
but the baseflow concentrat ions were relatively low.

California DPR Pesticide Use Database

The California Department of Pesticide Regulation (DPR) Pesticide Use database provides information by county about application of pesticides by vari ous licensed pesticide users. For the Newport Bay watershed, diazinon and chlorpyrifos applications have been estimated to comprise one-fifth the total reported for Orange County (because the watershed acreage is one-fifth that of Or ange County). In addition, land use analyses indicate that
commercial nurseries and residential areas are asso ciated with high pesticide application rates, and much higher detection in water during wet w eather. Urban uses account for over 90% of total diazinon and chlorpyrifos use in the Newport Bay Watershed, with residential use by homeowners accounting for roughly half the es timated total of 10,700 lbs of diazinon and 24,000 lbs of chlorpyrifos used in th e watershed in 1999. Similar studies reported in literature of pesticide use and water monitoring results have indicated that resident ial hotspots (individual homes) can account for most of the diazinon runoff from a neighborhood (Scanlin and Feng 1997; Cooper 1996).

summary document 26Newport Bay Toxic Pollutant TMDLs

Based on data from investigations ca rried out from 1996-20001, about 36 pounds of diazinon is discharged annually to San Diego Creek, mostly duri ng storm events. This is less than 0.4% of the estimated diazinon mass a pplied in the watershed. About 8 pounds of chlorpyrifos is discharged annually to San Di ego Creek and Upper Newport Bay, with most of the load delivered during storm events. This am ounts to about 0.03% of the applied chlorpyrifos
mass. Available data and studies indicate that in normal use, OP pesticides break down quickly and therefore only a small percentage of the to tal amount applied is av ailable to runoff to waterbodies. However, even small amounts of th ese pesticides are enough to cause acute and chronic toxicity in receiving water bodies.

In summary, surface runoff is the source of virtually all loadings. Contributions from sediment remobilization and groundwater are neg ligible, however, loading from atmospheric deposition to Upper Newport Bay is potential ly significant, though not well quantified. The chemical properties of diazinon a nd chlorpyrifos ensure that th ey do not accumulate in the environment. Runoff derived from urban land uses accounts for about 88% of the diazinon baseflow load, and 96% of the stormflow loa d. Agricultural source s (including nurseries)
account for the remainder of the load. For chlo rpyrifos, runoff derived from urban land uses accounts for about 85% to 88% of the baseflow and stormflow loads, while agriculture (including nurseries) accounts for ab out 12% to 15% of the load. On a per acre basis, different
land uses contribute diazinon and chlorpyrifos runoff at fairly e qual rates within the watershed and distinct source areas are not readily identifia ble. Median concentrations from 14 sampled drainage channels across the watershe d did not exhibit large differences.

Although it appears that some of the nurse ry/agricultural loca tions yield higher chlorpyrifos concentrations than the residentia l areas, it should be noted that the nursery monitoring locations are selected to monitor undiluted nursery discha rge, very close to where the chlorpyrifos is used. In contrast, runoff from individual homes where chlo rpyrifos is applied is not monitored; rather the monito ring location is further away within a channel thereby collecting mixed/diluted runoff from many homes. In ad dition, because of the i nherent immobility of chlorpyrifos, and its tendency to adsorb to sediment, higher chlor pyrifos concentrations are most likely to be encountered in area s nearby to where it is applied, before it partitions out of the aqueous phase and settles out along with the sediment.



### Loading Capacity/Linkage Analysis

These OP pesticide TMDLs use a concentration-based loading capacity and allocations for diazinon and chlorpyrifos. The concentra tion-based loading capacity will address the problems of aquatic toxicity within the wate rshed and Upper Newport Bay. Because diazinon and chlorpyrifos are generally not known to bio accumulate, there is no need to establish the loading capacity via mass based units. These concentration-based TMDLs will protect aquatic life from short-term exposure vi a acute targets and l ong-term exposure via chronic targets.

The concentration-based loading capacity values are exactly the same as those selected as the numeric targets (see Table 3- 1). For San Diego Creek, the lo ading capacity for diazinon has two components: the chronic or 4-day averag e concentration (50 ng/L), and a maximum 1-hour average (acute) concentration of 80 ng/L. The loading capacity for chlorpyrifos in San Diego

summary document 27Newport Bay Toxic Pollutant TMDLs

Creek also has two components: the chronic or 4-day average concentration (14 ng/L), with a maximum 1-hour average (acute) co ncentration of 20 ng/L. For Upper Newport Bay, the loading capacity for chlorpyrifos has tw o components: the chronic or 4-day average c oncentration (9 ng/L), and a maximum 1-hour average (acu te) concentration of 20 ng/L acute.

As discussed above regarding the numeric targ ets, this loading capacity (including the margin of safety discussed below) will result in achievement of the narrative water quality objective for aquatic toxicity because these numer ic targets arise from aquatic toxicity tests completed during the development of th ese recommended water quality levels.



### TMDL and Allocations

The TMDLs for diazinon and chlorpyrifos are bei ng established at levels equivalent to the loading capacities identified above. We have al so utilized concentratio n-based allocations for both wasteload allocations (WLA) and load allocations (LA). The WLA applies to point sources in the watershed, and includes the NPDES permittees . The LA applies to non-point sources such as agriculture, open space and atmospheric deposition.

For these OP pesticide TMDLs, EPA has establ ished an explicit (10%) margin of safety (discussed below); therefore the concentration-ba sed allocations are calc ulated as 90% of the numeric target level for each pesticide unde r acute and chronic exposure conditions. For example, the numeric target for diazinon under short term, acute conditions is 80 ng/L. The
wasteload and load allocations ar e set at 72 ng/L, after subtraction of 8 ng/L to provide the 10% margin of safety.

Allocations for Freshwater Water Bodies

Table 3-2 presents the concentration-based fr eshwater allocations for chlorpyrifos and diazinon; these apply to all point sources (waste load allocations) and to all non-point sources (load allocations). The diazinon allocations apply to freshwater discharges into San Diego Creek Reach 1 and Reach 2. The chlorpyrifos allocatio ns apply to freshwater discharges into San Diego Creek (Reach 1 and Reach 2) and discharges into other freshwater tributaries into Upper Newport Bay including Santa Ana Delhi Channe l, Big Canyon Channel and other drainages to Upper Bay. This includes discharges from agricu ltural and residential lands, including flows from the storm water systems. These limits apply regardless of season and flow; i.e., at all times of the year.

Table 3-2: Diazinon and Chlorpyrifos Allocations for San Diego Creek Category Diazinon (ng/L) Acute Chronic Chlorpyrifos (ng/L) Acute Chronic
Wasteload Allocation 72 45 18 12.6
Load allocation 72 45 18 12.6
MOS 8 5 2 1.4
TMDL 80 50 20 14

summary document 28Newport Bay Toxic Pollutant TMDLs

Allocations for Upper Newport Bay

Table 3-3 presents the saltwater allocations for chlorpyrifos; thes e apply to all point sources (wasteload allocations) a nd to all non-point sources (load allocations). It applies to saltwater allocations in Upper Newport Bay, de fined from San Diego Creek at Jamboree Rd. down to Pacific Coast Highway Bridge. These limits apply regardless of season and flow; i.e., at all times of the year.

Table 3-3. Chlorpyrifos Allo cations for Upper Newport Bay Category Acute (ng/L) Chronic (ng/L)
Wasteload allocation 18 8.1
Load allocation 18 8.1
MOS 2.0 0.9
TMDL 20 9 Chronic means 4-consecutive day average

Needed Reductions

Table 3-4 summarizes the estimated needed concentration based (load) reductions for diazinon and chlorpyrifos in orde r to achieve the TMDL numeric targets in San Diego Creek. Multiple samples are available from five separate storm events in the watershed from 1997-2000. The storm average concentrations in Table 3-4 are the maximum single storm averages at the San Diego Creek-Campus station. The difference be tween the current load and the allocation is the needed reduction. Chlorpyrifos concentrat ions may have begun to decline in 2000 and 2001, based on indications of a reduction in usage from th e DPR database as well as from the Sales and Use Survey (Wilen 2001) conducted in late 2000. To date, there are no clear indications of declining trends in diazinon usage in the watershed. This table indicates the estimated needed reduction during average storm flows. As discus sed above, the majority of the pesticide load
derives from stormflow.

Table 3-4. Needed Load (concentration based) Reductions for San Diego Creek.
Constituent San Diego Creek Campus Station Allocation Needed Reduction

Chlorpyrifos Storm Average (ng/L) Max (ng/L) Chronic (ng/L) Acute (ng/L) Chronic (ng/L) Acute (ng/L)
120 580 12.6 18 90% 97%
Diazinon 848 960 45 72 95% 93%

Phase out agreements

Diazinon – In January 2001, USEPA released a revised risk assessment and an agreement with registrants to phase out mo st diazinon uses (USEPA 2001b). Under the agreement, all indoor uses will be terminated, and all outdoor non-agricultural uses will be phased out over the next few y ears. In addition, on a national basis, about one-third of the agricultural crop uses wi ll be removed. Within the Newpor t Bay watershed, non-agricultural and non-nursery uses account for over 90% of the diazi non use in Orange County. It is thus likely

summary document 29Newport Bay Toxic Pollutant TMDLs

that the EPA agreement will result in the cessa tion of most diazinon use in the Newport Bay watershed soon after the outdoor non-agricultu ral use registration expires on December 31, 2004

.
Chlorpyrifos – In June 2000, the EPA published its revised risk assessment and agreement with registrants for chlorpyrif os (USEPA 2000b). The agreement imposes new restrictions on chlorpyrifos use in agriculture, cancels or phases out nearly all indoor and outdoor residential uses, and also cancels non-reside ntial uses where children may be exposed. Application rates for non-residential areas wher e children will not be exposed will be reduced, and public health use for fire ant eradication and mosquito control wi ll be restricted to professionals. In Orange County, residentia l use likely accounts for over 90% of total chlorpyrifos use. Thus, it appears that over 90% of the current chlorpyrif os use in the Newport Bay watershed will be eliminated by the EPA agre ement. Retail sales are scheduled to stop by December 31, 2001, and structural uses will be phased out by December 31, 2005.

While these agreements should result in signif icant decreases in OP pesticide use and the resulting discharge concentrations to the waterb odies, additional measures may be necessary to
achieve the reductions set forth above.



### Seasonal variation/Critical conditions

Pesticide usage correlates r oughly with the season, with incr easing usage in the warmer months due to increased pest activity. However, runoff into the drainage channels is greatest during the wet season, and higher pesticide concentrations are observed during storm events. The higher pesticide concentrations primarily ac count for the toxicity observed in stormwater samples collected in the watershed. The chronic cr iteria used as the basis for the numeric targets are designed to ensure protection of aquatic lif e during all stages of life, including the most sensitive stages. Because the TMDL is being expr essed as a concentration, a detailed analysis of
critical conditions is unn ecessary. The concentration-based allo cations (Table 3-2 and 3-3) will apply and be protective during all flow conditions and seasons.



### Margin of Safety

An explicit 10% margin of safety was applie d to the recommended criteria derived by the CDFG (2000a) and EPA (1986) for diazinon and chlorpyrifos. This explicit margin of safety is
intended to account for uncertainties in TMDL calculation methods and concerning pesticide effects (e.g., potential additive and synergistic im pacts from exposure to multiple OP pesticides) that may aggravate water quality impacts due to diazinon and chlorpyrifos usage in the
watershed.

In addition to the explicit margin of safe ty, conservative assumptions were used in applying the numeric targets with in the watershed. These conservative assumptions serve as implicit margins of safety to provide additiona l protection for aquatic life and minimize aquatic toxicity.

1. No adjustment was made to reflect the possi bility of pesticide br eakdown from point of discharge to San Diego Creek. Scientists ha ve measured that half -lives of diazinon and chlorpyrifos in water range from a few days up to six months, therefore some degradation is likely to be occurring after ap plication and within flowing wa ters. Assuming discharges are

summary document 30Newport Bay Toxic Pollutant TMDLs

within the specified concentration-based alloca tions, and that such degradation (via biotic and abiotic processes) occurs, there will be sufficient protection for aquatic life.

2. No adjustment was made to reflect the possibili ty of mixing and dilution within the drainage channels. In particular, the dilution capacity provided by gr oundwater seepage has not been
factored into the TMDLs.

summary document 31Newport Bay Toxic Pollutant TMDLs



## IV. Selenium TMDLs

TMDLs are required for selenium (Se) for San Diego Creek, Upper Bay, Lower Bay, and Rhine Channel. Much of the work presente d below and in the Technical Support Document—
Part D for Selenium is based on the Se draf t TMDLs written by Regiona l Board staff (2001b).



### Problem Statement

Selenium is a naturally occurring element that persists in soils and aquatic sediments and readily bioaccumulates through the food chain at le vels that can cause adverse effects on higher level aquatic life and wildlife including fish and birds that prey on fish and invertebrates.
Selenium can become mobilized and concentrated by weathering and evaporation in the process
of soil formation and alluvial fan deposition in arid and semiar id climates (Presser, 1994). Moreover, selenium may be leached from sediment s as a result of irriga tion practices, elevation of the groundwater table, or other modifi cations in the natura l hydrologic regime.

Dissolved selenium concentrations in San Di ego Creek at Campus, and in tributaries to San Diego Creek, consistently exceed the chronic (4-day average) CTR criterion for freshwaters (5 μ g/L). This has been observed in numerous st udies, which also cite occasional exceedances of the acute (1 hour max.) criterion (Hibbs and Lee 1999, IRWD 1999, Lee and Taylor 2001a). Dissolved selenium concentrations in Newpor t Bay do not exceed the CTR saltwater criterion (71 μ g/L); nonetheless, fish tissue data indicate that selenium loadings may be causing toxicity or contributing to conditions threatening wildlife in Upper and Lower Bay (see next paragraph). Freshwater and saltwater toxicity tests (designed for metals and trace elements such as selenium) are currently in progr ess (SCCWRP 2001a, b).

In the majority of aquatic sediment samples analyzed from Newport Bay watershed,
selenium concentrations are below levels of co ncern (2—4 mg/kg dry) as defined by Enberg et al. (1998). Mussel and fish tissue concentrations from all waterbodies are below the screening value (20 mg/kg wet) for protection of huma n health as established by OEHHA (1999). However, these same tissue results are within the range of levels of concern (4 – 12 mg/kg dry) for toxicological and reproductive effects to wildlife (Enberg et al. 1998 and Henderson et al. 1995). In San Diego Creek, tissue concentrations of selenium in small whole fish show an increasing trend from 1983 to 2000 (TSM 2000). Fish fillet results in Newport Bay do not appear to have the same trend and maximum levels barely approach 4 mg/kg dry (TSM database), which is below reported levels of concern. Studies of av ian reproductive success, specifically including selenium concentra tions in eggs, have not been completed.



### Numeric Targets

As discussed in Section II, the California Toxics Rule (CTR) in cludes numeric water quality standards (objectives) for selenium whic h are designed to prot ect aquatic life (USEPA 2000a). EPA and Regional Board staff have re-evaluated freshwater flow histories for nearly 20 water year records (see TSD part B). These record s have been divided into four flow tiers as shown in Table 4-3 for San Diego Creek. Our re-e valuation indicates that mean water residence time of 4 consecutive days occurs in flow rates below 814 cfs. Thus the CTR chronic target (5

summary document 32Newport Bay Toxic Pollutant TMDLs

μ g/L) applies to base, small and medium storms. During the large flows, shorter residence time (<4 days) exists and so an acute value is applied, 20 μ g/L. EPA has incorporated this high flow (or “large storm”) value into selenium targets, flow tiers and loading capacity.

Mean water residence time in the Bay also exce eds 4 days on average. Because the more stringent chronic standards are applied based on a 4 day averaging period, EPA has determined that it is appropriate to apply the chronic selenium standards at three of four flow tiers in San Diego Creek and in Newport Bay. These are equiva lent to the chronic fr eshwater and saltwater objectives included in the CTR. The acute fres hwater objective is from National Toxics Rule (NTR, USEPA 1997) and is applied for the highest flow tier for San Diego Creek because the frequency of flows in this tier exceeds 4 days fewer than once in three years on average.

EPA is currently engaged in a process of re vising its national cr iteria recommendations for selenium based, in part, on the USFWS opinion concerning the CTR. However, the numeric objectives for selenium water column concentrati ons have not yet been changed, and it is not
clear whether the freshwater criteria will need to increase or decrease in order to protect aquatic life and aquatic dependent species. On one hand, several commenters supported the option of basing the TMDLs on more stringent targets base d on the analysis provided by USFWS. On the other hand, several commenters identified site sp ecific characteristics of Newport Bay watershed which could support a conclusion that objectiv es less stringent than the CTR would be protective. In light of these uncertainties concerning the need to either lower or raise the selenium standard, we concluded that it woul d be appropriate to set the TMDLs based on the existing numeric standard. The evidence that th e CTR objectives are not be protective of San Diego Creek was not definitive e nough to warrant selection of more stringent target values.

Freshwater targets

EPA is applying two numeric targets for diffe rent freshwater flow conditions in San Diego Creek. Based on re-evaluation analysis of daily flow records for water years 1977/78 and 1985 to 2001, EPA divided all observed flows into 4 flow categories or tiers: baseflow ( ≤ 20 cubic feet/second (cfs)), small flows (between 20 and 181 cfs), medium flow (between 181 and 814 cfs), and large flow (>814 cfs). EPA is basi ng these TMDLs on a different period of flow record than proposed in the draft TMDLs because we have concluded that the flow record for 1978/79 and 1983/84-2000/01 reflects more recently ava ilable data and is more reflective of long term flow patterns. The percenta ge of flows in the base, small and medium flow categories that exceeded 4 days in duration during this period far exceeded the once in 3 year recurrence interval
that is assumed in calculation of selenium criteri a. Therefore, it was ap propriate to apply the more protective chronic standard under these flow conditions. During the high flows associated with large storms, the duration does not extend to four days mo re than once in 3 years on average, so it is appropriate to apply an acute target concentration fo r the high flow tier (20 μ g/L, based on National Toxics Rule [USEPA 1999]). The Technical Support Document—Part B provides a complete explanation of these flow tiers and the associ ated mean annual flow volumes for calculating loads.

summary document 33Newport Bay Toxic Pollutant TMDLs

Saltwater target

The numeric target for dissolved selenium in saltwater is 71 μ g/L from CTR (USEPA 2000a). The USFWS concurred with this saltwater value in its revi ew of the CTR. Therefore, this target is expected to result in protection of all designated uses in Newport Bay. Additionally, since San Diego Creek is the major contributor of freshwater flows to Newport Bay (>95%),
reductions of selenium in the creek shoul d also result in reductions in the Bay.

Table 4-1. Numeric targets for Selenium in San Diego Creek and Newport Bay ( μ g/L). Waterbody/type Total Se* Dissolved Se# Acute Chronic San Diego Creek/freshwater 20 5 N/a Newport Bay & Rhine N/a N/a 71 Channel/saltwater *Total recoverable = unfiltered sample
#dissolved = <0.45 μ m filter



### Source Analysis

Several monitoring studies, completed with a specific focus on selenium during short time periods, provide most of our current unde rstanding of selenium sources (IRWD 1999, Hibbs and Lee 2000, Lee and Taylor 2001a). The synopsis is presented below; the Technical Support Document—Part D presents a more thorough source analysis and description of these studies.

An investigation of selenium sources shows that shallow groundwater is a significant and constant source of selenium to surface waters in the San Diego Creek watershed (Hibbs and Lee 2000). Groundwater may seep into surface waters vi a natural processes or it may be pumped as part of groundwater cleanup or de watering operations which discharge into surface waters. Thus
selenium contributions to th e watershed include both non-point sources (seepage) and point sources (cleanup and dewatering). Surface channels immediately downstream of nurseries were
found to have low selenium concentrations du ring base flow conditions (Hibbs and Lee 2000, Lee and Taylor 2001a).

