## Total Maximum Daily Loads
For Toxic Pollutants San Diego Creek and Ne wport Bay, California

U.S. Environmental Protection Agency Region 9

Public Review Draft April 12, 2002Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 1 Table of Contents

Summary TMDL Document I. Introduction....................................................................................... 2 II. Overview of TMDLs and Available Data....................................................11 III. Organophosphate (OP) Pesticide TMDLs....................................................22 IV. Selenium TMDLs................................................................................30 V. Metals TMDLs...................................................................................39 VI. Organochlorine Compound TMDLs..........................................................50 VII. Chromium and Mercury TMDLs..............................................................61
VIII. Arsenic Analysis.................................................................................67
IX. References........................................................................................69 X. Glossary/Abbreviations.........................................................................74

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 MercuryNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 2 

## I. Introduction

What Is the Purpose of This Action?

This document describes Total Maximum Dail y Loads (TMDLs) being established for several toxic pollutants by U.S. Environmental Protection Agency (EPA) to help protect and restore the water quality of Newport Bay, San Diego Creek, and their tributaries. A TMDL identifies the maximum amount of a pollutant that 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 opportunities. EPA is establishing these TMDL s pursuant to a 1997 consent decree in which EPA committed to ensure that these TMDLs would be establ ished in 2002. EPA has worked closely with the California Regional Water Quality Control Board, Sa nta Ana Region (Regional Board) in the development of these TMDLs. Although the State has primary responsibility for developing TMDLs under the Clean Water Act, the State was unable to complete its fo rmal 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 St ate shall identify those waters within its boundaries for which the effluent limitations...are not stringent enough to implement any water quality standard applicable to such waters.” The CWA also requires states to establish a priority ranking for waters on the 303(d) list of impaired waters and establish Total Maximum Daily Loads (TMDLs) for such waters. As part of Californ ia’s 1996 and 1998 Section 303(d) lists, the Regional Board identified Newport Bay and San Diego Creek as water quality limited due to several toxic pollutants (in addition to other pollutants not addre ssed in these TMDLs) and designated this watershed as a high 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 documen ts (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 po llutant loadings (the Loading 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 determine if they meet all TMDL requirements. If EPA approves the State TMDLs, they will supercede the TMDLs being established now by EPA.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 3 

### 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 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 now proposing to establish the TMDLs for these toxic pollutants in order to meet the requirements of the decree. EPA is pr oposing the TMDLs described in this document and providing the public with the opportunity to comm ent on the draft TMDLs. EPA will consider any comments received during the comment pe riod (up until May 28) in our final TMDL decisions, which will be made by June 15, 2002.



### What TMDLs Are Being Established?

EPA is establishing TMDLs for several toxic 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 addresse d concurrent with the similar pesticide chlorpyrifos, which is addre ssed 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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 4 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 (2001), and in this summary TMDL document below, EPA and the State dete rmined that the list of water body-pollutant combinations warranting TMDL development shoul d be fine-tuned to refl ect the best current information concerning water body impairment. Ba sed on our assessment of the most current local data and national EPA guidance concerning arsenic, EPA has concluded that TMDLs are not needed for arsenic for waters 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 impa irment, reduced reproductive success, and carcinogenic responses. Two primary adverse impact s are associated with toxic substances in these water bodies: a) chemicals may bioaccumula te and are harmful to human health when we consume fish or shellfish and b) chemical concen trations in water, sedi ment or biota may cause ecological risks. Available da ta indicate that the pollutants addressed in these TMDLs were found in water column, bottom sediments, or fish tissue at potentially unsaf e levels which exceed applicable water quality standard s. There is no current evidence of adverse effects on human health due to consumption of contaminated fish or direct exposure to to xic pollutants. Evidence of adverse impacts to aquatic life as a result of direct or indirect exposures to these toxic pollutants is limited. However, because the po llutants addressed in these TMDLs have the potential to cause short term adverse impacts to aquatic life or long term human health and aquatic life impacts due to pollutant bioaccumula tion, actions to reduce discharges of these pollutants to the aquatic environment are warr anted. The TMDLs are designed to assist in targeting pollutant reduction activities. 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, PCBsNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 5 

### 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 conditions in saltwate r bodies, EPA has now conclude d that Newport Bay and its tributaries are not impaired due to arsenic pollu tion. This summary 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. Pursua nt to these decree provisions, EPA is making the determination that arsenic TMDLs are not need ed for waters 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 relate d information. A TSD is also provided that discusses EPA’s anal ysis of freshwater flows in San Diego Creek, which was used to identify the appropriate numeric targets for certain pollutants, address seasonal variations and critical conditions in flows and po llutant loads, and evaluate the best approaches for calculating pollutant loading capacities and allocations. An other TSD provides more maps of the San Diego Creek, Santa Ana-Delhi Channel an d Newport Bay watersheds and analysis concerning water residence times in Upper and Lower Bay. Once the TMDLs become final, a summary of public comments and EPA’s responses to those comm ents will be provided in another TSD.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 6 

### 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.)

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; therefore, the direct e ffect of EPA’s TMDLs is that NPDES permits for point source discharges addressed in the TMDLs will need to be modified as necessary to be consistent with the TMDLs. Permit modification may occur when the permits are reopened or reissued. Federal regulations require that NPDES pe rmits must be consistent with wasteload allocations specified in TMDLs, and the State has some discretion in determining the appropriate permit provisions 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 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 someNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 7 nonpoint sources, remedial action plans to a ddress contaminated sediment sites, and opportunities for voluntary action to comply with load allocations. The Regional Board is currently in the process of de veloping implementation plans for several of the toxic pollutant TMDLs and will address the remaining toxic pollutant TMDLs in the near future.

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. Remediation is scheduled to begin in 2003/2004. The provisions of these toxic pollutant TMDLs could affect the sediment removal project, and EPA and the Regional Board intend to coordinate with the project sponsors to discuss this potential issue.

EPA’s pesticide program has intiated a pha se-out of household uses of diazinon and chlorpyrifos (EPA 2000b, EPA 2001b). It is expected that the phase-out w ill greatly assist in reducing the levels of these pesticides found in the waters of Newport Bay watershed.



### Environmental Setting

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, Agua Ch inon Wash, Borrego Canyon Wash and Serrano Creek

Important freshwater drainages to Lower Newport Bay, together covering 49 square miles, include the Santa Ana-Delhi Channel, Big Cany on Creek, Bonita Creek, Costa Mesa Channel and other local drainages.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 8 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.

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 summe r months. San Diego Creek has a mean base flow rate of approximately 8 cubic feet per s econd (cfs) with significant increases (150 to 4000 cfs) during storm events. San Diego Creek is fr eshwater with wide range of hardness and small influences by the slightly saline water table (less th an 1 or 2% salinity). Upper Bay is an estuary with saline water conditions during dry weather and yet there is heavy freshwater influx (from San Diego Creek and Santa Ana-Delhi Channel) during major storms. Lower Bay waters are dominated by twice-daily ocean tides via the jett y 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 an d early 20th centuries,Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 9 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 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. Following World War II, land use again be gan to change from grazing and open farming to residential and commercial development. As urban development in the watershed proceeded (and continues), drainages were further modifi ed through removal of riparian vegetation and lining of stream banks to expand their capacity and to provide flood prot ection. These changes culminated in the channelization 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 portions of the historic marsh upstrea m 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 insecticides and metals associated with human habitation (e.g., buildings, landscap ing, and motor vehicles). Th is continual conversion of agricultural land to urban deve lopment often includes large c onstruction projects, which may release dirt particles laden with legacy pest icides, and possibly yield runoff that contains pesticide discharges from the structural and landscape control of pests.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 10 Table 1-3 Land Use types in watersheds of Newport Bay San Diego Creek Santa Ana Delhi Newport Bay Land use type Acres % total Acres % total Acres % total Residential 11,668 15.2 5285 18.2 19420 19.7 Commercial 6381 8.3 2397 8.3 9641 9.8 Industrial 3965 5.2 1102 3.8 5263 5.4 Agricultural/ 5092 6.6 0 0 5147 5.2 Vacant 21,910 28.5 1 060 3.7 23,462 23.9 Education/Religion/ Recreation 15,811 20.6 825 2.8 17,393 17.7

No assigned land code 440 0.6 339 1.1 936 0.9

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

Total 76,739 99.9 29003 100 98,362 99.9 Source: OCPFRD land use data defined by sub-wa tersheds to compose each watershed. Most accurate and recent land use data pr ovided by OCPFRD GIS Dept., 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. A summary of the comments received and EPA’s responses will be provided in the Technical Support Document—Part J. The EPA notice of ava ilability was published in the Orange County Register, mailed to the Basin Plan distributi on list provided by the Regional Board, and posted on the EPA Region 9 TMDL website. Additionall y, EPA is scheduled to present the proposed toxics TMDLs to the Newport Bay Watershe d Management committee meeting on April 16, 2002. Public comments on these draft TMDLs s hould be sent to the following address by May 28, 2002:

Peter Kozelka Monitoring and Assessment Office (WTR-2) EPA Region 9 75 Hawthorne Street San Francisco, CA 94105Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 11 

## 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 sett ing, 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 nume ric 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 relative contributions of polluta nt 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,Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 12 • 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, 2001). 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. We examined monitoring data for th e past fifteen years; however, to maximize the relevance of our assessment to present-day water quality, we focused on the most recent results (since 1995). Our assessment evaluated each chemi cal identified in the de cree for four separate water bodies: San Diego Creek, Upper Newport Bay, Lower Newport Bay and Rhine Channel. The water body-pollutant combinations for whic h 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, and/or tissue goals or endpoints for the TMDL which equate to attainment of the water quality standards. In some cases, multiple indicators and associated numeric target values may be needed to interpret applicable water quality standards (e.g. where there is uncertainty that a single indicator is sufficient to measure protection of designated us es). In addition, some TMDLs may incorporate multiple numeric targets to account for differences in acceptable pollutant levels in a particular water body at different time scal es (e.g., short term acute toxici ty effects versus long term chronic 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. Applicable standard s of concern for these toxic pollutant TMDLs include the designated uses and both narrative and numeric water qualityNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 13 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 most sensitive desi gnated aquatic life and wildlife beneficial uses of concern in the wa tershed—RARE and WILD. One primary objective is to protect the special biological and wildlife habitat of the Newport Bay Nature Preserve and Ecological Reserve, in the upper pa rt of Upper Newport Bay. The Na ture Preserve is considered a critical estuary of Southern California. The Upper Newport Ba y 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, Belding's savannah sparrow, leas t tern, brown pelican, peregrine falcon, black rail, and California gnatcatcher. Tw o endangered plants, the salt marsh birds-beak and the rare Laguna live-forever, are also found at the reserve. The second objective is to reduce build up of toxicants in fish and shellfish w ithin all water bodies, th ereby minimizing adverse impacts associated with wildlif e and human consumption of cont aminated food. Seventy-eight species of fish inhabit the Upper Newport Bay waters, including the California halibut and barred sand bass—two 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. The CTR did not establis h numeric objectives for chlorpyrifos, diazinon, or mercury, and the selenium and cadmium objectiv es were established c ontingent on an EPA commitment to revise the objectives prom ptly 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 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 TMDLNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 14 for Se, the Regional Board proposed to apply more protective Se targets based on USFWS recommendations. Therefore, EPA is pr oposing TMDLs based on the promulgated CTR standards, but is inviting comment on the alte rnative approach of basing the Se TMDLs on the more protective targets proposed by the Regi onal Board. (See section 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 settings (e.g. embayments), it makes more sense from the standpoint of source control and impact as sessment 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 tissue endpoints may pr ovide more discriminating indicators of the beneficial use impacts of concern in a TMDL (e.g., pollutant bioaccumulation in the food chain and resultant human health or aquatic life impacts from consumption of contaminated organisms).

