copper speciation survey from uk marinas, harbours and estuaries

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Marine Pollution Bulletin 54 (2007) 1127–1138

Copper speciation survey from UK marinas, harbours and estuaries

Bryn Jones *, Thi Bolam

Cefas Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex CM0 8HA, United Kingdom

Abstract

The use of copper in antifouling paints has increased in the UK in the last 20 years as TBT and several other organic biocides havebeen phased out. To assess the probable impact of copper on estuarine systems a survey was undertaken to measure the different frac-tions of copper present in the water column at current usage. The different fractions measured were; labile copper, (LCu) considered asboth the free copper ions and inorganically bound copper, the total dissolved copper (TDCu) present, and the difference between themtaken as the organically bound likely non-toxic copper fraction. The survey considered sites with different levels of boat use, namelymarinas, harbours and estuaries, differing physical parameters of suspended and dissolved organic matter, different seasons of the yearand different depths in the water column all of which control speciation behaviour.

Suspended particulate matter (SPM) values were measured at all sites and increased from West to East coast locations (5.7–34.4 mg/l).Dissolved organic matter (DOM) values ranged from 0.58 to 2.2 mg/l C. The total dissolved copper concentrations ranged from 0.30 to6.68 lg/l, with labile fraction ranging from 0.02 to 2.69 lg/l, and most labile copper concentrations below 1 lg/l. None of the yearlymean copper measurements exceeded the 76/464/EEC EQS of 5 lg/l. Of the 306 measurements, only one dissolved copper value inone season was above 5 lg/l.

This ratio of labile to total copper was between 10 and 30%. The results from this survey suggest that if toxicity of copper is due to thelabile fraction then using the total dissolved copper concentrations as an indicator of impact overestimate the risk by a factor of fourtimes.Crown Copyright � 2007 Published by Elsevier Ltd. All rights reserved.

Keywords: Copper; Labile copper; Total dissolved copper; Marinas; Harbours; Estuaries

1. Introduction

Despite our knowledge on the toxicity and speciationmechanisms, there is surprisingly little data on the copperspecies present in marine systems close to sources of copperinputs and the changes in ratios of different forms, andhence toxicity, of copper as it disperses. We conducted sur-veys to measure the different forms of copper present inmarine waters around the UK using a simple fractionationsystem. The different fractions measured were: (i) labilecopper, considered as both the free copper ions and inor-ganically bound copper, (ii) total dissolved copper andthe difference between these measurements assigned (iii)

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doi:10.1016/j.marpolbul.2007.04.021

* Corresponding author. Tel.: +44 1621 787273.E-mail address: [email protected] (B. Jones).

organically bound copper fraction. The survey evaluatedthe spatial distribution of copper at sites with different lev-els of vessel use, namely marinas, harbours and estuarieswith inherent differing physical parameters, which are con-sidered to affect speciation behaviour. This survey alsoincluded temporal measurements to evaluate seasonalchanges of concentrations.

Because of the ban on use of tributyltin antifouling coat-ings, copper use within these coatings has increased tomaintain the biocide properties. Concerns are growing thatcopper has an adverse effect on the environment but it alsorealised that measurements of total dissolved copper mayprovide an over estimation of toxicity as the organicallybound copper is considered to be largely non-toxic.

Copper is a ubiquitous element present in all compart-ments of the marine environment. It may exist in many dif-ferent chemical species from free copper ions, inorganic

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1128 B. Jones, T. Bolam / Marine Pollution Bulletin 54 (2007) 1127–1138

salts and organically bound copper. It is an essential ele-ment, required by most organisms for normal metabolicfunction, only becoming toxic when an organism is unableto regulate excessive concentrations. The free Cu+ andCu++ ions are the most toxic forms to marine life, with tox-icity decreasing in the order, Cu+ and Cu++ > inorganiccopper > organic copper. Many marine organisms haveinducible detoxification systems (Bryan and Langston,1992) and have adapted to thrive in different concentra-tions of copper, even to the extent that organisms fromthe same species are able to adapt and tolerate differentconcentrations at different locations (Qixing et al., 2003).

Coating manufacturers have exploited the short-termtoxic effects of copper as an antifouling agent in paint onmarine vessels. Free copper ions released at the surface ofthe paint prevent organisms from attaching to the vessel,however on entry to the water column free copper isquickly complexed to carbonates, hydroxides and boundby organic ligands, reducing its effect on the marine species(Tubbing et al., 1994).

2. Methods

A number of studies have utilised electrochemical meth-ods to titrate the excess (free copper ions) with organicmaterial and to therefore derive the free copper content,(Van den Berg, 1984; Donat et al., 1992; Donat et al.,1994; Lucia et al., 1994). For this study, the approachtaken was to measure the electrochemical (labile) copperby anodic stripping voltammetry, which is selective forthe free copper ions and inorganic copper species together.Total dissolved copper, the copper present after filtration,acidification and UV digestion was also measured by elec-trochemical means. This measures both the free labile,inorganic and organic copper species. The differencebetween the two methods is taken as the organically boundcopper.

Fig. 1. Sampling sites

3. Survey sites

The study design considered 4 sites around the UK, withselection based upon physical factors such as particle load-ing, organic matter and flushing rates (Fig. 1).

Three scenarios were considered: – commercial har-bours, estuarine harbours, and marinas. The classificationis taken from conditions described in the MAMPECmodel, a computer-based simulation of predicted environ-mental concentrations of antifouling biocides (Van Hat-tum, 1999). For each of the scenarios, sites were chosenwhere possible to include a range of conditions from puta-tive low suspended solids at locations on west coast risingto high-suspended solids on the east coast. Similarly siteswith organic enrichment were expected in the southern sitesand lower levels of organic ligands elsewhere. Samples werecollected quarterly over a period of one year to include allfour seasons and therefore differing boat usage and weatherconditions.

At each site, three stations were sampled at three depths(i.e. surface, 1 m under surface and 1 m above substrate) toprovide a putative concentration gradient away from thelikely source of copper. For example at each harbour siteone sampling station would be in the inner harbour, onein middle of the harbour and one located outside the har-bour mouth.

Three commercial harbours were sampled, MilfordHaven harbour, a traditional fishing harbour which nowberths both fishing and pleasure yachts. The site is locatedon the west coast and generally has a low level of solids sus-pended in the water column. Devonport a naval harboursituated on the river Tamar on the southern coast withmedium to low suspended solids, berths a range of militaryvessels from small craft to large ships. Harwich harbourlocated on the east coast with very high-suspended loads,is a very large commercial container-ship terminal and liesopposite to a number of continental ferry terminals.

around UK coast.

B. Jones, T. Bolam / Marine Pollution Bulletin 54 (2007) 1127–1138 1129

Three estuarine harbours were selected, two of which arelocated in the same vicinity as the commercial harbours atMilford and Plymouth. The third estuarine harbour isSouthampton Water. Each of the estuaries services a rangeof large ship and smaller recreational boat use. All threemarinas, Neyland, Queen Anne’s Battery and Ocean Vil-lage are situated off these estuaries and contain berthingand mooring facilities for a range of pleasure craft.