San Diego Creek contributes the largest lo ad of selenium among all tributaries to Newport Bay (Lee and Taylor 2001a). Of the lo ad from San Diego Creek, Peters Canyon Wash, which conveys selenium from selenium-laden sh allow groundwater, represents the major source in dry weather. These sources may include runoff from hillsides, open spaces, agricultural lands, and commercial nursery sites. High concentratio ns were found in nursery channels during rain events, although it remains unclear if the selenium sources are from the commercial nurseries or from sources existing upstream of the nurseries. During rain events, the selenium load from the upper reach of San Diego Creek was comparable to that from Peters Canyon Wash, suggesting runoff from open space is a significant source during rain events . Low concentrations were found in nursery channels during baseflow conditions.

summary document 34Newport Bay Toxic Pollutant TMDLs

Table 4.2 Reported Selenium conc. in San Diego Creek and Santa Ana-Delhi Channel ( μ g/L)

Location Lee and Taylor * 5/31/00 Hibbs and Lee ¥

10/31/99 IRWD @

12/97–3/99 San Diego Creek 22.1 19 42.5 (at Campus Dr.)
Santa Ana-Delhi 11.9

--- --- (at Irvine Ave.) *Lee and Taylor (2001a) results for unfiltered samples

¥ Hibbs and Lee (1999) results for dissolved sample

@ IRWD (1999) result is arithmetic average of time period indicated, dissolved sample

Urban runoff is found to contain very low selenium concentrations (< 1.5 μ g/L) (Lee and Taylor 2001a). Atmospheric deposition of selenium is not significa nt compared to loading from San Diego Creek and other freshw ater tributaries (Mosher and Du ce 1989). The concentration of selenium in ambient seawater (0.080 μ g/L) is unlikely to cause ecological impacts (Nriagu, 1989), and seawater is not believed to comprise a significant source of selenium loading to Newport Bay.

Figure 4-1 summarizes the sources of seleni um in the watershed. The significance of these sources varies both on discharge location and season of the year. Nursery runoff shows moderate concentrations (~10 μ g/L) in dry weather and are pote ntial sources during storms (Lee and Taylor 2001a). There is some evidence that runoff from open space, hillsides, and agricultural lands are significant sources during rain events although this evidence is inconclusive. Groundwater seepage/infiltra tion, treated groundwater discharges, and groundwater dewatering discharges represen t significant and constant sources.

Nurseries Groundwater Cleanup Groundwater Dewatering

Groundwater Agricultural
Runoff Open Space &
Hillside Runoff 

### San Diego Creek & other tributaries Newport Bay Urban
Runoff

Atmospheric Deposition

Figure 4.1 Sources of selenium in the Ne wport Bay/San Diego Creek watershed. (Nurseries have been grouped with agricultura l runoff in Table 4-5 for allocations.)



### Loading Capacity/Linkage Analysis

The loading capacities and associated TMDLs a nd allocations for selenium are expressed as mass loads per time. Different approaches we re used to calculate loading capacities for the
freshwater and saltwater wate r bodies in the watershed.

summary document 35Newport Bay Toxic Pollutant TMDLs

San Diego Creek

This TMDL uses a flow-based approach to determine the loading capacity for selenium in San Diego Creek. This approach addresses contributions of seleni um under various flow regimes or tiers. Four flow tiers were chosen ba sed on a statistical analysis of daily flow records for San Diego at Campus Drive. (See Techni cal Support Document – Pa rt B for more explicit
information about freshwater flow s.) Specific loading capacities fo r each flow tier are calculated from the desired selenium concentration (i.e., the numeric target) and the annual mean flow volume associated with each tier (Table 4-3). Th e sum of loads in these four tiers constitutes the total loading capacity for San Diego Creek per year.

Table 4-3 Flow based tiers and corresponding volumes in San Diego Creek
Flow tier Corresponding Flow Volume* Se conc. Loading capacity flow associated with tier with tier per tier @ (cfs) (million cubic ft.) (ug/L) (lbs/yr.)
Base flow 0—20 275.4 5 86
Small flows 21—181 347.5 5 108.4
Medium flows 182—814 357.6 5 111.6 Large flows >814 468.8 20 585.4

Total annual 1449.4 891.4

amount *Annual mean volume based on USGS & OCPFRD records for water years: 1978, 1984 to 2001.

@ Se per tier (lbs/yr) = flow volume (ft 3 /yr) x desired Se target (ug/L) x conv. factor (6.243 x 10 -8 lbs x L/mg x ft 3 )

Newport Bay

The loading capacity for Newport Bay is presente d in Table 4-4. This loading capacity is calculated using the selenium saltwater numeric target (71 μ g/L) and the volume of water in Newport Bay. (Mean volume is 19 million cubic meters based on low and high tide estimates [RMA 1999]).

Table 4-4 Loading capacity of San Die go Creek and all Newport Bay waterbodies Waterbody Loading capacity (lbs/yr.) San Diego Creek and tributaries 891.4
Santa Ana Delhi 185.3 ¥

Upper and Lower Bay and Rhine Channel 232,000 *

¥ Se value determined via similar method to those used fo r San Diego Creek but flow records for Santa Ana Delhi Channel were for water years 1995/96 – 00/01
*based on calculation of the CT R saltwater chronic value (71 μ g/L) and the volume of Newport Bay water, adjusted to account for daily water movement into an d out of the Bay from the Pacific Ocean.



### TMDL and Allocations

EPA is setting the TMDL equal to the load ing capacity for each waterbody presented above (Table 4-4). For this TMDL, EPA has de fined wasteload allocations (WLAs) for point sources and load allocations (LA s) for non-point sources. Allocations for San Diego Creek are inclusive and have been sub-divided into categories presented below and allocations outlined in

summary document 36Newport Bay Toxic Pollutant TMDLs

Table 4-5. The loading capacity for Santa Ana Delhi has been defined to set an upper limit on
selenium contributions from that waterbody into Newport Bay.

TMDL = Σ (wasteload allocations) + Σ (load allocations) + Margin of Safety

Sub-categories of allocations for Se in San Diego Creek.

Wasteload allocation s Load allocations

Groundwater cleanup Groundwater dewatering
Urban runoff Groundwater (background) Nurseries & Agricultural runoff Open space and hillside runoff Atmospheric deposition

EPA adopted the selenium allocation scheme de veloped by Regional Board staff for their draft
selenium TMDL. Wasteload and load allocations are assigned based on the following general guidelines:

• Allocations among source categories are assigned in proporti on to the relative significance of the sources, and indicate d by available data concerning reported monitoring concentrations, disc harge flow rates, and Se lo ading (see Source Analysis section), and/or acreage of land uses. In general, significant s ources require larger reductions in loading than minor sour ces to attain the numeric target.

• Within the same source category, allocations for individual dischargers are prorated
based on land area.

• For each flow tier, allocations are assigned based on the nature of each source. For example, runoff from hillside, open space, and agricultural lands is minimal in dry season but loads dramatically increase during high stre am flows associated with wet weather. Loading from shallow groundwater is likely to change because creeks may change from gaining streams (water input from groundwat er during dry weather) to losing streams (surface runoff percolates into shallow groundwat er areas) as a result of high water level in the creeks during and/or im mediately after rain events.

• Atmospheric deposition is not given a specifi c allocation due to the very low loading from this source (see TSD, pg. D-12). Any loading from atmospheric deposition is less than the explicit margin of safety discussed below and can be considered accounted for in the explicit MOS.

• Discharges from groundwater cleanup and groundwater dewateri ng are significant sources and loading from those operations depends on their location. However, the quantification of loading from individual discharges is not fe asible at this time due to lack of Se data in effluent from those operations . In this TMDL, allocations are assigned as group allocations groundwater cleanup discharges and groundwater dewatering discharges. In addition, a sepa rate wasteload allocation is pr ovided to account for future new groundwater dewatering discharges.

Table 4-5 shows the wasteload and load allo cations for San Diego Creek. The estimated
current annual load is considered as the curr ent load of selenium at Campus Drive based on IRWD monitoring data (4/98-3/99 ). The selenium TMDLs and allocations are expressed in mass-based annual loads. Daily loads could be calculated by dividi ng the annual TMDLs and allocations by 365. However, annual loading-base d TMDLs and allocations are more appropriate because prospective adverse effects associated with selenium are associated more with long term

summary document 37Newport Bay Toxic Pollutant TMDLs

mass loadings and bioaccumulation effects than w ith short term or acute effects. An explicit margin of safety (MOS) of 10% was included to account for uncertainty in the analysis and ensure compliance with water quality objectives.

Table 4-5 Se allocations for San Diego Creek watershed
Source Loading capacity (lbs/year) Current load # Estimated reductions
Tier 1 Tier 2 Tier 3 Tier 4 Annual total*
WLA
MCAS Tustin 1.6 2.0 1.8 7.9 13.2 GW clean up 6.2 7.8 7.5 36.9 58.4
Silverado
GW 3.1 3.9 4.0 21.1 32.1

GW dewatering 3.9 4.9 4.5 21.1 34.3
Future GW facilities 0.4 0.5 0.5 2.6 4.0

Stormwater
Permit 0.4 1.0 1.0 5.3 7.6

WLA subtotal 15.5 20.0 19.3 94.8 149.7

LA
All nurseries 3.1 3.9 4.0 21.1 32.1 Ag runoff 5.4 7.3 8.0 44.8 65.6
Undefined

sources @ 53.4 66.4 69.1 366.2 555.0

LA subtotal 61.9 77.6 81.1 432.0 652.6

Total allocations 77.4 97.6 100.5 526.8 802.3 2443 67%

MOS 89.1

Total TMDL 891.4

* sum of loading capacity for San Diego Creek only (based on 5 ug/L applied to all flow tiers) # undefined sources includes: open space and hillside runoff, shallow GW and saltwater Se ¥ current load based on IRWD Se data (1998 -99) and corresponding OCPFRD flow records § other GW facilities refers to future permits

summary document 38Newport Bay Toxic Pollutant TMDLs



### Seasonal variation/Critical conditions

As previously described, EPA is calculating these selenium TMDLs based on freshwater
flow rates instead of seasons. The flow ra tes correspond to flow tiers which address the continuous range of San Diego Creek flow rates throughout the year. In this flow-based approach, allocations are based on in-stream flow rates which are influe nced by precipitation and runoff. Given that storm events may occur at any time of the year, th e corresponding elevated stream flows are addressed by this flow-based approach.



### Margin of Safety

In this TMDL, an explicit margin of safe ty is used to accoun t for other technical uncertainties. The margin of safety is set at 10% of the annual loading capacity (ca. 89 lbs/year). Some of the uncertainty associated with calc ulation of the TMDL for selenium relates to freshwater flow rates. Given the revised time period (nearly 20 years of daily flow records for San Diego Creek), this uncertainty has been re duced. That is, the draft TMDLs were based on five years of OCPFRD flow data, whereas thes e final TMDLs are based on flow records for 19 years that better represent the range of flows during wet and dry water years.

summary document 39Newport Bay Toxic Pollutant TMDLs



## V. Metals TMDLs

TMDLs are required for dissolved copper, lead and zinc in San Diego Creek, Upper Bay, Lower Bay and Rhine Channel. TMDLs are re quired for cadmium in San Diego Creek and Upper Bay only. Information related to thes e metal TMDLs can be found in two Technical Support Documents, Part B which describes freshw ater flows and Part E which describes metals source analysis and methods used to determ ine loading capacity and existing loads.



### Problem Statement

Cadmium, Copper, Lead and Zinc —Dissolved heavy metal concentrations in San Diego Creek and other freshwater tributaries exceeded CTR standards during wet weather only. More specifically, cadmium, copper and lead results exceeded chronic CTR values; copper and zinc data exceeded acute CTR values (OCPFRD 2000). Water column concentrations measured in Newport Bay are highly variable . In general OCPFRD results exceed water quality standards and these data are much higher than data reported by IRWD (1999) which rarely exceed saltwater CTR values. While direct comparis on of these results is not feasible, EPA has identified some quality control problems with metals analyses in saltwater by OCPFRD’s contract lab and has concluded that they s hould be considered with caution in TMDL development.

Sediment metal concentrations generally increase along the gr adient from freshwater to
saltwater with maximum levels found in Rhine Cha nnel. Sediment toxicity has been repeatedly observed in sediment and porewaters of U pper and Lower Bay, including Rhine Channel (BPTCP 1997; Bay et al. 2000, SCCWRP 2001a). Porewater is water found within the bottom sediments. Evidence of degraded benthic organi sms also exists in these saltwater bodies. The cause of toxicity and benthic degradation is un known, however a statistica l correlation was found between sediment and porewater toxicity to amphipods and sea urchin larvae and elevated copper, lead and zinc sediment concentrations (BPTCP 1997). Toxicity identification evaluation (TIE) studies of saltwater bodies are currently in pr ogress (SCCWRP 2001a).

Bioconcentration of copper and zinc has been observed in mussels within Lower Bay and Rhine Channel (SMW 2000). However, fish tiss ue concentrations of these metals are not elevated relative to respectiv e metal screening values defi ned by OEHHA (1999) . Cadmium, Copper, Lead and Zinc may bioc oncentrate in lower organisms but these metals generally do not bioaccumulate and therefore are not likely to thre aten organisms higher in the food chain such as fish-eating birds.



### Numeric targets

In freshwater systems, the dissolved cadmi um, copper, lead and zinc water quality criteria are hardness dependent as defined in CTR (USEPA 2000a). Like many flowing freshwater bodies in southern California, San Di ego Creek waters exhibit a wide range of flow rates and hardness levels. Monitoring data show that low flow rates have high hardness values (e.g., 20 cfs corresponds to ≥ 400 mg/L hardness) whereas high flow rates have lower hardness (e.g., 814 cfs corresponds to 236 mg/L hardness). Th is inverse relationship between flow rate
and hardness influences both acute a nd chronic metals numeric targets.

summary document 40Newport Bay Toxic Pollutant TMDLs

Based on re-evaluation of freshwater daily fl ow records measured at San Diego Creek at Campus (see TSD part B), EPA has identified four flow tiers for fresh water segments for use in
TMDL calculation. A hardness value is defined for each flow tier which is used to calculate the associated acute and chronic targets for dissolved metal. (Table 5-2). For the baseflow tier, EPA used the maximum hardness value (400 mg/L) as allowed in CTR (USEPA 2000). A review of
available data indicated that ac tual hardness associated with fl ows in these tiers often exceeds 400 mg/L; however, the CTR caps the allowable hardne ss value that can be used to calculate the resulting hardness. For the small and medium fl ow tiers EPA selected the highest flow value
within this tier to determine the corresponding hardness value. For large flows, EPA used the median flow rate value to determine the corresponding hardness value.

EPA is identifying numeric targets and TMDL s for both chronic and acute conditions. It is appropriate to set TMDLs fo r chronic conditions in the lowe r three flow tiers based on an analysis of flow durations. The chronic standards for metals were calculated based on the assumption that flows of 4 days or longer in duration would reoccur no more than once in three years on average. Our analysis of the flow records showed that in each of the lower three tiers, the recurrence frequency of flows lasting 4 days or longer was greater than once in three years. For the highest flow tier, the re currence frequency of flows lasti ng 4 days or longer was less than once in three years. Therefore, TMDLs are se t for the high flow tier based solely on acute standards, which apply regard less of flow duration.

It was appropriate to calculate TMDLs for Newport Bay based on chronic targets because average water residence time in the Bay was esti mated to exceed 4 days under all likely flow conditions. The investigation of precipitation, flow rates and the relationship to hardness is explained more thoroughly in the Te chnical Support Document—Part B.

Table 5-1. Flow based tiers and corres ponding hardness values in San Diego Creek.

Flow tier Corresponding flow rate (cfs) Flow volume associated
with tier # (million cubic ft.) Flow rate used to
determine hardness Corresponding
Hardness

(mg/L)
Base flow 0 - 20 275.4 N/a* 400
Small flows 21 - 181 347.5 181 322
Medium flows 182 - 814 357.6 814 236

Large flow >814 468.8 1595 197

# mean volume for each tier based on daily flow records for 19 water years: 1977/78, 83/84 to 00/01. (combination of USGS and OCPFRD data)

* flow rate not used for these tiers; ha rdness determined by CTR (max = 400 mg/L)

Freshwater bodies

For freshwater bodies in San Diego Creek, EPA calculated th e hardness-based dissolved metals numeric targets (Table 5- 2) using equations provided in CT R. EPA is identifying targets representing concentrations of the metals in th e water column for each flow tier. As discussed above, we are identifying targets for both ac ute and chronic conditions for base, small and medium flows and for acute conditions only in large flows (>814 cfs) . Given that water residence time is longer than four days during most of the year, we antici pate the chronic targets

summary document 41Newport Bay Toxic Pollutant TMDLs

will be most important for compliance, however, the acute targets also set an upper limit for input concentrations. The Technical Support Document - Part E presents a step-by-step discussion of how numeric targets were calculated based on CTR equations for each pollutant, fresh water flow rates, and corresponding hardness values.

Table 5-2. Metals Numeric Targets (ug/L) based on flow tiers for San Diego Creek.

Dissolved
Metal Base Flows (<20 cfs) hardness @ 400 mg/L Small Flows (21 - 181 cfs) hardness @ 322 mg/L Medium Flows (182 -815 cfs) hardness @ 236 mg/L Large Flows (>815 cfs) @ 197 mg/L Acute Chronic Acute Chronic Acute Chronic Acute
Cd 19.1 6.2 15.1 5.3 10.8 4.2 8.9
Cu 50 29.3 40 24.3 30.2 18.7 25.5
Pb 281 10.9 224 8.8 162 6.3 134
Zn 379 382 316 318 243 244 208
Note: actual ambient hardness must be determined for each monitoring sample regardless of which
flow condition exists

Saltwater bodies

In saltwater systems, EPA uses the chronic dissolved metals numeric targets to develop mass based TMDLs. Saltwater targets are straig htforward since hardness is not involved. The dissolved saltwater targets are outlined in Table 5-3. Additional numeric targets have also been selected to address toxicity in saltwater sedime nts. These sediment targets are the threshold effect levels for saltwaters as defined by NOA A SQuiRTs (Buchman 1999). Sediment metal concentrations below these target values are likel y to alleviate toxicity to benthic organisms. Both dissolved water column and sediment targ ets apply for Cu, Pb and Zn within Upper Bay, Lower Bay and Rhine Channel, and for Cd only in Upper Bay.

Table 5-3. Numeric targets for metals in Newport Bay

Metal Dissolved saltwater acute target (ug/L) Dissolved saltwater chronic target (ug/L) Alternate target in saltwater sediments (mg/kg dry)
Cd* 42 9.3 0.67
Cu 4.8 3.1 18.7
Pb 210 8.1 30.2
Zn 90 81 124 (Source: CTR values for dissolved metals in saltwaters; NOAA TEL values for sediments) *Cd value applies to Upper Newport Bay only

EPA also considered setting targets for both fr esh water and salt water in terms of total
metals instead of dissolved metals due to the potential concern that pa rticulate metals could
become bioavailable. There are several reasons for selecting dissolved metal targets. The existing numeric standards are expr essed in the CTR in terms of dissolved metals (EPA 2000a).
The CTR rationale is that dissolved forms are the most bioavailable to aquatic organisms.
Particulate/dissolved metal ratios were estimate d from OCPFRD stormwater data and could be used to translate these dissolved metal mass loads into total loads. However, these translator values developed from paired metals data are clos e to unity. For example, we calculated a sitespecific translator ratio for copper of 1.16 total Cu to dissolved Cu; this is reasonably close to the generic EPA value that dissolved is roughly 80% of total concentration. Therefore, dissolved

summary document 42Newport Bay Toxic Pollutant TMDLs

metals measures are probably fairly good predicto rs of total metals conc entrations. Moreover, we have incorporated an extra e xplicit margin of safety to account for the possibility that a focus on dissolved metals does not fully account for to tal metals concentrations. EPA recognizes the Sediment TMDLs already established for these wa terbodies will augment efforts to reduce total metal loadings into the saltwater bodies and help to achieve the sediment targets to protect benthic organisms by reducing discharges of metal-contaminated sediments.



### Source Analysis

This section summarizes our analysis of the major sources of dissolv ed cadmium (Cd) for San Diego Creek and Upper Newport Bay and for di ssolved copper (Cu), disso lved lead (Pb) and dissolved zinc (Zn) within al l water bodies of Newport Bay. This synopsis draws conclusions from several different studies which report concen trations of metals in the water column and sediments of all water bodies. Where applicable this synopsis also pres ents information about inputs of copper from sediments and from recr eational boats moored in Newport Bay. The Technical Support Document—Part E presents a more thorough presentation of all monitoring results and source analysis pertaining to metals.