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 po llutants 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 nu meric objectives. It appears that the sediment and tissue numeric targets may be somewhat mo re protective than the numeric objectives for these pollutants although the accuracy of translator s between these media is somewhat uncertain. 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 en sure that all applicable standard s are attained. In addition, EPA’s decision to use sediment quality and fish tissue va lues as numeric targets for these pollutants 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 disso lved phase; that is, th ese compounds are either sorbed to bottom sediments or as sociated with extremely fine su spended sediments. Also, there are technological challenges accompanied w ith sampling and accurately detecting these compounds in water column samples. Therefore, these pollutants are unlik ely to be detected in the water column in dissolved form even in wa ters 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 interpretati on of narrative standards. Since a TMDL is an inherently quantitative analysis, it is necessary to determine appropriate quantitative indicators of the water quality problem of con cern in order to calculate a TMDL . It is sometimes possible to supplement water column indicators (i.e., pollutant con centrations in water) with measures in sediment or tissue media since these alternative i ndicators are more directly associated with the pollutant effects of concern.

Where sediment indicators are used in these TMDLs, they are based on sediment quality guidelines developed by the Florid a Department of Environmenta l Protection (MacDonald et al 1996). Where fish or shellfish tissue indicators are used, they are based on tissue screening values established by EPA (EPA 2000d a nd EPA 2000e), the California Office ofNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 15 Environmental Health Hazard Assessment (OEH HA, 1999), or the New York Department of Environmental Conservation (NY DEC 1994; 1998). The specific basi s for these target indicators is discussed 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 2000b and c) and Californ ia 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 ha s selected the lowest recommended values (as provided by either EPA or CDFG) for chlorpyrifos and diazinon.



### 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 Ne wport Bay. Metals loading is associated with historical and ongoing discharg es of urban runoff. Selenium loadings are estimated to come primarily from natural r unoff 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. No sewage treatment pl ants discharge effluent into water bodies of Newport Bay. Some individual permits may be affected by San Diego Creek TMDLs, others by Newport Bay TMDLs or a few not at all. A gene ral permit is in place to regulate discharges associated with groundwater cleanup, which a ffects 21 permittees and focuses principally upon total suspended sediment, petroleum hydrocarbons and chlorinated solven ts. Another general permit is in place which regulates groundwater dewatering operations of 12 permittees and focuses principally on suspended sediment discha rges. Runoff from state highways is regulated through the statewide CalTrans permit.

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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 16 Table 2.1: NPDES Permits In San Diego Creek/Newport Bay Watershed Individual NPDES permits in San Diego Creek watershed: Name Comments

Orange County Stormwater Include s many cities as co-permittees John Wayne Airport Stormwater r unoff flows into Santa Ana-Delhi Channel, therefore this source is addressed in Newport Bay TMDLs (but not TMDLs for San Diego Creek) Tustin Marine Base/GW general At presen t this is general permit, although RWQCB is currently drafting an individual permit Silverado Constructors/GW cleanup TSS under emergency conditions only Irvine Ranch Water District Discharges tertiary treated wa ter into Sand Canyon Reservoir and permit regula tes stormwater overflows from Sand Canyon Reservior Serrano Water Treatment Plant this is a drinking water filtering plant City of Tustin groundwater de salter Irregular discharges Great Lakes Chemical/GW cleanup No longer 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 before r eaching the main stem of San Diego Creek. The Regional Board is currently evaluating whethe r WDRs are needed for two other nurseries (Nakase Nursery and AKI nursery). There are some unpermitted nurseries that are smaller in size than the permitted nurseries. Runoff from other agricultural operations in the watershed, including row crops, orchards, and vine yards, 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.



### TMDLs and Allocations

For each pollutant and water body, this documen t identifies the necessary TMDLs (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 andNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 17 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.

Load allocations for nonpoint sources may be expressed as specific allocations for specific dischargers or as “gross allotments” to nonpoint source discharg er categories. TMDLs usually provide separate load al locations for natural background lo ads. Separate load allocations for background loads are calcu lated for metals. Separate background allocations are inappropriate for pesticides and organochlor ine compounds because they of anthropogenic origin. Separate background allocations could not be calculated for selenium, chromium and mercury because insufficient information was available to support these calculations. Background levels of selenium associated with groundwater inputs to surface water may be significant; however, the physical and hydrological stru cture of the watershed has been highly altered as a result of hydrologic modifications , groundwater pumping, ir rigation practices, and water imports to the watershed. As a result, it would be very difficult to estimate “naturally occurring” selenium discharge levels. Bac kground 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. Pollutant specific allocation schemes are proposed in these TMDLs; EPA is willing to consider altern ative ideas and invite comments that include rationale. Criteria applied to determine the di vision of available pollu tant loading capacity include:

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

• Selenium: Allocations were generally divided in proportion to land use areas of the different allocation categories for nonpoint sources and in proportion to discharge flow rates for point source categories. Consider ation of flow rates in freshwater bodies, directly linked to precipitat ion events, is included.

• Metals: Allocations were divide d in proportion to the tota l estimated existing loads associated with each source category.

• Organochlorine Compounds: Allocations to watershed sour ces were generally divided in proportion to land use areas of different allo cation categories, with some consideration of the feasibility of reduci ng loads for DDT. Allocations between watershed sources and in-Bay sediment sources were divided in proportion to the percentage of total loads associated with watershed vers us 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 watershed sources and in-Bay sediment s ources were divided in proportion to the percentage of total loads associated with watershed versus in-Bay sediment sources.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 18 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 e ach 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.



### 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 flowNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 19 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 organorchlorine (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 which were collected by Orange County Public Facilities and Resource Departme nt (OCPFRD). This data sp ans July 1985 to June 2000; unfortunately OCPFRD flow records for 1995 to 1996 do not exist (pers. commun., L. Waldner). For calculating the flow based approach to Se and dissolved metals TMDLs, EPA used annual flow records for water year 1995, 1997, 1998, 1999, 2000. This time span covers a reasonable diversity of rainfall conditions based on precipitation measurements from 1958 to 2000. That is, it includes the exceptionally wet El Nino year, 1 998, as well as relatively drier years, 1999 and 2000. Table 1-4 shows rainfall recorded at Tustin/ Irvine Ranch gage station for each year within the time span utilized by EPA, as well as hist orical high and low rainfall records. These data illustrate that the data years used by EPA for this approach are reasonably representative of the entire time period. Technical Support Document —Part B gives more explanation of freshwater flows and seasonal variations.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 20 Table 1-4 Annual Precipitation R ecords at Tustin /Irvine Ranch
Water year* Annual Rainfall (inches) Water year* Annual Rainfall (inches) comment

1985 10.3 1995 24.7
1986 14.4 1996 11.2
1987 8.8 1997 16.2
1988 11.1 1998 34.7
1989 8.2 1999 8.6
1990 5.9 2000 8.8
1991 11.2 2001 14.6 1992 17.2 1960--2000 13.3 Annual average 1993 27.1 1961 4.1 Minimum value 1994 10.2 1998 34.7 Maximum value Source: OCPFRD *for example the water year 1997 includes July 1996 to June 1997.



### 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 most relevant studies to these toxics polluta nt TMDLs address sediment toxicity in Newport Bay (2001a), fish bioaccumulation in Newport Ba y (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 2-2.

Table 2-2 Overview of monitoring data Organization Period of record Geographic Scope Measured
Features Measured Parameters and comments Lee & Taylor (2001a) 319(h) report (for SA RWQCB) Winters 1999; 2000 San Diego Creek Watershed stormwater runoff Se; metals and OP pesticides in watershed, Draft report provided May 2001

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 watershedNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 21 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 fourconsecutive day sampling; semiannual 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 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 studyNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 22 

## 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 explici tly 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 a nd in the Technical Suppo rt 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. Toxi city 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 concentrations in surface wate rs of San Diego Creek have exceeded the freshwater chronic numeric target of 50 ng/ L both during baseflow (200 ng/L) and during stormflow (445 ng/L). Average chlorpyrifos con centrations in San Diego Creek have exceeded the freshwater chronic numeric target of 14 ng/ L during baseflow (111 ng/L) and stormflow (87 ng/L).

Upper Newport Bay

Evidence exists indicating water column toxic ity due to chlorpyrif os in Upper Newport Bay. This is restricted to storm events when freshwater inputs from San Diego Creek and Santa Ana Delhi linger in the Upper Bay (Lee and Taylor 2001a;b). Average chlorpyrifos concentrations in surface waters of Upper Ne wport Bay have exceeded the saltwater chronic numeric target of 5.6 ng/L during stormflow cond itions (43.3 ng/L). Toxicity attributed to chlorpyrifos does not extend into Lower Bay. Diazinon does not appear to cause toxicity in saltwater 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. Mussel tissue concentrations of both OP pestic ides have never exceeded the OEHHA screening values. Therefore, there is no compelling eviden ce of bioaccumulation of these substances toNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 23 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, 2001b). Adverse impacts may also be affecting fish survival and reproduction.



### Numeric Targets

At present, there are no promulgated water qua lity criteria for chlorpyrifos and diazinon. For these TMDLs, EPA has selected the numer ic targets from the recommended acute and chronic criteria derived by the California Dept. of Fish and Ga me for chlorpyrifos and diazinon in freshwater (CDFG 2000a) and by EPA for sa ltwater (USEPA 1986). 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 suffici ent to remove impairment caused by OP pesticide toxicity. The selected targets are th e most conservative numeric values for these two OP pesticides. Target concentra tions are shown in Table 3-1; sa ltwater chronic and acute targets for diazinon are not applicable si nce TMDLs are not required for this pollutant in any of the saltwater bodies covered by these TMDLs.

Table 3-1 Selected Numeric Targets Concentration (ng/L)
Pesticide Criterion Freshwater 1 Saltwater 2

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

Chlorpyrifos Chronic 14 5.6 Chlorpyrifos Acute 20 11

1 from Calif. Fish & Game (2000a) 2 from EPA (1986) 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 estimate s of pesticide applicat ions by land use within the watershed; however this does not comprehens ively depict all sources in San Diego Creek.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 24 Additional analysis via land use information indi cates that residential contributions are also significant. The synopsis is presented below, whereas the reader will find a more complete source analysis in the Techni cal 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. Table 3-2 summarizes monitoring results by water body groups such as San Diego Creek Reaches 1 and 2, Peter’s Canyon Channel and Upper Newport Bay. Maximum concentrations were observed in Hines Channel (which drains into Peters Canyon Channel, 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.

The average values for stormflow and base flow exceed the freshwater chronic numeric target (14 ng/L). Within the drainage channe ls, 44% of the chlorpyrif os results exceeded the chronic target. In the Upper Ba y, 92% of the samples were above the saltwater chronic numeric target of 9 ng/L.

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 thatNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 25 commercial nurseries and residentia l areas are associated with hi gh 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 stud ies 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).

Based on data from investigations ca rried out from 1996-2001, about 32 pounds of diazinon are discharged annually to San Diego Creek, mostly duri ng storm events. This is less than 0.3% of the estimated diazinon mass annually applied in the watershed. About 7 pounds of chlorpyrifos are annually discha rged to Upper Newport Bay, with most of the load delivered during storm events. This amounts to about 0.03% of the estimat ed annually applied chlorpyrifos mass. Available data and studies in dicate that in normal use, OP pesticides break down quickly and therefore only a small percentage of the total amount a pplied is available to runoff to waterbodies. However, even small amounts of these pesticid es are enough to cause acute and chronic toxicity in receiving water bodies.

In summary, surface runoff is the source of vi rtually all the loadings. Contributions from atmospheric deposition, sediment remobilizatio n, and groundwater are negligible, and the chemical properties of diazinon a nd chlorpyrifos ensure that th ey do not accumulate in the environment. Runoff derived from urban la nd 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 theNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 26 loading capacity via mass based or toxic units. These concentration-based TMDLs will protect aquatic life from short-term exposure via acute targets and long-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 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 (5.6 ng/L), and a maximum 1-hour average (acu te) concentration of 11 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).