3.1. Collection of samples

Samples of water were taken using a Winchester sam-pler; a cleaned glass Winchester bottle was deployed tothe required depth before opening and closing of the bottleunderwater (Kelly et al., 2000). The sample of water wasthen transferred to an acid-cleaned labelled storage bottle.Salinity, pH and temperature were determined on a sepa-rate sub-sample using a portable universal calibrated meterin situ. Sub-samples of 100 ml of seawater from each depthwere decanted into 125 ml polypropylene bottles andstored in polythene bags for analysis of dissolved organiccarbon.

Samples returned to the laboratory were filtered using anucleopore 0.4 lm filter. Filters were air-dried and the con-centration of suspended particulate matter determinedgravimetrically, the results are reported in mg/l. The fil-tered water sample was then split in two and used for theanalysis of labile and total dissolved copper.

3.2. Analysis methods

The sample for measurement of total dissolved copperwas acidified to pH < 1 by the addition of nitric acid,hydrogen peroxide was also added to aid breakdown oforganic ligands and the sample digested under UV lightfor at least 12 h. Analysis of total dissolved copper wasconducted by differential pulse anodic stripping voltamme-try at a hanging mercury dropping electrode, DPASV-HMDE.

The labile copper fraction was defined as those copperspecies that are electrochemically active after filtrationbut before any acidification or digestion of the samplehas taken place. These species include inorganic boundand free copper species. Due to low concentrations presentthe method used was differential pulse anodic stripping vol-tammetry at a thin mercury film on a rotating glassy car-bon electrode (DPASV TMF RGCDE) (Peterson andWong, 1981).

4. Results

During 2001/2, 306 water samples were collected andanalysed for total dissolved and labile copper, suspendedparticulate matter, dissolved organic matter, chemico-physical parameters of salinity temperature and pH weremeasured on site. Due to operational difficulties andweather conditions, two sampling events (one at Harwich

in winter and one Devonport in the autumn) were aban-doned but a full seasonal cycle was completed for the othersites.

4.1. Salinity and pH

The commercial harbours showed the greatest rangefrom pH, 7.3 to 8.4, the pH for marinas were similar witha range from 7.4 to 8.3. Estuaries showed a much lowerrange both over the year and between sites, 7.8–8.3 overall.Salinities for commercial harbours showed the greatestrange from 9.4 to 33.3 psu followed by marinas 16.5–34.2 psu with estuaries having the lowest range 25.2–34.3 psu.

The lower values for both pH and salinity were found inthe winter season, these differences are all likely to beaccounted for by fresh water input, such as rain runoff.Harwich harbour is dominated by the tidal flow of the estu-ary and does not exhibit the same seasonal pattern withboth pH and salinity, which remained similar over the per-iod of study Table 1.

4.2. SPM and DOM

The profile of SPM, which was expected to rise fromWest to East around the UK coast was observed with amean of 5.7 mg/l at Milford Haven on the West coast, ris-ing to 10.6 mg/l at Southampton, with a highest mean of34.3 mg/l, found at the East coast harbour of Harwich.

The sites located around Plymouth including Devon-port, Plymouth Sound and Queen Anne’s Battery marinawere expected to have the highest dissolved organic matter,due to run off from moorlands above the river, but theresults indicate these were similar to the range of most val-ues found at all sites ranging from 0.58 to 2.2 mg/l C.DOM did exhibit seasonal variation, generally increasingfrom winter through to autumn Table 2.

4.3. Copper

4.3.1. Total dissolved copper

The concentrations of total dissolved copper found inthis study from all stations, sites and depths ranged from0.30 to 6.68 lg/l. The highest seasonal mean total dissolvedcopper concentration was found in Milford Haven harbour(2.75 lg/l) in the summer period. The highest single har-bour concentration was recorded at Milford (4.77 lg/l)and highest marina value found at Ocean Village(6.68 lg/l). Only 10 of the 306 samples recorded concentra-tions above 4 lg/l, seven of these are samples taken withinmarinas and the other three inside commercial harbours. Ingeneral, the concentrations are low with mean concentra-tion in harbours 2.75,1.49, and 1.53 lg/l, Milford Haven,Devonport and Harwich respectively, for marina’s1.97,1.72, and 2.39 lg/l, Neyland, Queen Anne’s Batteryand Ocean Village, respectively and for estuaries,1.35,1.80 and 1.73 lg/l, Milford, Plymouth Sound and

Table 1pH, temperature and salinity

ID Winter Spring Summer Autumn Winter Spring Summer Autumn Winter Spring Summer Autumn

