# COPPER EMISSIONS FRO M

ANTIFOULING PAINT ON

RECREATIONAL VESSELS

Kenneth Schiff* 1



### , Dario Diehl 1



### , Aldis Valkirs 2

1 Southern California Coastal Water Research Project. Westminster, CA 02683

www.sccwrp.org

2 Computer Sciences Corporation. San Diego, CA

* author to whom correspondence can be addressed:

714.372.9202 kens@sccwrp.org

June 22, 2003

Technical Report #405Copper emissions from antifouling paint

2 

### ABSTRACT

Trace metals, especially copper, are commonly occurring contam inants in harbors and marinas. One source of copper to these environs is copper

- based antifouling coatings used on vessel hulls. The objective of this study was to measure dissolved copper contributions from recreational vessel antifouling coatings for b oth passive leaching and hull cleaning activities. To accomplish this goal, three coating formulations, including hard vinyl, modified epoxy and a biocide free bottom paint were applied on fiberglass panels and placed in a harbor environment. In situ mea surements of passive leaching were made using a recirculating dome system. Monthly average flux rates of dissolved copper for the hard vinyl and modified epoxy coatings were 3.7 and 4.3 μg/cm 2 /day, respectively, while flux rates for the biocide free coati ng was 0.2 μg/cm 2 /day. The highest passive flux rates were measured initially after cleaning activities, rapidly decreasing to a baseline rate within 3 days, regardless of coating formulation. Hull cleaning activities generated between 8.6 and 3.8 μg dis solved copper/cm 2 /event for the modified epoxy and hard vinyl coatings, respectively. Aggressive cleaning using an abrasive product doubled the copper emissions from the modified epoxy coating, but produced virtually no change in the much tougher hard vin yl coating. When compared on a mass basis, roughly 95% of copper is emitted during passive leaching compared to hull cleaning activities over a monthly time period for a typical 9.1 m power boat.

Keywords: antifouling paint, copper, recreational vessel , hull cleaning, passive leachingCopper emissions from antifouling paint

3 

### INTRODUCTION

Trace metals have been identified as important constituents of concern contaminating sediments in marinas and harbors. For example, sediment quality surveys around the nation routinely find high copper con centrations in marinas and harbors (US EPA 1996a, NOAA 1994). Where dissolved trace metals in the water column are measured, they frequently exceed levels of concern in marinas (Hall et al. 1988; Zirino et al. 1978, Zirino et al. 1998). These elevated tr ace metal concentrations in marinas partly result from the physical processes of mixing and dispersion. Marina and harbor areas are inherently protected thus providing calm water for navigation, but at the same time this restricts

circulation. To exacerb ate the lack of mixing, marina and harbor areas typically have a multitude of potential contaminant inputs. Some of these marina and harbor areas might host local point sources such as municipal or industrial wastewaters. Many of these

marina and harbor areas likely receive surface runoff, which will vary in water quality as a function of the development within the adjoining watershed. However, all of these marina and harbor areas receive inputs from vessel activities. There are a variety of

activities associated with vessels that could contribute trace metals including antifouling paint hull coatings, sacrificial anodes, motor exhaust, and hazardous material spills.

Of all the vessel related activities, antifouling bottom paints are amongst the large st source of trace metals, in particular copper. Current day hull coatings are impregnated with copper and sometimes co

- biocides whose goal is to retard the growth of algae and other encrusting organisms. These encrusting organisms will foul hulls and ot her underwater parts that will impede progress underway, lengthening transit times and increasing fuel consumption (WHOI 1952). The copper impregnated coatings are designed to slowly release copper, in the dissolved and most toxic form, so as to retard

gr owth and maintain a smooth underwater surface.

There are more coating formulations than there are coating manufacturers. Aside from the active ingredient, which typically varies from 20 to 76% copper content, hull coatings also have a variety of formul ations for the inert matrix and delivery. There are self

polishing copolymers, ablative, and epoxy

- based formulations. The passive flux of copper from each of these formulation differs as a result of the matrix. For example,

epoxy

- based coatings use a h oneycomb matrix that enables the impregnated cuprous oxide to leach through “micro

- channels” in the coating. Regardless of the release process, each of these coating formulations requires periodic (ca. monthly) underwater hull cleaning to maintain a smoot h surface and improve the copper release on pleasure craft. Hence, the biocide does not prevent fouling, it merely prolongs the natural process

of hard substrate recruitment and succession.