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 freshw ater discharges into Upper Newport Bay including Santa Ana Delhi Channel, Big Canyon Channel and other drainages to Upper Bay. This includes discharges from agricultural and re sidential lands, includi ng flows from the storm water systems. These limits apply regardless of s eason and flow; i.e., at all times of the year.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 27 Table 3-2: Diazinon and Chlorpyrifos Allocations for San Diego Creek Category Diazinon (ng/L) Chlorpyrifos (ng/L) Acute Chronic 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

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 9.9 5.04

Load allocation 9.9 5.04 MOS 1.1 0.56 TMDL 11 5.6 Chronic means 4-consecutive day average

Needed Reductions

Table 3-4 summarizes the estimated needed concentration based (load) reductions for diazinon and chlorpyrifos in or der to achieve the TMDL numeric targets in San Diego Creek. The difference between the current load and the al location is the needed reduction. Chlorpyrifos concentrations may have begun to decline in 2000 and 2001, based on indications of a reduction in usage from the DPR database as well as from the Sales and Use Survey (Wilen 2001) conducted in late 2000. To date, there are no clea r indications of declining trends in diazinon usage in the watershed. This table indicates the estimated needed reduction during average storm flows. As discussed 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 (1996-2001) Allocation Needed Reduction

Storm Average Max Chronic Acute Chronic Acute (ng/L) (ng/L) (ng/L) (ng/L) (ng/L) (ng/L) Chlorpyrifos 120 580 12.6 18 90% 97% Diazinon 848 960 45 72 95% 93%Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 28 Phase out agreements

Diazinon— In January 2001, EPA released a revise d risk assessment and an agreement with registrants to phase out most diazinon uses (EPA 2001b). Under the agreement, all indoor uses will be terminated, and all outdoor non-agri cultural uses will be phased out over the next few years. Retail sales will be banned after D ecember 31, 2002. The EPA expects, on a national basis, that these actions will end over 90% of cu rrent uses. Within the Newport Bay watershed, about one-third of the agricultural crop uses will be removed.

Chlorpyrifos-- In June 2000, EPA published its revi sed risk assessment and agreement with registrants for chlorpyrifos (EPA 2000b) . The agreement imposes new restrictions on chlorpyrifos use in agriculture, cancels or pha ses out nearly all-indoo r and outdoor residential uses, and also cancels non-residential uses wher e children may be expose d. Application rates for non-residential areas where children will not be e xposed (golf courses, road medians, industrial plant sites) will be reduced. Public health use for fire ant eradication and mosquito control will be restricted to professionals. Non-structural wood treatments will continue at current rates. Since the EPA estimates, on a nation-wide basis, that about 50% of the chlorpyrifos use (both licensed and unreported) takes place at residential si tes, the agreement is likely to result in more than 50% decrease in ch lorpyrifos use.

While these agreements should result in signif icant decreases in OP pesticide use and the resulting discharge concentrations to the waterbod ies, additional measures appear to 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 cr iteria 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 asNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 29 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 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.

3. The selected numeric targets for chlorpyr ifos and diazinon are the most stringent concentration-based values for both freshwater and saltwater bodies. For these TMDLs, EPA has selected the lowest recommended values from California Dept. of Fish & Game or (in the case of chlorpyrifos in saltwater) the EPA crite rion as the best water quality indicators for diazinon and chlorpyrifos.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 30 

## 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 fa n deposition in arid and semiarid climates (Presser, 1994).

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 ug/L). This has been observed in numerous st udies, which also cite occasional exceedances of the acute (1 hour max.) criter ion (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 ug/L); nonetheless, fish tissue da ta 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 Se) are currently in progre ss (SCCWRP 2001a; 2001b).

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 (20mg/kg wet) for protection of huma n health as established by OEHHA (1999). However, these same tissue results are within th e range of levels of concern (4—12 mg/kg dry) for toxicological and reproductive effects of 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, 2001)). 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 co ncern. Studies of avia n reproductive success, specifically including Se concentrations 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). As discussed below, EPA’s analysis of flows in San Diego Creek indicates that the duration of measured high flows exceeded 4 days in numerous instances during the evaluated period of record. Mean water residence time in the Bay also exceeds 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 a pply the chronic selenium standards at all flow levels in San Diego Creek and in Newport Bay. Therefore, the numeric targets proposed for theNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 31 Newport Bay watershed selenium TMDLs are the chronic freshwater and saltwater objectives included in the CTR.

The U.S. Fish and Wildlife Service conc luded that the current CTR freshwater chronic water quality criter ion for fresh waters (5 μ g/L) may not be fully protective of threatened and endangered fish and wildlife sp ecies. In response to EPA’s request for a formal consultation on the CTR pursuant to the Endangered Species Act, USFWS prepared a biological opinion document on the effects of the promulgation of the CTR on the listed species and critic al habitats in California (U SFWS 2000). USFWS found that the chronic selenium criterion for fresh waters may not protect threatened and endangered fish and wildlife dependent on the aquatic ecosystem for deve lopment and/or foraging. USFWS opinion was based on extensive review of experimental and field data conducted over the past decade. USFWS concluded th at a chronic criterion for selenium of ≤ 2 μ g/L would be appropriate based on its review of availa ble research. In response to this opinion, USEPA has agreed to reevaluate the cr iteria for selenium and to propose revised aquatic life criteria for selenium in California by January of 2003.

EPA is currently engaged in a proces s of revising its national criteria recommendations for selenium based, in part, on the USFWS opinion concerning the CTR. However, the numeric objectives for selenium water column concentrations have not yet been changed. The Regional Boar d proposed numeric targets for its draft selenium TMDLs which are based on the USFWS recommended chronic criterion of 2

μ g/L. The Regional Board draft TMDLs also apply a higher numeric target of 10 μ g/L under high flow conditions based on its judgment of the level of prot ection needed under higher flows.

EPA is basing the proposed Se TMDLs on the currently applicable chronic
numeric standard of 5 μ g/L under all flows because the pr ocess of reviewing and revising the water column objectives has not been completed.

EPA is also inviting comment on two a lternative approaches to setting the TMDLs. The first method is based on the more stringent target level of 2 μ g/L recommended by USFWS. This target value w ould be applied to all flow tiers. Adoption of TMDLs based on this more stringent num eric target would result in TMDLs and allocations that are 40% of the TMDLs and allocations based on the currently applicable
chronic standard of 5 μ g/L. This alternative would re sult in more stringent TMDLs than the proposed approach but is not based on an adopted numeric water column objective that replaces the existing water column objective.

We are also inviting comment on the State’s proposed variant on th is alternative. The draft State TMDLs apply the 2 μ g/L target at baseflow a nd small flow tiers, and a 10

μ g/L target at the medium and high flow tiers . This alternative would allow higher Se concentrations under high flows based on the State’s conclusion that high flow conditions are temporary and that numeric targets based on acute Se effects are more appropriate for these higher flow conditions. Adoption of th is alternative approach would result in TMDLs that are 160% of the TMDLs and allocat ions based on the currently applicable
standard of 5 μ g/L. This alternative is less string ent overall than the proposed approach although it is based on a more stringent stan dards interpretation under low flows and aNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 32 less stringent standards interpretation under high flows. The rationale for setting basing TMDLs and allocations for higher flow situ ations on the less stringent acute numbers may not be fully supported by local flow histories.

Freshwater targets

EPA is applying the same numeric targets based on the 5 μ g/L chronic water quality standard under all freshwater flow conditions in San Diego Creek. EPA has decided to apply only the chronic standards because these standard s appear to be applicable under all the flow conditions observed in the San Diego Creek watershed. The app licable chronic water quality standards are based on the presumption that polluta nt exposures of 4 days or longer in duration will not occur more than once in any three year pe riod. Based on EPA’s analysis of daily flow records for 1995, 1997, 1998, 1999 and 2000, EPA divided all observed flows into 4 flow categories or tiers: baseflow (<20 cubic feet/second (cfs)), sma ll flows (between 20 and 42 cfs), medium flow (between 42 and 190 cfs), and larg e flow (>190 cfs). EPA has concluded that a significant percentage of flows in all flow categories, and in th e medium flow and large flow categories in particular, exceeded 4 days in dur ation during this period. Therefore, it was appropriate to apply the more protective chronic standard under all flows. The Technical Support Document—Part B provides a complete explanation of these flow tiers and the associated mean annual flow volumes for calculating loads.

Saltwater target

The numeric target for dissolved Se in sa ltwater is 71 ug/L from CTR (USEPA 2000a). The USFWS concurred with this saltw ater value in its review of the CTR. Therefore, this target is expected to result in protection of all designated uses in Newport Bay.

Table 4-1. Numeric targets for Selenium in San Diego Creek and Newport Bay (ug/L). Total Se* Waterbody/type Acute Chronic Dissolved Se#

San Diego Creek/freshwater 5 5 N/a Newport Bay & Rhine Channel/saltwater N/a N/a 71

*Total recoverable = unfiltered sample #dissolved = <0.45 um filter



### Source Analysis

Several monitoring studies, completed with a specific focus on Se during short time periods, provide most of our current understand ing of Se 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 1999). Groundwater may seep into surface waters via 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 pointNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 33 sources (cleanup and dewatering). Surface channels immediately downstream of nurseries were found to have low Se concentrations in base flow conditions (Hibbs and Lee 1999; 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 Se s ources are from commercial nurseries or from sources existing upstream of the nurseries. During rain events, the Se load from upper reach of San Diego Creek was comparable to that fr om Peters Canyon Wash; suggesting runoff from open space is a significant source during rain even ts. Low concentrations were found in nursery channels during baseflow conditions.

Table 4.2 Reported Selenium conc. in San Die go Creek and Santa Ana-Delhi Channel (ug/L)

Location Lee andTaylor * 5/31/00 Hibbs and Lee ¥
10/31/99 IRWD @

12/97–3/99

San Diego Creek (at Campus Dr.) 22.1 19 42.5

Santa Ana-Delhi (at Irvine Ave.) 11.9 --- ---

*Lee and Taylor (2001a) results for unfiltered samples

¥ Hibbs and Lee (1999) results for dissolved sample

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

Urban runoff is found to contain ve ry low Se concentrations (< 1.5 μ g/L) (Lee and Taylor 2001a). Atmospheric deposition of selenium is not significant compared to loading from San Diego Creek and other freshwater tributaries (M osher and Duce, 1989). The concentration of selenium in ambient seawater (0.080 ug/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). Runoff from open space, hill sides, and agricultural lands could also be significant sources during rain events. In genera l, groundwater seepage/infiltration represents a significant and constant source.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 34 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 Newport Bay/San Diego Creek watershed. (For EPA TMDLs, nurseries have been grouped with agricultural runoff in Table 4-5 and allocations tables.)



### 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.

San Diego Creek

This TMDL uses a flow-based approach to determine the loading capacity for Se in San Diego Creek. This approach addr esses contributions of Se under va rious flow regimes or tiers. Four flow tiers were chosen based on a statistical analysis of daily flow records for San Diego at Campus Dr. (See Technical Support Document—P art B for more explicit information about freshwater flows.) Specific loading capacities for each flow tier are calculated from the desired Se concentration (i.e., the numeric target) and the annual mean flow volume associated with each tier (Table 4-3). The 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 (cfs) Flow Volume* associated with tier (thousand cubic ft.) Se

conc. with tier (ug/L) Loading capacity per tier @ (lbs/yr.)

Base flow 0—20 305 5 95 Small flows 20—42 107 5 33 Medium flows 42—190 126 5 39 Large flows >190 1208 5 377
Total annual
amount 1746 545

*Annual mean volume based on OCPFRD records for water years: 1995, 1997, 1998, 1999, 2000.

@ Se per tier (lbs/yr) = flow volume (ft 3 /yr) x desired Se target (ug/L) x conv. factor (0.00006243 lbs x L/mg x ft 3 )Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 35 Newport Bay

The loading capacity for Newport Bay is presen ted in Table 4-4. This loading capacity is calculated using the Se saltwater numeric target (71 ug/L) and the volum e 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 545 Santa Ana Delhi 110 ¥

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 for water years: 1995, 1997, 1998, 1999, 2000 *based on calculation CTR saltwater chronic value (71 ug/L) and the volume of Newpor t Bay water, adjusted to account for daily water movement into and 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. Table 4-5 lists the source categories for which allocations are proposed.

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

Table 4.5 Sub-categories of allocatio ns 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

Wasteload and load allocations are assigne d 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 loading (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 seasonNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 36 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 removed from the a llocation scheme due to low loading from this source (see TSD pg. D-12). Any loadi ng from atmospheric deposition is less than the explicit margin of safety discussed below.