pH pH pH pH Temp Temp Temp Temp Salinity Salinity Salinity Salinity

�C �C �C �C psu psu psu psu

Milford 10A 7.92 8.17 N/R 7.38 7.9 13.1 20.5 13.8 14.9 31.3 29.5 11.2Milford 10B 7.86 8.18 N/R 7.77 7.8 13 20.1 13.7 25.6 31.6 31.9 24.8Milford 10C 7.94 8.16 N/R 7.93 7.8 12.3 19 13.9 31.4 32.4 32.4 31.1Milford 11A 7.28 8.18 8.35 7.76 8.8 14 20.4 13.5 16.1 31.2 31.6 9.4Milford 11B 7.7 8.19 8.34 7.74 8.4 13.3 19.2 13.6 27.6 31.7 31.4 24.1Milford 11C 7.89 8.15 8.2 7.92 8.3 12 18.4 13.4 31.9 32.8 32.6 30.4Milford 12A 7.95 8.17 8.21 N/R 8.5 13 18.5 N/R 25.2 32.4 32.6 30.1Milford 12B 7.92 8.17 8.22 N/R 7.9 12.7 17.9 N/R 28.4 32.4 32.6 30.2Milford 12C 7.95 8.19 8.22 N/R 7.9 12.2 17.7 N/R 32 32.5 32.7 30.3Milford Estuary 1A 7.96 8.28 8.08 N/R 8.2 13.9 19.6 N/R 29.2 32.9 32.3 31.2Milford Estuary 1B 7.95 8.24 8.14 N/R 8.2 12.9 18.5 N/R 30.4 33 32.4 31.1Milford Estuary 1C 7.97 8.2 8.13 N/R 8.3 12.4 18.1 N/R 33 33.1 32.4 31.3Devonport 13A 7.28 8.26 8.25 N/R 8.3 11 17 N/R 22.6 30.3 31.4 N/RDevonport 13B 7.57 8.27 8.44 N/R 8.3 11.7 17.3 N/R 22.9 30.2 31.6 N/RDevonport 13C 7.8 8.21 8.37 N/R 7.4 10.9 16.9 N/R 28.1 32.6 32.6 N/RDevonport 14A 7.66 8.19 8.38 N/R 7 11.5 17.3 N/R 20.7 28.9 31.4 N/RDevonport 14B 7.84 8.16 8.36 N/R 6.4 12.1 17.4 N/R 21.3 30 31.8 N/RDevonport 14C 7.88 8.15 8.29 N/R 7.6 11.5 16.9 N/R 28.2 32.3 33.1 N/RDevonport 15A 7.92 8.17 8.34 N/R 5.6 11.5 17.3 N/R 22.5 29.3 31.9 N/RDevonport 15B 7.93 8.17 8.33 N/R 7.4 11.5 17.4 N/R 24.4 30.1 32 N/RDevonport 15C 7.91 8.17 8.29 N/R 6.4 11.4 17.2 N/R 29.2 33 32.8 N/RHarwich 16A N/R 8.13 7.74 8.19 N/R 16.7 22.8 9.1 N/R 32.3 31.8 32.5Harwich 16B N/R 8.11 8.01 8.11 N/R 14.9 21.6 8.6 N/R 32 33.1 32.4Harwich 16C N/R 8.09 8.05 8.1 N/R 14.7 21.3 8.5 N/R 32 33.3 32.5Harwich 17A N/R 8.13 8.05 8.07 N/R 15.2 21.7 8.3 N/R 32.5 33.1 32.3Harwich 17B N/R 8.13 8.04 8.08 N/R 14.5 21.3 8.3 N/R 32.6 33.2 32.3Harwich 17C N/R 8.13 8.05 8.08 N/R 14.2 20.9 7.9 N/R 32.5 33.2 32.1Harwich 18A N/R 8.18 8.05 8.09 N/R 14.6 21.8 8.2 N/R 32.5 33.1 32.3Harwich 18B N/R 8.2 8.08 8.08 N/R 14.1 21.3 8.2 N/R 32.4 33.3 32.4Harwich 18C N/R 8.16 8.07 8.08 N/R 14.2 20.8 8.3 N/R 32.7 33.3 32.5Milford Estuary 1A 7.96 8.28 8.08 N/R 8.2 13.9 19.60 N/R 29.2 32.9 32.3 31.2Milford Estuary 1B 7.95 8.24 8.14 N/R 8.2 12.9 18.50 N/R 30.4 33 32.4 31.1Milford Estuary 1C 7.97 8.2 8.13 N/R 8.3 12.4 18.10 N/R 33 33.1 32.4 31.3Milford Estuary 2A 7.91 8.1 7.83 N/R 9.8 14.7 17.00 N/R 31.2 31.1 31.9 31.6Milford Estuary 2B 7.96 8.11 8.1 N/R 9 13.6 17.20 N/R 31.3 31.3 31.9 N/RMilford Estuary 2C 7.97 8.12 8.13 N/R 8.9 12.7 17.10 N/R 32.4 31.8 32.3 N/RMilford Estuary 3A 7.98 8.14 8.14 N/R 8.8 14.6 17.50 N/R 31.4 30.6 31.6 30.8Milford Estuary 3B 7.97 8.12 8.14 N/R 9.4 12.8 17.40 N/R 31.8 31.1 31.7 N/RMilford Estuary 3C 7.97 8.12 8.14 N/R 9 12.3 17.10 N/R 32.9 31.5 32.1 N/RPlymouth Sound 4A 7.96 8.2 8.26 N/R 7.5 12.2 16.7 N/R 27.9 32.8 33.7 30.6Plymouth Sound 4B 7.96 8.2 8.26 N/R 6.9 11.8 16.5 N/R 27.8 33.4 33.8 30.4Plymouth Sound 4C 7.98 8.21 8.24 N/R 6.9 11.6 16.4 N/R 27.8 34.3 34 32.4Plymouth Sound 5A 7.98 8.19 8.27 N/R 6.3 12.3 17.3 N/R 29.1 32.4 32.8 33.6Plymouth Sound 5B 7.94 8.2 8.27 N/R 7.1 12 17.1 N/R 28 34.2 32.7 33.7Plymouth Sound 5C N/R 8.21 8.28 N/R N/R 11.6 17 N/R N/R 34.1 33.2 33.9Plymouth Sound 6A 7.94 8.21 8.21 N/R 6.9 13.5 17.8 N/R 30.4 33.5 33 32.4Plymouth Sound 6B 7.98 8.25 8.23 N/R 7.2 12.7 17.4 N/R 30.7 33.3 33.2 32.4Plymouth Sound 6C 7.93 8.21 8.23 N/R 6.7 12.4 17.1 N/R 33.1 34 33.1 33Southampton 7A 7.89 8.14 7.92 8.06 9.5 13.4 19.9 12.7 27.9 28.2 31.1 29.9Southampton 7B 7.92 8.11 7.93 8.07 9.2 13.1 19.8 13 29.2 29.5 31.3 30.4Southampton 7C 7.92 8.13 7.93 8.07 9 12.9 19.6 13 30.8 30.6 31.3 30.5Southampton 8A 7.93 8.11 7.9 8.1 7.93 13.5 19.7 13.4 29.6 30.1 31.2 30.1Southampton 8B 7.94 8.1 7.92 8.09 9.8 12.8 19.5 13.7 29.3 30.6 31.3 30.7Southampton 8C 7.93 8.15 7.92 8.09 9.1 12.4 19.4 12.6 31.6 30.8 31.3 30.8Southampton 9A 7.95 7.91 7.89 8.12 10.4 15.3 18.3 13.6 25.2 28.4 30.4 30.8Southampton 9B 7.92 8.04 7.95 8.08 9.6 14.3 18.6 13.8 26.9 29.3 30.5 30.5Southampton 9C 7.97 8.06 7.96 8.09 9.2 12.4 18.1 12.8 31.1 31.4 31.1 31.1Neyland 19A 8 8.18 8.16 7.43 13.2 8.3 14.3 18.6 23 26.9 29.4 16.5Neyland 19B 7.94 8.15 8.13 7.63 13.2 8.3 13.2 18.5 24.9 30.6 30.4 18.7Neyland 19C 7.94 8.16 8.1 7.93 13.6 7.7 12.4 18.1 31.7 32.1 31.5 28.4Neyland 20A 7.96 8.14 8.16 7.49 13.6 8.2 14.6 18.3 22.3 29.2 30.3 18.2


Table 1 (continued)

ID Winter Spring Summer Autumn Winter Spring Summer Autumn Winter Spring Summer Autumn