Within San Diego Creek and its tributaries, metal inputs are heavily influenced by rainfall
and stream flow rates. Base flow conditions yield approximately 25% of total loadings, storm events yield approximately 55% of total loadi ngs, the remainder is associated with low and
medium flows. Surface runoff is estimated to be the largest source of me tals; this includes both
natural and man-made contributions. A recent st udy of pollutant inputs fro m tributaries within the San Diego Creek watershed concluded that th e largest metals inputs come from “urban stations”, whereas agricultural and open space exhibit the lowest loadings (Lee and Taylor 2001a). The difference could be as much as five fold higher for urban areas based on estimates of total copper per acre of runoff (see Table E-7 in TSD – Part E). While this study does provide a basis for estimating the relative importance of metals loadings from different land uses within the watershed, insufficient data were available to accurately estimate annual loads from each

source.

Currently, the only published annual metal loadin g estimates from freshwater tributaries are based on total (unfiltered) metal concentrat ions (OCPFRD 2000). These estimates for Cu, Pb and Zn indicate that San Diego Creek contributes up to ten times more of each metal than Santa Ana-Delhi Channel. Within San Diego Creek, i nputs from Peters Canyon Wash and the rest of the San Diego Creek drainage are about the same . Table 5-4 summarizes these estimates for San Diego Creek and Santa Ana-Delhi Channel for the 1998 and 1999 water years. (The 1998 water year is defined from July 1997 to June 1998.) Thes e results show considerable variability due to different rainfall amounts and fluctuating freshw ater flows during each water year. The 1998 water year is considered an extremely wet ye ar (38.4 inches of rainfall) due to El Nino conditions; whereas, 1999 water year is considered relatively dry (8.8 inches) relative to average annual rainfall (13.3 inches).

Another study of surface water runoff during storm events has approximated the relative contribution of metals associated with natural sources such as soil minerals versus the metal inputs from anthropogenic activities. The authors used results from unfiltered (i.e., total metal) samples in the Santa Ana River watershed and report the anthropogenic contribution is metal specific: Cd (63% human-caused), Cu(42%), Pb (35%) and Zn (33%) (Schiff and Tiefenthaler

summary document 43Newport Bay Toxic Pollutant TMDLs

2000). Total metals loading estimates in Table 5-4 have also been adjusted based on these results to report the approximate load believed to be associated with anthropogenic activities.

Table 5-4 Estimates of Total metal loadings from two freshwater inputs to Upper Bay

Metal Site 1998 water year

(OCPFRD) Adjusted* 1998
results (Man-made) 1999 water year

(OCPFRD) Adjusted* 1999
results (Man-made) Total load (lbs.) Tota l load (lbs.) Total load (lbs.) To tal load (lbs.)
Cu San Diego Creek Santa Ana –Delhi 15,087
1643 6261
682 1643
185 682
77
Pb San Diego Creek Santa Ana –Delhi 10,385 1297 3977 497 449
124 172
47
Zn San Diego Creek Santa Ana –Delhi 63,021
7031 20,985
2341 3784
805 1260
286 Source: 1998 and 1999 water year results from OCPFRD 2000 *Adjustments made from man-made approximations reported by Schiff and Tiefenthaler 2000

Several other sources of metals exist in the watershed: runoff from open spaces, nursery and agricultural applications , groundwater dewatering and clea nup, and atmospheric deposition. Monitoring data exist for background dissolved metals concentrations in surface runoff from hillsides and open spaces. EPA has selected wet weather results from the San Joaquin Channel site (Lee and Taylor 2001a) to serve as proxy fo r these open spaces because the area upstream from this site is essentially undeveloped. Mu ch of the metals loadi ng associated with open spaces is probably naturally occurring; however , it is likely than some portion of loads from these areas is human caused (e.g., from atmospheri c deposition or historic land use activities). Based on State pesticide use reports (CDPR 1999) for some nurseries, applications of copper sulfate appears as the most prominent metal cont aining substance used in nurseries; nonetheless annual metal applications are small (e.g., 72 lbs/ yr) relative to watershed wide surface runoff estimates (ranging from 1643 to 15,087 lbs/yr, Table 5-4). To date, reliable dissolved metal concentrations in shallow ground waters have not been reported. Atmospheric deposition—onto
the watershed land surface and into San Diego Creek and othe r freshwater tributaries—has already been included within surf ace runoff estimates. It is considered minimal in comparison to
other contributions to surface runoff because ther e are no likely local airborne sources of these
metals.

For the salt waters of Upper and Lower Newport Bay, including the Rhine Channel, the largest ongoing sources of most dissolved metals (except fo r copper) are estimated to be the freshwater-borne loads from San Diego Creek (9 5% of freshwater-related loads), Santa AnaDelhi Channel (<5%) and other drainages (<1%). Ambient surface seawater may be the next most significant source. Concentrations of di ssolved metals in seawater collected off the Southern California coast range from 0.06 ug/L for Pb, 0.1 ug/L for Cd, 0.2 ug/L for Cu, to 2.4 ug/L for Zn (pers. commun., R. Gossett). The in fluence of ambient seawater on metal levels within Newport Bay depends on marine tides an d freshwater flows from the watershed. During high tides and low freshwater flows, surface seaw ater contributions could be relatively higher, yet low tides concurrent with dramatically higher freshwater inputs during storm events would yield much lower ambient seawater contributions.

The phenomenon of dissolved copper inputs to ma rine waters from recreational boats has been repeatedly monitored in San Diego Bay as re ported in the draft TMDL for dissolved Cu for Shelter Island yacht harbor (San Diego RWQCB 2001). Usin g mass loading calculations

summary document 44Newport Bay Toxic Pollutant TMDLs

presented in that TMDL and loca l data concerning boats in Ne wport Bay, passive leaching from
recreational boats and underwater hull cleaning are estimated to comprise the most significant sources (>80%) for dissolved Cu into Lower Ba y, Rhine Channel and, to some extent, Upper Bay.

To date, no study within Upper Bay has exam ined whether sediment resuspension or porewater fluxes contribute significant metals loads to the water column. Porewater concentrations measured in Lower Bay (not includ ing Rhine Channel) suggest that Cu levels are elevated enough to create potenti ally negative impacts (B ight ’98). Levels for the other metals are within the range of con centrations observed in ambient seawater and well below the dissolved saltwater numeric targets.

Air deposition of metals is traditionally assessed in two parts—indirect and direct. Indirect deposition, where metals are deposited on to dry land areas and then washed into streams via surface runoff, has already been included as pa rt of the freshwater inputs from San Diego Creek, Santa Ana Delhi Channel and other drainages to Newport Bay. Direct deposition, where metals directly enter the water surface, comprise s less than 1% of metal contributions to Upper and Lower Bay and can be considered accounted for in the explicit margin of safety.



### Loading Capacity/Linkage Analysis

In the draft TMDLs, EPA outlined two opti ons for defining dissolved metals loading capacity and associated TMDLs. These two options were to apply a concentration based or a mass based approach for to each water body. Based on our review of public comments and further analysis, we are establishing TMDLs ba sed on concentration for San Diego Creek and
both concentration and mass loads for Ne wport Bay as discussed below.

San Diego Creek and tributaries

The metals loading capacities and TMDLs for San Diego Creek are set on a concentration basis for dissolved metals. The rationale for addressing dissolved metals is that dissolved metal forms are the most bioavailable to aquatic organi sms. These metals are generally not know to bioaccumulate from one organism to the next, nor has sediment toxicity attributed to metals in the Creek been reported; ther efore, long term mass loadi ng which could contribute to bioaccumulation or sediment toxicity concerns is less of an issue in San Diego Creek. For these reasons, a concentration-based approach is mo re appropriate for these pollutants. These concentration-based loading capac ity will protect aquati c life from short term exposure via acute targets (for all flow conditions ) and longer term exposure via ch ronic targets (for flows <814 cfs).

These concentration based loading capacity values are hardness dependent. Freshwater systems experience a wide range of flows and in dividual hardness conditions . In the future, it will be necessary to measure actual ambient hardness concurrent with each metals monitoring sample (grab or composite) in order to help determine compliance with the TMDLs. The CTR sets an upper limit for hardness is 400 mg/l; the lower recommended limit is 25 mg/l.

summary document 45Newport Bay Toxic Pollutant TMDLs

The acute and chronic targets and associated loading capacities and TMDLs apply to base, small and medium flows. However, target s, loading capacities, an d TMDLs for the highest flow tier (>814 cfs) are based on acute standards only. As discussed above, this approach is
based on our review of flow records for San Di ego Creek to examine the duration of elevated flows and the frequency of chronic conditions (See TSD Part B for freshwater flow).

Newport Bay

For Upper and Lower Bay, including Rhine Channel, the loading capacities were calculated by multiplying the chronic numeric target by the volume of water in the Bay, accounting for water exchange ra tes between Newport Bay and th e Pacific Ocean. The loading capacities are based on the saltwater dissolved metals targets (Table 5-3). The mass-based loading capacity for all of Newpor t Bay is shown in Table 5-5a. (A complete description of this calculation is presented in TSD – Part E.)

The rationale for setting mass-based meta ls TMDLs and allocations is to address observed sediment toxicity in all areas of Newport Bay. Over longer time frames, cumulative metals discharges are of concern in embaymen ts and possibly fresh water waterbodies because metals may associate with sediment and accumu late in bottom sediments, where they may contribute to sediment toxicity a nd associated ecosystem impacts. The alternate metals sediment targets (Table 5-3) will help to evaluate acceptable conditions fo r benthic organisms.

Mass based allocations set a definitive upper limit on the amount of each metal allowed to be discharged from San Diego Creek into Newport Bay, which w ould probably be most effective in addressing long term sediment toxic ity concerns. Loading contributions from San Diego Creek and Santa Ana Delhi Channel were calculated by multiplying the chronic numeric target for base, small and medium flow tiers and acute target for large flow tier (see Table 5-1) by the mean annual water flow volume associated with each tier to yield an allowable mass load for each flow tier. This approach is similar to that presented in the Se TMDLs. (An example of this calculation for dissolved coppe r is provided in the TSD – Part E.) The sum of all four tiers yields the upper limit to the mass-based loading capacity for San Diego Creek (Table 5-5a).

Table 5-5a. Mass-based dissolved me tal loading capacity for Newport Bay
Dissolved Metal Upper and Lower Bay including Rhine Channel

Dissolved load (lbs/yr)
Cd 14,753*
Cu 11,646
Pb 27,136
Zn 285,340

* Cd load applies to Upper Bay only, where volume of Upper Bay is approximately 40% of the total volume of Newport Bay

To ensure that Newport Bay is protected fr om potential adverse effects of short term metals loading “spikes”, the loading capacities a nd associated TMDLs for Newport Bay are also
defined in terms of the concentration-based wate r quality standards for the Bay. In the absence of this complementary approach, it would be possible for the Bay to meet the annual loadingsummary document 46Newport Bay Toxic Pollutant TMDLs

based TMDL and still exceed water quality standa rds on a short term basis. The concentration
based TMDLs are listed in Table 5.5b

Table 5.5b Concentration-based dissolved metal loading capacity for Newport Bay

Metal Dissolved saltwater acute loading capcity (ug/L) Dissolved saltwater chronic loading capacity (ug/L)
Cd* 42 9.3
Cu 4.8 3.1
Pb 210 8.1
Zn 90 81



### TMDLs and Allocations

The freshwater dissolved meta ls TMDLs are concentration–b ased; whereas the saltwater
TMDLs are both mass-based and concentration- based. The TMDLs and allocations may be expressed in terms of the following general equation:

TMDL = Σ (wasteload allocations for point sources) + Σ (load allocations from non-point sources and background) + Margin of Safety

San Diego Creek

As discussed in the loadi ng capacity section, EPA is e xpressing the San Diego Creek
metals TMDLs on a concentration basis. The freshwater allocations are equivalent to the concentration-based targets, re duced by 20% to provide the marg in of safety discussed below (see Table 5-6 for freshwater TMDLs and allocations ). These allocations apply to all freshwater discharges to San Diego Creek, Santa Ana-Delhi Channel, Big Canyon Channel, East Costa Mesa Channel and other drainage s. This includes discharges from agricultural, urban and residential lands, including flows from the storm water systems. These allocations would apply at all times of the year. Because flow tiers for the freshwater channels other than San Diego Creek were not specifically calculated, it is a ssumed that the same TMDLs applicable to San Diego Creek during different flow conditions apply to the other cha nnels at the same times. For example, when flow is 50 cfs in San Diego Creek, the “small flows” TMDLs and allocations listed in Table 5-6 apply in all the other freshw ater channels in addi tion to San Diego Creek.

Table 5-6. Metals WLAs, and LAs in (ug/L) (based on flow tiers for San Diego Creek)

Dissolved
Metal Base Flows (<20 cfs) hardness @ 400 mg/L Small Flows (21 - 181 cfs) hardness @ 322 mg/L Medium Flows (182 -815 cfs) hardness @ 236 mg/L Large Flows (>815 cfs) @ 197 mg/L Acute Chronic Acute Chronic Acute Chronic Acute
Cd 19.1 6.2 15.1 5.3 10.8 4.2 8.9
Cu 50 29.3 40 24.3 30.2 18.7 25.5
Pb 281 10.9 224 8.8 162 6.3 134
Zn 379 382 316 318 243 244 208
Values are 80% of freshwater numeric targets in Table 5-2 Note: actual ambient hardness must be determined fo r each monitoring sample re gardless of which flow
condition exists

summary document 47Newport Bay Toxic Pollutant TMDLs

The wasteload allocations apply to the following NPDES discharges:

• Orange County Stormwater

• CalTrans

• Other NPDES Discharges (see Section II, p. 19 for description of this allocation category)

The load allocations apply to the following source categories:

• Agricultural runoff (including nurseries)

• Air deposition

• Other sources (includes open space runo ff, background, and undefined sources).

Newport Bay

Table 5-7a presents the mass based TMDLs and allocations for dissolved metals in Newport Bay. These allocations apply to the water column in Upper Newport Bay (defined from San Diego Creek at Jamboree Rd. down to Pacifi c Coast Highway Bridge), Lower Newport Bay (defined from PCH Bridge to the Newport Jett y) and to Rhine Channel (confined by line drawn
from 20 th St. across to Lido Beach St. to channel end) . These allocations apply to the receiving waters of Newport Bay at all times of the year , regardless of freshwater flow from San Diego Creek, Santa Ana-Delhi, Costa Mesa Channel and other tribut aries into Newport Bay.

Several methods were used to determine a llocations. First, because NPDES boatyard permittees are not authorized to discharge into salt waters of Newport Bay, the wasteload allocation for boatyards is zero. Second, air de position and undefined sources (background from medium and large storm runoff and ambient seawater contributions ) were assigned mass loadings based on existing loadi ng since reductions were not exp ected. Third, agriculture runoff was also assigned an explicit mass loading of one -half the total annual estimated loads based on the assumption that erosion control planned under the sediment TMDL implementation plan would result in approximately a 50% reduction in erosion-related metals loading, and that the
small amount of metals load associated with agricultural chemical use could be reduced through use of best management practices (EPA, 1993). Th e allocations for the remaining sources (urban stormwater, CalTrans, other NPDES, and boats (for copper and zinc)) were based on best professional judgement, as discussed below, b ecause insufficient data were available to accurately estimate their relative co ntributions to existing loads. The allocation for runoff from
the watershed from urban stormwater and CalTra ns facilities and discha rges from the other NPDES permittee category is based on the assump tion that approximately half the metals loading can be reduced through use of availabl e management practices (EPA, 1993). The runoff
allocation is divided between th e Orange County stormwater permit, CalTrans permit, and other NPDES facility category based on the relative proportions of waters hed land area under the jurisdiction of these three permits. The remaini ng allocation for boats represents a reduction in metals loadings from boats of greater than 80%, based on the assumption that changes in boat paint usage and maintenance practices could subs tantially reduce the dire ct loading of copper (and potentially zinc) into Bay waters (EPA 1993) . Table 5-7b presents the concentration-based allocations for Newport Bay.

summary document 48Newport Bay Toxic Pollutant TMDLs

Table 5-7a. Mass-based Allocation Sc heme for Metals in Newport Bay Category Type Copper Zinc Lead Cadmium*
WLA Urban runoff 3,043 174,057 17,638 9,589
CalTrans 423 22,866 2,171 1,185 Boatyards 0 0 0 0

Other NPDES permittees 190 17,160 1,154 596

Sub-total 3,656 lbs/yr 21 4,083 lbs/yr 20,963 lbs/yr 11,370 lbs/yr

LA Ag runoff 215 114 0 0
Boats 4,542 1,056 0 0 Air deposition 101 606 68 4 Undefined (open space, existing sed.) 803 11,414 678 428

Sub-total 5,661 lbs/yr 13,189 lb s/yr 746 lbs/yr 431 lbs/yr

MOS 2,329 lbs/yr 57,068 lbs/yr 5,427 lbs/yr 2,951 lbs/yr

Total
TMDL 11,646 lbs/yr 285,340 lbs/yr 27,136 lbs/yr 14,753 lbs/yr

*values apply to Upper Bay only (estimated as 40% of Newport Bay volume)

Table 5.7b Concentration-based dissolved metal TMDLs, WLAs, and LAs for Newport Bay

Metal Dissolved saltwater acute TMDLs and allocations (ug/L) Dissolved saltwater chronic TMDLs and allocations (ug/L)
Cd* 42 9.3
Cu 4.8 3.1
Pb 210 8.1
Zn 90 81

The concentration based WLAs and LAs apply only to the sour ces which discharge directly to the Bay, including st ormwater discharges from stormd rains directly to Bay segments (such as Costa Mesa Channel and Santa Ana Delhi Channel) and metals loading associated with
boats. The concentration-based WLAs and LAs for San Diego Creek and the other fresh water
tributaries will address short term metals concentr ations associated with discharges to the fresh water system.



### Seasonal Variations/Critical Conditions

These TMDLs rely on careful analysis of the full range of potentia l flow conditions to
address seasonal variations and crit ical conditions in loads and flow s. In general, base and low flows do not present conditions within San Diego Creek that result in either exceedances of numeric targets. This is due to higher hardne ss levels during low flows that mitigate metals toxicity through competitive binding by calcium and magnesium ions present in freshwater.

Wet weather conditions, which may occur at any time of the year, yield medium and large flows and a range of hardness values. Hi gh flows are more likely to produce both low

summary document 49Newport Bay Toxic Pollutant TMDLs

hardness and higher metal levels; these conditions are the biggest threat to aquatic organisms in San Diego Creek and its tributaries. For New port Bay, the TMDLs address long term metals
accumulations which are associated with metals-cau sed sediment toxicity measured in the Bay. Therefore, there is no single season or critical season of greatest concern for metals loadings and effects in Newport Bay. The saltwater allocations apply during all seasons , regardless of flow.

For both San Diego Creek and Newport Bay, th e approach of setting concentration based TMDLs and allocations based on chronic and acute targets helps address and mitigate any short term effect associated with brief periods of high metals loading.



### Margin of Safety

EPA has applied a 20% explicit margin of safe ty to the dissolved metals TMDLs for both
freshwater and saltwater bodies of Newport Bay watershed. This explicit margin of safety is intended to account for uncertainty concerning tota l (particulate and dissol ved) metal loads into San Diego Creek which are transported downstrea m and deposit in the sediments of Upper and Lower Bay, including Rhine Channel. These meta ls TMDLs address aquatic life toxicity due to concentrations in the dissolved fraction; this is consistent with current regulatory status for metals as defined by CTR (USEPA 2000a). In r ecognition of sediment toxicity in Newport Bay correlated to elevated metals, we have selected the 20% margin of safety based on the default total/dissolved metal translator provided in CTR. Our estimates of site-specific total/dissolved translator values are fairly close to the CTR value. It is reasonable to assume that reductions in the particulate metal load will achieve the concentration-based dissolved metal targets.