Since there are numerous variations in copper content and matr ix formulations, paint

manufacturer s have developed a standard method for estimating biocide release rates (ASTM 2000). Copper release rates are measured from coated rotating cylinders exposed to artificial standard seawater under controlled temperature a nd pH conditions. After an initially high flux and when the release rate has stabilized, the copper release rate isCopper emissions from antifouling paint

4 calculated by sampling the seawater in which the drum is immersed. Other investigators have reported that the ASTM methods generate flux ra tes that are higher than in situ measurements under static conditions, and under environmental exposure (Schatzberg 1996, Thomas et al. 1999)

The goal of this study was to assess the contributions of dissolved copper to receiving

waters via antifouling co atings from recreational vessels. The objective was to measure

these contributions in

- situ to estimate flux rates under environmentally relevant conditions. The primary question addressed by this study is a comparison of dissolved copper flux rates for b oth passive leaching and hull cleaning activities. Three subquestions were also addressed in this study relevant to dissolved copper release rates from antifouling coatings. The first subquestion focused on quantifying the change in dissolved copper flux

during passive leaching between cleaning events as biofilms, algae, and other encrusting organisms begin to grow on coated surfaces. The second subquestion focused on quantifying the effect of best management practices (BMPs) on hull cleaning activities. This is important since BMPs are a potentially important mechanism for controlling antifouling coating discharges. The third subquestion focused on evaluating the effect of different coating formulations. Differences among coating formulations may prod

uce differential flux rates for copper during both passive leaching and underwater hull cleaning activities.



### METHODS

There were three design factors investigated including coating formulation, cleaning method, and time since underwater cleaning (Table 1). There are three basic types of bottom coatings available to boat owners that we evaluated. Each varies in its biocide content and mode of action. These included hard vinyl, modified epoxy, and biocide

- free coatings. We measured the copper flux of e ach coating type during passive leaching, and again during underwater hull cleaning activities.

The flux of copper was quantified using two different methods of underwater hull cleaning. The first was a hand method by a professional underwater hull cle aning company using BMPs. The BMP paradigm mandates using the softest cleaning materials possible in order to minimize copper contributions and maximize the lifetime of hull coatings. The second method was a non

- BMP hand cleaning method using a more

abra sive cleaning material than was necessary to remove fouling.

Time since cleaning was evaluated by measuring the flux of copper during passive leaching at periodic intervals following a cleaning event. Since most recreational vessels

are cleaned on monthl y schedules (sometimes slightly less during winter or slightly more during summer) by professional services, an interval of 1, 3, 5, 7, 14, and 28 days was

selected.Copper emissions from antifouling paint

5 Hull Surfaces and Coatings

Fiberglass panels from a local boat manufacturer were used to simulate a recreational boat hull. These 40.6 cm wide x 40.6 cm high x 0.48 cm thick panels were prepared for antifouling coating application by removing wax, lightly sanding the gel

- coat, and applying two coats of non

- sanding primer. Two coats of pai nt were then applied onto the panels with a roller. After drying, panels were hung from the side of a boat dock in ambient seawater 40 cm below the surface in a randomly assigned order. Similar to any recreational vessel, a professional boat hull cleanin g service provided monthly maintenance beginning 60 days after submersion prior to the initiation of the sampling phase . The exception was the biocide

- free coated panels that were cleaned every two weeks upon emersion as a result of rapid fouling.

Two co mmercially available antifouling coatings and a biocide free coating were tested in the study. The antifouling coatings had cuprous oxide (Cu 2 O) as the primary biocide within an insoluble matrix of modified epoxy or hard vinyl enhanced with TeflonTM. The matrix for the biocide free coating was a two

- part epoxy with TeflonTM. A standard application technique was applied to all panels regardless of coating types to ensure biocide release rates would not vary as a result of coating thickness or other applicat ion

variable.