pH pH pH pH Temp Temp Temp Temp Salinity Salinity Salinity Salinity

�C �C �C �C psu psu psu psu

Neyland 20B 7.94 8.13 8.15 7.62 13.5 8.1 13.7 18.2 29.6 27.7 30.5 21.5Neyland 20C 7.95 8.13 8.14 7.75 13.7 8.1 13.1 17.7 31.7 31.6 31.8 29.5Neyland 21A 8 8.1 8.15 7.7 13.4 8 13.3 18.1 27 30.3 30.7 24.1Neyland 21B 7.95 8.11 8.14 7.59 13.8 7.8 13.2 18.1 30.2 30.3 30.8 25.1Neyland 21C 7.96 8.12 8.13 7.88 13.6 7.9 12.7 18.1 30.9 30.7 31 24.8Queen Anne’s 22A 7.99 8.22 8.22 8.1 12.6 6.7 13.1 18.1 27.3 30 30.5 28.6Queen Anne’s 22B 7.99 8.18 8.2 8.1 13 6.7 12.6 18 27.2 31.2 30.7 31.6Queen Anne’s 22C 7.98 8.17 8.19 8.15 11.6 6.8 12.2 18 27.3 33.3 31.4 32.4Queen Anne’s 23A 7.91 8.14 8.25 8 12.9 6.9 12.5 17.5 28 30.3 31.5 28.3Queen Anne’s 23B 7.96 8.12 8.26 8.01 12.6 7.6 12.1 17.3 27.7 31.4 32.2 30.4Queen Anne’s 23C 7.95 8.15 8.25 8.09 13.3 8.1 11.8 17.2 28.4 33.7 32.8 32.2Queen Anne’s 24A 7.79 8.2 8.25 N/R N/R 7.7 12.5 16.9 28.9 32.7 33 28.3Queen Anne’s 24B 7.99 8.18 8.25 N/R N/R 8.1 12.3 16.8 29.1 33.1 33.1 31Queen Anne’s 24C 7.99 8.21 8.23 N/R N/R 8.3 11.8 16.8 31 34.2 33.7 32.2Ocean Village 25A 7.94 8.09 7.87 8 14.3 10.5 20.5 14.1 22.4 24.8 25.8 26.1Ocean Village 25B 7.92 8.1 7.87 N/R N/R 9.7 19.9 12.5 26.6 29.3 29.6 29.2Ocean Village 25C 7.91 8.18 7.88 N/R N/R 9.9 20.6 12.6 31.3 31.6 30.9 30.4Ocean Village 26A 7.91 8.12 7.87 8.01 13.3 10 19.5 12.6 21.2 24.5 27.7 26Ocean Village 26B 7.91 8.12 7.89 8 14.1 9.5 19.4 12.2 23.6 28.2 29.4 29.2Ocean Village 26C 7.9 8.13 7.89 N/R N/R 9.1 19.4 11.9 30.2 31.3 30.5 30.6Ocean Village 27A 7.92 8.09 7.88 8.05 13.7 9.8 21.1 14.1 25.8 25.1 29.1 27.9Ocean Village 27B 7.91 8.14 7.92 8.05 13.8 9.2 20.1 12.4 28.4 30.1 30.8 30.3Ocean Village 27C 7.92 8.16 7.92 8.03 14.5 8.9 19.8 12 30.9 31 30.8 30.8

Key: A = Surface measurement; B = 1 meter depth; C = 1 m above sediment; 1,4,7,10,13,16,19,22,25 = inner most station (closest to source);2,5,8,11,14,17,20,23,26 = middle station; 3,6,9,12,15,18,21,24,27 = Ou = outer station (furthest from source).


Southampton water respectively. No concentrations exceedthe annual average of the EQS for Copper, set at 5 lg/l (setas an annual average) in fact only one dissolved copperconcentration was found above 5 lg/l and in only one sea-son (Ocean Village, autumn).

Concentration gradients from the reference points toinner sampling areas existed in marinas and harbours. Sea-sonal gradients were particularly evident in harbours andmarinas, rising from winter to late summer, and thendecreasing during autumn to winter.

4.4. Labile copper

The highest labile concentration was found at OceanVillage at 2.69 lg/l. Only 9 out of the 306 concentrationsmeasured were found to be above 1 lg/l, two of these wereabove 2 lg/l and were from Milford Haven harbour orOcean Village marina. The concentration range for labilecopper measurements was between 0.02 and 2.69 lg/l,The mean labile copper concentrations in commercial har-bours were 0.84,0.57, and 0.56 lg/l, Milford Haven, Dev-onport and Harwich respectively, for marinas 0.46, 0.41,and 0.65 lg/l, Neyland, Queen Anne’s Battery and OceanVillage respectively and for estuaries, 0.22, 0.32, and0.43 lg/l, Milford, Plymouth Sound and SouthamptonWater respectively. In the three estuaries studied, the labilerange was from 0.11 lg/l to 0.43 lg/l, no labile fractionswere recorded above 1 lg/l and only 3 of these stations

were above 0.5 lg/l. The seasonal variation followed thesame pattern as for the total dissolved copper. Table 3and Fig. 2.

4.5. Depth profiles

Water samples were taken from three depths, at the sur-face, at 1 m depth and approximately 1 m above the sea-bed. The depth profiles for both total dissolved and labilecopper show a great deal of variation the highest concen-trations were generally found in the surface sample or at1 m depth sample. Fig. 3 gives typical example of such pro-files for harbours across the seasons. This variation doessuggest complex processes in the reduction of labile copperwithin the water column.

5. Discussion

The sites for this study were chosen to be distant fromoutfalls and other potential sources of copper other thannatural background inputs. The sites should, therefore,predominantly reflect increases in copper inputs from anti-fouling leachates, if present. The samples reflect a widevariety of input scenarios and provide temporal and spatialinformation on copper speciation under parameters such asproximity to sources, suspended particulate matter content,organic matter, salinity, water movement, temperature,vessel type and frequency of movement of vessels. The

Table 2Suspended particulate mattter (SPM), dissolved organic matter (DOM) and sampling depths

Winter Spring Summer Autumn Winter Spring Summer Autumn Winter Spring Summer Autumn