In addition to the explicit margin of safe ty, conservative assumptions were used in applying the numeric targets with in the watershed. These conservative assumptions provide an implicit margin of safety to ensure that TMDLs are set at levels that will attain applicable standards and prot ect aquatic life.

1. No adjustment or lowering has been made to address mixing and dilution within the drainage channels contributing to San Diego Creek. Also, there has been no consideration of precipitation (f orming particulate metals forms) of dissolved metals as
freshwater mixes with saltwater.

2. Chemical speciation has not been included w ithin calculations of loading capacity nor allocations. Aquatic chemists believe the trul y bioavailable metal fraction (free metal ion concentration) is much lower (at least 10 times) than dissolved metal concentration. This has been reported for Cd, Pb, Cu and Zn w ithin freshwater and saltwater systems (Buffle 1988, Bruland 1991, Sunda et al. 1987).

3. Setting both acute and chroni c-based TMDLs and allocations for San Diego Creek and Newport Bay helps ensue that short-term toxi c effects are not allow to occur even if longer term mass loading-based TMDLs and allo cations are met. This approach helps ensure that water quality standard s will be met throughout the year.

summary document 50Newport Bay Toxic Pollutant TMDLs



## VI. Organochlorine TMDLs

TMDLs are being established for chlordane, tota l DDT and total PCBs in all waterbodies: San Diego Creek, Upper Bay, Lower Bay and Rh ine Channel. Dieldrin TMDLs are being established for San Diego Creek, Lower Bay and Rhine Channel. A TMDL for toxaphene is being established for San Diego Creek only. Th e term “organochlorin e compounds” includes all of these pollutants and the phras e “organochlorine (OC) pesticides” refers to DDT, chlordane, dieldrin and toxaphene. Additional information on the source analysis , modeling approach a nd relevant monitoring results for these TMDLs is provided in Technical Support Document – Part F.



### Problem Statement

Use of these pollutants has been banned b ecause of potential harm to human health and/or wildlife. However, many of the environm ental concerns associated with their use and ultimate transport to the environment are directly re lated to their ability to persist in water, soil, and biological tissue for long pe riods of time after their introd uction to the environment.

Monitoring results show exceedances of EPA and State fish tissue screening values, which indicate the applicable narrative water quality standards are not being met. Specifically, toxaphene exceedances (87%, n=15) of the OEH HA tissue screening value occur only in San Diego Creek (TSM). Tissue exceedances have also occurred for Chlordane (40%), Dieldrin (93%), total DDT (93%), and total PCBs (67%) in San Diego Creek (n= 15 for all, TSM).
Similar elevated fish tissue concentrations in dicate bioaccumulation for Chlordane, Dieldrin,
total DDT and total PCBs in all saltwater bodies of Newport Bay (except for dieldrin in Upper Bay). Conclusions for Newport Bay are based on finfish and shellfish tissue results from several monitoring efforts (SMW, TSM, CF CS and SCCWRP databases, see Table 2-2). A review of tissue data for a 20 year period i ndicates that fish tissue concentr ations are declining for the OC compounds, yet exceedances of OEHHA tissue screeni ng values are still oc curring. Freshwater
and saltwater tissue concentrations show declinin g trends, with higher leve ls generally occurring in San Diego Creek than in Newport Bay. The sedi ment data did not exhibit clear trends, rather erratic spikes, which is common for this heterogeneous media.



### Numeric Targets

As discussed in Section II, EPA evaluated the applicable water quality criteria and sediment and tissue screening levels to determ ine the appropriate numeric targets for these organochlorine TMDLs. We have prioritized sediment quality guideline s over tissue screening
values and water column criteria. This de cision is based on the fo llowing factors: 1) these pollutants are directly associated with sediments (i.e., fine particulate matter); 2) sediments are the transport mechanism for these organochlorine compounds from freshwaters to salt waters; 3) limited water column data are available to adequately describe the past or current
conditions 4) attainment of the sediment targets will be protective of the water column criteria and tissue screening values.

summary document 51Newport Bay Toxic Pollutant TMDLs

The use of sediment criteria in this analys is yields an environmentally conservative interpretation of water quality criteria, includ ing the narrative water quality objectives in the Regional Board Basin Plan (1995).

The numeric targets for freshwater and saltwater systems for chlordane, dieldrin, DDT, PCBs and toxaphene, are shown in Table 6-1a an d 6-1b. The primary target value is based on sediment levels, and the alternate target s are provided for fish and shellfish tissues and for water column concentrations in freshwater. The specific numeric values for sediment targets were selected from NOAA Sediment Screening Quick Reference Tables (SQuiRTs) (Buchman 1999). By selecting sediment targets, EPA will addre ss protection of benthic organisms as well as bioaccumulation of these organochlorine compounds into tissues of higher organisms such as fish, wildlife predators and humans. Sediment targets are used for TMDL development except where sediment data were not available; e.g., toxaphene in San Diego Creek. The alternate targets – fish tissue screening values from OE HHA and water column objectives from the CTR– are included in this TMDL report as means of gauging improvement in the water quality and progress towards achievement of the TMDL, and to assist in assessing the accuracy of the analysis supporting the TMDLs.

Table 6-1a. Numeric targets for orga nochlorine compounds for all waterbodies. Waterbody Pollutant Sediment target ¥ (ug/dry kg or ppm) Fish tissue target# (ug/kg wet or ppb) San Diego Creek and Chlordane 4.5 30
tributaries Dieldrin 2.85 2.0
Total DDT 6.98 100
Total PCBs 34.1 20 Toxaphene 0.1* 30

Upper and Lower Newport Chlordane 2.26 30 Bay, and Rhine Channel Dieldrin 0.72 2.0
Total DDT 3.89 100
Total PCBs 21.5 30 *this value assumes 1% total organic carbon in sediment sample

¥ sediment targets equivalent to thre shold effect levels (TEL) from Buchman 1999, except toxaphene from NY Dept. Environmental Conservation #all tissue targets from OEHHA

Numeric targets for water column concentra tions are provided in Table 6-1b based on CTR criteria. These concentrations apply to freshwater bodies (USEPA 2001a); numeric objectives are not available for seve ral of the pollutants in saltwater. We used these targets when modeling the maximum allowable concentrations for water-associated loads from particulate pollutants. (See modeling a nd analysis section). Table 6-1b. Freshwater column target values for organochlorine compounds. Pollutant CMC (acute) CCC (chronic) ( μ g/L) ( μ g/L)

PCBs

-- 0.014
DDT * 1.1 0.001 Chlordane 2.4 0.0043
Dieldrin 0.24 0.056 Toxaphene 0.73 0.0002
* DDT value cited for 4,4’ DDT, but value will apply to one one isomer or sum of all isomers detected

summary document 52Newport Bay Toxic Pollutant TMDLs



### Source Analysis

Except for PCBs and possibly small amounts of DDT, the pollutants addressed in this TMDL are no longer believed to be discharged in the watershed except in association with erosion of sediments to which these pollutant s may have adhered in the past. The source analysis is therefore primarily a qualitative asse ssment. The assessment is based on reviews of available information on the physical and chemi cal properties of each chemical, the expected uses of each, the likely locations of use, and av ailable monitoring data that characterizes current conditions in the environment. A wide range of information was evaluated to identify potential sources and to characterize contributions, includ ing monitoring data, data from national, state and county program databases, and sc ientific literature. More details on the efforts to identify and characterize potential sources of organochlorine compounds are provided in the Technical Support Document – Part F.

Available data and analyses i ndicate that there is an existi ng “reservoir” ofhistoricallydeposited organochlorine pollutant s in Newport Bay sediment, to which continuing relatively low levels of ongoing pollutant loads are contribu ting from the watershed. The main source of continuing loadings of organochlorine compounds in the Newport Bay watershed is estimated to be erosion of surface soils or in-stream sediments to which these pollutants have adsorbed (binded). Sediment-adsorbed pollutants enter Newport Bay from San Diego Creek (88%) and various smaller tributaries and local drainages (1 2%). The sediment load is then distributed throughout Newport Bay via internal circulation patterns under a va riety of flow conditions. In preliminary results from one sampling event of sub-surface waters in Lower Bay, SCCWRP (2001a) reported detections of total PCBs a nd DDT. At the Turning Basin, these compounds were associated with particulate matter (P CBs = 8.86 ug/kg dry; DDT = 15.3 ug/kg dry) and in the dissolved phase (PCBs = 0.15 ng/L; DDT 0.43 ng/L). Dieldrin and Chlordane were not reported.

These organochlorine compounds may also ex ist in groundwater (due to percolation), may transport via volatilization (f rom surface soils or water surf ace) and as implied above they may become resuspended into the water colu mn via physical proce sses in water bodies.
Insufficient data were available to estimate the loads from thes e sources. Ground water-related loading is expected to be minor because only a small proportion of organochlorine pollutant loads generally occurs in dissolved form. On the other hand, resuspension of sediments to which organochlorine pollutants have adhered is likely to be a more important “loading” source.

Organochlorine (OC) pesticides

Because of the legacy nature of the sources of the OC pesticides, assessment of possible nonpoint sources of these types of pollutants has been based on a review of available monitoring data, historical land use practices , literature reviews, and anec dotal information. One of the major routes for the OC compounds to enter Newport Bay and its tributaries is believed to be runoff and erosion processes. Masters and Inma n (2000) have examined fluvial transport of DDT and other legacy pesticid es in Upper Newport Bay; th ey hypothesize that historic agricultural and urban a pplications of these compounds are the primary upstream sources. In general, these runoff and erosion processes have the ability to pick up and transport these OC

summary document 53Newport Bay Toxic Pollutant TMDLs

pesticides and deposit them in a different location in the watershed, to stre am systems, or to the Bay. The amount of transport and the locations of deposition depend on many factors, including the presence of the pollutant and the intensity and duration of the pr ecipitation event, which drives stream flow velocity and possibly direct ion. Because organochlorine residuals from past applications still remain in soils , the potential still exists for th ese chemicals (and their degraded metabolites) to be transported into water bodies during runoff-producing rainfall events. Insufficient information exists on the specific lo cation and actual magnitude of these sources to support precise loading estimates; therefore, we inferred existing loadings based on limited data and we estimated the pollutant distributions amongst many diffuse sources. No local “hot spots”-specific locations with highly elevated levels of OC pesticides-- were identified.

The only potentially active application of any of the OC pesticides identified is the application of Dicofol, a register ed pesticide that may contains small amounts of DDT (i.e., up to .015% based on its registered formulation). Th e actual DDT content of Dicofol, if any, is unknown. The DPR pesticide use database indicates that Dicofol (trade name “Kelthane”) was recently applied to agricultura l fields within the Newport Ba y watershed (502 lbs. in 1998 and 470 lbs. in 1999). Relative to other sources of DDT (i.e., residuals in soils and aquatic sediments), Dicofol is not estimated to be a significant source of DDT to Newport Bay. However, because DDT in low concentrations may pose an continuing ecological concern, it may be appropriate to further investigate and reduce possible runoff of DDT associated with
Dicofol.

Polychlorinated biphenyls (PCBs)

Electrical transformers are the most common use of PCBs. Existing PCB projects such as the Hudson River project in New York and the Housatonic River proj ect in Massachusetts have found that historical discha rges caused sediment contamina tion and that the contaminated
soils tend to collect in slow ri ver stretches or reservoirs (GE 1999). The contaminated soils remain there until they are dredged or dislodged by storms. Based on our review of limited information about PCB spills and waste sites c ontaining PCBs, we hypothesi ze that accidental PCB spills, which were most likely to have occurred at the El Toro and Tustin Air Stations as well as other hazardous waste sites, are the most likely historical load ing source of PCBs. Insufficient information exists on the specific lo cation and actual magnitude of these sources, thus we inferred existing loadings based on limited data and we estimated the pollutant distributions amongst many diffuse sources.



### Modeling and Analysis

This section describes the methods used to de termine the loading capacity and to estimate the existing loads for each organochlorine contam inant with respect to each waterbody. The modeling approach and various re sources utilized to complete these tasks are outlined here, although more details, such as equations and specific values, are provided in the Technical Support Document – Part F. To the extent possible, we used hydrologic and modeling information previously compiled by Resource Management Associates (RMA 1997, 1998, 1999) for the U.S. Army Corp of Engineers (ACO E). This model provides sediment deposition information used to determine both loading capacities and estimate existing loads for (for the Upper and Lower Bay, including Rhine Channel. RMA model calibration results were utilized because these results incorporate circulation patterns, spatial dist ribution and net settling rates for

summary document 54Newport Bay Toxic Pollutant TMDLs

each area of Newport Bay. These RMA results were generated using a wide spectrum of flow rates from San Diego Creek addressing a 12 year time span (1985 to 1997). Thus the RMA model has implicitly addressed sediment transpor t and resuspension in Newport Bay as well as dry and wet weather conditions and fl ow rates in San Diego Creek.

Within San Diego Creek, the RMA model does not provide more speci fic data such as spatial distribution of sediments, so sediment deposition and the corresponding pollutant load
must be estimated via stream flow rates. EPA us ed nearly 20 water years of flow records for San Diego Creek. The time span of daily flow ra tes covers water years 1977/78 and 1984/85 - 00/01.
This is discussed more in TSD Part B – Flow a nd consistent with flow records used in Se and dissolved metals TMDLs. For the OC TMDLS, three flow tiers were used -- low flow (0 to 181 cfs), medium (between 181 and 814 cfs) and hi gh flow (>814 cfs). This was designed to represent conditions during dry w eather and very light rains (low flow events), intermediate storms (medium flows) and those large storms (h igh flows) when extensive sediment transport occurs. Pollutants associated with fine part icles (especially clay) and dissolved phase are assumed present in all three flow tiers.

Loading capacity

San Diego Creek For the listed OC pollutants in San Diego Creek the loading capaci ties were calculated based on pollutant contributions from water colu mn and sediments. The sediment associated loading capacity was determined from target sediment concentrations and sediment load estimates, which were based on regression result s presented in RMA model (1997) to link flow
rates with sediment loads. We estimated th e associated water column loading capacity by backcalculating, from sediment loads to particulat e concentrations and dissolved concentrations, using partition coefficients. Where appropriate, these water column derived loads were constrained by chronic water target s for low and medium flows and ac ute targets for large flows. The sum of the allowable loads in particulate fo rm and dissolved form represents the loading capacity in San Diego Creek. The loading capaci ties are presented as long term annual loading estimates consistent with the pa tterns of sediment deposition in the system. Loading capacities for San Diego Creek are pr esented in Table 6-2.

Newport Bay

The loading capacity for Newport Bay relied on RMA (1998) sediment deposition budget and bottom sediment conditions with target co ncentrations. The Bay was sub-divided into
discrete areas for which indivi dual loading capacities were calc ulated and summed to provide loading capacities for each water body of the Ba y (Upper, Lower and Rhine). To determine the particulate associated load, several factors were used and included: saltwater sediment target, net sediment deposition (volume), porosity, a nd sediment density. Sediment volume is converted to dry weight by an estimated por osity (0.65). The net loading capacities are presented as average mass per year for each water body to reflect the long-term accumulation patterns associated with sediment and pollu tant accumulation in Newport Bay. Loading capacities for Newport Bay are presented in Table 6-3.

summary document 55Newport Bay Toxic Pollutant TMDLs

Existing Loads

San Diego Creek A slightly different approach was required to estimate the existing loading to San Diego Creek. Due to incomplete sediment monitoring data for all organochlorine pollutants in San Diego Creek, we used recent fish tissue results (TSM data from 1998) to help estimate water and (indirectly) sediment loads. Water column a ssociated loads were back calculated by using pollutant- and fish species- specif ic bioconcentration factors (BCF s). The particulate load was
estimated from these water column derived values using partition coefficients. The sum of the particulate and water column associated loads yi elds the estimated existing loads for San Diego
Creek based on the most reliable and current data for these hydrophobic compounds. Existing loading estimates for San Diego Creek are presented in Tables 6-5.

Newport Bay The methods used to estimate existing load s in Newport Bay were similar to those described earlier for loading capac ity in Newport Bay. Fortunatel y, more monitoring data exists for Newport Bay and, in particular recent sediment data (OCPFRD 1999/00 and SCCWRP 2001a) was maximized to give more representative or current conditions in each portion of the bay. These monitoring results were used with the RMA sediment deposition budget to yield the existing pollutant loads. Resuspension and re circulation of sediments, along with the water associated load was implicitly included sin ce these conditions were included in the RMA approach for Newport Bay. (Upper and Lower Ba y existing loads represent the sum of several individual areas, as defined in Appendix Table 3 in TSD – Part F.) The net pollutant existing loading estimates for Newport Bay segments are presented in Tables 6-6 to 6-8.



### Loading Capacity/Linkage Analysis

The loading capacity for each pollutant was calculated for San Diego Creek, Upper and Lower Bay, and Rhine Channel. The loading capacity for each water body was derived as described above and in the Technical Support Document – Part F. The loading capacity was
determined to define the maximum amount of loading which could occu r and still result in attainment of the sediment target s, and at the same time, not ex ceed water quality targets. The model takes into consideration such factors as the particulate and dissolved contributions and flow rates in San Diego Creek. In Newport Ba y, the loading capacities were determined via the RMA model and target sediment concentrations . The OC compound loading capacities for San Diego Creek and Newport Bay are listed in Tables 6-2 and 6-3, respectively.

The loading capacity was determined to define the maximum amount of loading which
could occur and still resu lt in attainment of the sediment targ ets. The model links estimates of ongoing pollutant contributions from the watershed with existing pollutant concentrations in the bottom sediments and predicts the cumulative effects in terms of future pollutant concentrations
in the bottom sediments and associated trends. The model takes into consideration such factors as the existing water column concentrations (e ither observed or calculated based on fish or mussel tissue concentrations), da ta and modeling of sediment deposition into the water bodies, decay rate for a pollutant in the water column, thickness of the water column and active sediment layer, sediment resuspension rate s, and sediment burial rates.

summary document 56Newport Bay Toxic Pollutant TMDLs

Table 6-2. Loading Capacity for San Diego Creek

Pollutant Name Sediment Target
Concentration

(ug/kg dry) Loading capacity (g/year)
Chlordane 4.5 314.7
Dieldrin 2.85 261.5
DDT 6.98 432.6
PCBs 34.1 2226 Toxaphene 0.1 8.9

Table 6-3. Estimated Loading Capacity for Newport Bay

Waterbody Sediment Target Concentration (ug/kg dry) Loading Capacity (g/year)

Chlordane Dieldrin DDT PCBs Chlordane Dieldrin DDT PCBs Upper Bay 2.26 0.71 3.89 21.5 160.4 N/A 276.5 1528.2 Lower Bay * 2.26 0.71 3.89 21.5 59.2 18.6 101.85 562.9
Rhine Channel 2.26 0.71 3.89 21.5 1.7 0.53 2.92 16.2 (This table is summary of information pr esented in Table F-4 in TSD—Part F.)



### TMDLs and Allocations

For these organochlorine TMDLs, we have expressed the TMDLs and allocations in mass-based units (grams per year) for each waterbody. For each organochlorine compound, the loading capacity in each waterbody is equal to th e sum of allocations and an explicit margin of safety. Identification of the TMDL is based on a comparison of the ex isting loading with the loading capacity. In situations where existing loadings are less than the loading capacity, the TMDLs and allocations are set at the existing load ing levels in order to ensure that the TMDL targets are eventually met, and to ensure that pol lutant levels in the se diments do not increase in the future (defined as Condition 1 in Table 6-4 below). In situ ations where existing loads are greater than the loading capacity, the TMDLs a nd allocations are set equal to the loading capacity (after subtracting the expl icit margin of safety). This situation is defined as Condition 2
in Table 6-4 below. Table 6-4 identifies the de cision rules applied for each water segment and OC pollutant to define the individual TMDLs.

Table 6-4. Decision rules applied to define TMDLs based on condition applicable to each waterbody/pollutant combination.