Sampling for Passive Leaching of Coated Surfaces

Passive leaching was measured using a closed, recirculating system (520 ml min

- 1 ) developed by the US Navy (Seligman et al. 2001, Valkirs et al. 2003 ). Each system

consisted of a 30.5 cm diameter polycarbonate dome with a double edge gasket connected to Teflon hoses and a peristaltic pump. For each coating type, a randomly selected panel was placed in a pre

- cleaned 59 L plastic tub filled with ambient seawater. Each panel was gently plac ed into the tub followed by the dome system. After purging all air from the system, the dome was pressed onto the sunny

- side of the panel and hydrostatically attached using negative pressure by removing a small volume of water from the system. Water samp les were then drawn from the system every 15 minutes for one hour. A pressure gauge monitored the system for leakage and allowed dome volume calculations. Filtered samples were collected from each composite using a 50 mL syringe

fitted with a 25 mm diame ter filter cassette using 0.45 μ m pore size Metricel  filters. Samples were preserved with nitric acid to pH < 2.

Sampling for Cleaning Activities

Panel cleaning activities were sampled using precleaned 59 L plastic tubs filled with
ambient seawater, which prevented advective losses of copper due to currents and harbor mixing. Three panels were randomly selected from each coating type and gently placed in individual tubs. At time zero, a sample was collected from each tub as a blank. Immediately fol

lowing, each panel was cleaned either using a BMP or nonBMP method,Copper emissions from antifouling paint

6 then removed at the end of 5 minutes. Particles were allowed to settle for one hour and a second water sample was collected from the tub. BMPs vary among underwater hull

cleaning service s. The BMP procedure selected for this study by a professional service agency used a low abrasive shag carpet and minimal applied pressure. The nonBMP procedure selected for this study used an amateur individual with a nylon 3M scouring pad with greater

applied pressure. Filtered samples were collected from each composite using a 50 mL syringe fitted with a 25 mm diameter filter cassette using 0.45 μ m pore

size Metricel

 filters. Samples were acidified with nitric acid to pH < 2.

In an effort to eva luate any bias between the use of a smaller panel system relative to an actual vessel hull, a validation experiment was conducted using actual vessels and a

BottomLiner

 boat bag. The boat bag is a rectangular plastic liner with a partially filled

volume of 8,400L that submerses in a marina slip. The boat bag is closed on three sides
to allow a boat to enter, then the fourth side closes to isolate the hull from the ambient environment. A total of 12 liters of water were collected at multiple locations an d depths throughout the bag at time zero as a blank. The vessel was then cleaned using a professional cleaning service with identical BMPs as used in the panel experiments. Particles were allowed to settle for one hour and a second 12 L composite water s amples was collected. Filtered samples were collected from each composite using a 50 mL syringe fitted with a 25 mm diameter filter cassette using 0.45 μ m pore size Metricel  filters. Samples were acidified with nitric acid to pH < 2.

Analytical Chemis try

Filtered and acidified seawater samples were extracted using an iron

- palladium precipitation technique following Bloom and Crecilius (1983). This extraction method
removes matrix related interferences to quantify copper at low levels (0.1 μ g/L) in

se awater. The extract was reconstituted in deionized water and analyzed using Inductive Coupled Plasma Mass Spectrometry (ICP

- MS) using EPA Method 1640 (U.S. EPA 1996b) . Quality assurance measurements indicated that all laboratory blanks were below

method detection limits and duplicate samples were within a 10% reproducible percent

difference.

Data Analysis

Three types of data analysis were conducted for this study. The first analysis calculated dissolved copper flux rates for passive leaching from each coating type. The second analysis calculated dissolved copper flux rates for each hull cleaning method from each coating type. The third analysis compared the relative copper input of passive leaching to hull cleaning by estimating dissolved copper mass emissions for a typical vessel using the rates calculated in this study.

Dissolved copper emissions and flux rates were determined for each coating type. Determination of passive leaching flux rates for each dome sampling event was estimatedCopper emissions from antifouling paint

7 by first p lotting each of the sample copper masses, calculated as the product of the sample concentration and known volume of the dome sampling system, versus time over
the course of the one hour sampling event. Flux rates, given as μ g/cm 2 /day, were derived

from th e slope of the line based on linear regression of these samples (Zar 1984). Since these individual flux rates can vary by time since cleaning, an average flux rate for each coating type was calculated by integrating the area under the curve of the one mon th passive leaching experiments. Since replicate curves were derived for each coating type,

a t

- test of slopes was used to test for significant differences in passive leaching copper fluxes among coating types.

Hull cleaning flux rates, either in tubs or boat bags, were calculated using one hour samples corrected for time zero blank samples and any passive leaching that may have occurred during this time period. The resultant concentrations were converted to dissolved copper mass using the known surfac e area of the fiberglass panel or vessel hull, and the known volume of the tub or boat bag. The comparison among coating types and hull cleaning methods was accomplished using a non

- parametric two

- factor ANOVA
(Zar 1984).