Discharges from groundwater cleanup and gr oundwater dewatering could be significant sources and loading from those operations depends on their location. However, the quantification of loading fr om individual discharges is not feasib le at this time due to lack of Se data in effluent from those operations. In th is TMDL, allocations are assigned to groundwater cleanup and dewatering as one poi nt source group each. EPA r ecommends that the Regional Board monitor flow and Se concentrations in discharges from cleanup and ground water dewatering operations as part of an implementati on strategy for this TMDL. Loading limits for individual discharges can then be assigned based on the monitoring data.

Table 4-5 shows the wasteload and load allocati ons based on the sum of loading capacity for San Diego Creek and Santa Ana-Delhi Channel. Th e estimated current annua l load is considered as the current load of selenium at Campus Dr ive based on IRWD monitoring data (4/98-3/99). The Se TMDLs and allocations are expressed in ma ss-based annual loads. Daily loads could be calculated by dividing the a nnual TMDLs and allocations by 365. However, annual loadingbased TMDLs and allocations are more approp riate because prospective adverse effects associated with Se are associated more w ith long term mass loadings and bioaccumulation effects than with short term or acute effects. An explicit margin of safety (MOS) of 10% was included to account for uncertainty in the analys is and ensure compliance with water quality objectives.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 37 Table 4-5 Wasteload and Load allocations of Selenium for Newport Bay watershed.
Source Loading capacity (lbs/year) Current load Estimated reductions
Tier 1 Tier 2 Tier 3 Tier 4 Annual total
WLA
MCAS Tustin 2.06 0.72 0.75 6.12 9.64 Silverado GW 4.12 1.44 1.70 16.31 23.6

GW clean up 8.23 2.89 3.2 28.55 42.9
GW dewatering 5.15 1.81 1.92 16.31 25.2

Other GW facilities 0.51 0.18 0.21 2.04 2.9

Stormwater Permit 0.51 0.36 0.43 4.08 5.4

WLA subtotal 20.58 7.40 8.20 74.41 109.64

LA All nurseries 4.1 1.4 1.7 16.3 23.6 Ag runoff 7.2 2.7 3.4 34.7 48.0 Undefined

sources # 71.0 24.6 29.3 283.5 408.3

LA subtotal 82.3 28.7 34.4 334.4 479.9

MOS 65.5

Total 102.9 36.1 42.6 407.9 655.04* 3248 ¥ 82%

* sum of loading capacity for San Diego Creek and Santa Ana-Delhi Channel, (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



### Seasonal variation/Critical conditions

As previously described, EPA is calculating these Se TMDL s based on freshwater flow rates instead of seasons. The flow rates corres pond to flow tiers whic h 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 wh ich are influenced by pr ecipitation and runoff. Given that storm events may occur at any time of the year, the corres ponding 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. 65 lbs/year).Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 38 Most of the uncertainty associated with calc ulation of the TMDL for selenium relates to freshwater flow rates. The average flow rates fo r dry and wet seasons were calculated using five years of OCPFRD flow data (water year 1995, 1997, 1998,1999, 2000, since 1996 flow data is not available). As discussed in the Techni cal Support Document—Par t B, the precipitation records (and therefore flow record s) for these five years are elevat ed relative to other five-year groups. This is attributed to 1998 when San Die go Creek has record stream flows due to El Nino weather conditions. Using these slig htly higher than average stream flows, this yields a loading capacity that is slightly elevated relative to drier water yearsNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 39 

## 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 fres hwater flows and Part E which describes metals source analysis and methods used to de termine 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 ma y not be reliable for 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, San Diego Cr eek waters exhibit a wide rang e of flow rates and hardness levels. That is, low flow rates have high har dness values (e.g., 20 cfs corresponds to >400 mg/L hardness) whereas high flow rates have lowe r hardness (e.g., 760 cfs co rresponds to 240 mg/L hardness). This inverse relati onship between flow rate and ha rdness influences both acute and chronic metals numeric targets.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 40 Based on conclusions drawn from analyzing fl ow records measured at San Diego Creek at Campus (OCPFRD), EPA proposes four flow tie rs for San Diego Creek. A hardness value is defined for each flow tier which is used to calcul ate the associated acute and chronic targets for dissolved metal. (Table 5-2). For the basefl ow and small flow tiers, EPA used the maximum hardness value (400 mg/L) as allowed in CTR (USEPA 2000). A review of available data indicated that actual hardness associated w ith flows in these tiers often exceeds 400 mg/L; however, the CTR caps the allowable hardness value that can be used to calculate the resulting hardness. For the medium flows EPA selected the highest flow value within this tier to determine the corresponding hardness value. For large flows, EPA reviewed daily flow rates for 4-consecutive days and used the highest (4 day) mean flow rate to determine the corresponding hardness value.

EPA is identifying numeric targets for bot h chronic and acute c onditions; however, the TMDLs are calculated based only on the chronic st andards and associated numeric targets. EPA is identifying the acute numeric targets solely to assist in interpreting future monitoring results for assessing instantaneous compliance with sta ndards. EPA considered applying acute targets to calculate TMDLs for the medium and large fl ow tiers. However, EPA decided to apply only the chronic targets because our review of daily flow records indicates that storm events produce sufficiently elevated flows (>190) that linger for 4-consecutive days or longer. Similarly, it was appropriate to calculate TMDLs for Newport Bay based on chronic targets because average water residence time in the Bay was estimated to exceed 4 days under all likely flow conditions. The investigation of precipitati on, flow rates and the relationship to hardness is explained more thoroughly in the Technical S upport Document—Part B.

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

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

(mg/L)
Base flow 0--20 305 N/a * 400 Small flows 20-42 107 N/a * 400 Medium flows 42-190 126 190 320

Large flow >190 1208 1861 190

# mean volume for each tier based on OCPFRD daily flow records for water years: 1995,97,98,99,00 * flow rate not used for these tiers; hard ness 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 CTR. 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 chronic cond itions (which are used in the calculation of these TMDLs) and for acute conditions (which are included solely to assist in interpreting future monitoring results. The Technica l Support Document—Part E presen ts a step-by-step discussion of how numeric targets were cal culated based on CTR equations for each pollutant, fresh water flow rates, and corresponding hardness values.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 41 Table 5-2. Metals Numeric Targets (ug/L) based on flow tiers for San Diego Creek.
Base and Small Flows (<42 cfs) hardness @ 400 mg/L Medium Flows (42 - 190 cfs) hardness @ 320 mg/L Large Flows (>190 cfs) hardness @ 190 mg/L Dissolved Metal Acute Chronic Acute Chronic Acute Chronic Cd 19.1 6.2 15.0 5.3 8.6 3.6 Cu 50 29.3 40.2 24.2 30.7 15.5 Pb 281 10.9 223 8.7 165 5.0 Zn 379 382 314 316 246 203.5

Saltwater bodies

In saltwater systems, the dissolved metals numeric targets are st raightforward; i.e., hardness is not involved. Additiona l numeric targets have also been selected to address toxicity in saltwater sediments. These sediment targets are the lowest (most protective) levels available in scientific literature and ar e derived from Florida Department of Environmental Protection studies (Macdonald et al, 1996). The dissolved water column and sediment targets apply for Cu, Pb and Zn within Upper Bay, Lower Ba y 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; Florida DEP values for sediments) *Cd value applies for 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:

a) The existing numeric standards are expressed in the CTR in te rms of dissolved metals (EPA 2000a). The CTR rationale is that dissolved forms are the most bioavailable to aquatic organisms. b) Particulate/dissolved metal ratios were estima ted from OCPFRD stormwater data and could be used to translate these dissolved metal ma ss loads into total loads. However, these translator values developed from paired metals data are close to unity. For example, we calculated a site-specific translat or 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, disso lved metals measures are prob ably fairly good predictors of total metals concentrations. Moreover, we ha ve incorporated an ex tra explicit margin of safety to account for the possibility that a focus on dissolved metals does not fully account for total metals concentrations.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 42 c) EPA recognizes the Sediment TMDLs already established for these waterbodies 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 metalcontaminated sediments.



### Source Analysis

This section summarizes our analysis of the major sources of dissolved 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 a ssociated 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, it is inf easible to accurately estimate a nnual loads since loading data are extremely limited.

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 as from July 1997 to June 1998.) These results s how considerable variability due to different rainfall amounts and fluctuating fres hwater 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 slightly 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 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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 43 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.) Total load (lbs.) Total load (lbs.) Total load (lbs.) Cu San Diego Creek 15,087 6261 1643 682 Santa Ana –Delhi 1643 682 185 77 Pb San Diego Creek 10,385 3977 449 172 Santa Ana –Delhi 1297 497 124 47 Zn San Diego Creek 63,021 20,985 3784 1260 Santa Ana –Delhi 7031 2341 805 286 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: natural runoff from open spaces, nursery and agricultural applic ations, groundwater dewatering and cleanup, and atmospheric deposition. Monitoring data exist for natural dissolved metals c oncentrations 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 for these na tural sources because the area upstream from this site is essentially undevelope d. Based on State pesticide use reports (CDPR 1999) for some nurseries, applications of copper sulfate appears as the most prominent metal containing substance; nonetheless annual metal applications are small (e.g., 72 lbs/yr) relative to watershed wide surface runoff estimates (rangi ng 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 other freshwater tributaries—has already been include d within surface runoff estimates. It is considered minimal in comparison to other cont ributions to surface runoff because there 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 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 significantNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 44 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 stream via surface runoff, has already been included as pa rt of the freshwater inputs from San Diego Creek, Santa Ana Delhi Channel and other draina ges to Newport Bay. Direct deposition, where metals directly enter the water surface, are le ss than 1% of metal cont ributions to Upper and Lower Bay.



### Loading Capacity/Linkage Analysis

San Diego Creek and tributaries

Metals loading capacities for San Diego Creek were calculated by multiplying the chronic numeric target calculated for each flow tier (see Table 5-1) by the mean annual water flow volume associated with each tier to yield an allowable mass lo ad for each flow tier. This approach is similar to that presented in the Se TMDLs. (An example of this calculation for dissolved copper is provided in the Technical Su pport Document—Part F.) The sum of all four tiers equals the mass-based loading capaci ty for San Diego Creek (Table 5-5).

Newport Bay

For Upper and Lower Bay, including Rhine Ch annel, the loading capacities were also calculated by applying the chroni c numeric target by the volume of water in the Bay, accounting for water exchange rates between Newport Bay a nd the Pacific Ocean. The loading capacities are based on the saltwater dissolved metals targets (Table 5-3); they are not hardness dependent. The mass-based loading capacity is shown in Table 5-5. (A description of this calculation is presented in Technical Support Document—Part F.)

Concentration-based Option

EPA is also considering expressing the lo ading capacities and associated TMDLs and allocations for San Diego Creek in terms of allowable chronic metals concentrations under different flows and associated hardness levels. Similarly, EPA is considering the alternative approach of expressing the loading capacities, TMDLs, and allocations for Newport Bay based on the allowable metals concentrations as expres sed in the chronic numeric targets for the Bay. EPA is inviting comment on the concentration-ba sed option, which is discussed further in the TMDL and allocations section below.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 45 Table 5-5. Dissolved metal loading capa city for San Diego Creek and Newport Bay

Dissolved

Metal San Diego Creek Dissolved load (lbs/yr) Upper and Lower Bay including Rhine Channel

Dissolved load (lbs/yr) Cd 488 12,367* Cu 2114 12,087 Pb 726 26,889 Zn 27,670 259,249 *Cd load applies to Upper Bay only, where volum e of Upper Bay is approximately 40% of the total volume of Newport Bay

The mass-based and concentration-based approaches to expressing these TMDLs and allocations both have advantages and disa dvantages, which are summarized below.

On one hand, metals TMDLs need to protec t against adverse effects on aquatic life associated with short term exposures to toxic metals. A concentration-based approach may be more sensitive to this kind of impact and less sensitive to problems associated with long term metals loading. Over longer time frames, cumu lative metals discharges are of concern in embayments and possibly fresh water waterbodies because metals may associate with sediment and accumulate in bottom sediments, where they may contribute to sediment toxicity and associated ecosystem impacts. A mass-based approach may be more sensitive to this kind of impact and less sensitive to short term, ambient toxicity effects.

Mass based allocations would set a definitiv e upper limit on the amount of each metal allowed to be discharged into San Diego Cr eek and Newport Bay, which would probably be most effective in addressing long term sediment toxicity concerns. However, mass-limit based allocations would be challenging to meet duri ng individual wet years, although the flow tier approach is designed to help address this co ncern. Moreover, atta inment of mass-based allocations may be more difficult to monitor.