SPM SPM SPM SPM DOM DOM DOM DOM Depths Depths Depths Depths

mg/L mg/L mg/L mg/L mg/l C mg/l C mg/l C mg/l C m m m m

Milford 10A 5.52 5.52 3.62 11.43 1.54 1.43 2.1 3.01 0 0 0 0Milford 10B 4 8.19 4.19 19.05 0.58 1.73 1.41 1.84 1 1 1 1Milford 10C 5.33 1.9 3.24 11.43 0.58 1.36 1.69 1.87 4.1 6.4 7.4 3.9Milford 11A 3.43 2.29 3.43 7.62 1 1.58 1.5 2.31 0 0 0 0Milford 11B 3.05 2.29 2.86 11.43 0.54 1.39 1.7 2.13 1 1 1 1Milford 11C 7.43 3.24 4.95 13.33 0.61 1.45 1.16 1.66 4.1 6.4 7.4 3.9Milford 12A 2.48 4.76 4.95 5.71 1.04 1.08 1.47 1.48 0 0 0 0Milford 12B 3.62 N/R 4.38 5.71 1.06 1.2 1.29 1.32 1 1 1 1Milford 12C 6.67 4.38 10.67 7.62 0.55 1.41 1.19 1.84 5 6.4 7.2 3.9Milford Estuary 1A 7.05 2.67 4.76 13.33 0.53 1.25 1.25 1.04 0 0 0 0Milford Estuary 1B 6.10 0.95 2.86 17.14 0.77 1.33 2.25 1.66 1 1 1 1Milford Estuary 1C 5.14 3.24 5.90 17.14 0.73 0.97 1.42 1.72 5.4 5.8 6.6 5.4Devonport 13A 5.14 3.05 1.52 N/R 0.9 1.12 1.39 N/R 0 0 0 0Devonport 13B 6.48 5.52 2.29 N/R 0.69 1.48 1.32 N/R 1 1 1 1Devonport 13C 8.57 3.24 4.00 N/R 1.1 1.3 1.2 N/R 12.2 11.3 11.1 11.1Devonport 14A 6.67 4 3.43 N/R 1.14 1.8 1.76 N/R 0 0 0 0Devonport 14B 4.57 4.57 3.24 N/R 0.86 1.12 1.85 N/R 1 1 1 1Devonport 14C 10.48 1.52 4.38 N/R 0.59 1.35 2.3 N/R 11.9 11.3 11.3Devonport 15A 18.29 N/R 8.57 N/R 0.74 1.64 1.48 N/R 0 0 0 0Devonport 15B 18.86 3.62 4.95 N/R 0.79 1.1 1.96 N/R 1 1 1 1Devonport 15C 19.81 3.05 3.81 N/R 0.72 1.1 1.23 N/R 19.8 19.3 19Harwich 16A N/R 38.29 5.14 22.86 N/R 1.23 1.76 1.92 N/A 0 0 0Harwich 16B N/R 37.9 3.62 24.76 N/R 0.98 1.74 1.58 N/A 1 1 1Harwich 16C N/R 57.14 6.86 34.29 N/R 1.61 1.61 2.15 N/A 13.1 13.2 12.3Harwich 17A N/R 44 10.86 15.24 N/R 0.14 1.5 3 N/A 0 0 0Harwich 17B N/R 55.24 16.38 15.24 N/R 1.09 1.39 1.75 N/A 1 1 1Harwich 17C N/R 64.19 36.95 17.14 N/R 1.23 1.55 1.74 N/A 16.4 16.6 15.9Harwich 18A N/R 34.67 21.14 9.52 N/R 1.1 1.75 2.53 N/A 0 0 0Harwich 18B N/R 56.38 24.00 17.14 N/R 1 1.96 1.35 N/A 1 1 1Harwich 18C N/R 149.52 92.19 17.14 N/R 1.11 2.24 1.53 N/A 16.6 16.8 15.7Milford Estuary 1A 7.05 2.67 4.76 13.33 0.53 1.25 1.25 1.04 0 0 0 0Milford Estuary 1B 6.1 0.95 2.86 17.14 0.77 1.33 2.25 1.66 1 1 1 1Milford Estuary 1C 5.14 3.24 5.90 17.14 0.73 0.97 1.42 1.72 5.4 5.8 6.6 5.4Milford Estuary 2A 4.95 5.14 4.76 15.24 0.53 1.43 2.33 1.27 0 0 0 0Milford Estuary 2B 8.95 5.14 4.38 N/R 0.68 1.84 1.58 N/R 1 1 1 1Milford Estuary 2C 8.19 9.52 5.71 N/R 0.53 1.44 1.24 N/R 13.9 9.1 9.7 11.6Milford Estuary 3A 6.1 2.48 6.48 13.33 0.6 1.71 1.83 1.53 0 0 0 0Milford Estuary 3B 6.29 8.19 3.62 N/R 0.35 1.44 1.47 N/R 1 1 1 1Milford Estuary 3C 12.76 5.33 4.76 N/R 0.52 1.2 1.46 N/R 9.5 4.8 5.8 7.1Plymouth Sound 4A 12.38 0 1.14 N/R 0.78 1.43 0.97 1.42 0 0 0 0Plymouth Sound 4B 19.81 5.91 4.76 15.24 0.8 1.1 1.48 2.09 1 1 1 1Plymouth Sound 4C 28.38 4.38 2.86 11.43 0.81 0.72 1.33 1.16 8.9 8.4 8.5 9.8Plymouth Sound 5A 10.48 6.1 4.38 17.14 0.96 1.68 2.42 0.72 0 0 0 0Plymouth Sound 5B 8.57 2.29 12.38 5.71 2.87 0.96 1.65 0.75 1 1 1 1Plymouth Sound 5C N/R 3.05 3.62 7.62 N/R 0.91 1.2 0.7 4.7 4.2 4.2 5.7Plymouth Sound 6A 6.48 4.19 0.38 5.71 0.73 1.01 2.34 1.3 0 0 0 0Plymouth Sound 6B 5.33 2.67 3.24 5.71 0.57 1.13 1.17 0.85 1 1 1 1Plymouth Sound 6C 12 1.52 5.90 3.81 0.84 0.69 2.3 1.26 3.5 4.7 4.7 6.1Southampton 7A 6.48 4 5.14 3.81 0.81 1.25 1.77 1.12 0 0 0 0Southampton 7B 9.71 8.19 9.14 5.71 0.53 1.08 1.54 1.58 1 1 1 1Southampton 7C 12.57 4.57 14.48 17.14 0.72 0.95 1.55 0.76 3.7 2.7 2.8 4.8Southampton 8A 9.33 2.67 28.19 11.43 0.72 1 1.4 1.5 0 0 0 0Southampton 8B 6.86 6.1 11.05 9.52 0.98 0.74 1.67 1.41 1 1 1 1Southampton 8C 10.48 N/R 17.33 13.33 0.75 0.86 1.34 1.7 3.4 3 3 4.6Southampton 9A 4 4.95 17.90 3.81 0.86 1.04 2.45 1.55 0 0 0 0Southampton 9B 6.1 3.24 17.90 11.43 1.12 1.08 1.28 1.25 1 1 1 1Southampton 9C 15.1 N/R 30.29 19.05 0.72 1.16 1.42 0.93 3 2.9 3.4 4.1Neyland 19A 2.67 9.91 3.62 5.71 0.69 1.22 1.9 2.13 0 0 0 0Neyland 19B 4.00 4.76 5.52 26.67 0.63 1.51 1.86 1.71 1 1 1 1Neyland 19C 5.52 34.67 4.95 15.24 0.55 0.9 1.26 1.58 7.1 5.8 6.6 5Neyland 20A 4.00 N/R 3.43 17.43 0.7 2.09 1.48 2.47 0 0 0 0


Table 2 (continued)


SPM SPM SPM SPM DOM DOM DOM DOM Depths Depths Depths Depths

mg/L mg/L mg/L mg/L mg/l C mg/l C mg/l C mg/l C m m m m

Neyland 20B 8.38 N/R 7.05 22.86 1.51 1.22 1.66 2.12 1 1 1 1Neyland 20C 7.43 9.71 0.19 11.43 0.76 1.43 1.47 1.44 7.1 5.2 6.1 4.7Neyland 21A 3.81 6.67 4.38 22.86 0.88 1.74 1.36 2.87 0 0 0 0Neyland 21B 7.62 7.42 5.14 5.71 0.95 1.3 1.98 2.7 1 1 1 1Neyland 21C 4.95 6.29 8.76 24.76 0.62 1.29 1.47 2.03 9.1 5.1 6 5.1Queen Anne’s 22A 12.95 2.29 10.10 7.62 1.04 1.39 1.93 1.72 0 0 0 0Queen Anne’s 22B 8.19 N/R 2.86 7.62 1.27 1.27 1.58 1.01 1 1 1 1Queen Anne’s 22C 4.76 9.52 3.62 19.05 0.6 1.5 1.38 1.3 1.7 2.3 2.3 4.7Queen Anne’s 23A 7.62 N/R 4.76 7.62 0.79 1.12 2.36 1.26 0 0 0 0Queen Anne’s 23B 10.29 1.14 9.52 11.43 0.68 1.7 1.85 1.21 1 1 1 1Queen Anne’s 23C 5.52 N/R 2.86 9.52 0.85 1.06 1.3 1.98 3.9 4 4 6.8Queen Anne’s 24A 5.52 4.38 6.48 3.81 1.09 1.1 1.62 1.4 0 0 0 0Queen Anne’s 24B 7.24 6.67 5.90 11.43 0.73 1.81 1.5 1.49 1 1 1 1Queen Anne’s 24C 12.00 5.14 10.48 7.62 0.53 1.35 2.42 1.34 14 13.8 13.7 16Ocean Village 25A 6.48 3.62 13.71 11.43 0.85 1.22 2.48 2.11 0 0 0 0Ocean Village 25B 4.57 3.62 6.67 3.81 0.58 1.32 1.72 1.55 1 1 1 1Ocean Village 25C 8.00 6.86 10.10 9.52 0.85 1.05 1.48 1.66 5.2 6 6.3 6.1Ocean Village 26A 5.71 3.62 5.90 7.62 1.22 1.21 1.71 1.8 0 0 0 0Ocean Village 26B 6.29 N/R 5.33 7.62 0.82 1.25 1.35 1.31 1 1 1 1Ocean Village 26C 6.48 3.43 7.62 15.24 0.58 1.27 1.44 0.96 5 5.6 6 6.2Ocean Village 27A 10.29 N/R 6.86 9.52 0.53 1.28 1.6 1.49 0 0 0 0Ocean Village 27B 6.48 6.67 8.19 7.62 0.87 1.32 1.74 1.66 1 1 1 1Ocean Village 27C 11.10 6.67 8.76 9.52 0.63 1.18 1.48 1.82 3 3.5 4.1 6