In an effort to compare the re lative contributions of copper during passive leaching and hull cleaning, copper mass emissions were estimated for a typical 9.1 m by 2.7 m powerboat. Surface area was estimated using the coating manufacturer’s formula (Length * Beam * 0.85). Since hull cleaning occurs on a monthly basis, dissolved copper emissions were calculated over a 28 day time period.

RESULTS

Passive Leaching

The enclosed system was able to measure in situ passive dissolved copper leach rates from fiberglass panels (Figure 1). Dissolved copper mass within the recirculating dome system for hard vinyl coatings originated near 10 μg at time zero, then increased more than one order of magnitude to 130 μg after one hour. Sequential samples collected over this time period increased in a strong linear fashion. We used this relationship to fit curves that approximated passive leaching rates. The passive leaching rates for modified epoxy resulted in a very similar curve as hard vinyl coatings. In contrast, the biocide

- free coatings had a very flat curve, demonstrating minimal leaching from this coating type.

Passive leaching rates varied between copper

- based and biocide

- free antifouling coatings (Table 2). As, expected, biocide

- free coatings had passive leaching rates that were nea r zero. In contrast, mean passive leaching rates for copper

- based antifouling coatings varied from 3.7 to 4.3 μg/cm 2 /day. Although these copper

- based passive leach rates varied by 15%, they were not significantly different from one another.Copper emissions from antifouling paint

8 The passiv e leaching rates were highest immediately following cleaning events, then rapidly declined until asymptotically reaching a baseline rate (Figure 2). Mean passive leach rates for modified epoxy and hard vinyl coatings one day following cleaning

activities were 18 and 15 μg/cm 2 /day, respectively. This is the time period when panels were free of fouling by biofilms, algae, or other organisms. These rates decreased three

fold within three days following cleaning activities, dropping to between 4 and 5 μg/cm 2 /day. Passive leach rates decreased slowly following day three, dropping to only 3 μg/cm 2 /day after 28 days following cleaning activities. Biocide free coatings exhibited minimal variability in copper concentration over time, remaining uniformly low to n on

detectable.

Hull Cleaning

Contributions of dissolved copper during normal cleaning activities varied among all three coating types (Table 2). The greatest fluxes, averaging 8.6 μg/cm 2 /event, arose from the cleaning of the modified epoxy coated surfa ces. The cleaning of the hard vinyl coated surfaces produced dissolved copper fluxes that averaged roughly half the modified epoxy fluxes. Dissolved copper fluxes of biocide

- free coatings were essentially zero.

The effect of BMPs can alter the flux of d issolved copper, depending upon the type of coating being cleaned (Table 2). The lack of BMPs during cleaning events doubled the flux of dissolved copper from surfaces painted with modified epoxy antifouling coatings. The flux of dissolved copper did not change with or without the use of BMPs for either the hard vinyl or biocide free coated surfaces. The mean flux of dissolved copper from hard vinyl coated surfaces remained near 4 μg/cm 2 /cleaning. The flux of dissolved copper from the surfaces coated wi th the biocide free formulation remained essentially

zero.

Estimates of Combined Mass Emissions

Passive leaching contributed more dissolved copper than hull cleaning activities for a typical recreational vessel on a monthly basis (Table 3). A 9.1 m pow erboat that is cleaned every four weeks using BMPs was estimated to contribute between 22 to 26 g/mo of dissolved copper. Between 4 and 7% of these emissions arise from hull cleaning activities, depending upon the type of coating. The remaining 93 to 96% of the copper emissions arose from passive leaching. The relative difference in loadings between passive leaching and hull cleaning activities is a function of frequency. On a daily basis, the flux of dissolved copper was slightly higher for cleaning ac tivities than passive leaching (Table 2). However, most vessels are cleaned once per month, whereas passive leaching is a continuous process.Copper emissions from antifouling paint

9 

### DISCUSSION

Flux rates of dissolved copper varied in our study as a function of biocide content within

the coating, hardness of the coating matrix, development of biofilms and other fouling organisms, amongst others. Release rates were highest for the modified epoxy coating in this study. This paint had a greater copper content (57.7%) than then the hard viny l (37.25%) or biocide free (0%) coating based upon the ingredients listed on the product container. Our study used three types of coatings, but there are many available on the commercial and industrial markets including ablative and self

