Copper Concentrations In Sediments Research Articles

Effects of fungicides on decomposer communities and litter decomposition in vineyard streams

Large amounts of fungicides are applied globally and partly enter freshwater ecosystems. A few laboratory studies examined their effects on decomposer communities and the ecosystem process of litter decomposition (LD), whereas the field situation remains largely unknown. We conducted a field study with 17 stream sites in a German vineyard area where fungicides represent the dominant pest control agent. Passive samplers were used to monitor 15 fungicides and 4 insecticides in streams and their toxicity was described using the toxic unit approach, whereas sediment samples were taken to characterise total copper concentrations. Microbial and leaf-shredding invertebrate community composition and related LD rates were assessed at each site. The structure of microbial and shredder communities as well as fungal biomass changed along the fungicide toxicity gradient. The changes in microbial endpoints were associated with a reduction of microbial LD rate of up to 40% in polluted streams. By contrast, neither the invertebrate LD rate nor in-situ measured gammarid feeding rates correlated with fungicide toxicity, but both were negatively associated with sediment copper concentrations. A subsequent laboratory experiment employing field fungicide concentrations suggested that the microbial community changes are causal. Overall, our results suggest that fungicides can affect LD under field conditions.

Historical trends (1998–2012) of nickel (Ni), copper (Cu) and chromium (Cr) concentrations in marine sediments at four locations in the Northern Adriatic Sea

Historical trends (1998–2012) nickel (Ni), copper (Cu) and chromium (Cr) concentrations in marine sediments were assessed at four locations in the Northern Adriatic Sea (Croatia) in the proximity of an oil refinery. Ecological risks were characterized by benchmarking the dataset against Sediment Quality Guidelines (SQG). A significant number of samples had Ni values above ERL with no exceedance of the ERL values for Cu and Cr. Weak positive historical trends were found for only for Cu. At all sites there were statistically significant correlations between Ni and Cr indicating a common origin of these heavy metals in the investigated marine sediments. There were statistically significant differences between the sites under the direct influence of the oil refinery compared to the control site indicating the possibility that the oil refinery is contributing to the concentration of these heavy metals in the marine sediments.

Metal bioavailability and bioaccumulation in the polychaete Nereis (Alitta) virens (Sars): The effects of site-specific sediment characteristics

The present study investigates the relationships between copper (Cu) and zinc (Zn) concentrations in sediment, pore water and their bioaccumulation in the polychaete Nereis (Alitta) virens, as well as the importance of site-specific sediment characteristics in that process. Sediment, pore water and N. virens were sampled from seven sites with different pollution histories along the English Channel coast. Results showed that site-specific metal levels and sediment characteristics were important in determining the bioavailability of metals to worms. Significant correlations were found between Cu in the sediment and in the pore water and between Zn in the pore water and in N. virens. Zn from the pore water was thus more readily available from a dissolved source to N. virens than Cu. Data also showed that metal concentrations in N. virens were lower than those found in other closely related polychaetes, indicating that it may regulate tissue concentrations of Cu and Zn.

Some selected heavy metal concentrations in water, sediment, and oysters in the Er-Ren estuary, Taiwan: chemical fractions and the implications for biomonitoring.

Studies of heavy metal contamination and ecological risk in estuaries are an important emerging area of environmental science. However, there have been few detailed studies of heavy metal contamination that concern the spatial variation of heavy metal levels in water, sediment, and oyster tissue. Because of the effective uptake of heavy metals, cultured oysters are a cheap and effective subject for study. This study, conducts an experiment in the Er-Ren river to examine the biological uptake of heavy metals in farmed, cultured oysters. The distribution of copper, zinc, lead, cadmium, and arsenic concentrations in water, sediment, and oysters from the Er-Ren river is also evaluated. By sequential extraction of the sediments, the following order of mobilities is found for heavy metals Pb > Cd > As > Zn > Cu. The highest percentages of heavy metals are found in the residual phase. The mean uptake rates for young oysters are 7.24mgkg(-1)day(-1) for Cu and 94.52mgkg(-1)day(-1) for Zn, but that for adult oyster is 10.79mgkg(-1)day(-1) for Cu and 137.24mgkg(-1)day(-1) for Zn. With good policies and management, the establishment of cultured oyster frames in these contaminated tributaries and near shore environments is a potential method for removing Cu and Zn and protecting the coast.