Key: A = Surface measurement; B = 1 meter depth; C = 1 m above sediment; 1,4,7,10,13,16,19,22,25 = inner most station (closest to source);2,5,8,11,14,17,20,23,26 = middle station; 3,6,9,12,15,18,21,24,27 = Ou = outer station (furthest from source).


concentrations of total dissolved copper found in thisstudy are very similar to those concentrations of total dis-solved copper found in other studies such as those com-piled by Hall Lenwood and Anderson Ronald (1999).Harbour and marina concentrations were generally ele-vated above reference site values but the data demon-strates that high values were restricted to the immediatevicinity of the specific source due to dilution and com-plexation reactions.

The rate of complexation appears to be rapid since alllabile concentrations seem to be low even within harboursand marinas. Mean labile values found for all three scenar-ios were all less than 0.5 lg/l and little variation in thelabile fraction found between the three different scenarios.For the whole dataset, there is a weak but observable trendthat at high dissolved total copper concentrations, labilemeasurements are more frequently elevated however veryfew individual labile measurements exceed 1 lg/l, indicat-ing that there are sufficient complexing agents, such asSPM and DOM to remove excess inorganic copper. Itremains unclear from the study data whether SPM orDOM is having the greater effect in regulating labile spe-cies, the data given in Figs. 4 and 5 where the ratio of labileto total copper values are plotted against increasing DOMor SPM values is inconclusive.

A plot of ranked increasing total copper against ratio oflabile to total fraction show that while total copperincreases the labile fraction remains fairly constant with

few values rising above 1 lg/l (Fig. 6). This indicates thatthere are complexing agents in the water likely to beDOM, inorganic ligands and particulates that activelycombine with labile copper, therefore preventing a buildup of toxic copper ions in the three scenarios studied (seeFig. 7).

5.1. Harbours

The harbours in our study are generally in use all yearround, with vessels residing at berths for a limited period.Accordingly, copper inputs from antifouling sourcesshould be episodic but distributed evenly throughout theyear. Devonport and Harwich harbours generally conformto this expectation with few clear variations in copper con-centrations over the year. If anything, the concentrations atDevonport are similar to the open estuary stations withpeak concentrations in the late winter possibly reflectingriverine inputs containing higher levels of metals. At Mil-ford Haven, seasonal variations in total dissolved coppermeasurements are apparent, rising from winter throughto summer Fig. 2. This may be due to part of the harbourhaving shared use with recreational craft, which generallyhave the antifouling coating cleaned more often and vesselsmoving more frequently during the summer period.Although total dissolved copper increases during this per-iod labile concentration do not follow a correspondingincrease Individual high concentrations of total dissolved