- polishing copolym

er coatings. Passive in

- situ leach rates of dissolved copper from ablative paints used by the U.S. Navy were measured to average 3.9 μg/cm 2 /day (Zirino and Seligman 2002). Valkirs et al. (2003) measured passive leach rates that ranged from 8

- 22 μg/cm

2 /d ay after two months at steady state conditions from ablative in service and copolymer self

polishing test coatings used on military vessels. In the United Kingdom, Thomas et al

. (1999) found ablative leach rates that ranged from 18.6

- 21.6 μg/cm 2 /day in 17 day experiments. Although ablative coatings appear to have a slightly higher flux rate, the use of these coatings has diminished in recent years in civilian pleasure craft. Interestingly, the reduction in ablative coatings stems not from concerns about water quality, but rather from concerns about air quality. It appears that these coatings have a large volatile component that makes it difficult for most boatyards, at least in southern California, to comply with clean air standards (Leigh Johnson person al communication )

.

The hardness of the coating matrix appeared to alter the flux rates of dissolved copper, particularly during cleaning events. In the case of the present study, both the modified epoxy and hard vinyl coatings were classified by the man ufacturer as hard, insoluble types that release biocide through contact leaching. However, water discoloration by coating particles was observed during cleaning operations on panels with modified epoxy, but not with the hard vinyl matrix. Moreover, the c oncentration of dissolved copper was higher following cleaning activities in the softer modified epoxy coating, which was only exacerbated when more abrasive cleaning techniques were applied. In contrast, the most abrasive cleaning technique did not alter dissolved copper flux rates for the hard vinyl coating.

Biofouling quickly reduced and, ultimately, equalized the passive leaching rates of both copper containing coatings examined in this study. Biofilms have been shown to alter release rates (WHOI 195 2, Mihm and Loeb 1988, Valkirs et al. 2003). Cleaning events allowed the passive leach rates of the paints to temporarily function above 10 μg/cm 2 /day, a leach rate known to retard biofouling (WHOI 1952, Caprari et al. 1986). However, as the biofilm laye r increases it may sequester leached metals. As evidence of this, biofilms have been reported to contain high (1.3

- 3.5 μ g/mg dry wt ) copper concentrations (French et al. 1984).

One point of concern for our study design was extrapolation of our results from fiberglass panels to the hulls of recreational vessels. This concern appears unfounded, though, because our measurements compared favorably to measurements from recreational vesselCopper emissions from antifouling paint

10 hulls (Fig 3). Valkirs et al. (2003), using the in situ methodology u sed in our study, reported passive leach rates on seven different recreational vessels of varying coating formulations with different copper content, time since application, and time since cleaning. The mean passive leach rate of the recreational vessels was approximately
double the fiberglass panels (8 vs. 4 μ g/cm 2 /day) , but the range of measurements for the vessels encompassed the mean of our panel system. In fact, the range of measurements

for the seven different recreational vessels was within the ra nge of measurements for the fiberglass panels ( 2

- 26 μ g/cm 2 /day) over our one month test period. Likewise, the flux rates measured during hull cleaning events using fiberglass panels were comparable to results measured from recreational vessels (Fig 3). S imilar to isolating fiberglass panels in a dockside tub system, we were able to measure replicate vessels by isolating them from the marina environment using a boat bag. The mean cleaning flux rate measured for the fiberglass panels and the boat bag syste ms were within 12% of each other. The range of hull cleaning flux rates from recreational vessels appeared much smaller than the passive leaching flux rates, perhaps because the vessels were all similar in size, coating formulation, time since application , and time since cleaning.

If managers wish to reduce dissolved copper emissions from hard vinyl or modified epoxy antifouling coatings on recreational vessels, it is most efficient to alter coating types rather than focus on hull cleaning BMPs. On a mas s basis, 95% of the loading from recreational hull coatings occurs via passive leaching. Therefore, even if a BMP existed that reduced all of the dissolved copper emissions, the total cumulative reductions would amount to only 5%. Furthermore, most comme rcial hull cleaners attempt to clean coatings with minimal abrasiveness. They use these techniques to not only reduce copper emissions, but also to prolong the life of the coating. The use of BMPs may be more effective on softer coatings such as copper

- b ased ablative paints. Switching to nontoxic alternatives may be the most effective mechanism to reduce overall copper emissions, but this alternative comes with a sacrifice. In this study, the nontoxic coating alternative fouled much more quickly, contai ned more “hard” growth (i.e. barnacles), and required increased cleaning effort and time.