Fish farming and anti-fouling paints: a potential source of Cu and Zn in farmed fish

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 5:163-171 (2014) - DOI: https://doi.org/10.3354/aei00101 Fish farming and anti-fouling paints: a potential source of Cu and Zn in farmed fish Marina Nikolaou*, Nikos Neofitou, Konstantinos Skordas, Ioanna Castritsi-Catharios, Lamprini Tziantziou School of Agriculture, Department of Ichthyology and Aquatic Environment, University of Thessaly, Fytokou St., N. Ionia, 38446 Volos, Greece *Corresponding author: maze55@live.com ABSTRACT: The accumulation of copper and zinc, the basic components of anti-fouling paints, was examined in cultured sea bass Dicentrarchus labrax and sea bream Sparus aurata. Samplings were carried out at 4 eastern Mediterranean fish farms. Two of the farms used nets treated with anti-fouling paints, and 2 used untreated nets. At each farm samples of sediment and fish tissue (muscle, liver and gills) were analysed for heavy metal concentrations. The results showed that while total copper and zinc concentrations in sediments were quite similar in samples collected from the 4 farms, the extractable copper concentration in sediment from farms using anti-fouling treatment was 2 to 3 times higher than from those using untreated nets. Statistical analysis revealed no significant differences for either metal between sediment samples from farms using anti-fouling treatment and those which did not, except for extractable copper concentrations. However, analysis of the biological samples showed that copper concentrations in muscle tissue were lower in samples from farms using untreated nets, with the highest copper concentrations being observed in fish livers from farms using anti-fouling paints. General linear model results indicated significant differences between heavy metal concentrations in fish samples from farms using anti-fouling paints and those which did not. Furthermore, 1-way ANOVA indicated that these differences were confined to liver tissue for zinc, whereas significant differences for copper were seen in all tissues (except for gills of sea bream) for both species studied. These results indicate that the use of anti-fouling paints may be a potential source of metal accumulation in cultured fish. KEY WORDS: Aquaculture · Anti-fouling · Copper · Zinc · Fish · Eastern Mediterranean Full text in pdf format PreviousNextCite this article as: Nikolaou M, Neofitou N, Skordas K, Castritsi-Catharios I, Tziantziou L (2014) Fish farming and anti-fouling paints: a potential source of Cu and Zn in farmed fish. Aquacult Environ Interact 5:163-171. https://doi.org/10.3354/aei00101 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 5, No. 2. Online publication date: June 18, 2014 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2014 Inter-Research.

Efficacy and environmental fate of copper sulphate applied to Australian rice fields for control of the aquatic snail Isidorella newcombi

Copper sulphate pentahydrate (CuSO4·5H2O) is widely used for controlling Isidorella newcombi, an aquatic snail that causes substantial damage to rice crops in southeastern Australia. We conducted field trials on a Birganbigil clay loam soil that demonstrate high levels of efficacy against adult I. newcombi (95% mortality at 6.38 kg ha−1 CuSO4·5H2O (1.14 mg Cu L−1)). Dissolved copper fell below the detection limit (0.02 mg Cu L−1) between 7 and 20 d after spraying at application rates up to 2.16 mg Cu L−1 (12 kg ha−1 CuSO4·5H2O). Total copper concentrations in the water column fell below the detection limit (0.007 mg Cu L−1) 7–12 d after spraying at initially applied concentrations of 0.52–1.12 mg Cu L−1, but remained detectable (0.01–0.02 mg Cu L−1) until 30 days after spraying (the conclusion of monitoring) when applied at higher initial concentrations (1.18–2.16 mg Cu L−1). There was a strong positive correlation (r2 = 0.90, P < 0.001) between copper application rate and copper concentrations in surface sediments 30 d after spraying. Bioassays with immature snails using three different test soils beneath irrigation water showed that underlying soil type strongly influenced the response of snails to applied copper, with significant (P < 0.05) differences between LC90 values which ranged from 0.41 to 1.04 mg applied Cu L−1. Laboratory studies showed that dissolved copper concentrations remained significantly higher (P < 0.05) in the water column above the soil that had the most deleterious effect on copper toxicity. Dissolved organic carbon concentrations were significantly (P < 0.05) higher in both this soil and in the overlying water in the corresponding bioassay system, and correlated more closely with LC90 values than other water chemistry parameters such as total hardness. Our results support the ongoing use of a variable copper application rate of 6–12 kg ha−1 CuSO4·5H2O to allow for site-specific variations in efficacy, and suggest that variations in the release of dissolved organic carbon compounds from flooded soils may be a key factor moderating copper toxicity to I. newcombi in rice fields.

Effects of copper exposure on hatching success and early larval survival in marbled salamanders, Ambystoma opacum.

The creation of wetlands, such as urban and industrial ponds, has increased in recent decades, and these wetlands often become enriched in pollutants over time. One metal contaminant trapped in created wetlands is copper (Cu(2+)). Copper concentrations in sediments and overlying water may affect amphibian species that breed in created wetlands. The authors analyzed the Cu concentration in dried sediments from a contaminated wetland and the levels of aqueous Cu released after flooding the sediments with different volumes of water, mimicking low, medium, and high pond-filling events. Eggs and larvae of Ambystoma opacum Gravenhorst, a salamander that lays eggs on the sediments in dry pond beds that hatch on pond-filling, were exposed to a range of Cu concentrations that bracketed potential aqueous Cu levels in created wetlands. Embryo survival varied among clutches, but increased Cu levels did not affect embryo survival. At Cu concentrations of 500 µg/L or greater, however, embryos hatched earlier, and the aquatic larvae died shortly after hatching. Because Cu concentrations in sediments increase over time in created wetlands, even relatively tolerant species such as A. opacum may be affected by Cu levels in the posthatching environment.