Table 3Total dissolved copper and labile copper


Cu TD Cu TD Cu TD Cu TD CuLabile

CuLabile

CuLabile

CuLabile

CuOrganic

CuOrganic

CuOrganic

CuOrganic

lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l

Milford 10A 1.17 3.48 4.32 1.72 0.37 0.53 1.39 1.22 0.8 2.95 2.93 0.5Milford 10B 2.33 3.26 3.16 3.32 0.55 0.6 0.9 0.89 1.78 2.66 2.26 2.43Milford 10C 1.38 2.64 1.43 0.62 0.2 0.18 0.31 0.16 1.18 2.46 1.12 0.46Milford 11A 1.53 3.27 4.58 1.96 0.65 0.66 2.15 0.85 0.88 2.61 2.43 1.11Milford 11B 2.38 1.56 3.79 3.37 1.51 0.58 0.95 0.75 0.87 0.98 2.84 2.62Milford 11C 2.29 1.25 2.22 1.41 0.28 0.16 0.62 0.27 2.01 1.09 1.6 1.14Milford 12A 2.04 2.31 4.31 1.12 0.6 0.22 1.1 0.12 1.44 2.09 3.21 1Milford 12B 2.1 1.72 3.57 4.77 0.41 0.3 1.07 0.47 1.69 1.42 2.5 4.3Milford 12C 1.05 2.29 2.34 0.86 0.11 0.28 0.94 0.08 0.94 2.01 1.4 0.78Milford Estuary 1A 0.93 1.62 0.87 0.49 0.43 0.19 0.23 0.08 0.5 1.43 0.64 0.41Milford Estuary 1B 1.42 1.22 1.22 0.69 0.12 0.07 0.25 0.13 1.3 1.15 0.97 0.56Milford Estuary 1C 0.99 1.39 1.21 0.86 0.15 0.09 0.22 0.23 0.84 1.3 0.99 0.63Devonport 13A 1.47 2.02 1.65 N/R 0.4 0.29 0.43 N/R 1.07 1.73 1.22 N/RDevonport 13B 1.32 1.42 2.08 N/R 0.59 0.15 0.46 N/R 0.73 1.27 1.62 N/RDevonport 13C 1.34 1.13 0.99 N/R 0.49 0.23 0.3 N/R 0.85 0.9 0.69 N/RDevonport 14A 1.33 1.69 1.9 N/R 0.63 0.45 0.53 N/R 0.7 1.24 1.37 N/RDevonport 14B 1.41 1.68 1.41 N/R 0.86 0.32 0.37 N/R 0.55 1.36 1.04 N/RDevonport 14C 2.04 1.97 1.37 N/R 0.27 0.24 0.38 N/R 1.77 1.73 0.99 N/RDevonport 15A 1.59 1.72 1.4 N/R 0.78 0.4 0.43 N/R 0.81 1.32 0.97 N/RDevonport 15B 1.77 0.65 1.73 N/R 0.51 0.32 0.37 N/R 1.26 0.33 1.36 N/RDevonport 15C 2.64 0.93 0.85 N/R 0.56 0.16 0.39 N/R 2.08 0.77 0.46 N/RHarwich 16A N/R 1.07 1.65 0.77 N/R 0.31 0.63 0.48 N/R 0.76 1.02 0.29Harwich 16B N/R 0.69 2.1 1.69 N/R 0.24 0.54 0.25 N/R 0.45 1.56 1.44Harwich 16C N/R 2.3 1.21 1.35 N/R 0.32 0.63 0.13 N/R 1.98 0.58 1.22Harwich 17A N/R 1.04 1.5 1.46 N/R 0.19 0.64 0.15 N/R 0.85 0.86 1.31Harwich 17B N/R 0.63 1.71 1.56 N/R 0.25 0.61 0.21 N/R 0.38 1.1 1.35Harwich 17C N/R 0.74 1.9 2.02 N/R 0.17 0.51 0.25 N/R 0.57 1.39 1.77Harwich 18A N/R 0.57 0.99 1.55 N/R 0.3 0.58 0.24 N/R 0.27 0.41 1.31Harwich 18B N/R 1.47 1.54 1.51 N/R 0.1 0.49 0.27 N/R 1.37 1.05 1.24Harwich 18C N/R 0.79 1.15 1.54 N/R 0.55 0.38 0.18 N/R 0.45 0.77 1.36Milford Estuary 1A 0.93 1.62 0.87 0.49 0.43 0.19 0.23 0.08 0.5 1.43 0.64 0.41Milford Estuary 1B 1.42 1.22 1.22 0.69 0.12 0.07 0.25 0.13 1.3 1.15 0.97 0.56Milford Estuary 1C 0.99 1.39 1.21 0.86 0.15 0.09 0.22 0.23 0.84 1.3 0.99 0.63Milford Estuary 2A 1.28 1.58 1.18 0.71 0.07 0.12 0.24 0.09 1.21 1.46 0.94 0.62Milford Estuary 2B 1.54 1.41 0.72 N/R 0.39 0.22 0.16 N/R 1.15 1.19 0.56 N/RMilford Estuary 2C 0.64 0.58 1.55 N/R 0.16 0.21 0.31 N/R 0.48 0.37 1.24 N/RMilford Estuary 3A 1.72 2.22 1.52 0.73 0.1 0.13 0.25 0.07 1.62 2.09 1.27 0.66Milford Estuary 3B 1.11 1.04 0.99 N/R 0.21 0.15 0.14 N/R 0.9 0.89 0.85 N/RMilford Estuary 3C 1.47 1.05 1.02 N/R 0.34 0.1 0.21 N/R 1.13 0.95 0.81 N/RPlymouth Sound 4A 1.34 1.46 0.61 0.86 0.16 0.2 0.28 0.27 1.18 1.26 0.33 0.59Plymouth Sound 4B 2.51 1.2 0.95 0.67 0.28 0.15 0.18 0.14 2.23 1.05 0.77 0.53Plymouth Sound 4C 1.98 1.15 0.39 1.24 0.25 0.02 0.26 0.07 1.73 1.13 0.13 1.17Plymouth Sound 5A 1.18 2.07 1.12 1.24 0.32 0.23 0.32 0.05 0.86 1.84 0.8 1.19Plymouth Sound 5B 1.41 1.13 0.62 0.84 0.53 0.07 0.31 0.04 0.88 1.06 0.31 0.8Plymouth Sound 5C N/R 1.75 0.92 0.47 N/R 0.05 0.36 0.06 N/R 1.7 0.56 0.41Plymouth Sound 6A 2.62 1.7 0.95 0.47 0.23 0.26 0.41 0.15 2.39 1.44 0.54 0.32Plymouth Sound 6B 2.54 1.26 0.79 0.3 0.24 0.15 0.41 0.17 2.3 1.11 0.38 0.13Plymouth Sound 6C 0.85 0.55 0.92 0.39 0.18 0.09 0.32 0.06 0.67 0.46 0.6 0.33Southampton 7A 1.21 1.75 0.88 1.68 0.21 0.6 0.33 0.19 1 1.15 0.55 1.49Southampton 7B 1.25 1.51 1.01 2.05 0.26 0.44 0.37 0.16 0.99 1.07 0.64 1.89Southampton 7C 1.24 1.85 1.11 1.42 0.27 0.36 0.42 0.18 0.97 1.49 0.69 1.24Southampton 8A 1.09 1.55 1.16 0.78 0.25 0.31 0.4 0.28 0.84 1.24 0.76 0.5Southampton 8B 1.54 1.81 2.04 0.73 0.16 0.36 0.25 0.24 1.38 1.45 1.79 0.49Southampton 8C 1.51 1.99 1.21 1.02 0.12 0.42 0.22 0.28 1.39 1.57 0.99 0.74Southampton 9A 0.95 2.31 1.93 1.61 0.34 0.74 0.34 0.34 0.61 1.57 1.59 1.27Southampton 9B 1.92 1.06 2.09 1.31 0.38 0.39 0.33 0.18 1.54 0.67 1.76 1.13Southampton 9C 1.26 1.72 1.8 2.1 0.21 0.26 0.36 0.16 1.05 1.46 1.44 1.94Neyland 19A 0.56 4.37 2.11 1.54 0.22 0.64 0.44 0.4 0.34 3.73 1.67 1.14Neyland 19B 0.58 1.96 1.56 1.15 0.19 0.04 0.44 0.45 0.39 1.92 1.12 0.7Neyland 19C 0.53 0.69 1.83 0.59 0.09 0.06 0.31 0.16 0.44 0.63 1.52 0.43Neyland 20A 0.73 2.69 4.41 1.55 0.23 0.44 0.71 0.65 0.5 2.25 3.7 0.9Neyland 20B 3.25 1.92 1.96 0.92 0.15 0.3 0.49 0.5 3.1 1.62 1.47 0.42Neyland 20C 0.98 2.72 1.2 0.93 0.14 0.2 0.32 0.3 0.84 2.52 0.88 0.63Neyland 21A 0.99 1.14 1.2 0.76 0.19 0.15 0.49 0.39 0.8 0.99 0.71 0.37Neyland 21B 0.99 0.6 1.55 1.03 0.14 0.14 0.52 0.11 0.85 0.46 1.03 0.92Neyland 21C 1.21 1.61 1.09 0.71 0.21 0.27 0.4 0.57 1 1.34 0.69 0.14Queen Anne’s 22A 1.69 1.69 1.64 4.04 0.41 0.26 0.53 0.44 1.28 1.43 1.11 3.6Queen Anne’s 22B 1.38 1.21 1.47 2.18 0.4 0.19 0.4 0.09 0.98 1.02 1.07 2.09Queen Anne’s 22C 1.34 0.48 1.66 0.77 0.35 0.12 0.47 0.21 0.99 0.36 1.19 0.56Queen Anne’s 23A 1.34 0.45 1.59 1.62 0.12 0.28 0.43 0.31 1.22 0.17 1.16 1.31Queen Anne’s 23B 1.51 1.07 1.57 1.17 0.3 0.24 0.48 0.26 1.21 0.83 1.09 0.91Queen Anne’s 23C 1.36 1.03 1.59 0.85 0.2 0.21 0.41 0.64 1.16 0.82 1.18 0.21Queen Anne’s 24A 1.44 0.87 1.04 3.41 0.19 0.26 0.34 0.47 1.25 0.61 0.7 2.94Queen Anne’s 24B 1.46 0.98 0.8 0.96 0.19 0.34 0.33 0.25 1.27 0.64 0.47 0.71Queen Anne’s 24C 1.44 1.01 0.54 0.47 0.32 0.15 0.33 0.16 1.12 0.86 0.21 0.31Ocean Village 25A 4.67 2.77 4.41 4.25 1.14 1.19 0.68 0.91 3.53 1.58 3.73 3.34


Table 3 (continued)