### ACKNOWLEDGMENTS

The authors are deeply indebted to Dr. William R. Crawford III (Scuba Duba Corp), a businessman with tremendous integrity. Additional acknowledgem ents include Francois Aquin and Shawn Whisnant (Scuba Duba Corp), Pete Michael (San Diego Regional Water Quality Control Board), Kevin Kelly (Department of Pesticide Regulation), Peter Seligman (US Navy), Leigh Johnson (University of California Sea Grant E xtension Program), David Tsukada, Liesl Tiefenthaler, Drew Ackerman, Kerry Ritter and Steven Bay (SCCWRP). Laboratory analysis was conducted by CRG Marine Laboratories (Torrance, CA). Fiberglass panels were constructed by Crystaliner Corp. (Costa Mesa,

C A). Boat bags were provided by Bottom Liner Corp. (Long Beach, CA). Portions of this study were funded by the San Diego Regional Water Quality Control Board and the State of California Department of Pesticide Regulation.Copper emissions from antifouling paint

11 

### REFERENCES

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dard Test Method for Copper Release Rates of Antifouling Coating Systems in Seawater., ASTM Method D 6442

- 99. 6pp.

Bloom, N.S., and B.A. Crecelius. 1983. Determination of silver in seawater by coprecipitation with cobalt pyrrolidine dithiocarbamate and Zeeman graphite

- furnace atomic absorbtion spectrometry. Analytica Chimica Acta 156:139

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Caprari, J.J., O. Slutzky, P.L. Pessi, and V. Rascio. 1986. A study of the leaching of cuprous oxide from vinyl antifouling paints. Progress in Organic Coating s 13: 431

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French, M.S., L.V. Evans, and R. Dalley. 1984. Raft Trial Experiment on Leaching from Antifouling Paints. Trans. IMarE (C), Vol. 97, Conf.2, Paper 19. 127

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Hall, W., S. Bushong, L. Hall, M. Lenkevich, and A. Pinkney. 1988. Monitoring dissolved copper concentrations in Chesapeake Bay. Environmental Monitoring and

Assessment 11:33

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Kiil, S., C.E. Weinell, M.S. Pedersen, K. Kam

- Johansen. 2001. Analysis of self

polishing antifouling paints using rotary experiments and mathematical modeling. Ind. Engineering and Chemical Research 40:3906

- 3920.

Mihm, J.W., and G.I. Loeb. 1988. The effect of microbial biofilms on organotin release by an antifouling paint. In Biodeterioration 7 (pp. 309

- 314). D.R. Houghton, R.N. Smith and H.O.W. Egg ins (Eds.). Elsevier Applied Science, London.

NOAA. 1994. Inventory of chemical concentrations in coastal and estuarine sediments. NOAA Technical Memorandom, NOS ORCA 76. Natinal Oceanic and Atmospheric
Administration, National Ocean Service. Silver Springs, MD.

Schatzberg, P. 1996. Measurement and significance of the release rate for tributyltin. Chapter 19, pp. 383

- 403. In: Organotin: Environmental Fate and Effects. M.A. Champs and P.F. Seligman Eds. Chapman and Hall. New York. 623pp.

S eligman, P.F., A.O. Valkirs, J.S. Caso, I. Rivera

- Duarte, and E. Haslbeck. 2001. Copper release rates from antifouling marine coatings and its relationship to loading and toxicity in San Diego Bay, California. In: Symposium on Pollution Prevention from S hips and Shipyards. Oceanology International 2001 Conference. Miami, Florida, April 4

- 5, 2001. M.A. Champ, Ed. pp. 64

- 81.

Thomas, K., K. Raymond, J. Chadwick, and M. Waldock. 1999. The effects of short

term changes in environmental parameters on the rel ease of biocides from antifouling coatings: cuprous oxide and tributyltin. Applied Organometallic Chemistry 13:453

- 460.Copper emissions from antifouling paint

12 US EPA. 1996a. The national sediment quality inventory: A report to Congress on the extent and severity of sediment contamination in surface waters of the United States. US Environmental Protection Agency, Office of Science and Technology. Washington, DC.

