1

Assessment of Antifouling 

Paint Use Indicators in 

California Marinas

Nan Singhasemanon

CA Department of Pesticide Regulation

CAHMPC Annual Conference, Ventura 2008
2

Background

• Documentation of elevated copper at SIYB in 

San Diego Bay sparked follow-up investigations

• Dissolved copper (DCu) concentrations observed 

above W.Q. standards–CA Toxics Rule (CTR)

• SIYB TMDL identified boat AFPs as source

• Main question–do similar conditions exist 

elsewhere in CA? 

• DPR planned study under consultation w/ CSG, 

an interagency sub-workgroup of MRBW

• Study co-funded by DPR, SWRCB & U.S. EPA
3

AFP Use in CA

• ~ 180 AFP pesticide products registered

• More than 90% utilizes copper-based biocides

Copper oxide, copper hydroxide, copper thiocyanate

• Booster biocides are often co-formulated

Zinc pyrithione (a.k.a. omadine, ZnPt2)

Irgarol 1051

Sea-Nine (a.k.a. DCOI)
4

Study Objectives

• Determine occurrences & magnitude of AFP-use 

indicators (i.e., Cu, Zn, & Irgarol/M1) in marina 

areas 

• Determine if indicators exceed established water 

quality standards, criteria, guidelines, or other 

relevant benchmarks

• Determine if marina conc. of indicators are higher 

than background conc.
5

Study Objectives (cont.)

• Determine if differences exist among AFP 

indicators in fresh, brackish, & salt water areas

• Apply U.S. EPA’s Biotic Ligand Model (BLM) 

or other scientifically-relevant models to estimate 

bioavailability & toxicity of copper.

• Measure toxicity of marina waters w/ coppersensitive species & endpoints

• If toxicity exists, identify the likely cause
6

Study Overview

• Selected 23 (medium–large) CA marinas

• Avoided marinas w/ potential interferences from 

adjacent sources

• Sampled each marina 3 times (replicates) 

between July & October 2006

• Water and sediment from 4 points inside marina 

area & 4 points outside of the marina area (local 

reference sites or LRS)

• Took sub-surface samples from center of fairway 

& half way down docks
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Marina Sampling Diagram

Diagram 1

Land

Dock

slip slip

slip

Dock Dock Dock Dock

X X X X

 Marina Entrance

Open Water

X = Sampling 

point is middle 

of fairway and 

adjacent to midpoint of dock
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9
10

Monitoring Summary

• 67 of 69 total events sampled

• ~ 600 water samples taken, ~ 7,000 individual 

analytical results (most feed into models)

• Sediment from only 3 marinas collected (fresh 

water). Remainder of sediment worked cancelled 

due to safety & liability issues

• Field & Lab QA/QC very good overall

• Metals data within range of other studies
11

Results

Dissolved Copper (DCu)
12

Marina Median DCu Concentrations by Water Types

Salt Water LRSs

Salt Water Marinas

Brackish Water LRSs

Brackish Water Marinas

Fresh Water LRSs

Fresh Water Marinas

14

12

10

8

6

4

2

0

DCu Concentrations (in μg/L)
13

Marina

Marina Median 

Concentration 

(ug/L)

LRS Median 

Concentration 

(ug/L)

Estimated 

Number of 

Slips

Folsom Lake Marina 0.5 0.3 675

Tahoe Keys Marina 0.6 0.2 250

San Francisco Marina 1.1 0.4 700

Alamitos Bay Marina 1.2 0.3 1,191

Coyote Point Marina 2.1 1.3 565

Antioch Marina 2.2 1.5 310

Pittsburg Marina 2.1 1.5 486

South Beach Harbor 2.2 0.7 700

Clipper Yacht Harbor 2.4 0.8 735 fresh water

Marina Bay Yacht Harbor 2.6 1.7 850 brackish water

Benicia Marina 2.7 1.7 320 salt water

Sacramento Marina 3.0 0.7 547

Ballena Isle Marina 2.8 1.4 504

Village West Marina 3.4 1.8 700

Vallejo Marina 3.4 1.5 800

Berkeley Marina 3.3 0.7 1,052

Santa Cruz Harbor 4.3 0.3 1,000

Monterey Harbor 4.9 0.2 413

Santa Barbara Harbor 5.7 0.1 1,133

Loch Lomond Marina 5.8 1.7 517

Downtown Shoreline Marina 6.6 0.7 1,800

Marina del Rey Front Basins 12.4 1.0 ~ 5000

Marina del Rey Back Basins 13.6 1.0 ~ 3000

Median DCu Concentrations by Marina Areas 
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Findings - DCu 