Cu TD Cu TD Cu TD Cu TD CuLabile

CuLabile

CuLabile

CuLabile

CuOrganic

CuOrganic

CuOrganic

CuOrganic

lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l lg/l

Ocean Village 25B 0.83 1.73 3.46 1.63 0.4 0.49 0.7 0.35 0.43 1.24 2.76 1.28Ocean Village 25C 2.42 1.68 1.72 0.83 0.25 0.38 0.32 0.32 2.17 1.3 1.4 0.51Ocean Village 26A 1.22 3.37 3.6 6.68 0.33 0.55 0.72 2.69 0.89 2.82 2.88 3.99Ocean Village 26B 1.27 2.59 2.49 1.37 0.3 0.53 0.6 0.36 0.97 2.06 1.89 1.01Ocean Village 26C 2.33 2.64 1.37 0.79 0.2 0.28 0.47 0.24 2.13 2.36 0.9 0.55Ocean Village 27A 1.56 2.1 1.54 3.6 0.41 0.48 0.38 0.38 1.15 1.62 1.16 3.22Ocean Village 27B 1.41 1.19 1.51 0.67 0.43 0.31 0.45 0.24 0.98 0.88 1.06 0.43Ocean Village 27C 1.21 1.52 1.39 1.18 0.36 0.32 0.31 0.34 0.85 1.2 1.08 0.84

Key: A = surface measurement; B = 1 meter depth; C = 1 m above sediment; 1,4,7,10,13,16,19,22,25 = inner most station (closest to source);2,5,8,11,14,17,20,23,26 = middle station; 3,6,9,12,15,18,21,24,27 = Ou = outer station (furthest from source).

Key 10 = Innermost station 11 = Middle station 12 = Outermost station

Milford Haven Harbour-November-TD Cu

-5

-4

-3

-2

-1

0

0 2 4 6

Copper Level (ppb)

Dep

th (

m)

10 11 12

Milford Haven Harbour-February-TD Cu

-6

-4

-2

0

0 1 323

Copper Level (ppb)

Dep

th (

m)

10 11 12

Milford Haven Harbour-May-TD Cu

-8

-6

-4

-2

0

0 1 2 3 4

Copper Level (ppb)

Dep

th (

m)

10 11 12

Milford Haven Harbour-August-TD Cu

-8

-6

-4

-2

0

0 2 4 6

Copper Level (ppb)

Dep

th (

m)

10 11 12

Fig. 3. Depth profiles of dissolved copper in Milford Haven harbour across the seasons.

Fig. 2. Seasonal variation of total dissolved copper at Milford Haven harbour.


Ratio of Labile to Total Dissolved Copper with respect to SPM

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1 11 21 31 41 51 61 71 81 91 101

111

121

131

141

151

161

171

181

191

201

211

221

231

241

251

261

271

281

291

301

Stations ranked in increasing SPM

Rat

io o

f Lab

ile to

TD

Cu

0

20

40

60

80

100

120

140

160

SPM

mg/

l

Ratio L Cu: TD CuSPM

Fig. 4. Total and labile copper concentrations and dissolved organic matter, plotted as ranked by increasing suspended particulate matter.

Ratio of Labile Copper to Total Dissolved Copper with respect to DOM

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1 12 23 34 45 56 67 78 89 100

111

122

133

144

155

166

177

188

199

210

221

232

243

254

265

276

287

298

Stations ranked by increasing DOM

Rat

io o

f L C

u to

TD

Cu

0

0.5

1

1.5

2

2.5

3

3.5

DO

M m

g/l C

Ratio L Cu :TD CuDOM

Fig. 5. The total and labile copper concentrations and suspended particulate matter, plotted as ranked by increasing dissolved organic matter.


copper do not always have a corresponding high labile con-centration. This again enforces the evidence that there are

complexing agents that rapidly remove inorganic copperfrom the water column.

Ratio of Labile Copper to Total Dissolved Copper with Respect to Total Dissolved Copper

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 50 100 150 200 250 300Stations ranked in increasing TDCu

Rat

io o

f L

Cu

to

TD

Cu

0

1

2

3

4

5

6

7

8

TD

Cu

ug

/l

Ratio L Cu: TDCu

Total Dissolved Cu

Fig. 6. Ratio of labile to total copper in relation to total copper concentration.

Fig. 7. Total and labile copper variation in Milford harbour.


5.2. Estuaries

The total dissolved concentration of copper in estuariesdoes not show the same variation as in the harbours, onlyranging from 0.3 to 2.6 lg/l. The results indicate that thesites are outside any mixing zone from discrete copperinputs. Plymouth sound provides an example where winterrunoff and disturbance of sediments lead to higher levels ofdissolved copper in the water early in the year. The estuarysites studied show that any copper contribution from anti-fouling paint is difficult to observe from the general back-ground concentrations and that the lower concentrationsof labile copper would suggest that the larger water bodyis able to dilute or complex any excess labile copper tothe organic form.

5.3. Marinas

In contrast to harbour situations in marinas boats tendto reside longer in their berths and are frequently cleaned,or often repainted in the spring or summer months. Manymarinas are semi-enclosed to provide shelter but thereforehave reduced water exchange with the open estuary. Pub-lished profiles of other antifouling biocides suggest thatwe would expect occasional winter high values due to hos-ing off activity, but also a general increase in concentra-tions in the spring associated with boat use (Thomaset al., 2001). This is indeed what was observed in all themarinas sampled. The marinas studied generate more ofthe higher individual total dissolved copper concentrations,while again labile copper is not observed to always increasewith these high total values.

6. Conclusion

The study set out to establish the concentrations of totaldissolved copper found in three marine areas where anti-fouling coatings are in use and to establish the proportionsof inorganic to total copper present. The overall mean ratioof labile to total dissolved copper was found to be 27%, i.e.almost three quarters of the copper present is in a non-toxicform. This implies that using the total copper concentra-tion as an indicator of toxicity could be overestimating riskby a factor of 4.

Of the three scenarios, harbours had the highest totaldissolved mean concentration at 1.84 lg/l and highestmean labile fraction 0.48 lg/l while the estuaries had thelowest means of both fractions, 1.27 lg/l total and


0.24 lg/l for labile The results indicate that in areas whereboat usage is confined in specific areas of low waterexchange such as marinas and harbours, copper concentra-tions are higher but gradients decrease rapidly away fromthe source such that concentrations soon return to back-ground levels. Gradients from point sources were notobserved within the estuarine harbour sites.

The distribution of the electrochemically labile copper atall sites appears to be relatively low and stable and does notnecessarily increase as the total copper increases. This isconsistent with the fact that a number of different processesare contributing to the complexation of free copper namelysuspended particulate load, dissolved organic matter andinorganic ligands.

The consistency of the ratio of labile to total dissolvedcopper at the sites indicate the ratio is controlled by a rapidequilibrium process, and that even at elevated concentra-tions of total dissolved copper, the natural environmenthas sufficient buffering capacity to maintain this ratio.

Acknowledgements

We thank the following for their assistance in collectionof samples: – Ministry of Defence at Devonport and theHarwich Harbour Authority. Also, Andy Smith for helpwith small boat work and sample collection. The fundingfor this project was provided by the EU antifouling CopperTask Force.

References

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copper speciation survey from uk marinas, harbours and estuaries

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