Concentration-based allocations accommodate the dynamic nature of freshwater systems with diversity of flows and indi vidual hardness conditi ons. Metals concentr ations are generally easier to monitor; however, hardness measuremen ts would be needed in addition to metals concentration measurements. However, a focu s solely on concentrations could result in compliance with concentration-based allocations and still allow metals loadings at levels that contribute to unacceptable downstream sediment t oxicity. This option could rely on alternate seawater sediment targets (Table 5-3) to pr ovide acceptable conditions for benthic organisms.



### TMDLs and Allocations

The proposed TMDLs allocations are based on th e mass-based approach discussed above. The TMDLs and allocations may be expressed in terms of the following general equation:
TMDL = Σ (wasteloads from stormwater runo ff, groundwater cleanup and dewatering discharges) + Σ (load from hillside runoff, agricultural runoff, atmospheric deposition and undefined sources) + Margin of SafetyNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 46 San Diego Creek

Table 5-6a identifies the proposed mass based allocations for dissolved metals from San Diego Creek. They are based on the chronic targ ets and the associated flow volume per tier. The total allocation has been reduced by 20% to a ddress load associated with particulate-metals as discussed below in the margin of safety sec tion. These allocations apply to the annual amount to be recorded at San Diego Creek at Campus Drive. Additional mass-based allocations (using similar calculation methods) apply to Santa Ana-Delhi Channel.

Table 5-6a Mass-based Allocat ions for San Diego Creek Categor

y Type Copper Zinc Lead Cadmium

Urban runoff 712 18,078 492 314 CalTrans 127 1660 44 30 Other NPDES permittees 106 1384 36 24

Sub-total 945 lbs/yr 21,122 lb s/yr 572 lbs/yr 368 lbs/yr WLA

Nurseries 140 12 0 4 Ag runoff 7 5 0 4 Undefined (natural) 600 1,000 9 14

Sub-total 747 lbs/yr 1017 lb s/yr 9 lbs/yr 22 lbs/yr LA

MOS 422 lbs/yr 5535 lbs/yr 145 lbs/yr 98 lbs/yr

Total
TMDL 2114 lbs/yr 27,674 lbs/yr 726 lbs/yr 488 lbs/yr

As discussed in the loading capacity section, EPA is also considering the option of expressing TMDLs on a concentration basis. If this alternative approach is selected in the final TMDLs, the freshwater allocations would be the concentration-ba sed targets, reduced by 20% to provide the margin of safety discussed below (s ee Table 5-6b for freshwater allocations under this option). These alternative a llocations would apply to all fresh water discharges to San Diego Creek, Santa Ana-Delhi Channel, Big Canyon Cha nnel, East Costa Mesa Channel and other drainages. This includes disc harges from agricultural, urba n and residential lands, including flows from the storm water systems. These alloca tions would apply at all times of the year.

Table 5-6b. Concentration-based Dissolved Me tals Allocations for Sa n Diego Creek (ug/L)
Base & Small Flows (<42 cfs)

hardness @ 400 mg/L Medium Flows (42 - 190 cfs)

hardness @ 320 mg/L Large Flows (>190 cfs)

hardness @ 190 mg/L Dissolved Metal Chronic Chronic Chronic
Cd 4.96 4.2 2.9 Cu 23.4 19.4 12.4 Pb 8.8 7.0 4.0 Zn 305.9 252.8 162.8
Values are 80% of freshwater numeric targets in Table 5-2Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 47 Newport Bay

Table 5-7a presents the proposed mass based allocations for dissolved metals in Newport Bay; they are not hardness dependent. These allocations apply to the water column in Upper Newport Bay (defined from San Diego Creek at Jamboree Rd. down to Pacific Coast Highway Bridge), Lower Newport Bay (defined from PC H Bridge to the Newport Jetty) and to Rhine Channel (defined by line drawn from 20 th St. across to Lido Beach St.). These allocations apply to the receiving waters of Newport Bay at all ti mes of the year, regardle ss of freshwater flow from San Diego Creek, Santa Ana-Delhi, Costa Me sa Channel and other tr ibutaries into Newport Bay. It is assumed that NPDES boatyard permitt ees are not discharging into salt waters of Newport Bay, rather the boatyard ef fluent is contained in site sumps or re-routed to Orange County Sanitation District treatment plant as part of pre-treatment program. Table 5-7b presents the concentration-based dissolved metal allocations for Newport Bay.

Table 5-7a. Mass-based Allocation Sc heme for Metals in Newport Bay Category Type Copper Zinc Lead Cadmium Urban runoff 3204 184,908 20,237 9200 CalTrans 121 2592 269 123 J. Wayne Airport 60 1296 134 62 Boatyards 0 0 0 0

Other NPDES permittees 181 3889 403 186

Sub-total 3566 lbs/yr 192,685 lbs/ yr 21,043 lbs/yr 9571 lbs/yr WLA

Ag runoff 30 296 0 8
Boats 5007 1000 0 0 Air deposition 101 606 68 3.5 Undefined (natural) 966 12,813 400 311.5

Sub-total 6104 lbs/yr 14,715 lb s/yr 468 lbs/yr 323 lbs/yr LA

MOS 2417 lbs/yr 51,849 lbs/yr 5378 lbs/yr 2473 lbs/yr

Total
TMDL 12,087 lbs/yr 259,249 lbs/yr 26,889 lbs/yr 12,367 lbs/yr

20% margin of safety applied to total loading capacity

Table 5-7b. Concentration-based Dissolved metal allocations for Newport Bay (ug/L)

Metal Dissolved saltwater chronic (ug/L)
Cd 7.4
Cu 2.5
Pb 6.5
Zn 64.8 Values are 80% of seawater numeric targets in Table 5-3.



### 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 Die go Creek that result in either exceedances of numeric targets nor impairment. This is due to higher hardness levels during low flows thatNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 48 mitigate metals toxicity through competitive bind ing 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 hardness and higher metal levels; these conditions ar e 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.



### 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. The flow-based approach to determining metal loading for freshwater bodies has utilized the more protective chronic water quality criteri a. For all flow tiers, the chronic numeric targets—the lowest possible value—was used to determine the appropriate water quality criteria. For saltwater bodies, the chroni c criteria were applie d at all times.

2. 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.

3. 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).Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 49 4. OCPFRD estimates of metal load ing have used unfiltered sample results and this yields an overestimate since dissolved metal concentrations may be lower than total metal concentrations.

5. The flow-based approach to determining metal loading for freshwater bodies has utilized the more protective chronic water quality criteri a. For all flow tiers, the chronic numeric targets—the lowest possible value—was used to determine the appropriate water quality criteria. For saltwater bodies, the chroni c criteria were applied at all times.

6. No adjustment or lowering has been made to address mixing and dilution within the drainage channels contributing to San Diego Creek. Also, no allowance was made for the process of metals precipitation (forming partic ulate metals forms) of dissolved metals as freshwater mixes with saltwater.

7. Chemical speciation has not been included w ithin calculations of loading capacity nor allocations. The truly bioavailable metal fr action (free metal ion concentration) may be much lower (at least 10 times) than dissolv ed metal concentration. This has been reported for Cd, Pb, Cu and Zn within fr eshwater and saltwater systems (Buffle 1988, Bruland 1991, Sunda et al. 1987).Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 50 

## VI. Organochlorine TMDLs

TMDLs are required for chlordane, total DDT and total PCBs in all waterbodies: San Diego Creek, Upper Bay, Lower Bay and Rhine Cha nnel. Dieldrin TMDLs are required for San Diego Creek, Lower Bay and Rhine Channel. A TMDL for toxaphene is required for San Diego Creek only. The term “organochlorine compounds” includes all of these pollutants; whereas, the phrase “organochlorine (OC) pes ticides” refers to DDT, chlordan e, 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 narrative water quality standa rds discussed are not bei ng met. Specifically, toxaphene exceedances (87%, n=15) of the OEH HA tissue screening value occur only in San Diego Creek (TSM, 2001). Bioaccumulation of PCBs , DDT, chlordane and dieldrin appears to be occurring in San Diego Creek and in all salt water bodies of Newport Bay, except for dieldrin in Upper Bay. This conclusions is based on an alysis of fish tissue results from several monitoring efforts (SMW, TSMP, CF CS and SCCWRP databases, se e 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 EPA and OEHHA ti ssue screening values are still occurring. The sediment concentrations do no t show the same declining tre nd in freshwater and saltwater sediment results.



### 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 decisi on has been based on the following 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 saltwaters; 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.

The use of sediment criteria in this analys is is believed to be the most protective interpretation of water quality criteria and th e sediment targets will serve as the optimal interpretation of the narrative water quality obj ectives established by Regional Board Basin Plan (1995).Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 51 The numeric targets for freshwater and saltw ater systems for chlordane, dieldrin, DDT, PCBs and toxaphene, are shown in Table 6-1. Th e primary target value is based on sediment levels, and the alternate targets ar e provided for fish and shellfish tissues. The specific numeric values for sediment targets were selected fr om Florida Dept. of Environmental Protection (MacDonald et al. 1996) as previously discussed in Section II of this summary document. By selecting sediment targets, EPA will address prot ection of aquatic and benthic organisms as well as bioaccumulation of these organochlorine com pounds into tissues of higher organisms such as fish, wildlife predators and humans. Sediment targets will be used for TMDL development except where sediment data were not availabl e; e.g., toxaphene in San Diego Creek. The alternate targets—fish tissue values from New York Dept. of Environmental Conservation—are included in this TMDL report as means of gauging improvement in the water quality and progress towards achievement of th e TMDL, and also because they directly relate to the human health water quality objective. [Note sediment va lues are presented in dry weight units whereas fish tissue values are wet weight basis.]

Table 6-1. Numeric targets for organoc hlorine compounds for all waterbodies. Waterbody Analyte Sediment target@ (ug/dry kg) Fish tissue target (ug/g wet) Chlordane 2.26 0.5 Dieldrin 0.71 0.12 Total DDT 1.19 0.2 Total PCBs 21.5 0.11 San Diego Creek and tributaries

Toxaphene 0.1* 6.3

Chlordane 2.26 0.5 Dieldrin 0.71 0.12 Total DDT 1.19 0.2 Upper and Lower Newport Bay, and Rhine Channel Total PCBs 21.5 0.11 *this value assumes 1% total organic carbon in sediment sample @sediment targets equal to threshold effect levels (TEL) from MacDonald et al. 1996 all tissue targets from NY Dept. Environmental Conservation



### 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; therefore the source analysis is primarily a qualitative assessment. The assessmen t is based on reviews of available information on the physical and chemical properties of each ch emical, the expected uses of each, the likely locations of use, and available monitoring data that characterizes cu rrent conditions in the environment. A wide range of information was evaluated to identify potential sources and to characterize contributions, including monitori ng data, data from nati onal, state and county program databases, and scientific literature. More details on the efforts to identify and characterize potential sources of organochlorine compounds are provided in the Technical Support Document—Part F.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 52 The main source of organochlorine compounds in the Newport Bay watershed is believed to be surface soils or in-stream sediments to which these pollutants have adsorbed (binded). Sediment-adsorbed pollutants are believed to enter Newport Ba y from San Diego Creek (88%) and various smaller tributaries and local drainages (12%). The sedi ment 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 detected. These organochlorine compounds may also ex ist in groundwater (due to percolation), may transport via volatilization (f rom surface soils or water surface) and as implied above they may become resuspended into the water column via physical processes in water bodies. Without sufficient local analytical data, it is difficult to qu antify these sources, yet th is may be revisited in the future.

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. Two researcher s, Masters and Inman ( 1998), have examined fluvial transport of DDT and ot her legacy pesticides in Uppe r Newport Bay; they hypothesize that historic agricultural and urban applications of these co mpounds are the primary upstream sources. In general, these runo ff and erosion processes have the ability to pick up and transport these OC pesticides and deposit them in a different location in the watershed, to a stream system, or to the Bay. The amount of transport and the locations of deposition depend on many factors, including the presence of the pollu tant and the intensity and durati on of the precipitation event, which drives stream flow velocity and possibl y direction. Because or ganochlorine residuals from past applications still remain in soils, the potential still exists for these chemicals (and their degraded metabolites) to be transported in to water bodies during runoff-producing rainfall events. Insufficient information exists on the sp ecific location and actual magnitude of these sources to support precise loading estimates; ther efore, we inferred existing loadings based on limited data and we estimated the pollutant distributions amongst many diffuse sources.