• DCu ranged from 0.1–18.4 μg/L

• Particularly elevated levels in Central & South 

Coast marinas–except Alamitos Bay Marina

• MdR Basins consistently very high in DCu

• Low to Moderate levels in SF Bay Area & 

brackish water marinas

• Very Low to Moderate levels observed in fresh 

water marinas
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Findings - DCu (cont.)

• Salt & brackish water marinas ↑ fresh water 

marinas (higher use?)

• Marina ↑ vs. LRS for marinas of all 3 water types 

(statistically significant)

• Many salt & brackish marinas exceeded W.Q. 

stds. 

16 of 17 marinas exceeded CTR chronic stds. (3.1 ppb)

10 of these 16 marinas also exceeded acute stds. (4.8 ppb)
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Findings - DCu (cont.)

• 30% (118/388) of samples from salt & brackish 

water samples exceeded chronic stds.

• 17% (67/388) of these exceeded acute stds.

Thus, ecological risks may exist 

• Very few LRS samples (4) exceeded chronic stds.

• For fresh water, none of the samples exceeded 

fresh water CTR standards

Thus, ecological risks unlikely in fresh water marinas
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Results

Dissolved Zinc (DZn)
18

Marina Median DZn Concentrations by Water Types

Salt Water LRSs

Salt Water Marinas

Brackish Water LRSs

Brackish Water Marinas

Fresh Water LRSs

Fresh Water Marinas

50

40

30

20

10

0

DZn Concentration (in ug/L)
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Findings - DZn

• Ranged from 1.0–66.6 μg/L

• Marinas ranked similar to DCu 

Exception: Alamitos Bay (very low DZn)

• Tends to be higher than DCu by factor of 2–4

• Much higher DZn in salt water marinas compared 

to brackish & fresh water marinas

• Marina vs. LRS is statistically significant for salt 

& brackish water marinas

• Zn CTR fresh & salt water stds. never exceeded
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Results

Irgarol & M1
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Irgarol & M1 Concentrations by Rounds

Irgarol Round 1 Irgarol Round 3 M1 Round 1 M1 Round 3

600

500

400

300

200

100

0

Irgarol/M1 Concentration (ng/L)
22

Findings - Irgarol/M1

• Irgarol & M1 detected in all 45 samples

• Irgarol ranged from 12–712 ng/L

• M1 ranged from 1.6–217.1 ng/L

• Highest Irgarol & M1 conc. documented @ Loch 

Lomond Marina

• Higher conc. in salt water marinas 

• Higher conc. in Round 1 (Summer) vs. Round 2 

(Fall) (applications in summer? higher 

leaching?)
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Findings - Irgarol/M1 (cont.)

• Irgarol range overlaps more sensitive 

phytoplankton endpoints

Photosynthetic activity

Reproduction/growth 

• Irgarol exceed aquatic benchmark values (i.e., 

136 & 251 ng/L) protective of 90% of aquatic 

plant species

• M1 never exceeded benchmark (12,500 ng/L)
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Results

Toxicity & Toxicity Identification 

Evaluation
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Findings - Toxicity/TIE

• 8 of 47 samples (17%) exhibited statistically 

significant toxicity

• 7 of 8 toxic samples came from MdR; remaining 

sample from MBYH in Richmond

• TIE strongly points to metal (most likely copper) 

as the cause of toxicity

• Toxicity test/species used is commonly used. 