Pollutant San Diego Creek Upper Newport Bay Lower Newport Bay Rhine Channel

Chlordane
Dieldrin
DDT
PCBs Toxaphene Condition 2 Condition 2
Condition 2
Condition 1 Condition 2 Conditio n 2
NL Condition 2 Condition 1
NL Condition 1 Condition 1
Condition 2
Condition 1
NL Condition 1 Condition 2
Condition 2
Condition 2
NL NL: Not listed for this pollutant

summary document 57Newport Bay Toxic Pollutant TMDLs

Tables 6-5 through 6-8 summari ze the existing loads, the estimated loading capacity, and
the total allocation for each pollutant with respect to each waterbody. For most pollutant/waterbody combinations, th e loading capacity value is le ss than the existing load and thus the loading capacity determines the TMDL, as seen in Table 6-4. A 10% margin of safety was subtracted from the loading capacity or existing load, whichever is smaller value.

Table 6-5. Summary of San Diego Creek Loadings and TMDL

Pollutant Existing Load 1 Loading Capacity 2 TMDL Margin of Safety (g/year) (g/year) (g/year) (g/year)
Chlordane 615.7 314.7 314.7 31.5
Dieldrin 381.8 261.5 261.5 26.2
DDT 3733.8 432.6 432.6 43.3
PCBs 282.1 2226 282.1 28.2 Toxaphene 582.1 8.9 8.9 0.9

1 existing load based on observed data (OCPFRD 1999/00 and SCCWRP 2001a)

2 loading capacity based on sediment targets TMDL is lesser value of existing load or loading capacity; TMDL = Total allocation + MOS

Table 6-6. Summary of Upper Newport Bay Loadings and TMDL

Pollutant Existing Load 1 Loading Capacity 2 TMDL Margin of Safety (g/year) (g/year) (g/year) (g/year)
Chlordane 290.7 160.6 160.6 16.1
DDT 1080.2 276.5 276.5 27.7
PCBs 858.7 1528.2 858.7 85.9

1 existing load based on observed data (OCPFRD 1999/00 and SCCWRP 2001a)

2 loading capacity based on sediment targets TMDL is lesser value of existing load or loading capacity; TMDL = Total allocation + MOS

Table 6-7. Summary of Lower Newport Bay Loadings and TMDL

Pollutant Existing Load 1 Loading Capacity 2 TMDL Margin of Safety (g/year) (g/year) (g/year) (g/year)
Chlordane 50.2 59.2 50.2 5.0
Dieldrin 5.9 18.6 5.93 0.59
DDT 438.4 101.85 101.8 10.2
PCBs 409.8 562.95 409.8 41.0

1 existing load based on observed data (OCPFRD 1999/00 and SCCWRP 2001a)

2 loading capacity based on sediment targets TMDL is lesser value of existing load or loading capacity; TMDL = Total allocation + MOS

Table 6-8. Summary of Rhine Channel Loadings and TMDL

Pollutant Existing Load 1 Loading Capacity 2 TMDL Margin of Safety (g/year) (g/year) Allocation (g/year) (g/year)
Chlordane 0.33 1.70 0.33 0.3
Dieldrin 3.76 0.53 0.53 0.05
DDT 5.60 2.92 2.92 0.23
PCBs 70.0 16.2 16.2 1.6

1 existing load based on observed data (SCCWRP 2001a)

2 loading capacity based on sediment targets TMDL is lesser value of existing load or loading capacity; TMDL = Total allocation + MOS

summary document 58Newport Bay Toxic Pollutant TMDLs

Tables 6-9, 6-10, 6-11, and 6-12 present the a llocations for each OC pollutant-waterbody combination. The explicit margin of safety (10%) has been incl uded for clarification. Allocations were assigned for sources to San Diego Creek primarily in proportion to land use
area. The allocations to nurseries and other agriculture factor in two considerations. First, it was assumed that erosion control activities pursuan t to the sediment TMDL implementation plan would result in approximately a 50% reduction in OC pollutant r unoff from agriculture. In addition, these load allocations factor in a sma ll amount of possible DDT loading associated with possible DDT content in the pesticide Dicofol. The allocations are based on the assumption that only a small fraction of Dicofol reaches wate r ways, and that DDT loading to waterways
associated with Dicofol is a minor source. Unde fined sources (existing se diments, air deposition, possible groundwater contributions ) were assigned 3% based on ex isting loading estimates. The remaining portion (approximately 72%) was allotted to urban runoff. We estimate that erosion control practices will result in substantial reducti on in OC pollutant loadings associated with eroded sediments (EPA, 1993).

PCBs are particularly stable in aquatic se diment, so we assigned a slightly higher percentage of available alloca tions to undefined sources (10%) and 4% to other NPDES permits because PCBs chemicals are more likely to be pr esent in groundwater and therefore they may be contained in discharges of groundw ater clean up and treatment faci lities. This quantity may be modified in subsequent TMDL revisions after subsequent mon itoring with adequate sampling and analytical methods to verify PCB loads.

Table 6-9. Allocations for San Diego Creek watershed Category Type DDT (including Dicofol) Chlordane Dieldrin PCBs Toxaphene

WLA Urban runoff 302.8 220.3 183.4 177.7 6.2

Caltrans 8.7 6.3 5.2 42.3 0.2

Other
NPDES permittees 34.6 25.2 21.0 5.6 0.7

Sub-total 346.1 g/yr 25 1.8 g/yr 209.6 g/yr 225.6 g/yr 7.1 g/yr

LA Ag runoff 8.6 6.2 5.2 5.6 0.2
Undefined
* 34.6 25.2 21.0 22.6 0.7

Sub-total 43.2 g/yr 31 .4 g/yr 26.2 g/yr 28.2 g/yr 0.9 g/yr

MOS 43.3 g/yr 31.5 g/yr 26.2 g/yr 28.2 g/yr 0.9 g/yr

Total
TMDL 432.6 g/yr 314.7 g/yr 262.0 g/yr 282.0 g/yr 8.9 g/yr

*undefined = existing se diments + air deposition Total TMDL = WLA + LA + MOS

summary document 59Newport Bay Toxic Pollutant TMDLs

Table 6-10. Allocations for Upper Newport Bay Category Type DDT (including dicofol) Chlordane PCBs

WLA Urban runoff 207.4 120.5 609.7

CalTrans 2.8 1.6 8.6

Other NPDES permittees 2.8 1.6 8.6

Sub-total 212.9 g/yr 12 3.7 g/yr 626.9 g/yr

LA Ag runoff 2.8 1.6 8.6
Undefined* 33.2 19.3 137.4
Sub-total 35.9 g/yr 20 .9 g/yr 146.0 g/yr

MOS 27.7 g/yr 16.1 g/yr 85.9 g/yr

Total TMDL 276.5 g/yr 160.6 g/yr 858.7 g/yr *undefined = existing se diments + air deposition Total TMDL = WLA + LA + MOS

Table 6-11. Allocations for Lower Newport Bay Category Type DDT ( including
dicofol ) Chlordane Dieldrin PCBs

WLA Urban runoff 76.3 12.6 4.45 303.3

CalTrans 0 0 0 4.10

Other NPDES permittees 0 0 0 0

Sub-total 76.3 g/yr 12.6 g/yr 4.45 g/yr 304.7 g/yr

LA Ag runoff 0 0 0 0
Undefined* 15.3 32.6 0.89 61.5
Sub-total 15.3 g/yr 32.6 g/yr 0.89 g/yr 73.8 g/yr

MOS 10.2 g/yr 5.0 g/yr 0. 59 g/yr 41.0 g/yr

Total TMDL 101.8 g/yr 50.2 g/yr 5.93 g/yr 409.8 g/yr *undefined = existing se diments + air deposition Total TMDL = WLA + LA + MOS

Table 6-12. Allocations for Rhine Channel Category Type DDT Chlordane Dieldrin PCBs
WLA Urban runoff 0.7 0.1 0.13 4.1

Other NPDES permittees 0 0 0 0

Sub-total 0.7 g/yr 0.1 g/yr 0.13 g/yr 4.1 g/yr

LA Undefined* 1.9 0.21 0.34 10.5
Sub-total 1.9 g/yr 0.21 g/yr 0.34 g/yr 10.5 g/yr

MOS 0.3 g/yr 0.03 g/yr 0.05 g/yr 1.6 g/yr

Total TMDL 2.9 g/yr 0.33 g/yr 0.53 g/yr 16.2 g/yr *undefined = existing se diments + air deposition Total TMDL = WLA + LA + MOS

summary document 60Newport Bay Toxic Pollutant TMDLs


### Margin of Safety

EPA has applied an explicit 10% margin of sa fety to the loading capacity for these OC TMDLs. The specific mass-based margin of safety for each pollutant with respect to each waterbody is included in Tables 6-5, 6-6, 6-7 a nd 6-8. This margin of safety will provide additional protection for aquatic life, wildlife predators and human health. The explicit margin of safety is intended to address uncertainties in the relationship between OC pollutant loadings and environmental responses in di fferent areas of the watershed.

In addition, EPA is providing an implicit margin of safety through the selection of several conservative analysis approaches and assumptions used to calc ulate the TMDLs. Insufficient information is available to specifically quantify th e potential uncertainty associated with each of the assumptions used in the analysis. The para meters used in analysis were based on best
available information and were sele cted to be conservative (i.e., mo st protective) where possible. The use of an explicit margin of safety and recommendation of subseque nt follow-up monitoring is intended to ensure that numeric targets are su ccessfully achieved and th at the adequacy of the load allocation is evaluated over time. Key areas of uncertainty recogni zed in the margin of safety include the following:

• The loading capacity is calculated as a long- term annual average that results in meeting water quality standards (expresse d as sediment, water column , and/or tissue targets). Because the analysis is focused on long-term predictions, periodic fluctuations are not represented, and actual loading may differ in the short-term.

• Long-term sediment deposition patterns were used to calculate the total amount of sediment deposited in each region. This long-term average valu e does not represent
short-term or localized fluctuations in de position rates. Periodic accumulation or scouring could be significant du ring large storm events. This could result in higher or lower deposition rates than the predicte d sediment deposition and pollutant
concentrations.

• A constant sediment porosity value was used to calculate loads associated with deposited sediment. Sediment porosity values used in the model to estimate loading capacity for San Diego Creek and Newport Bay (0.65) were s lightly lower than thos e used to estimate historical loads (0.80) by RMA. No sedime nt consolidation was assumed. This resulted in a conservative assumption, since consolida tion would result in a lower porosity, which
would increase the load associ ated with deposited sediment.



### Seasonal variation/Critical conditions

OC pollutants are of potential concern in th e Newport Bay watershed due to possible long term loading and food chain bioaccumulation eff ects. There is no evidence of short term potential effects. However, pollutant loads a nd transport within the watershed may vary under
different flow and runoff conditions. Therefore the TMDLs consider seasonal variations in loads
and flows but are established in a manner wh ich accounts for the longer time horizon in which ecological effects may occur.

summary document 61Newport Bay Toxic Pollutant TMDLs

These TMDLs rely on careful analysis of the full range of potentia l flow conditions to
address seasonal variation and cri tical conditions in loads and flow s. The sediment transport and deposition within each waterbody is driven by th e velocity and sheer conditions of flow. The annual deposition is accounted for by using the sediment budget developed by RMA (1998) which incorporates various flow regimes thr oughout each year. The sediment budget (generated via model) represents various weather patt erns and flow conditions for 12 years.

Obviously the wet weather events, which ma y occur at any time of the year, produce
extensive sediment redistributi on and transport downstream. This would be considered the critical condition for loading. Ho wever, the effects of organoch lorine compounds are manifested over long time periods in response to bioaccumulati on in the food chain. Therefore, short term loading variations (within the time scale of wet and dry seasons each year) are not likely to cause significant variations in beneficial use effects.

summary document 62Newport Bay Toxic Pollutant TMDLs



## VII. Chromium and Mercury TMDLs

TMDLs are being established for chromium (Cr) and mercury (Hg) only for the Rhine Channel area of Lower Newport Bay. Additional information on the source analysis, modeling approach and relevant monitoring results for these TMDLs is provide d in Technical Support
Document—Part G.



### Problem Statement

Chromium —Chromium levels are elevated in Rh ine Channel mussel tissue samples over the tissue screening value (1.0 mg/kg wet), providing some evidence of chromium bioaccumulation (31%, n= 13). Chromium in Rhine Channel sediments are occasionally (8%, n= 13) above the sediment quality guideline (52 mg/kg dry).

Mercury —Mercury sediment concentrations in Rhine Channel are above sediment quality guidelines levels associated with negati ve impacts on benthic organisms in all samples tested (100%, n=6). The mercur y levels in the limited number of available samples were very high (e.g., recent data shows 5.3 ppm versus PEL le vel 0.7 ppm). Sediment toxicity has been consistently reported for Rhine Channel (BPTCP 1997, SCCWRP 2001a) although specific contaminants causing this toxicity have yet to be identified. Mussel tissue concentrations were not above the EPA tissue screening value (0.3 mg/kg wet methylmercury), and there is no current evidence that mercury has bioaccumulated to levels of concern.



### Numeric Targets

The numeric targets for chromium and mercur y in Rhine Channel are presented in Table 7-1. Two targets are provided for each chemical, one for sediment and one for tissue levels. The primary target value (sediment) is for TMDL deve lopment, whereas the alternate target (tissue) is designed to provide another means of asse ssing desired water quality conditions of Rhine
Channel.

There are several available scr eening values for mercury concentrations in sediment and fish tissue. For mercury in Rhine Channel, EPA applied the sediment numeric target, 0.13 mg/dry kg, as the most appropriate indicator of de sired water quality. This threshold effect level (TEL) is associated with no observed effect on benthic organisms as part of a study by MacDonald et al. 1996 and cite d in NOAA SQuiRTs (Buchman 1999). For comparison, the TEL value is much lower than the probable e ffects level (PEL = 0.696 mg/kg dry). The NOAA Effects Range-Low (ERL) value for mercury (ERL = 0.15 mg/kg dry) is close to the TEL target value. The alternate mercury num eric target is fish tissue (0.3 mg/kg wet methylmercury), from EPA proposed criteria and anal ysis provided in the USFWS Biological Opinion on the CTR (2000). This methylmercury target is designed to protect human health, yet it will also be effective at reducing impacts to wildli fe predators due to bioaccumulation.

EPA has also evaluated the available water qua lity criteria and levels for sediments and fish tissue to determine the appr opriate numeric target for chromium TMDL in Rhine Channel. EPA selected the sediment target (52 mg/kg dry, Buchman 1999) as the best available target to

summary document 63Newport Bay Toxic Pollutant TMDLs

protect both wildlife predators and benthic organisms. The alternat e chromium numeric target is fish tissue, 0.2 mg/kg wet (USFWS 2001). This fish tissue targ et is more stringent than the screening value used to evaluate State mussel watc h data in order to ensure protection of wildlife predators.

Table 7-1. Numeric target s for Chromium and Mercury in Rhine Channel. Waterbody Analyte Sediment target (mg/kg dry) Alternate Fish tissue target (mg/kg wet)
Rhine Channel
Rhine Channel Chromium (Cr) Mercury (Hg) 52 0.2
0.13 0.3*

* mercury tissue target is interpreted as 0.3 mg/kg wet methylmercury (EPA proposed criteria and USFWS 2000 )



### Source Analysis

Chromium (Cr)

Probable sources of chromium include the heavily contaminated sediments existing in Rhine Channel, previous discharges by metal pl ating facilities near Rhine Channel, historic deposits in the San Diego Creek watershed and atmospheric deposition. The Regional Board has documented two previous investigations of meta ls contamination at Newport Plating Company. These investigations found extremely high levels of chromium in sediment boring samples. Furthermore, a storm drain which drains runoff from the Newport Plating fac ility area discharges into Rhine Channel. This facility should be considered a potential s ource and should receive further investigation. More complete informati on on this source is presented in TSD part G – Chromium and Mercury.

Chromium may also be leaching from treated wood pylons in marine areas (Weis et al. 1991). Chromium is a naturally occurring element in many area, which can be found in volcanic dust and gases. However, chromium emissions can also come from commercial and industrial facilities, resulting in chromium discharges into the atmosphere. Currently, there is not sufficient information to estimate chromium atmospheric deposition rates in the Newport Bay watershed. The heavily contaminated sediments in Rhine Cha nnel are most likely associated with historic discharges from industrial facili ties around Rhine Channel, and thes e legacy sources are likely to be the largest current sources of chromium.

Mercury (Hg)

No investigation has been completed to e xplain elevated (total) mercury sediment
concentrations within Rhine Channel. Ora nge County Coastkeeper (1999) measured mercury concentrations in one sediment core and the results provide historical perspective. Total mercury
results show lowest concentrations at the core top (3.4 mg/kg dry) and hi ghest concentrations (11 mg/kg dry) at the bottom of th e one foot long core. Other researchers have found similar sediment concentrations in Rhine Channel; S CCWRP (2001a) reports 5. 3 mg/kg dry and BPTCP (1997) reports (8.7 mg/kg dry) for surface (top six in ches) sediment samples. Perhaps historical uses of ship anti-fouling paints which contained mercury are res ponsible for elevated sediment

summary document 64Newport Bay Toxic Pollutant TMDLs

levels based on previous activities in Rhine Ch annel (Regional Board 1998). Most likely the existing sediments are the largest sources of mercury in Rhine Channel.

Another potential source of mercury is the historical mining operations at the old Red Hill mine in the western part of San Diego Creek watershed (in Tustin). Historic records show mercury mining and processing occurred at Re d Hill mine between 1880 and 1939 (CA Division of Mines 1976). The total amount of mercury produ ced is not known. Mine shafts were sealed off in 1976, though some shafts are still open and can receive storm runoff. The Red Hill mine is upgradient of the Swamp of Frogs and mine draina ge may have flowed to Peters Canyon Wash. Other minor sources of Hg deposits have been ma pped in the area. At this time, no additional information is available to accurately assess wh ether mercury from this mining location reached the Rhine Channel area. However, available evidence for all of Newport Bay suggests that mercury levels in the rest of Newport Bay are not elevated. It is unlik ely that mercury loads from the upper watershed would have contributed to mercury contamination of Newport Bay sediments solely in the Rhine Channel area. Ther efore, it is unlikely that discharges from the Red Hill mine area are a principal cause of mercury contamination in Newport Bay.

Based on water column measurements (IRWD 1999) of dissolved mercury (Hg) and chromium (Cr), the loads from San Diego Creek can be estimated. Analysis of previous hydrologic modeling studies for Newport Bay (R MA 1997), yields estimates of sediment transported from San Diego Creek to be deposited in the Rhine Channel annually (approx 6%). Assuming that most of the chromium and merc ury is adsorbed by suspended sediment, the
estimated annual loads for chromi um and mercury from San Diego Creek that are delivered to Rhine Channel are about 46.9 kg/year and 0.054 kg/year, respectively (Table 7-2).

Table 7-2. Estimated Mercury and Ch romium Loads from San Diego Creek.

Pollutant
Name Year Water Column Conc. (ug/L) Estimated Load to Rhine Channel (kg/yr)
Cr ‘97-99 16 46.9 Hg ‘97-99 0.0186 0.054 (source: water (IRWD 1999); sediment budget (RMA 1997, 1998)

Atmospheric deposition probably is contri buting small amounts of mercury to the watershed; however, there are no likely nearby so urces upwind of the watershed. In any event, atmospheric deposition is estimated to contri bute very small amounts of mercury to Rhine
Channel relative to the amounts of mercury in existing Rhine sedi ments as well as freshwater sediment deposition. Ambient seawater concentrat ions of mercury are extremely low, typically less than 1 ng/L.

summary document 65Newport Bay Toxic Pollutant TMDLs



### Modeling

The approach to determining the loading capac ities for mercury and chromium is similar to the approach used for the organochlorine compounds (TSD – Part F) and was based on an understanding of the sources of these compounds (past, present, a nd future) and the transport and ultimate fate of these compounds in various en vironmental media. Based on a review of literature sources, it was observed that mercury and chromium environmental persistence and affinity for adsorbing to sediment and accumulati ng in biota generally limits their presence in the water column, at least relative to sediment and biota.