The only active source of any of the OC pes ticides is the application of Dicofol, a registered pesticide that cont ains small amounts of DDT (i.e., up to .015%). The DPR pesticide use database reveals that Dico fol (trade name “Kelthane”) ha s been recently applied to agricultural fields with in the Newport Bay watershed (502 lbs. in 1998 and 470 lbs. in 1999). Relative to other sources of DDT (i.e., residuals in soils), Dico fol is not estimated to be a significant source of DDT to Newport Bay; nonethel ess future use of this pesticide must be minimized

Polychlorinated biphenyls (PCBs)

Electrical transformers are the most comm on 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 disc harges have resulted in sedime nt contamination and that theNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 53 contaminated soils tend to collect in slow river stretches or reservoirs (GE 1999). The contaminated soils remain there until they are dredged or dislodged by storms. Releases of PCBs into the San Diego Creek and Newport Bay waters heds could have resulted from accidental PCB spills, especially those lo cated in the El Toro and Tustin Air Stations as well as other hazardous waste sites. Insufficient information exists on the specific location and actual magnitude of these sources, thus we inferred existing loadings base d on limited data and we estimated the pollutant distributions amongst many diffuse sources.



### Modeling and Analysis

A sediment deposition budget model was deve loped for these toxics TMDLs. This sediment model was based on hydrologic and mo deling information previously compiled by Resource Management Associates (RMA 1997, 1998, 1999) for the U.S. Army Corp of Engineers (ACOE). Modeling and da ta analysis were used to deri ve linkages between selected target values, loading capacity, and allowable loading for each cr itical area of the receiving waters. Additional analyses were used to derive the time required to meet numeric targets if the long-term loading is maintained at or below the a llowable loading. If, in fu ture years, the actual pollutant discharges are below th e allowable loading, this would potentially expedite compliance with numeric targets and associated water quality objectives.

A relatively simple approach was employed to link the bottom sediment conditions with the water column pollutant concentrations and where necessary mussel (or fish) tissue concentrations. Site-specific bioconcentra tion factors (BCFs) and bi ota-sediment accumulation factors (BSAFs) were calculated and applied fo r each compound. In this manner, the sediment deposition budget model was interconnected to th e physical and chemical interactions within a specific location of Newport Bay. This approach was calibrated using all available monitoring data. The calibrated model was then used to ca lculate allowable loadings associated with the water column so that bottom sediment or approp riate tissue targets will ultimately be attained. Detailed descriptions of the modeling analys is are provided in Tec hnical Support Document— Part F. The modeling analysis included estimates of existing loadings, estimates of current sediment accumulation rates, derivation of re lationships between tissue/mussel data and sediment concentration of key pollutants, estimat es of pollutant accumulation, and conditions in deposited sediments over time.



### Loading Capacity/Linkage Analysis

The loading capacity for each pollutant was calculated for San Diego Creek and representative critical areas of Newport Bay. Each loading capacity was derived using a combination of analyses described briefly belo w and explained more t horoughly in the Technical Support Document—Part F. Selection of the appropriate technique and assumptions was dependent on the data available for each pollutant type and location. In most cases, we used the sediment target concentrations to calculate the associated water column concentrations and corresponding mussel tissue concen trations which were typically below the alternate tissue targets. However, in some cases we needed to work backwards from tissue to water to sediment to determine if the sediment targets would be met. The OC compound loading capacities for San Diego Creek and Newport Bay are listed in Ta bles 6-2 and 6-3, respec tively. To assist the reader, some references to specific tabl es in TSD—Part F are included here.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 54 For the listed OC pollutants in San Diego Creek the loading capaci ties were calculated based on both water-column criteria and identifi ed sediment target endpoints. Partition coefficients were used to estimate the particulate- associated portion of the pollutant load. Using bottom sediment targets as an endpoint, the appr opriate water-column con centration can be backcalculated to determine the loading capacity. Th e particulate loading associated with the water column will then result in meeting the sediment target when it settles to the bottom. The resulting loading capacities are li sted in Table 6-2 (and F-8 of TSD). Loading capacities are presented as long term annual loading consistent with the patterns of se diment deposition in the system. The loading capacity for San Diego Creek is estimated from analysis of historic flow records (USGS data, 1985 to 2000) a nd in-stream concentrations.

Based on the loading potential and an estimat e of the distribution of sediment deposition, the loading capacity for Newport Bay was es timated for Upper Bay, Lower Bay and Rhine Channel. The loading capacities for these areas within Newport Bay are estimated using the previously described sediment deposition budget model developed for this TMDL and the appropriate sediment (or tissue) target values. Previous modeling studies have examined the circulation patterns, and transp ort and deposition of sediments in Newport Bay (RMA 1998). By examining RMA model calibration results fo r Newport Bay from 1985-1997, the sediment deposition in each critical area of Newport Bay can be estimated (Table F-9 of TSD). Historic pollutant loads to the bottom sediment can be approximated by using observed pollutant concentrations in bottom sediments and net se dimentation rates (see Table F-10). Estimated loading capacity for Newport Bay is based on th e desired sediment targets as opposed to the observed pollutant concentrati ons, see Table 6-3 below (and Ta ble F-11 in TSD). Sediment volume is converted to dry weight by use of an estimated porosity (0.55). The loading capacities are presented as average mass per year to reflect the long-term accumulation patterns associated with sediment and pollutant accumulation in Newport Bay.

The loading capacity was determined using th e model discussed in the TSD and in the “Modeling and Analysis” section of the summary document, in order to determine the maximum amount of loading which could occu r and still result in attainment of the sediment targets. The model, as discussed, links source contributions to pollutant conc entrations in bottom sediments and predicts the trend of pollutants in the sedi ment. The model takes into consideration such factors as the existing water column concentrations (either observed or calculated from the tissue concentrations in mussels), data and modeling of sediment deposition into the waterbodies, decay rate for a pollutant in the water column, thickness of the water column and active sediment layer, resuspension rate and burial rate.

Table 6-2. Estimated Loading Capacity for San Diego Creek

Pollutant Name Water Column* Total Concentration (ug/L) Load capacity (g/year)
Chlordane 0.00147 71.80 Dieldrin 0.00060 29.31
DDT @ 0.00100 48.84 PCBs 0.001058 341.9 Toxaphene 0.000086 4.20
*All values derived from State Mussel Watc h data (1984-1993) at Macarthur Blvd. @DDT value from observed data (SCCWRP 2001a)Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 55 Table 6-3. Estimated Loading Capacity for Newport Bay Sediment Target Concentration (ug/kg dry) Loading Capacity (g/year) Waterbody Chlordane Dieldrin DDT PCBs Chlordane Dieldrin DDT PCBs Upper Bay 2.26 0.71 1.19 21.5 162.92 N/A 85.78 1513.81 Lower Bay * 2.26 0.71 1.19 21.5 59.18 18.59 31.16 229.36 Rhine Channel 2.26 0.71 1.19 21.5 1.70 0.53 0.89 15.79 (This table is summary of information pr esented in Table F-11 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. Identification of the TMDLs is based on consideration of the historic or existing loading (based on observed mussel or suspended sediment concentrations) versus the estimated lo ading capacity (based on sediment targets), and current conditions in the areas of concern. The sum of allocations for each compound in each waterbody segment is summed to equal the load ing capacity. In situ ations where existing loadings are less than the TMDLs, we expect wate r quality standards to be attained eventually without further loading reductions. However, given the potential for adverse environmental impacts associated with these compounds, it is im portant to minimize any future discharges to the watershed. In reviewing the conditions present for each pollutant and waterbody we identified two possible conditions (see Table 6- 4) under which the load allocation would be selected. A 10% margin of safety is included. The following discrete conditions were identified:

Condition 1 : If existing conditions will meet sedime nt targets, no additional reduction is applied. Allocation = Existing Loading – MOS. No load increase is allowed.

Condition 2 : If existing conditions do not meet sedime nt targets, then reduction is required. Allocation = Loading Capacity – MOS

Table 6-4. Summary of condi tion applicable to each waterbody/pollutant combination.

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

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

Existing loadings of many of the pollutants appe ars to be declining over time as historic accumulations degrade or are transported thr ough San Diego Creek to Newport Bay and the ocean. Examination of long-term records (1980- 2000) indicate that the average organochlorine compound concentrations in mussel tissues in Sa n Diego Creek and Newport Bay have declined 80 percent and 70 percent, respec tively, during that time.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 56 The load allocation was derived using the sediment deposition model for each of the critical areas. Two analytical methods were app lied depending on available data and the type of endpoint used. The first method, applied to San Diego Creek, ca lculates long-term sediment loading, derived from observed sediment concen trations (300 mg/L on average), and long term flow records (USGS data). Using the appropria te partition coefficients for each pollutant, the water column concentration and associated OC pollutant loading can be estimated.

The second method uses recent mussel ti ssue data (SMW 1993—1998 data) to estimate existing water column concentrations for selected pollutants in each critical area in Newport Bay (including Rhine Channel). The average concentr ations for each area are calculated. By using the sediment target, the water column concentrat ions can also be calculated. When comparing these two independently estimated concentrations , the lower concentration is used as water column concentration.

Tables 6-5 through 6-8 summari ze the existing loads, the estimated loading capacity, and the total allocation for each pollu tant with respect to each wa terbody. Values for Upper and Lower Bay represent the sum of several critical ar eas each, as defined in TSD—Part F, section 4. The time to meet water quality standards for each pollutant with respect to each waterbody is included as an approximation. The time (in years) is a slight ove restimate since it is based on the loading capacity prior to subtracting the margin of safety. Therefore, if the annual load allocations are strictly adhered, it would take s lightly less time to meet the desired target.

Table 6-5. Summary of San Diego Creek Loadings and Allocations (g/year)

Pollutant Existing Load (g/year) Loading Capacity (g/year) Total Allocation

(g/year) Margin of Safety (g/year) Approximate time to Meet Target (Year)
Chlordane 109.52 71.80 64.62 7.18 8
Dieldrin 39.71 29.31 26.38 2.93 S
DDT 271.64 48.84 43.96 4.88 S
PCBs 144.58 341.9 130.12 14.46 9 Toxaphene 378.82 4.20 3.78 0.42 15 S = satisfied; i.e., already meets numeric target Total allocation + Margin of Safety = lesser value in existing load or loading capacity

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

Pollutant Existing Load (g/year) Loading Capacity (g/year) Total Allocation

(g/year) Margin of Safety (g/year) Approximate time to Meet Target (Year) Chlordane 1 128.25 162.92 115.43 12.82 S
DDT 2 1273.12 85.78 77.20 8.58 12
PCBs 1 445.09 1513.81 400.58 44.51 0.5

1 existing load based on SMW data (1993-1998)

2 existing load based on observed part iculate water concentration (SCCWRP 2001a) S = satisfied; i.e., already meets numeric target Total allocation + Margin of Safety = lesser value in existing load or loading capacityNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 57 Table 6-7. Summary of Lower Newport Bay Loadings and Allocations

Pollutant Existing Load (g/year) Loading Capacity (g/year) Total Allocation

(g/year) Margin of Safety (g/year) Approximate time to Meet Target (Year) Chlordane 1 103.28 59.18 53.26 5.92 17 Dieldrin 1 46.13 18.59 16.73 1.86 1
DDT 2 1183.49 31.16 28.04 3.12 1.3
PCBs 1 844.97 229.36 206.42 22.94 5

1 existing load based on SMW data (1993-1998)

2 existing load based on observed part iculate water concentration (SCCWRP 2001a) Total allocation + Margin of Safety = lesser value in existing load or loading capacity

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

Pollutant Existing Load (g/year) Loading Capacity (g/year) Total Allocation

(g/year) Margin of Safety (g/year) Approximate time to Meet Target (Year) Chlordane 1 1.77 1.58 1.53 0.17 18 Dieldrin 1 3.76 0.53 0.48 0.05 3
DDT 2 8.48 0.89 0.80 0.09 4
PCBs 1 57.85 15.79 14.21 1.58 7

1 existing load based on SMW data (1993-1998)

2 existing load based on observed part iculate water concentration (SCCWRP 2001a) Total allocation + Margin of Safety = lesser value in existing load or loading capacity

Tables 6-9, 6-10, 6-11, and 6-12 summarize the allocations for each OC pollutantwaterbody combination. The explicit margin of sa fety (10%) has been in cluded for clarification.