EPA

- 823

- D

- 96

- 002

US EPA. 1996b. Method 1640: Determination of Trace Metal Elements in Ambient Waters by On

- Line Chelation Prec oncentration and Inductive Coupled Plasma

- Mass Spectrometry. U.S. Environmental Protection Agency, Office of Water, Engineering and Analysis Division, Washington, D.C.

Valkirs, A.O., P. F. Seligman, E. Haslbeck, J.S. Caso. 2003. Measurement of copper

r elease rates from

antifouling paint under laboratory and in

- situ conditions : implications

for loading estimation

to marine water bodies. Marine Pollution Bulletin , In press.

WHOI. See Woods Hole Oceanographic Institution.

Woods Hole Oceanographic Instit ution. 1952. Marine Fouling and Its Prevention , United States Naval Institute, Annapolis, MD. Contribution No. 580. 388 pp.

Zar, J. 1984. Biostatistical analysis. Prentice Hall. Engelwood Cliffs, NJ. 718 p

Zirino, A., S.H. Lieberman, and C. Clave ll. 1978. Measurement of Cu and Zn in San Diego Bay by automated anodic stripping voltametry. Environmental Science and Technology 12: 73

- 79.

Zirino, A., S.L. Belli, and D.A Van der Weele. 1998. Copper concentration and Cu II

activity in San Diego Bay

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Zirino, A. and P.F. Seligman. 2002. Copper Chemistry, Toxicity and Biavailabilitry and Its Relationship to Regulation in the Marine Environment. Space and Naval Warfare Systems Center Technical Document 3140. San Diego C ACopper emissions from antifouling paint

13 Table 1. Number of treatments for each of three factors evaluated during the antifouling coating project. All treatments had three replicates.

Treatment Factor No. of

Treatment

s Passive

Leachin

g Underwat

er Hull Cleaning Notes

Coating Types 3 Yes Yes Modified Epoxy, Hard Vinyl, Biocide

- free

Cleaning Types 2 No Yes BMP (nonabrasive) vs nonBMP (abrasive) on all three coatings

Time Since Cleaning 7 Yes No Day 1, 3, 5, 7, 14, 21, 28 on all three coatingsCopper emissions from antifouling paint

14 Table 2. Mean flux rates (95% confi dence intervals) of dissolved copper for three types of commercially available antifouling coatings for passive leaching, hull cleaning using best management practices (BMPs), and hull cleaning without BMPs..

Mean Dissolved Copper Flux

Modified Ep

oxy Hard

Vinyl Biocide Free

Passive Leaching (μg/cm 2 /day) 4.32 (0.44) 3.71 (0.86) 0.24 (0.08)

Hull Cleaning (μg/cm 2 /event)

BMP 8.57 (0.70) 3.84 (1.55) 0.03 (0.02)

No BMP 17.45 (1.65) 4.18 (0.35) 0.05 (0.03)Copper emissions from antifouling paint

15 Table 3. Estimated mean di ssolved copper mass emissions (grams per month) for three coating types (hard vinyl, modified epoxy, and biocide free) for a 9.1 m powerboat.

Flux (g/mo)

Modified Epoxy Hard

Vinyl Biocide

Free

Passive Leaching 24.9 21.4 1.4

(Min

- Max) 23.3

– 27. 8 15.7

–

24.5 0.9

–

1.8

Underwater Hull Cleaning with BMPs 1.8 0.8 <0.01

(Min

- Max) 1.7

– 2.0 0.5

- 1.2 0.00

- 0.01

Total Emissions 26.7 22.2 1.4

(Min

- Max) 20.5

- 33.6 15.0

– 31.5 0.9

–

1.8Copper emissions from antifouling paint

16 Figure 1. Passive leach rate curve for dissolved copper from a hard vinyl, modified epoxy, and biocide free antifouling paint. All data were collected 14 days after underwater cleaning.Copper emissions from antifouling paint

17 Figure 2. Mean ( + std dev) changes in passive leaching of dissolved copper from three types of h ull coatings (hard vinyl, modified epoxy, biocide free) over 28 days following a cleaning event.Copper emissions from antifouling paint

18 Figure 3. Ratio of mean (min, max) dissolved copper flux rates for passive leaching or hull cleaning activities from recreational vessels relative to fi berglass panels used in this experiment. Data for passive leaching from recreational vessels from Valkirs et al (2003).



### Passive Leach Hull CleaningRecreational Vessel / Fiberglass Panel



### 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5