Previous modeling studies, completed by RMA for the U.S. Army Corps of Engineers (USACE) have examined the circ ulation patterns, and transport and deposition of sediments in Newport Bay (RMA 1997, 1998). By examining model calibration results (RMA 1997) for Newport Bay from 1985-1997, the sediment depos ition in Rhine Channel was estimated. The approach relies on the following key information: sediment deposition rates, deposition patterns (from the RMA (1997) model), pollu tant targets (used for loading capacity) (see TSD Table G-2) and sediment moritoring data for mercury and chro mium concentrations (used for existing loads) (see TSD, Table G-1 and Appendix 1) Historic pollutant loads to the bottom sediment were estimated by using observed pollutant concentrations in bottom sediments and net sedimentation rates. Sediment volume was converted to dry weight using an estima ted porosity of 0.65. The loading capacities were determined by “back-calcu lating” the allowable load from the selected sediment target (Table 7-3) and the a ssociated estimates of sediment loads.



### Loading Capacity/Linkage Analysis

Determination of loading capacity has been de scribed above and uses similar methods to those outlined for organochlorine TMDLs (see S ection VI of this document and TSD Part G for more comprehensive explanation. These TMDLs express the loading capacities, TMDLs, and allocations in mass loading terms for Rhine Ch annel. Because most of the mercury and
chromium loads are associated w ith contaminated sediments already in Rhine Channel, it will be necessary to remediate contaminated sediments in order to meet water quality standards and prevent adverse ecological effects.



### TMDL and Allocations

For these TMDLs, EPA has calculated both wastel oad allocations (WLA) and load allocations (LA). Inputs from historically deposited sedi ments and atmospheric deposition are included in load allocations. Ongoing sediment depositi on (containing mercury and chromium) from San Diego Creek is addressed as a wasteload allocatio n because this source is generally subject to coverage under the existing NPDES stormwater permit.

For mercury, the on-going load, which is associ ated principally with local contaminated sediments, is higher than the estimated loadi ng capacity. Therefore, the mercury TMDL (0.10 kg/yr )and associated allocations are set based on this loading ca pacity. The opposite is true for chromium, where the existing load is slightly lower than the loading capacity, therefore the

summary document 66Newport Bay Toxic Pollutant TMDLs

chromium TMDL is based on 33.1 kg/yr. The load ing capacities for chro mium and mercury are expressed as annual av erages (Table 7-3).

Table 7-3. Historical Loading and Estimated Loading Capacity for Rhine Channel
Pollutant existing conc. * Estimated Load Sediment Target Loading Capacity (kg/yr) (mg/kg dry) (kg/yr) (mg/kg dry)
Chromium 44 33.1 52 39.1 Mercury 5.8 4.36 0.13 0.10 * (SCCWRP 2001a)

The wasteload and load allocations (Table 7- 4) were calculated base d principally on best professional judgement . Most of the availabl e loads were assigned to sediments already in Rhine Channel, which are by the far the largest s ource. These allocations to existing sediments
reflect substantial reductions in sediment loads from in-Channel sources based on the expected
effectiveness of remedial acti ons identified in the 1997 remedial action plan. The remaining available load was allocated roughly in propor tion to the land areas associated with the remaining source categories after allocating 5% of available loads for undefined sources. Further investigation of Newport Plating facility may warrant revision of such a high allocation to
sediments in Rhine Channel for Chromium.

Table 7-4. Rhine Channel Wasteload and Load Allocations (kg/yr) a nd % of total loads Mercury (Hg) Chromium (Cr)
Wasteload allocations
Stormwater 0.0171 (19%) 5.66 (19%)
Caltrans 0.0027 (3%) 0.89 (3%) Boat yards 0 0 Other NPDES permittees 0.0027 (3%) 0.89 (3%)

Load allocations : Existing sediment 0.063 (70%) 20.85 (70%)
Undefined sources: air 0.0045 (5%) 1.49 (5%) deposition, ambient seawater

0.01 3.30 Margin of safety

TMDL 0.1 kg/yr 33.1 kg/yr

TMDL = WLA + LA + MOS



### Margin of Safety

EPA has applied an explicit 10% margin of sa fety to the loading capacity for these TMDLs. The specific mass-based quantity for each pollutant with resp ect to each waterbody is included in Table 7-5. This margin of safety will provide additional protection for aquatic life, wildlife predators and human health.

A number of assumptions were used in the derivation of each TMDL. Insufficient information is available to quantify the potenti al uncertainty associated with each of the assumptions used in the analysis. The parameters used in analys is were based on best available
information and were selected to be conservative (i.e., most protective) where possible. The use of an explicit margin of safety and subsequent follow-up monitoring is intended to ensure that

summary document 67Newport Bay Toxic Pollutant TMDLs

numeric targets are successfully achieved and that the adequacy of the load allocation is evaluated over time. Key areas of uncertainty recognized in the margin of safety include the following:

• The loading capacity is calculated as a long- term annual average that results in meeting water quality standards (expresse d as sediment, and tissue targ ets). Because the analysis is focused on long-term predictions, periodic fluctuations are not re presented, and actual loading may differ in the short-term.

• Long-term sediment deposition patterns were used to calculate the total amount of sediment deposited in each region. This long-term average valu e does not represent
short-term or localized fluctuations in de position rates. Periodic accumulation or scouring could be significant du ring large storm events. This could result in higher or lower deposition rates than the predicte d sediment deposition and pollutant
concentrations.

• A constant sediment porosity value was used to calculate loads associated with deposited sediment. Sediment porosity values used in the model to estimate loading capacity for San Diego Creek and Newport Bay (including Rh ine Channel) (0.65) were slightly lower than those used (0.80) in RMA model. No c onsolidation was assumed. This resulted in a conservative assumption, since consolidati on would result in a lower porosity, which
would increase the load associ ated with deposited sediment.



### Seasonal variation/Critical conditions

These TMDLs rely on careful analysis of the full range of potentia l flow conditions to
address seasonal variation and cri tical conditions in loads and flow s. The sediment transport and deposition within each waterbody is driven by th e velocity and sheer conditions of flow. The annual deposition is accounted for by using the sediment model developed by RMA (1997) which incorporates various flow regimes thr oughout each year. The model represents various weather patterns and flow conditions for 12 years.

As previously stated, freshwater flows from San Diego Creek and Santa Ana-Delhi Channel do not significantly transport sediment s into Rhine Channel. The most important scenario may be the large flows associated w ith wet weather events, which may occur at any time of the year and produce extensive sediment redistribution and transportations downstream. This has yet to be verified in hydrologic modeli ng of chromium and mercury in Rhine Channel.

summary document 68Newport Bay Toxic Pollutant TMDLs



## VIII. Arsenic Analysis

EPA has concluded that an arsenic TMDL is not required because available data indicate that applicable numeric water quality standards, and the best available screening guidelines used to interpret narrative standards, are not being exceeded. Although the State and EPA initially
concluded that arsenic TMDLs were needed based on comparisons with older recommended screening values, we have revised our conc lusions based on an updated data set and new information concerning arsenic toxicity and consump tion risk. This section explains the basis for
EPA’s revised assessment of the need for arsenic TMDLs.

EPA’s initial assessment of fish tissue mon itoring results was based on comparisons with two screening values. Total arsenic concentrations in fish tissue were compared to the California OEHHA screening value (1.0 mg/kg wet for total ar senic). This screening value was developed from a human health study for chemical cont aminants in sportfish from two California freshwater lakes (OEHHA 1999). OEHHA recognized that inorgani c arsenic is the preferred contaminant to evaluate for potential human heal th risk; however, analytical methods to measure inorganic arsenic were not availa ble during that study. OEHHA deve loped a plan to a) evaluate total arsenic fish tissue results against the scr eening value for freshwater species and b) delay further decisions about water quality impairment or potential health risk until they had actually measured inorganic arsenic in popular sportfish (pers. commun. B. Brodberg). Furthermore, OEHHA recognizes its tota l arsenic screening value is ill-su ited for saltwater systems. EPA Region 9 has reconsid ered using this freshwater total arsenic tissue screening value and has determined that it would be inappropriate to make final decisions based only on comparison of
total arsenic in tissues with this screening value.

EPA’s initial assessment also considered an other fish tissue screen ing value, (0.026 mg/kg wet for inorganic arsenic); however no monitoring data exists for measurements of inorganic arsenic in Newport Bay fish. To enable a compar ison of available data to the inorganic arsenic screening value, EPA estimated levels of inorga nic arsenic present in Newport Bay fish as a percentage of total arsenic for finfish (4% of to tal) and for shellfish (60% of total). These percentages were based on information obtained from a literature search (for finfish, Donohue and Abernathy 1999) or discussion with analytical chemists (f or shellfish, pers. commun. J. Creed). Upon further review of the screening va lues cited in recent EP A guidance for assessing fish advisories (USEPA 2000d), EPA has determ ined the 0.026 mg/kg wet inorganic screening value is incorrect and that 1.2 mg/kg wet inor ganic arsenic is a more reliable risk-based screening value. Preferably this screening value should be compared to measurements of inorganic arsenic in local fish, although calculation of inorganic ar senic as a percentage of total arsenic is still acceptable.

In the process of developing these TMDLs, EPA reevaluated local fish tissue data in comparison with the new EPA screening value of 1.2 mg/kg wet inorga nic arsenic based on EPA’s fish advisory guidance. The most recentl y available set of fish tissue monitoring results was compiled from Toxics Substances M onitoring program (1995- 1998), California Fish Contamination Study (1999-2000) Southern Califor nia Coastal Water Research Project (2001b) and State Mussel Watch program (1995-2000). We evaluated result s from both San Diego Creek and saltwater bodies of Newport Bay but focused more on saltwater results since those results
showed some exceedances with re spect to the OEHHA screening va lue applied in EPA’s earlier
assessment. To be conservative and consiste nt with other agencies (e.g., FDA), EPA assumed

summary document 69Newport Bay Toxic Pollutant TMDLs

that inorganic arsenic comprised 10% of total arsenic for finfish and 60% of total for shellfish. We used only one screening value, 1.2 mg/kg wet fo r inorganic arsenic, which is consistent with both State and Federal agencies’ determination that human health risk from arsenic exposure is attributed to inorgani c arsenic exposures.

The final assessment of saltwater tissue resu lts (using calculated values of inorganic arsenic) shows no exceedances of the EPA inorgani c screening value (1.2 mg/kg wet). This is true for both finfish (0%, n = 80) and shellfish (0%, n = 24). There are also no exceedances of
freshwater tissue results. Table 8-1 summarizes arsenic tissue concentra tions for Newport Bay. Table 8-2 provides a perspective of arsenic ti ssue concentrations for Newport Bay and other
saltwater bodies. The raw data and calculated results for this reassessment are provided in Appendix B at the end of this summary document. Therefore, based on this revised assessment, EPA concludes that San Diego Creek and Newport Bay are not exceeding water quality
standards for arsenic and that no TMDLs are needed. This result is consistent with local ambient water column data for arsenic, which indicate that Bay arsenic levels are about the same as average sea water arsenic levels.

Table 8-1. Total Arsenic results in fish tissue in Newport Bay waterbodies (mg/kg wet) Waterbody Collection Org. n Min Max Mean Median
dates San Diego 1995 -- 98 TSMP 15 0.06 0.88 0.18 0.13 Creek Newport 1995 -- 98 TSMP* 4 0.4 8.6 2.93 1.3 Bay 1999 -- 00 CFCS 26 0.2 4.0 1.29 0.79 (finfish) 2000 - 01 SCCWRP 50 0.22 8.6 1.64 0.68 (shellfish) 1995 - 00 SMW 24 0.8 2.5 1.28 1.25 *these TSMP results for individual samples, all other results are tissue composites

Table 8-2. Total Arsenic results in marine waterbodies (mg/kg wet) Tissue Study n Range Mean Median
Finfish Newport Bay 80 0.2 – 8.6 1.5 0.7
Wash State 12 0.15 – 10.7 3.5 0.9
Donohue 77 0.2 – 65 5.1 2.1
Great Britain 720 0.9 – 30.1 5.6 4.3
Shellfish Newport Bay 24 0.8 – 2.5 1.3 1.3
Wash State 10 1.0 – 6.9 2.4 2.2
Donohue 57 0.2 – 126 15.9 4.2 Newport Bay results compiled from Table 8-1 Washington State results fr om Yilmazer et al. 2000 Donohue results from various North American waterbodies (1996)
Great Britain results from Collins et al. 1996

summary document 70Newport Bay Toxic Pollutant TMDLs



## IX. Implementation Recommendations

This section provides general recommenda tions of implementation actions and monitoring work to assist in im plementing the TMDLs and allocati ons identified in this decision. Several commenters, including the Regional Bo ard, dischargers, and environmental groups specifically requested that EPA discuss TMDL implementation recommendations when we made the final TMDL decisions. The implementation and monitoring actions are not required and are not part of the TMDL decisions being made by EP A at this time; rather, they are included with the TMDLs to assist followup planning and implementation work by the State and local stakeholders. As discussed in Section I a bove, the State—not EPA—is responsible for developing implementation plans ne cessary to attain TMDLs. In its comments concerning the EPA TMDLs, the Regional Board signaled its commitment to adopt TMDLs and implementation plans for these toxic pollutants in a timely manner.



### General Recommendations

The toxic pollutant TMDLs address several po llutant types which come from a variety of sources. Therefore a range of pollutant manageme nt options will be available to the State to address them. Based on information we gathered in developing the TMDLs as well as feedback
obtained from the State and local stakeholders during the development of the TMDLs, we have identified several appropriate implementa tion approaches for different pollutants.

Consistent with the State’s approach to developing and implementing other TMDLs in the Newport Bay watershed for sediments, nut rients, and pathogens, EPA believes a phased, iterative approach to implementation and mon itoring is appropriate to address the toxic pollutants of concern. Substantial uncertainty remains concerning pollutant sources and the relationship between pollutant loads and environm ental effects in the watershed. EPA believes some specific implementation actions should be ca rried out to address po llutant sources which are most clearly of concern. Several of these actions are already underway or in the planning stages. It is also appropriat e to collect and analyze additiona l monitoring data to improve the understanding of pollutant s ources and effects, periodi cally review the TMDLs and implementation actions in light of new mon itoring results, and revise the TMDLs and implementation actions if necessary. Depe nding upon the State’s pr iorities, additional monitoring data could also assist in reviewing and, if necessary revising the applicable water quality standards to provide the appropriate level of beneficial use protection. This combination of early actions to address clear pollutant sources and an ongoing commitment to iterative monitoring and adjustments provides an appropr iate balance in followup implementation work.

When the Regional Board considers adopti on of TMDLs for toxic pollutants along with associated implementation plans, the State may adopt the TMDLs identified in this decision or further assess these pollutants and adopt different TMDLs if wa rranted. EPA recommends that the State consider the specific areas of analytical uncertainty iden tified in the analysis supporting our TMDL decisions as a starting point in targ eting any additional analytical work (including monitoring) planned in s upport of TMDL adoption.

It is expected to take severa l years for toxic pollutant levels in the watershed to decline to the point where all applicable water quality stan dards are fully attained. For some pollutants

summary document 71Newport Bay Toxic Pollutant TMDLs

such as the diazinon and chlorpyr ifos, the pollutant levels w ill probably decline quickly in response to actions to reduce their use. For so me other pollutants with long residence times in the environment, or which are associated with hi storical discharge, there will probably be some lag time between the initiation of controls to re duce loading or remediate contaminated sites and the observation of decreased pollutant levels throughout the watershed. For these reasons, EPA supports the past State practice of identifying interim targets or be nchmarks in terms of pollutant control actions, pollutant loadings and/or receiving water responses to help ensure that control actions are taken and progress is being made toward attaining water quality standards. Specification of clear interim targets also assi sts in the evaluation of whether the TMDLs or implementation actions need to be adjusted in the future.

EPA’s TMDLs do not contain compliance timefr ames or interim implementation targets because these elements are addressed by the Stat e in the implementation planning process. EPA urges the State to work with local dischargers an d stakeholders to design and carry out effective implementation actions sufficient to implement the TMDL in a timely manner.

As discussed in Section 1, the Clean Water Act creates federal regulatory jurisdiction only over point sources. Therefor e, the direct implementation effect of EPA’s TMDLs is that when NPDES permits for point source discharges ar e issued or revised for discharges to waters in the watershed, the State is required to ensu re that the permits cont ain effluent limitations necessary to be consiste nt with the wasteload allocations (WLAs) contained in theTMDLs (40 CFR 122.44(d)). Permit modification may occur when existing permits are reopened or reissued, or when a new discharge source seeks a perm it. NPDES permit holders should contact the Regional Board to discuss how and when action w ill be taken to implement applicable WLAs.
The State has discretion to determine how th e point source permit provisions will be made consistent with applicable WLAs . Depending upon the situation and the level of precision in the WLA, it may be appropriate to:

• incorporate numeric effluent limitations for the pollutant(s) of concern in the permit,

• identify best management prac tices and associated pollutant control effectiveness which demonstrate that the WLAs will be attained, and/or

• require the discharger to submit a WL A compliance plan and schedule which demonstrates how the WLA will be implemented.

In addition to addressing WLA implementation through the NPDES permitting process, the
State should work with local stakeholders to id entify specific actions necessary to carry out load
allocations identified in the TMDLs. These act ions may be based on voluntary or regulatory approaches. We note that CWA Section 319(h) nonpoint source implementation grant funds may be available to assist in implementing cont rols necessary to implement load allocations. Section 319(h) projects designed to implement TMDLs currently receive priority for funding. Landowners or land managers interested in s eeking Section 319(h) funding assistance should contact the Regional Board staff for more in formation concerning th e State’s grant funding

process.



### OP Pesticide TMDL Impl ementation Recommendations

EPA’s pesticide program has intiated a phase-out of household uses of diazinon and chlorpyrifos (EPA 2000b, EPA 2001b). It is expected that the phase-out w ill greatly assist in

summary document 72Newport Bay Toxic Pollutant TMDLs

reducing the levels of these pesticides found in the waters of Newport Bay watershed. Because approximately 90% of diazinon and chlorpyrifos use in the watershed is estimated to be associated with urban and household uses, the phas e-out program may be su fficient to result in
attainment of the TMDLs and associated alloca tions. We recommend that the Regional Board
continue its work with nurseries in the waters hed to minimize use of these pesticides. We recommend continued monitoring in San Diego Creek and its tributaries to assess reductions in OP pesticide runoff in the next several years. If monitoring demonstrates that the urban use phase-outs are inadequate to implement the TMDLs, it may be necessary in the future to implement additional controls on agricultural uses of these pesticides in coordination with the California Department of Pesticide Regulation

We are concerned by potential conflicts be tween programs to reduce use of these pesticides and mandates to use these pesticides for fire ant control. EPA urges that Regional
Board to work with the State Water Resource s Control Board, California Department of Pesticide Regulation, California Department of Food and Agriculture, and EPA’s pesticide program to assess and, if necessary, reconcile these potentially conflicting mandates concerning OP pesticide use.



### Selenium TMDL Implementation Recommendations

EPA is in the process of revi ewing and potentially revising th e numeric criteria for Se in freshwater. In addition, other lo cal studies are underway to asse ss the potential e ffects of Se on aquatic organisms. EPA expects to complete th is review within appr oximately 2 years. EPA recommends that the State review and, if nece ssary, revise the Se TMDLs following adoption or promulgation of the revised water quality standard s. Several commenters raised concerns about whether the CTR criteria are appropriate for c onditions in the San Die go Creek watershed, and
identified several local factors (e.g. local water chemistry) whic h could support consideration of alternative site specific criteria. In consu ltation with EPA and the State Water Board, the Regional Board should consider whether it is feasib le and appropriate to a ssess the applicable Se water quality standards in light of these concerns, and potentially adopt site specific water quality standards.

The TMDL analysis found that the most signifi cant sources of Se lo ading appear to be associated with groundwater entering surface wate rs (sometimes directly and sometimes through discharge from dewatering operations) . Control of these sources will be difficult. However, EPA recommends that the State begin working w ith permitted dischargers to assess options for reducing Se discharges through discharge management practices and/or treatment technologies. The State may wish to sequence its planning acti vities to settle issues concerning applicable standards before carrying out actions to further ti ghten discharge controls.

EPA recommends that the Regional Board m onitor flow and Se concentrations in discharges from cleanup and ground water dewatering operations in or der to provide the basis for establishing effluent limits in the permits consis tent with the TMDLs. When NPDES permits for groundwater cleanup or dewatering operations are considered, the Regional Board will need to ensure that the total allowable Se loadings do not exceed the group WLA established in the
TMDL.