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

Urban runoff 35.5 60 24.3 110.5 3.0

Other NPDES permittees 0 0 0 5.2 0

Sub-total 35.5 g/yr 60 g/yr 24.3 g/yr 116.7 g/yr 3.0 g/yr WLA

Nurseries 4 0 0 0 0 Other ag 3 0 0 0 0 Undefined 1.5 5 2 14.3 0.8 Sub-total 1.5 g/yr 5 g/yr 2 g/yr 14.3 g/yr 0.8 g/yr LA

MOS 5 g/yr 7 g/yr 3 g/ yr 14 g/yr 0.4 g/yr

Total
TMDL 49 g/yr 72 g/yr 29.3 g/yr 144 g/yr 4.2 g/yr

Total TMDL = WLA + LA + MOSNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 58 Table 6-10. Allocation scheme for Upper Newport Bay Category Type DDT (including dicofol) Chlordane PCBs

Urban runoff 65.6 108.8 369

Other NPDES permittees 3.1 0 16

Sub-total 68.7 g/yr 108.8 g/yr 385 g/yr WLA

Ag discharges 5.4 0 0 Undefined 3.1 6.4 15.5 Sub-total 8.5 g/yr 6. 4 g/yr 15.5 g/yr LA

MOS 8.6 g/yr 12.8 g/yr 44.5 g/yr
Total TMDL 85.8 g/ yr 128 g/yr 445 g/yr Total TMDL = WLA + LA + MOS

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

Urban runoff 25.5 49.2 15.4 183.6

Other NPDES permittees 1.3 0 0 0

Sub-total 26.8 g/yr 49.2 g/yr 15.4 g/yr 183.6 g/yr WLA

Ag discharges 0 0 0 0 Undefined 1.3 4.1 1.3 22.9 Sub-total 1.3 g/yr 4.1 g/yr 1.3 g/ yr 22.9 g/yr LA

MOS 3.1 g/yr 5.9 g/yr 1. 9 g/yr 22.9 g/yr
Total TMDL 31.2 g/yr 59.2 g/yr 18.6 g/yr 229.4 g/yr Total TMDL = WLA + LA + MOS

Table 6-12. Allocation scheme for Rhine Channel within Lower Newport Bay Category Type DDT (including dicofol) Chlordane Dieldrin PCBs

Urban runoff 0.77 1.4 0.46 12.6

Other NPDES permittees 0 0 0 0

Sub-total 0.77 g/yr 1.4 g/yr 0.46 g/yr 12.6 g/yr WLA

Ag discharges 0 0 0 0 Undefined 0.03 0.1 0.02 1.6 Sub-total 0.03 g/yr 0.1 g/yr 0.02 g/yr 1.6 g/yr LA

MOS 0.09 g/yr 0.2 g/yr 0.05 g/yr 1.6 g/yr
Total TMDL 0.89 g/yr 1.7 g/yr 0.53 g/yr 15.8 g/yr Total TMDL = WLA + LA + MOSNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 59 

### 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, w ildlife 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 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, 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 deposition 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 suspended sediment concentra tion (300 mg/L) was used to calculate the loading capacity for San Diego Creek. In the short-term sediment concentration will vary resulting in potentially higher or lower loadings to the Creek and Newport Bay.

• 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 (0.55) were slightly lower than those used for historical loads (0.65). No sediment consolidation 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, 98, 99) which incorporates various flow regime s throughout each year. The model represents various weather patterns and fl ow conditions for 25 years. (See Figure F-3 in TSD Part F.)Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 60 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. However, the e ffects of OP compounds are manifested over long time periods in response to bioacc umulation in the food chain. Therefore, short term loading variations are not likely to cause significant variations in beneficial use effects.

Table 7-6. Allocation Scheme for Hg and Cr in Rhine Channel Category Type Mercury Chromium Urban runoff 0.013 1.19 CalTrans 0.0008 0.446 J. Wayne Airport 0.0004 0.297 Boatyards 0 0 Other NPDES permittees 0.0012 0.297 Sub-total 0.0154 kg/yr 2.23 kg/yr
Existing sediments 0.063 26.80 Undefined 0.0016 0.74 Sub-total 0.0646 kg/yr 27.54 kg/yr WLA

MOS 0.01 kg/yr 3.30 kg/yr

Total TMDL 0.09 kg/yr 33.08 kg/yrNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 61 

## VII. Chromium and Mercury TMDLs

TMDLs are required for chromium (Cr) and merc ury (Hg) for the Rhine Channel area of Lower Newport Bay only. Additional information on the source analysis, modeling approach and relevant monitoring results for these TMDL s is provided in Technical Support Document— Part G.



### Problem Statement

Chromium —Chromium levels are elevated in Rhin e Channel mussel tissue samples over the tissue screening value (1.0 mg /kg wet) used in the musse l water program, thus some bioaccumulation is evident (31%, n= 13). Ch romium in Rhine Channel sediments are occasionally (8%, n= 13) above the sediment quality guideline (52 mg/kg dry).

Mercury —Mercury sediment concentrations in Rh ine Channel are above sediment quality guidelines levels associated w ith negative impacts on benthic organisms in all samples tested (100%, n=7). These excessive sediment concentr ations (more than tenfold greater than these sediment guidelines) may be causing toxicity or contributing to conditi ons threatening aquatic life within Rhine Channel. However, mussel tissue concentrations we re not above the EPA tissue screening value (0.3 mg/kg wet methylmerc ury), 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 proposes 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 Florida Dept. of Environmental Protecti on (MacDonald et al. 1996). For comparison, the TEL value is much lower than the probable effects level (P EL = 0.696 mg/kg dry). This TEL value is slightly lower than NOAA Effects Range-Low value for me rcury (ERL = 0.15 mg/kg dry). The alternate mercury numeric target is fish tissue (0.3 mg/kg wet methylmercury), based on analysis provided the Biological Opinion on the CTR by USFWS (2000) . This methylmercury target is designed to protect human health, yet it will al so be effective at reducing impac ts to wildlife 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 targ et (52 mg/kg dry, from MacDonald et al. 1996) as the optimal mechanism to protect both wildlif e predators and benthic organism s. The alternate chromiumNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 62 numeric target is fish tissue, 0.2 mg/kg wet (USFWS 2001). This fish tissue target is more stringent than the screening value used to evalua te State mussel watch 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 Chromium (Cr) 52 0.2 Rhine Channel Mercury (Hg) 0.13 0.3* *mercury tissue target is interpreted as 0.3 mg/kg we t methylmercury (USFWS 2000)



### Source Analysis

Chromium (Cr)

Probable sources of chromium include the h eavily 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 deposit ion. Chromium may also be leaching from treated wood pylons in marine area s (Weis et al. 1991). Chromium is a naturally occurring element, which can be found in vol canic dust and gases. However, chromium emissions can also come from commercial and industrial facilities, resulting in chromium discharges into the atmosphere. Currently, th ere is not sufficient information to estimate chromium atmospheric deposition rates in the Ne wport Bay watershed. Presumably the heavily contaminated sediments are due to historic activities in and around Rhine Channel and these legacy sources have created the largest curren t source of chromium—the existing sediments.

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 resu lts 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 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 may be from mining operations at the old Red Hill mine in the western part of San Diego Creek wa tershed (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 drai nage would have been attributed to Peters Canyon Wash. Other minor sources of Hg deposits ha ve been mapped in the area. At this time,Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 63 no additional information is available to accurately interpret sediment transport processes from this historic mining site down to Rhine Channel.

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 g/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 Newport Bay (kg/yr) Estimated Load to Rhine Channel (kg/yr)
Cr ‘97-99 16 781.5 46.9 Hg ‘97-99 0.0186 0.91 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.



### Modeling

A bottom sediment model was developed to li nk water column concen trations to bottom sediment conditions for Hg and Cr in Rhine Ch annel. The sediment model algorithms and approach were similar to the model utilized for organochlorine compounds. (Technical Support Document—Part F, sections 5 and 6 give more thorough description of this bottom sediment model.) The model was applied to Rhine Channel to evaluate the response to long-term loadings and estimate the loading capacity. The initia l bottom sediment condition was determined from local data. Because no water column concentrations are available for Hg and Cr (all values are below detection limits), the water column concentration for model calibration was estimated from the bioaccumulation factor derived for San Diego Creek. Mean values of mussel and sediment concentrations of Cr and Hg (SMW 1980-1997) were used to estimate the bioaccumulation factor. The mean value of muss el data obtained from the Rhine Channel was used to estimate water column concentration. The estimated water column concentrations together with observed mussel data were used for the model calibration (Table 7-3). The partitioning coefficients for metals are not well documented; the potential values range from 0.1 to 0.00001. To estimate the fraction of dissolv ed pollutants from th e total (unfiltered) concentration, we estimated 0.8 for both Hg and Cr (Thomann and Mueller 1987). This is consistent with the first order approach applie d to these TMDLs. Atmospheric deposition of mercury and chromium was not explicitly modele d in this analysis, bu t is believed to be insignificant as discussed above. Instead, the mo del used total water co lumn concentrations,Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 64 which serve as an integrator of atmospheric and other loadings. The calibration results are shown in Figures G-1 and G-2 of TSD—Part G.

Table 7-3. Estimated Water Column Concentration Used For Model Calibration
Pollutant Mussel conc.* (mg/kg wet) Water conc. (ug/L)
Cr 0.62 21.31 Hg 0.07 7.13 *Mussel data from SMW database; water column conc derived from mussel data



### Loading Capacity/Linkage Analysis

These TMDLs express the loading capacity and allocations in mass terms for Rhine Channel. These mass limits are intended not only to attain numeric targets but also to reduce bioconcentration of chromium in mussels and minimize any bioaccumulation of mercury in all wildlife and humans. Again, due to the legacy nature of these metals within Rhine Channel sediments, it will be necessary to address that most significant metals source- contaminated sediments-- to resolve any toxi city to benthic organisms a ssociated with these heavily contaminated sediments.

The loading capacities for Rhine Channel we re estimated from the sediment budget analysis and the sediment target. The method used to calculate the loadin g capacities is similar to the method used for the organochlorine compounds. For both chromium and mercury, the ongoing loads, which are associated principally w ith local contaminated sediments, are higher than the estimated loading capacity. Therefore, the TMDLs and associated allocations are set based on this loading capacity. The loading capa cities for chromium and mercury, and hence the TMDLs, are 33.08 kg/yr and 0.10 kg/yr respectively, expressed as annual averages (Table 7-4).

Table 7-4. Historical Loading and Estima ted Loading Capacity for Rhine Channel Pollutant Historical conc. * (mg/kg dry) Historical Load (kg/yr) Sediment Target (mg/kg dry) Estimated Loading Capacity

(kg/yr) Chromium 44 38.79 52 33.08 Mercury 5.2 3.87 0.13 0.10 * historical conc. source: Coastkeeper (1999)



### TMDL and Allocations

For these TMDLs, EPA has calculated both wasteload allocations (WLA) and load allocations (LA). Inputs from historically deposited sediments and atmospheric deposition are included in load allocations. Ongoing sediment deposition (containing mercury and chromium) from San Diego Creek is addressed as a wastel oad allocation because this source is generally subject to coverage under the existing NPDES st ormwater permit. The generic TMDL equation is presented below with substitution for these sources of mercury.