Water Boards view this as exceedance of 

narrative WQO.
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Results

Bioavailability & Predictive Toxicity 

Modeling 
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Findings - Modeling

• Fresh water - BLM predicted 7 samples would 

have had DCu > 1 Toxic Unit (all from 

Sacramento Marina)

• Salt & brackish water - DOC Model predicted:

86 samples would exceed chronic toxicity threshold

Of the 86, 54 would also exceed acute threshold

• Comparison of DOC model to actual toxicity 

showed good agreement
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Findings - Modeling (cont.)

• Salt & brackish water - draft BLM predicted that 

some toxicity would still occur

67 samples would exceed M. galloprovincialis EC50 

• BLM & DOC model showed similar results

• Comparison of BLM to actual toxicity showed 

good agreement 

• Both models still tend to slightly over-predict 

toxicity when compared to actual toxicity, 

especially when close to EC50
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Conclusions

• CTR fresh water Cu stds. are not threatened.

• Water samples from CA salt & brackish marinas 

regularly exceed CTR salt water Cu standards.

Reality–beneficial uses are potentially impaired...

• Considering study results, scientific literature, 

leaching estimates & marina surveys - AFPs are 

likely the most significant source of Cu in salt water 

marinas, particularly during dry periods.
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Conclusion (cont.)

• Higher background DCu loads in S.F. Bay Area, 

brackish, & fresh water marinas account for a 

larger portion of marina DCu loads than Central 

& South Coast marinas.

Bay Area SSO’s raised regional Cu stds.

CTR still applies to other CA marinas

• Toxicity (in a copper-sensitive test) may not 

occur until DCu is well over current CTR stds.

Over-protective? Does this matter?
31

Conclusions (cont.)

• Copper-sensitive aquatic species in salt water 

marinas that exhibit high DCu conc. may be 

adversely impacted by exposure to Cu.

i.e., MdR Front & Back Basins

• DOC Model & BLM predict actual toxicity 

with good precision & are promising tools in 

assessing biological effects of copper.
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Conclusion (cont.)

• Zinc CTR standards are not threatened by 

marina concentrations of DZn.

Non-biocide applications of Zn may be important 

factors in determining DZn in salt water marinas.

• Irgarol may be adversely affecting moresensitive phytoplankton species in CA’s salt 

water marinas.
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Next Steps...

• DPR will pursue formal reevaluation for Cu 

AFPs & potentially other AFPs (ZnPt2, Irgarol, 

Sea-Nine).

• If approved, Cu AFP reevaluation will likely 

focus on mitigation, while non-Cu AFP

reevaluation will likely focus on W.Q. 

assessment & biological impacts.

• Registration status of reevaluated AFPs remains 

the same...

unless DPR or registrants take actions during process 
34

Next Steps...

• AFP product market shifts are already taking 

place. 

Zn AFPs have increased in market place

Less-toxic AFPs are becoming more available

• DPR has taken active role in supporting 2 

projects that are evaluating feasibility & costs of 

alternatives to Cu AFPs.

• Long-term solution: availability & use of 

multiple biocides rather than one (i.e., Cu).
35

Other Activities to Consider

• Federal risk assessment for CuO & ZnPt2

• Discharge standards for military vessels (UNDS)

• Changes to copper W.Q. criteria for aquatic life

Current stds. based on criteria

Will stds. be updated to include bioavailability?

• Proposed NPDES permits for recreational & 

commercial vessels & countering federal bills

• U.S. EPA proposal to clearly define and/or 

require additional data to allow for improved 

exposure & risk assessments for registration

Leaching, non-target toxicity, phytotoxicity studies
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Other Activities to Consider

• EU Biocidal Directive

• SCCWRP Reg. 9 marina monitoring

• Lower NPB marina monitoring

• DBW SIYB biological impact study 

• 303(d) listings & TMDLs

• Regional or statewide marina permits

• Local mitigation projects
37

Questions?

Nan Singhasemanon

Staff Environmental Scientist/MAA Coordinator

Environmental Monitoring Branch

Surface Water Protection Program

1001 I St., Sacramento, CA 95812

nsinghasemanon@cdpr.ca.gov

(916) 324-4122