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### Metals TMDL Implementation Recommendations

Metals loading in the waters hed is associated primarily with ongoing runoff from urban and undeveloped areas, and aquati c sediments containing previous ly discharged metals. Our
recommendations address all the metals for wh ich TMDLs are establis hed, including mercury
and chromium. EPA recommends five areas of action to address metals loading in the
watershed.

First, metals levels in the Rhine Channel area are estimated to be substantially higher
than in other areas of the watershed. No significant ongoing loading sources were identified, and the aquatic sediments in Rhine Channel have b een identified as a signif icant toxic hot spot. EPA recommends aggressive action to complete and implement the contaminated sediment remediation plan initiated by the State and Regional Boards in 1997. One potential ongoing source of concern with respect to chromium lo ading is the Newport Plating facility. EPA
recommends that the State further assess this facility and, if necessary, carry out discharge
controls or remedial actions necessa ry to address any ongoing loadings.

Second, the source analysis indicated that copp er leaching from boat paints is probably a significant source of copper loading to the Ba y. In coordination with marina and boatyard operators, other Regional Boards, the State Bo ard, and EPA, the Santa Ana Regional Board should develop specific actions to reduce the use of copper-containing boat paints or their leaching to water bodies through use of additi onal boat storage and maintenance practices.

Third, the Regional Board should work with the stormwater discharge permittees to further assess the potential effectiveness of av ailable management practices to reduce metals loading in discharges of urban runoff under high and low flows. In future iterations of the stormwater permits, provision should be made to implement effective metals reduction practices, with particular emphasis on implementation of the more cost-effective methods identified.
Additional work will be needed in the immediate future to more thoroughly assess and document the prospective effectivene ss of available practices.

Fourth, he State adopted a sediment TMDL and implementation plan in 1999 which called for an overall 50% reduction in sedime nt loading from San Diego Creek through implementation of a locally developed sediment reduction plan. Reductions in sediment loading should assist in reducing loadings of total me tals. EPA recommends th at the State continue implementation of this sediment reduction plan and monitor to determine whether both total and dissolved metals loading levels decline over time.

Fifth, the State may wish to consider reevalua tion of the metals criteria and associated TMDLs in the future based on application of cr iteria calculation methods which are currently under development. Metals cr iteria calculation protocols ar e nearing completion which may
enable States to calculate metals standards that more accurately represent the bioavailable portion of total metals loading th rough consideration of water effe cts ratios (WERs). It may be relatively straightforward recalc ulate metals criteria based on local hardness and organic carbon data and revised WER equations. In light of the potential cost of extensive actions to further control metals loading from urban runoff in the watershed, EPA believes it may be reasonable to consider whether newly emerging criteria calculation methods w ould result in protective but easier-to-implement standards.

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### Organochlorine Compound TMDL Implementation Recommendations

This TMDL decision addresses two types of organochlorine compounds whose use is no longer authorized: severa l chlorinated pesticides (DDT, chlord ane, dieldrin and toxaphene) and PCBs, which were used in electrical equipment. Because these compounds are very stable in the environment and often adhere to sediments, they may continue to reach and remain in water bodies at levels of concern for many years follo wing their discharge to the environment. Two potential routes of environmental exposure of these compounds are of greatest potential concern—ongoing loadings from the watershed of historically depos ited pollutants and exposures to organochlorine com pounds already present in aquatic sediments (principally in Newport Bay). There is substa ntial evidence indicating that le vels of these compounds in Bay sediments and aquatic organisms has declin ed over the past 20 years or more.

No terrestrial “hot spots” (l ocations with significantly elev ated levels of these pollutants were located during the TMDL development pro cess; however, limited historical information indicates that there may have been some spills (e.g., PCB spills at El Toro and Tustin Air Stations). We recommend that the State conduct more thorough inve stigations of potential spill sites based on the preliminary information compiled for this TMDL effort in order to determine whether there are any significan t hot spot sites in the waters hed warranting further remedial
action.

The most likely source of ongoing loading of organochlorine pollutants is erosion of sediments to which these compounds have adhere d. The State adopted a sediment TMDL and implementation plan in 1999 which called for an overall 50% reduction in sediment loading from San Diego Creek through implementation of a lo cally developed sediment reduction plan. EPA recommends that the State continue implementati on of this sediment reduction plan and monitor to determine whether levels of organochlorine compounds continue to decline. Monitoring should examine not only the levels of organochl orine pollutants in the water column, but also sediment running into tributary streams, sediment moving down San Diego Creek, and sediments in Newport Bay.

If future monitoring indicates that declines in levels of the pollutants in the watershed are continuing or accelerating, it may be unnecessary to implement additional erosion and sediment controls. If the levels of these pollutants in se diments and tissue do not d ecline or actually begin to rise, the State will need to revisit and potentia lly revise terrestrial sedi ment control strategies in the watershed as a whole and aquatic se diment management strategies in the Bay.

summary document 75Newport Bay Toxic Pollutant TMDLs

Newport Bay sediment and tissue monitori ng programs should continue to test for organochlorine pollutants. Although no obvious a quatic sediment “hot spots” were found for these pollutants (with the possibl e exception of Rhine Channel for some pollutants), the available data appear to indicate that the reservoir of these pollutants still found in Bay sediments far outweighs the additional loads to the Bay from th e watershed. Therefore, in coordination with monitoring and assessment programs to evaluate the full suite of toxic pollutants of concern, the
State should continue to cons ider whether any specific locati ons warrant remedial action to remove, cap, or otherwise immobilize Bay sediments. It is always important to consider whether the long term benefit of aquatic sediment remedial action is ou tweighed by the potential short term adverse effects associated with disturbing contaminated sediments. The remedial action plan adopted by the State for Rhine Channel should help reduce any ongoing availability of these pollutants at that location, and we repeat our recommendation that this remedial action plan be carried out in a timely manner.

The U.S. Army Corps of Engineers and Orange County have been examining the feasibility of removing sediment from containm ent basins in Upper Newport Bay (ACOE 2000). This study has refined various alternatives, obta ined necessary funding and is presently entering the preconstruction, engineering a nd design phase. Restoration is scheduled to begin in
2003/2004. We recommend that the St ate work with the project spons ors to ensure that potential
disturbance of sediments containi ng the pollutants addressed in this TMDL report is considered in the design process and minimi zed during project implementation.



### Monitoring Recommendations

This action establishes TMDLs for numerous toxic pollutants, in a watershed for which several other TMDLs have previously been estab lished. We recommend that the State work with the other State and federal agencies, the County, permitted cities, local industries, and perhaps local academic institutions to develop a coordinated monitoring program for Newport Bay and its tributary streams. While much of this wo rk could be carried out pursuant to the NPDES stormwater permit, the scope of the monitoring n eeded to more fully characterize toxic pollutant
trends in the watershed and the effectiveness of pollutant control strategies goes beyond the scope of traditional monitoring required under these permits. Substantial monitoring has conducted in the past but it wa s (with the exception of the County’s monitoring) usually relatively narrow in scope in terms of pollutant coverage, geographical extent, and temporal scope. Newport Bay watershed is a good candidate for development of a more integrated and comprehensive monitoring approach which could re sult in a more cost-effective overall approach to monitoring than currently created by independent monitoring approaches.

We recommend that the State consider the ar eas of uncertainty in each TMDL analysis as discussed in the margin of safety sections and TS Ds in order to identify the types of monitoring data which are most important to reduce analytical uncertainty and improve our ability to target meaningful cont rol actions.

summary document 76Newport Bay Toxic Pollutant TMDLs



## X. References

The list below may include some references cite d only in the Technical Support Documents.

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March. California Department of Fish and Game (CDFG) 2000a. Water Quality Criteria for Diazinon and Chlorpyrifos

. CDFG. 2000b. Results of Chemical and Toxicological Analyses of Sediment and Chemical Analysis of Fish Tissue in Conjunction with the Red Imported Fire Ant (RIFA) Control Project . Memorandum to Santa Ana RWQCB. October California Department of Pesticide Regulation (CDPR) 2000 RIFA Insecticides and other Organophosphates: Use Pattern, Concentration, and Toxicity in Runoff Water, Source Identification, and Mitigation Measures

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CDPR 1999 Annual Pesticide Use Data; User Documentation . July. California Division of Mines and Geology. 1976 Environmental Geology of Orange County, CA . Open-file report 79-8. pp. 244-45. Camp Dresser & Mckee, Inc. 1985 Shallow Groundwater Investigation West Central Part of the Irvine Subbasin , a report submitted to The Irvine Company. Canadian Council of Ministers of the Environment. 1999 Canadian Sediment Quality Guidelines for the Protection of Aquatic Life: Summary Tables . In: Canadian Environmental Quality Guidelines, 1999, Canadian Council of Minister of the Environment, Winnipeg. Chadwick, DB, I Rivera-Duarte, T Hampton, B Davidson and E Crecelius. 2001 Contaminant Fluxes From Sediments – Risk Or Recovery?

, International Conference on Remediation of Contaminated Sediments, October 10-12, 2001, Venice, Italy. City of Newport Beach . 1999 Final Sampling and Analysis Plan for Newport Harbor Sediment Characterization, Newport Beach, California , Ogden Environmental and Energy Services, Inc. Coastal Sport Fish Contamination Study, unpublished da ta. 2001 State Water Resource Board and OEHHA database. R.K. Brodberg, Office of Environmental Health Hazard Assess ment, Calif. EPA, Sacramento, Calif. Collings, SE; MS Johnson and RT Leah. 1996 Metal contamin ation of Angler-caught fish from the Mersey Estuary.
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. 29 : 639-644. Donat, JR; K Lao and KW Bruland 1994 Speciation of copper and nickel in South San Francisco Bay: a multimethod approach. Anal. Chim. Acta 284 : 547-572. Donohue, JM and CO Abernathy 1996 Exposure to Inorganic Arsenic (As) from Fish and Shellfish . Proceedings of International Arsenic conf. Duce RA, Hoffman GL, Ray BJ and PR Walsh 1976 Trac e Metal Concentration as a Function of Particle Size in
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Enberg, RA et al. 1998 Federal and State Perspectives on Regulation and Remediation of Irrigation-Induced Selenium Problems, in Selenium in the Environment , Ed. by W T Frankenberger Jr. and S Benson, Marcel Dekker, Inc. New York, pp. 1-25. EXTOXNET. 1995-1996 Pesticide Information Profiles. http://ace.orst.edu/info /extoxnet/pips/ghindex.html Fowler, SW, and G. Benayoun 1976 Influence of En vironmental Factors on Selenium Flux in Two Marine Invertebrates, Mar. Biol . ( 37 ): 59. Francesconi, KA and JS Edmonds 1994 Biotransformations of Arsenic in the Marine Environment. in Arsenic in the Environment, Part 1: Cycling and Characte rization. J.O. Nriagu, editor. pp. 221-262. Geiszinger, AE; W Goessler and KA Francesconi. 2002 The marine polychaete Arenicola marina : its unusual arsenic compound pattern and its uptake of arsenate from seawater. Mar. Env. Res. 53 , 37-50. Giesy JP, Solomon KR, Coats JR, Dixon K, Giddings J, and EE Kenaga. 1998 Ecological Risk Assessment of Chlorpyrifos in North American Aquatic Environments: Report of an Expert Panel . Dow AgroSciences LLC Study ID: GH-C 4660. Hall. L and R Anderson 2000 A Site-specific probabilistic Ecological Risk Assessment for Diazinon in California’s Newport Bay Watershed . September. Henderson, J. D. et al . 1995 Assessing Selenium Contamination in two San Joaquin Valley, CA, Sloughs, US Fish and Wildlife Service, Region 1, Division of Environmental Contaminants, Sacramento, CA. Hibbs, BJ and MM Lee. 2000 Sources of Selenium in the San Diego Creek Watershed. Kozelka, PB and KW Bruland 1998 Chemical Speciation of dissolved Cu, Zn, Cd and Pb in Narragansett Bay, Rhode Island. Mar. Chem. 60 : 267—282. IRWD 1999 Irvine Ranch Water Dist rict Wetland Water Supply Project Monito ring Data Base 1997—99. Irvine Ranch Water District. Irvine, California. Lee, GF and S Taylor 2001a Results of Aquatic Toxicity Testing Conducted During 1999-2000 in the Upper Newport Bay Watersheds . USEPA 319(h) project report. May. Lee, GF and S Taylor 2001b Results of Aquatic Life Toxicity Studies Conducted During 1997-1999 in the Upper Newport Bay Watershed and Review of Existing Water Quality Characteristics of Upper Newport Bay and its Watershed . USEPA 205(j) project report. Lemly, AD 1993 Guidelines for Evaluating Selenium Data from Aquatic Monitoring and Assessment Studies, Environmental Monitoring and Assessment

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, 5 : 253-278. Maider, KJ et al. 1993 Comparative Toxicity of Selenate, Selenite, Seleno -DL-methionine, and Seleno-DL

cysteine to Daphia Magna : Environ. Toxicol. Chem. ( 12 ): 755-763. Masters, P and D Inman 2000 Tranport and Fate of Organochlorines Discharged to the Salt Marsh at Upper Newport Bay, California, USA. Environ. Toxicol. Chem

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Res. 88 : 6761-6676. Muller, FLL 1996 Interactions of copper, lead and cadmium with the dissolved, colloidal and particulate components of estuarine and coastal waters. Mar. Chem 52: 245-68. National Academy of Sciences 1973 Water Quality Criteria (Blue Book) . EPA-R3-73-033. USEPA Ecological Research Series. Neff, JM 1997 Ecotoxicology of arsenic in the marine environment . Environ. Tox. Chem., 17 (4): pp. 917-927. New York Department of Environmental Conservation 1994 Niagra River biota contamin ation project - fish flesh criteria for piscivorous wildlife. NYDEC, Division of Fish and W ildlife, Bureau of Environemtnal Protection Technical Report 87-3, 182p.

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New York Department of Environmental Conservation 1998 Technical guidance for screening contaminated sediments (for wildlife bioaccumulation). Albany, NY, Di v. of Fish and Wildlife, Div. of Marine Resources. 36pp. Novartis Crop Protec tion Inc. 1997 An Ecological Risk Assessment of Diazinon in the Sacramento and San Joaquin River Basins. Technical Report 11-97

. Nriagu, JO. 1989 Global Cycling of Selenium, in Occurrence and Distribution of Selenium , ed. M. Ihnat, CRC Press, Inc. Florida, pp. 327-340.
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OEHHA 1999 Prevalence of Selected Target Chemical Contaminants in Sport Fish from Two Californa Lakes : Public Health Designed Screening Study. June 1999, RK Brodberg and GA Pollack, Pesticide and Environ. Toxic. Sctn, Office of Environm ental Health Hazard Assessment , Calif. EPA, Sacramento, Calif. Ogden Environmental and Energy Services. 2000 Final Sampling and Analysis Plan for Newport Harbor Sediment Characterization. Orange County Coastkeeper 1999 Rhine Channel Sedime nt Metal Characterization. Report prepared by MBC Applied Environmental Services, Costa Mesa, Calif. Presser TS 1994 Geologic Origin and Pathways of Seleni um from the California Coast Ra nges to the West-Central San Joaquin Valley, in Selenium in the Environment , Ed. by WT Frankenberger, Jr. and S. Benson, Marcel Dekker, Inc. New York, pp. 139-155. Resource Management Associates (RMA ) 2001 Newport Bay Water Quality Model Development—3-D Stratified Flow Analysis. prep ared for California Regional Water Quality Control Board, Santa An a Region, February. RMA 1999 Upper Ne wport Bay Feasibility Report—A lternative Analysis. prepared for US Army Corps of Engineers. RMA 1998 Upper Newport Bay Feasibility Report —Numerical model development and baseline conditional analysis. (for US Army Corps of Engineers). RMA 1997 Upper Newport Bay Feasibility Report—Final mode l and GUI development and implementation report. (for US Army Corps of Engineers). San Diego Regional Water Qua lity Control Board 2001 Draft Dissolved Copper TMDL for Shelter Island Yacht
Basin. California Regional Water Quality Cont rol Board, San Di ego California. Santa Ana Regional Water Quality Control Board (RWQCB) 2001a Draft TMDL for OP Pesticides in San Diego Creek and Newport Bay. Staff report, California Re gional Water Quality Control Board, Santa Ana Region, Riverside, California. Santa Ana RWQCB 2001b Draft TMDL for Selenium in San Diego Creek and Newport Bay. Staff report, California Regional Water Quality Control Board, Santa Ana Region, Riverside, California. Santa Ana RWQCB 2000 Final Problem Statement for the Total Maximum Daily Load for Toxic Substances in Newport Bay and San Diego Creek. Staff report, Calif ornia Regional Water Quality Control Board, Santa Ana Region, Riverside, California. Santa Ana RWQCB 1998 Water Quality Assessment and Clean Water Act Section 303(d) List . California Regional Water Quality Control Board, Sant a Ana Region, California Environmental Protection Agency, Riverside, California. Santa Ana RWQCB 1995 Water Quality Control Plan for the Santa Ana River Basin California Regional Water Quality Control Board, Santa Ana Regi on, California Environmen tal Protection Agency, Riverside, California. Scanlin, J and A Cooper 1997 O utdoor Use Characterization of Diazinon and other Pesticides in Alameda County

. Prepared for the Alameda County Flood Control and Water Conservation District. September. Scanlin, J and A Feng 1997 Characterization of the Presence and Source s of Diazinon in the Castro Valley Creek Watershed . Prepared for the Alameda Countywide Clean Water Program and the Alameda County Flood Control and Water Conservation District. June. Schiff, K and L Tiefenthaler 2000 Anthropogenic versus natural mass emission from an urban watershed. SCCWRP Annual report. pp. 63-70. Schoof, RA, LJ Yost, J Eickhoff, EA Crecilius, DW Crag in, DM Meacher, and DB Menzel 1999 A Market Basket Survey of Inorganic Arsenic in Food. Food and Chem. Toxic

. 37 : 839—846. Seiler, RL et al. 1999 Areas Susceptib le to Irrigation-Induced Selenium Cont amination of Water and Biota in the Western United States: US Geological Survey Circular 1180, pp. 36. Smith, SL, DD MacDonald, KA Keenleyside, CG Ingersoll and LJ Field 1996 A Preliminary Evaluation of Sediment Quality Assessment Values for Freshwater Ecosystems

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SMW 2000 State Mussel Watch Program 1983-00 Data Base and 1995-97 Data Report . State Water Resources Control Board, California Environmental Protection Agency, Sacramento, California Southern California Coastal Water Re search Project (SCCWRP) 2001a Newport Bay Sediment Toxicity Study— Progress Report. (for contract with Santa Ana RWQCB, dated Oc t. 23, 2001.) Southern California Coastal Water Research Program. SCCWRP 2001b Newport Bay Fish Bioaccumulation Study—Progress Report. (for contract with Santa Ana RWQCB, dated Oct. 4, 2001.) Southern California Coastal Water Research Program. SCCWRP, unpublished data 1998 Sediment Chemistry from Southern California Bight including offshore Harbors and estuaries. Southern California Coasta l Water Research Program. Stoecker, DK, WG Sunda and LH Davis 1986 E ffects of copper and zinc on two planktonic ciliates. Mar. Biol

. 92 : 21-29. Stolzenbach, KD; R Lu; C Xiong; S Friedlander; R Turco; K Schiff; and L Tiefenthaler 2001 Measuring and Modeling of Atmospheric Deposition on Santa Monica Bay and the Santa Monica Bay Watershed. Final Report to Santa Monica Restoration Project. 41pp. Sunda, WG; PA Tester and SA Huntsman 1987 Effects of cupric and zi nc ion activities on the survival and reproduction of marine copepods. Mar. Biol

. 94 : 203-210. TDC Environmental 2001 Diazinon and Chlorpyrifos Products: Screening for Water Quality Implications Thomann, R and J Mueller 1987 Principles of Surface Water Quality Modeling and Control . Harper Collins Pub. Tokunaga, TK et al. 1994 Field Investigations of Selenium Sp eciation, Transformation, and Transport in Soils from Kesterson Reservoir and Lahontan Valley, in Selenium in the Environment , WT Frankenberger and S Benson, editors, Marcel Dekker, Inc. Yew York, pp. 119-138. TOXSCAN, Inc. 1995 Chemical Analysis and Toxicity Ev aluation of Sediment Proposed for Dredging and Ocean Disposal: Unit I Sediment Basin and Access Channel. Trimble, SW 1987 Field Research Re port for San Diego Creek Channel Study, Summer 1987. Univ. of California at Los Angeles, Los Angeles, California Tsai, P; E Hansen; K Lee; D Yee; D Tucker and R Hoenicke 2001 Atmospheric Deposition of Trace Metals in the San Francisco Bay area . abstract for WEFTEC conf. Atlanta, GA
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. USEPA 2000a California Toxics Rule [CTR], Water Quality Standards; Es tablishment of Numeric Criteria for Priority Toxic Pollutants fo r the State of California; Federal Register Rule—40CFR Part 131. U.S. Environmental Protection Agency, Washington, D.C. USEPA 2000b Chlorpyrifos Revised Risk Assessment and Agreement with Registrants

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USEPA 1993. Guidance Specifying Management Measures For Sources of Nonpoint Pollution In Coastal Waters. EPA 840-B-92-002. U.S. Environmental Protecti on Agency, Office of Water, Washington DC.

summary document 80Newport Bay Toxic Pollutant TMDLs

USEPA 1991 Guidance for Water Quality-based Decisions: The TMDL Process. EPA-440/4-91-001. Office of Water, Washington, DC. USEPA 1991b Technical Support Document for Water Quality-based Toxics Control. EPA-505-2-9-001. Office of Waer, Washington, DC.
USEPA 1997 National Toxics Rule [NTR], Water Quality Standards; Es tablishment of Numeric Criteria for Priority Toxic Pollutants fo r the State of California; Federal Register Rule—40CFR Part 131. U.S. Environmental Protection Agency, Washington, D.C.
USEPA 1980 Ambient Aquatic Life Water Quality Criteria: DDT. EPA-440/5-80-038. Office of Water, Washington, DC.