TMDL = Σ (wasteload allocations) + Σ (load allocations) + Margin of SafetyNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 65 The sediment model developed for Rhine Channe l was used to estimate the time required to meet the sediment target with a specified wa ter column concentration and associated loading. The water column concentration for chromium observed in 2001 (16.0 ug/L from IRWD 1999?) was used to estimate the time required to meet the target value under these loading conditions. The water column concentration for mercury wa s calculated by using back -calculation from both the sediment target and detection limits. The de tection limit presumes that existing loading is at or below the identified detection limit ( 0.0186 ug/L, IRWD 1999). An average sediment concentration of 300mg/l was assumed and used to estimate the particulate-associated mercury and chromium. For mercury the detection limit was selected as the basis for the load allocation since this represents a value closer to existi ng conditions and results in more expeditiously meeting water quality standards. For both chromium and mercury, the estimated loading capacity for Rhine Channel equals the TMDLs, a nd therefore the sum of total allocations and margin of safety (Table 7-5).

Table 7-5. Rhine Channel Allocations

Pollutant Total Allocation (kg/year) Margin of Safety (kg/yr) Approximate time to meet target (year)
Cr 29.78 3.30 < 1 Hg 0.09 0.01 18 Total Allocation + Margin of Safety = estimated loading capacity

Table 7-6. Allocation Scheme for Hg and Cr in Rhine Channel Category Type Mercury Chromium Urban runoff 0.013 1.19 CalTrans 0.0008 0.446 J. Wayne Airport 0.0004 0.297 Boatyards 0 0 Other NPDES permittees 0.0012 0.297 Sub-total 0.0154 kg/yr 2.23 kg/yr
Existing sediments 0.063 26.80 Undefined (natural) 0.0016 0.74 Sub-total 0.0646 kg/yr 27.54 kg/yr WLA

MOS 0.01 kg/yr 3.30 kg/yr

Total TMDL 0.09 kg/yr 33.08 kg/yr



### 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 availableNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 66 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 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 suspended sediment concentra tion (300 mg/L) was used to calculate the loading capacity from San Diego Creek to wa ter bodies downstream. In the short-term, sediment concentration will vary resulting in potentially higher or lower loadings to Rhine Channel.

• 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) (0.55) were slightly lower than those used for historical loads (0.65). No 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

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, 98, 99) which incorporates various flow regime s throughout each year. The model represents various weather patterns and flow conditions for 25 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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 67 

## VIII. Arsenic Analysis

EPA has concluded that an arsenic TMDL is not required because av ailable data indicate that applicable numeric water quality standards, and the best available sc reening 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 assumedNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 68 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 ti ssue in Newport Bay waterbodies (mg/kg wet) Waterbody Collection dates Org. n Min Max Mean Median

San Diego Creek 1995—‘98 TSMP 15 0.06 0.88 0.18 0.13

1995—‘98 TSMP* 4 0.4 8.6 2.93 1.3 1999—2000 CFCS 26 0.2 4.0 1.29 0.79 Newport Bay (finfish) 2000-2001 SCCWRP 50 0.22 8.6 1.64 0.68 (shellfish) 1995-2000 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 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 Finfish

Great Britain 720 0.9 – 30.1 5.6 4.3 Newport Bay 24 0.8 – 2.5 1.3 1.3 Wash State 10 1.0 – 6.9 2.4 2.2 Shellfish

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 (1996) Great Britain results from Collins et al. 1996Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 69 

## IX. References

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

Bay Protection Toxic Cleanup Program (BPTCP) 1997 Chemistry, Toxicity and Benthic Community Conditions in Sediments of Selected Southern California Bays and Estuaries SWRCB, EPA, NOAA, Calif. F&G, UC-Santa Cruz, Moss Landing Labs, Columbia Analytical Services, data collected in 1994 &1996. Bay, SM and D Lapota, J Anderson, J Armstrong, T Mikel, AW Jirik, S Asato. 2000 Southern California Bight 1998 Monitoring Program: IV Sediment Toxicity . Southern California Coastal Water Research Project. Westminster, CA. Bruland, KW, JR Donat, and DA Hutchins 1991 Interactive influen ces of bioactive trace metals on biological production in oceanic waters. Limnol. Oceanogr . 36: 1555—1577. Buchman, MF 1999 NOA A Screening Quick Reference Tables, NO AA HAZMAT Report 99-1, Seattle, WA Coastal Protection and Restoration Division, National Oceanic and Atmospheric Admininstration, 12 pp. Buffle, J 1988 Complexation reactions in aquatic systems: an analytical approach . Chichester, Ellis Horwood. California Department of Food and Agriculture (CDFA) 1999 Red Imported Fire Ant. California Action Plan. 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

. September. 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.
Mar. Envir. Res

. 41 : 281-297. Cooper, A. 1996 Diazinon in Urban Areas . Prepared for the Palo Alto Regi onal Water Quality Control Plant. August. Creed, J. 2001 pers. comm., EPA Cincinnati Office of Water research labs Cutter, GA 1991 Trace element in estuarine and co astal waters: United States studies from 1986-1990. Rev. Geophys

. 29 : 639-644. Donat, JR; K Lao and KW Bruland 19 94 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 Marine Aerosols from Bermuda". Geophys. Res. Let. 3 (6): 339-341. Eisler, R. 1994 A review of arsenic hazards to plants an d animals with emphasis on fish ery and wildlife resources. In: Arsenic in the Environment. Part II Human Health and Ecosystem effects . JO Nriagu, Ed. John Wiley & Sons, Inc. NY. pp185—251.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 70 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

, 28 , pp. 83-100. Lemly, AD 1995 A Position Paper on Selenium in Ecotox icology: A Procedure for De riving Site-Specific Water Quality Criteria, Ecotoxicology and Environmental Safety

, 39 , pp. 1-9. Long, ER, LJ Field and DD MacDonald 1998 Predicting Toxicity in Marine Sediments with Numerical Sediment Quality Guidelines

, Environ. Toxicol. Chem

. 17 :4, pp. 714-727. Luoma, S. et al . 1992 Determination of Seleni um Bioavailability to a Benthic Biva lve from Particulate and Solute Pathways, Environ. Sci. Technol. 26 , pp. 485-491. Luoma, SN and TS Presser. 2000 Forecasting Selenium Discharges to the San Francisco Bay-Delta Estuary: Ecological Effects of a Proposed San Luis Drain Extension , USGS report 00-416. MacDonald, DD; RS Carr, FD Calder; ER Long and CG Ingersoll 1996 Development and evaluation of sediment quality guidelines for Florida coastal waters, Ecotoxicology

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

. 19 :8 2076-84. Mosher BW and RA Duce 1989 The Atmosphere, in Occurrence and Distribution of Selenium , Ed. by Milan Ihnat, CRC Press, Inc. Florida, pp. 309. Mosher BW and RA Duce 1983 Vapor Phase and Particulate Selenium in the Marine Atmosphere. J. Geophys.
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. 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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 71 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. OCPFRD 2000 Orange County NPDES Stormwater Program, Annual Progress Report . Data from 1996 to June 2000. Orange County Public Facilities and Resources Depa rtment, Santa Ana, California. OCPFRD 1999 Peters Canyon Wash/San Diego Creek Nutrient Study. 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 C ontrol 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. Skorupa, JP 1998 Selenium Poisoning of Fish and Wild life in Nature: Lessons from Twelve Real-World Examples, in Environmental Chemistry of Selenium , WT Frankenberger Jr. and RA Engberg, editors, Marcel Dekker, Inc. 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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 72 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 TSMP 1987-99 Toxic Substance Monitoring Program 1987-99 Data Base . State Water Resources Control Board, California Environmental Protecti on Agency, Sacramento, California US Army Corp of Engineers (ACO E) 2000 Upper Newport Bay Ecosys tem Restoration Feasibility Study: Environment Impact Statement/Report. Final Report, September. US Fish & Wildlife Service 2001 Environmental Contaminant Encyclopedia . www.nature.nps.gov/toxic/ National Park Service website. US Depa rtment of Interior report. US Fish & Wildlife Service 2000 Biological Opinion on EPA’s “Wat er Quality Standards: Establishment of Numeric Criteria for Priority Toxic Pollu tants or the State of California”. US Fish & Wildlife Service 1998 Guidelines for Interpretation of the Biological Effect of Selected Constituents in Biota, Water, and Sediment . US Department of Interior report. US Geological Survey 2000 Stormflow Chemistry in the Santa Ana River below Prado Dam and at the Diversion Downstream from Imperial Highway, Southern California, 1995-98

. USEPA 2001a Update of Ambient Water Quality Criteria for Cadmium. EPA-822-R-01-001. U.S. Environmental Protection Agency, Office of Water, Wash. DC. Notice of availability April 12, 2001 USEPA 2001b Diazinon Revised Risk Assessment and Agreement with Registrants

. 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

. USEPA 2000c Ambient Aquatic Life Water Quality Criteria: Diazinon (Draft)

. USEPA 2000d Guidance for Assessing Chemical Contaminant Data for Use in Fish Consumption Advisories, Vol. 1: Fish Sampling and Analysis , 3 rd ed. EPA-823-B-00-007. U.S. Environmental Protection Agency, Office of Water, Wash. DC. USEPA 2000e Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health. EPA-822-B-00-004. U.S. Environmental Protection Agency, Office of Water, Wash. DC. USEPA 1999a Environmental Risk Assessment for Diazinon

. USEPA 1999b Pesticides Industry Sales and Usage. 1996 and 1997 Market Estimates . EPA-733-R-99-001. U.S. Environmental Protection Agency, Of fice of Prevention, Pesticides and Toxic Substances, Wash. DC. USEPA 1991 Guidance for Water Quality-based Decisions: The TMDL Process. EPA-440/4-91-001. Office of Water, 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 1986 Ambient Aquatic Life Water Quality Criteria: Chlorpyrifos. EPA-440/5-005-86-001. Office of Water, Washington, DC. USEPA Region 9 2000 Guidance for Developing TMDLs in California. USEPA Region 9 2001 Decision Docu ment for Assessment of San Diego Creek an d Newport Bay Water QualityNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 73 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 C ounty 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.Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 74 

## X. 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 DepartmentNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 75 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 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]Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 76 

### 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 habitatNewport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 77 

### Appendix B

Arsenic Fish Tissue Monitoring data

SPECIES NAME Date Total Arsenic Inorganic Arsenic Screening Value (mg/kg wet) OEHHA = 1.0 EPA = 1.2

#/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 PCH Br Shiner Surfperch 06/00/2000 10 0.969 0.039 0.097

Newport Bay/above PCH Br Spotted Turbot 06/00/2000 5 1.775 0.071 0.177

Newport Bay/above PCH Br Yellowfin Croaker 06/00/2000 4 0.585 0.023 0.059

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 0.574Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 78 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)



### saltwater finfish results count 80

max 8.62 0.34 0.86

mean 1.59 0.06 0.08
median 0.78 0.03 0.08Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 79 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)



### Saltwater shellfish results count 24

max 2.50 0.04
mean 1.28 0.02
median 1.25 0.02Newport Bay Toxic Pollutant TMDLs Public Review Draft

summary document 80 Tot. As Inorg. As

TSMP data '96--'98 4% 10% San Diego Creek San Diego Creek/Michelson Red Shiner 6/9/98 0.344 0.014 0.034

Peters Canyon Channel Red Shiner 6/9/98 0.116 0.005 0.012

San Diego Creek/Barranca Red Shiner 6/9/98 0.200 0.008 0.020

Delhi Channel Striped Mullet 6/9/98 0.882 0.035 0.088 San Diego Creek/Michelson Red Shiner 6/19/97 0.134 0.005 0.013

Peters Canyon Channel Red Shiner 6/19/97 0.057 0.002 0.006

Peters Canyon Channel Red Shiner 6/19/97 0.063 0.003 0.006

San Diego Creek/Barranca Red Shiner 6/19/97 0.148 0.006 0.015

Delhi Channel Red Shiner 6/18/97 0.085 0.003 0.009 San Diego Creek/Michelson Red Shiner 11/6/96 0.06 0.002 0.006

San Diego Creek/Michelson Red Shiner 11/6/96 0.07 0.003 0.007

Peters Canyon Channel Red Shiner 11/6/96 0.15 0.006 0.015

San Diego Creek/Michelson Red Shiner 6/17/95 0.150 0.006 0.015

San Diego Creek/Michelson Red Shiner 6/17/95 0.170 0.007 0.017

Peters Canyon Channel Red Shiner 6/17/95 0.090 0.004 0.009



### Freshwater finfish results count 15

max 0.88 0.04 0.09
mean 0.18 0.01 0.02
median 0.13 0.01 0.01