USEPA Region 9 2002 Decision Docu ment for Assessment of San Diego Creek an d Newport Bay Water Quality USEPA Region 9 2000 Guidance for Developing TMDLs in California. http://www.epa.gov/region09/water/tmdl/index.html Waldner, L. 2001 pers. comm. Orange County Public Facilities Resource Division Wang, WX et al . 1996 Kinetic Determinations of Trace Element Bioaccumulation in the Mussel Mytilus edulis : Mar. Ecol. Prog. Ser

. 140 : 91-113. Weis, P; JS Weis and LM Coohill 1991 Toxicity of estuarine organisms of leachat es from chromated copper arsenate treated wood. Arch

. Environ. Contam. Toxicol. 20 : 118-124. White AF, Benson SM, Yee AW, Wollenberg HA and S Flexser 1991 Groundwater Contamination at the Kesterson Reservoir, California. 2. Geochemical Parameters In fluencing Selenium Mobility Wat. Resour. Res. 27 (6): 1085-1098. Wiemeyer, SN; DR Clark, JW Spann, and AA Belisle 200 1 Dicofol Residues in Eggs and Carcasses of Captive American Kestrels. Environ. Toxicol. Chem

. 20 (12): 2848-2851. Wilber, CG. 1980 Toxicology of Selenium: A Review, Clin. Toxicol

. 17 : 171. Wilen, C. 2001 Residential Pesticide Use and Attitude Survey, San Diego Creek Watershed of Orange County, California. Report for California Department of Pesticide Regulation. University of California Statewide Integrated Pest Management Program. Wisconsin Department of Natural Resources 1997 Polych lorinated Biphenyl (PCB) Contaminated Sediment in the Low Fox River. PUBL-WT-482-97. Yilmazer, M and S Shawky, RN Sanga, RM Lorenzana 2001 Concurrent Exposure Evaluations Arsenic MCL Options and Arsenic in seafood. Toxicol. Sci. 60 (1): p90.

summary document 81Newport Bay Toxic Pollutant TMDLs



## XI. Glossary and abbreviations

205(j) Section 205, part j of Clean Wate r Act, addresses water monitoring grants 319(h) Section 319, part h of Clean Water Act, addresses non-point source pollution ACOE Army Corps of Engineers

ai active ingredient ambient existing environmental conditions (or concentrations)

BAF Bioaccumulation factor

BCF Bioconcentration factor

BSAF Biota-sediment accumulation factor bgs Below ground surface, re lates to monitoring wells Bight ‘98 Southern California Bight (coastal waters) study BMP best management practice BPTCP Bay Protection and Toxic Cleanup Program

CCC criterion continuous concentration = chronic CDFG (California) Department of Fish and Game

cfs Cubic feet per second, pert ains to stream flow rates CFCS California Fish Contamination Study (OEHHA)

CMC criterion maximum concentration = acute

CTR California Toxics Rule

cv coefficient of variation

CWA Clean Water Act DO dissolved oxygen DPR (California) Department of Pesticide Regulation DTSC (California) Dept. of Toxic Substances Control ELISA Enzyme Linked Immunosorbant Assay EPA U.S. Environmental Protection Agency ERL Effects Range-Low, sediment quality gui deline for low impact ERM Effects Range-Median, NOAA sediment quality guideline for median negative impact FIFRA Federal Insecticide, Fu ngicide and Rodenticide Act

f lip Fraction (of organic compou nd associated) with lipid

f
oc Fraction (of organic compound associated) with octanol GC Gas chromatograph GC/MS Gas chromatography/mass spectrometry HPLC/MS high performance liquid chromatography/mass spectrometry IPM Integrated Pest Management, part of UC-Cooperative Extension

IRWD Irvine Ranc h Water District LA Load allocation for non-point sources (including background)

MLLW mean low low water MOS Margin of safety NAWQA National Water Quality Assessment Program ng/L Nanograms per liter (= parts per trillion) NOAA National Oceanic Atmospheric Administration

NPDES National Pollutant Disc harge Elimination System NY DEC New York Dept. of Environmental Conservation OC Organochlorine compound; e.g., chlordane, dieldrin, DDT, PCB, toxaphene OCHCA Orange County Health Care Agency OCPFRD Orange County Public F acilities and Resources Department

summary document 82Newport Bay Toxic Pollutant TMDLs

OEHHA Office of Environmental Health Hazard Assessment

OP Organophosphate, type of pesticide OPP Office of Pesticide Programs PCB polychlorinated biphenyl PCH Pacific Coast Highway PCW Peters Canyon Wash, a tributary of San Diego Creek PEL Probable Effects Level, sediment quality gu ideline for Florida Dept. of Env. Protection PERA probabilistic ecolo gical risk assessment POTW Publicly owned treatment works ppb Part per billion = ug/L (for solution concentration) or ng/g (for dry soil conc.) ppm Part per million = mg/L (for solution con centration) or ug/g (for dry soil conc.) PPT parts per thousand (salinity) Porewater (interstitial) wate r contained in sediments RIFA Red Imported Fire Ant RMA Resource Management Associates, developed hydrologic models for US Army Corp of Eng. SA RWQCB Santa Ana Regional Water Quality Control Board SD RWQCB Santa Diego Regional Water Quality Control Board

SAD Santa Ana-Delhi Channel

SCCWRP Southern California Co astal Water Research Program SDC San Diego Creek

se standard error [as used in table column headings]

SMW State Mussel Watch

SWRCB State Water Resources Control Board TAC Technical Advisory Committee TEL Threshold Effects Level, sediment quality guide line (for Florida Dept. of Env. Protection) TIE toxicity investigation evaluation = study to id entify and characterize chemicals causing toxicity TMDL total maximum daily load TOC total organic carbon TSMP Toxic Substances Monitoring Program (State Water Board)

TUa acute toxic units UCD University of California, Davis ug/L micrograms per liter (= parts per billion)

US FWS United States Fish & Wildlife Service USGS United States Geological Survey WDR Waste discharge report, WLA Wasteload allocation for point sources (including general stormwater permit) WYL San Diego Creek at Culver sampling site

xe mean error [as used in table column headings]

summary document 83Newport Bay Toxic Pollutant TMDLs


### Appendix A

Designated beneficial uses for Newpor t Bay and San Diego Creek watershed.

Water Body M
U
N A
G
R I
N
D P
R O
C G
W
R N
A
V P O
W R
E C
1 R
E C
2 C
O
M
M W
A
R
M C
O
L
D B
I O
L W
I
L
D R
A
R
E S
P
W
N M
A
R S
H
E
L E S
T

Lower NB + x x x x x x x x x Upper NB + x x x x x x x x x x San Diego
Creek Reach 1 + x x x x

San Diego
Creek Reach 2 + I I I I

Tributaries of San Diego
Creek + I I I I

x present or potential beneficial use
I intermittent beneficial use

+ excepted from MUN

MUN = municipal and domestic supply AGR = agricultural supply IND = industrial service supply PROC = industrial process supply GWR = groundwater recharge NAV = navigation POW = hydropower generation
REC1 = water contact recreation
REC2 = non-contact water recreation COMM = commercial and sport fishing
WARM = warm freshwater habitat
COLD = cold freshwater habitat BIOL = preservation of biological habitats
WILD = wildlife habitat RARE = rare, threatened , or endangered species SPWN = spawning, reproduction, and/or early development
MAR = marine habitat SHEL = shellfish harvesting
EST = estuarine habitat

summary document 84Newport Bay Toxic Pollutant TMDLs



### Appendix B

Arsenic Fish Tissue Monitoring data

SPECIES NAME Date Total Inorganic Arsenic Arsenic Screening Value OEHHA = 1.0 EPA = 1.2 (mg/kg wet) #/samp. (4% Tot. As) (10% Tot. As) OEHHA data ' 00 Newport Beach Barred Surfperch 6/00/2000 10 0.601 0.024 0.060 Newport Beach Shiner Surfperch 06/00/2000 10 1.130 0.045 0.113 Newport Beach White Croaker 06/00/2000 5 0.778 0.031 0.078 Newport Beach Pier Barred Surfperch 06/00/2000 10 0.577 0.023 0.058 Newport Beach Pier White Croaker 06/00/2000 5 0.668 0.027 0.067
Balboa Pier Barred Surfperch 06/00/2000 3 0.911 0.036 0.091
Balboa Pier Diamond Turbot 06/00/2000 4 3.094 0.124 0.309 Newport Jetty Black Surfperch 06/00/2000 5 0.774 0.031 0.077 Newport Jetty Shiner Surfperch 06/00/2000 10 0.906 0.036 0.091 Newport Jetty Spotted Turbot 06/00/2000 5 3.673 0.147 0.367 Newport Bay/above Shiner Surfperch 06/00/2000 10 0.969 0.039 0.097
PCH Br Newport Bay/above Spotted Turbot 06/00/2000 5 1.775 0.071 0.177
PCH Br Newport Bay/above Yellowfin Croaker 06/00/2000 4 0.585 0.023 0.059
PCH Br Newport Beach Barred Surfperch 8/4/99 5 0.811 0.032 0.081 Newport Beach California Corbina 8/4/99 5 0.449 0.018 0.045 Newport Beach Walleye Surfperch 6/22/99 3 0.618 0.025 0.062 Newport Pier Barred Surfperch 8/4/99 5 1.06 0.042 0.106 Newport Pier California Corbina 8/4/99 5 0.411 0.016 0.041 Newport Pier Spotted Turbot 6/16/99 3 2.69 0.108 0.269 Newport Pier Yellowfin Croaker 8/4/99 3 0.529 0.021 0.053
Balboa Pier Diamond Turbot 6/15/99 5 4 0.160 0.400
Balboa Pier Walleye Surf perch 6/9/99 5 0.587 0.023 0.059 Newport Jetty Spotted Scorpionfish 5/19/99 5 0.202 0.008 0.020 Newport Jetty Spotted Turbot 5/19/99 5 3.12 0.125 0.312 Newport Bay Diamond Turbot 5/19/99 5 1.88 0.075 0.188 Newport Bay Shiner Surfperch 5/27/99 5 0.672 0.027 0.067

SCCWRP Winter '01
barred sand bass Outer Lower 1 1 0.65 0.026 0.065 black perch Outer Upper 1 2 0.53 0.021 0.053 black perch Outer Lower 1 3 0.96 0.038 0.096 black perch Outer Lower 2 4 0.86 0.034 0.086 black perch Outer Lower 3 5 0.69 0.028 0.069
California halibut Outer Upper 1 6 0.58 0.023 0.058
California halibut Outer Upper 2 7 0.85 0.034 0.085
California halibut Outer Upper 3 8 0.47 0.019 0.047
California halibut Outer Lower 1 9 0.91 0.036 0.091
California halibut Outer Lower 2 10 0.41 0.016 0.041
C-O sole Outer Lower 1 11 5.74 0.230 0.574

summary document 85Newport Bay Toxic Pollutant TMDLs

C-O sole Outer Lower 2 12 5.01 0.200 0.501
diamond turbot Outer Upper 1 13 1.82 0.073 0.182
diamond turbot Outer Upper 2 14 3.89 0.156 0.389
diamond turbot Outer Upper 3 15 2.85 0.114 0.285
diamond turbot Outer Lower 1 16 4.20 0.168 0.420
diamond turbot Outer Lower 2 17 3.45 0.138 0.345
fantail sole Outer Lower 1 18 0.97 0.039 0.097 shiner perch Outer Upper 1 19 0.67 0.027 0.067 spotted sand bass Outer Upper 1 20 0.47 0.019 0.047 spotted sand bass Outer Lower 1 21 0.63 0.025 0.063 spotted turbot Outer Upper 1 22 3.92 0.157 0.392 spotted turbot Outer Lower 1 23 7.28 0.291 0.728 spotted turbot Outer Lower 2 24 8.57 0.343 0.857 spotted turbot Outer Lower 3 25 5.53 0.221 0.553
SUMMER 2001
barred sand bass Outer Lower 1 13 0.44 0.018 0.044 black perch Outer Lower 1 10 0.50 0.020 0.050 black perch Outer Lower 2 11 0.40 0.016 0.040 black perch Outer Lower 3 12 0.58 0.023 0.058
California corbina Outer Lower 1 17 1.24 0.050 0.124
California corbina Outer Lower 2 18 1.15 0.046 0.115
California corbina Outer Lower 3 19 1.57 0.063 0.157
California halibut Outer Lower 1 25 0.52 0.021 0.052
diamond turbot Outer Upper 1 20 2.52 0.101 0.252
diamond turbot Outer Upper 2 21 2.89 0.116 0.289
diamond turbot Outer Lower 1 22 2.12 0.085 0.212 jacksmelt Outer Upper 1 1 0.51 0.020 0.051 jacksmelt Outer Upper 2 2 0.53 0.021 0.053 jacksmelt Outer Upper 3 3 0.58 0.023 0.058 kelp bass Outer Lower 1 4 0.49 0.020 0.049 spotfin croaker Outer Lower 1 23 0.68 0.027 0.068 spotfin croaker Outer Lower 2 24 0.93 0.037 0.093 spotted sand bass Outer Lower 1 14 0.22 0.009 0.022 spotted sand bass Outer Lower 2 15 0.24 0.010 0.024 spotted sand bass Outer Lower 3 16 0.25 0.010 0.025 yellowfin croaker Outer Lower 1 5 0.36 0.014 0.036 yellowfin croaker Outer Lower 2 6 0.34 0.014 0.034 yellowfin croaker Outer Lower 3 7 0.47 0.019 0.047 yellowfin croaker Inner Lower 1 8 0.49 0.020 0.049 yellowfin croaker Inner Lower 2 9 0.27 0.011 0.027
TSMP data '95--'98 Upper NB/Dunes Brown Sm. Shark (F) 6/10/98 1 8.620 0.345 0.862 Upper NB/Dunes Diamond Turbot (F) 6/20/97 1.480 0.059 0.148
NB/Rhine Channel Chub Mackerel (F) 7/11/97 0.427 0.017 0.043
NB/Rhine Channel Black Croaker (F) 6/18/95 1.200 0.048 0.120 (Data is for Individual Filet Samples)

count 80 

### saltwater finfish results

max 8.62 0.34 0.86

mean 1.59 0.06 0.08
median 0.78 0.03 0.08

summary document 86Newport Bay Toxic Pollutant TMDLs

Tot. As Inorg. As

State Mussel Watch mussels Upper Newport Bay (60% of As Total)
UNB/Mariner's Drive TCM 1/27/97 1.10 0.018
UNB/Mariner's Drive TCM 3/24/98 1.70 0.028
UNB/Mariner's Drive TCM NA
UNB/Mariner's Drive TCM 2/2/00 0.90 0.015 UNB/ PCH Bridge TCM 1/30/95 NA UNB/ PCH Bridge TCM 1/17/96 1.40 0.023 UNB/ PCH Bridge NA NA UNB/ PCH Bridge TCM 3/24/98 1.40 0.023 UNB/ PCH Bridge TCM 3/29/99 1.40 0.023 UNB/ PCH Bridge TCM 2/2/00 1.00 0.017

Lower Newport Bay LNB/Turning Basin TCM 1/30/95 NA LNB/Turning Basin TCM 1/17/96 1.20 0.020 LNB/Turning Basin na NA LNB/Turning Basin RBM 3/24/98 0.80 0.013 LNB/Turning Basin TCM 3/29/99 1.30 0.022 LNB/Turning Basin TCM 2/2/00 1.00 0.017
LNB/Police Docks RBM 3/24/98 1.10 0.018
LNB/Entrance TCM 3/29/99 2.50 0.042
Rhine Channel
Rhine Ch./Crows Nest TCM 1/30/95 NA
Rhine Ch./Crows Nest TCM 1/17/96 1.20 0.020
Rhine Ch./Crows Nest TCM 1/27/97 1.20 0.020
Rhine Ch./Crows Nest TCM 3/24/98 1.60 0.027
Rhine Ch./Crows Nest TCM 3/29/99 1.50 0.025
Rhine Ch./Crows Nest TCM 2/2/00 1.10 0.018
Rhine Ch./End TCM 1/30/95 NA
Rhine Ch./End TCM 1/17/96 1.30 0.022
Rhine Ch./End TCM 1/27/97 1.30 0.022
Rhine Ch./End TCM 3/24/98 1.40 0.023
Rhine Ch./End TCM 3/29/99 1.30 0.022
Rhine Ch./End TCM 2/2/00 0.90 0.015 Rhine Ch./Upper TCM 2/2/00 1.00 0.017 (Data is for Composite Mussel Samples)

count 24 

### Saltwater shellfish results

max 2.50 0.04

mean 1.28 0.02
median 1.25 0.02

summary document 87Newport Bay Toxic Pollutant TMDLs

Tot. As Inorg. As

TSMP data '96--'98 San Diego Creek San Diego Creek/Michelson Peters Canyon Channel San Diego Creek/Barranca Delhi Channel San Diego Creek/Michelson Peters Canyon Channel Peters Canyon Channel San Diego Creek/Barranca Delhi Channel San Diego Creek/Michelson San Diego Creek/Michelson Peters Canyon Channel San Diego Creek/Michelson San Diego Creek/Michelson Peters Canyon Channel Red Shiner 6/9/98

Red Shiner 6/9/98

Red Shiner 6/9/98

Striped Mullet 6/9/98

Red Shiner 6/19/97

Red Shiner 6/19/97

Red Shiner 6/19/97

Red Shiner 6/19/97

Red Shiner 6/18/97
Red Shiner 11/6/96

Red Shiner 11/6/96

Red Shiner 11/6/96

Red Shiner 6/17/95

Red Shiner 6/17/95

Red Shiner 6/17/95



### Freshwater finfish results count

max

mean median 4% 10%

0.344 0.014 0.034

0.116 0.005 0.012

0.200 0.008 0.020

0.882 0.035 0.088
0.134 0.005 0.013

0.057 0.002 0.006

0.063 0.003 0.006

0.148 0.006 0.015

0.085 0.003 0.009
0.06 0.002 0.006

0.07 0.003 0.007

0.15 0.006 0.015

0.150 0.006 0.015

0.170 0.007 0.017

0.090 0.004 0.009

15

0.88 0.04 0.09
0.18 0.01 0.02
0.13 0.01 0.01

summary document 88