Toxicity of copper and zinc to Puntius parrah (Day, 1865)

The toxicities of the trace metals copper and zinc on the fish Puntius parrah were assessed based on standard renewal bioassay methods, and the 96 h LC50 values for copper and zinc were 0.5 mg/L and 9 mg/L, respectively. The zinc and copper concentrations in water and sediment were high in a highly industrialized area compared with those in non-industrialized zones of the Periyar River. The fish exposed to a sublethal concentration of 0.05 mg/L of Cu and 0.9 mg/L of Zn showed a higher accumulation of both of the metals in the liver than in the kidneys, gills, and muscles. The histological changes induced by copper and zinc on the test organism under sublethal concentrations on the 3rd, 7th, 14th, and 28th -days of exposure were also studied. There was a significant decrease (p < 0.001) in the erythrocyte count after exposure to sublethal concentrations, whereas the hemoglobin, hematocrit, and mean corpuscular hemoglobin concentrations were significantly decreased after 28 days of exposure. Effective management strategies need to be developed and implemented to protect water bodies and aquatic organisms from trace metal pollution and its toxic effects.

Horticultural Use of Copper-Based Fungicides Has Not Increased Copper Concentrations in Sediments in the Mid- and Upper Yarra Valley

The use of Cu-based fungicide can pose a risk to nearby surface water bodies due to the run-off of accumulated Cu from agricultural soils. In 2008, we conducted a reconnaissance survey of the presence and concentration of copper in sediments at 18 sites within the Yarra River Catchment, an important horticultural production system in south-eastern Australia. Observed Cu concentrations in sediment samples from the study sites (mean (95 % confidence interval) 12.0 (10.6–13.6) mg/kg dry weight) were similar to the concentrations present in the samples from the reference sites (mean (95 % confidence interval) 12.0 (6.7–16.8) mg/kg dry weight). The data on Cu and other metals in the sediments suggest that that there is unlikely to have been wide spread, diffuse, off-site transport of Cu from the soils of horticultural properties to nearby surface waterways in the Yarra River Catchment and that that observed sediment metal concentrations are unlikely to pose an ecological risk to sediment-dwelling organisms at the study sites.

Copper use and accumulation in catfish culture in the Mekong Delta, Vietnam

Aquaculture of Pangasius hypophthalmus (striped catfish) in Vietnam reached 1.1 million tonnes in 2011 and catfish fillets are exported worldwide. The intensive cultures of catfish mainly in earth ponds have made it necessary to apply CuSO4 and other chemicals to control external parasites and other pathogens. However, accumulation of Cu in aquaculture ponds may pose a hazard to growth of fish or to the aquatic environment. The aim of this study was to determine accumulation of Cu in sediment, water and fish in a catfish pond with a history of repeated treatment with CuSO4 in the Mekong Delta, Vietnam. Copper concentrations in pond sediment were in the interval 21.3–45.7 mg kg−1 dw and did not exceed the Vietnamese values for soil to be used for agricultural production (70 mg kg−1 dw.). During three samplings the total mean concentration of Cu in pond water (4 μg L−1) did not exceed the LC50-value (70 μg L−1) for catfish and the mean dissolved concentration of Cu (0.986 μg L−1) did not seem to constitute a risk for the stability of the aquatic ecosystem. No significant variation in Cu concentrations between sampling sites in the pond and depth of sediment profile were determined. The accumulation of Cu in catfish was highest in the liver compared to the skin, gills and muscle tissue. With the current practice of removing pond sludge three to four times during a production cycle little if any Cu seems to accumulate in catfish ponds despite repeated anti-parasite treatments with CuSO4. Further studies are needed to assess the eco-toxicity and impact on agricultural production when pond sediment is discharged into aquatic recipients and used as soil fertilizer.

Metal-macrofauna interactions determine microbial community structure and function in copper contaminated sediments.

Copper is essential for healthy cellular functioning, but this heavy metal quickly becomes toxic when supply exceeds demand. Marine sediments receive widespread and increasing levels of copper contamination from antifouling paints owing to the 2008 global ban of organotin-based products. The toxicity of copper will increase in the coming years as seawater pH decreases and temperature increases. We used a factorial mesocosm experiment to investigate how increasing sediment copper concentrations and the presence of a cosmopolitan bioturbating amphipod, Corophium volutator, affected a range of ecosystem functions in a soft sediment microbial community. The effects of copper on benthic nutrient release, bacterial biomass, microbial community structure and the isotopic composition of individual microbial membrane [phospholipid] fatty acids (PLFAs) all differed in the presence of C. volutator. Our data consistently demonstrate that copper contamination of global waterways will have pervasive effects on the metabolic functioning of benthic communities that cannot be predicted from copper concentrations alone; impacts will depend upon the resident macrofauna and their capacity for bioturbation. This finding poses a major challenge for those attempting to manage the impacts of copper contamination on ecosystem services, e.g. carbon and nutrient cycling, across different habitats. Our work also highlights the paucity of information on the processes that result in isotopic fractionation in natural marine microbial communities. We conclude that the assimilative capacity of benthic microbes will become progressively impaired as copper concentrations increase. These effects will, to an extent, be mitigated by the presence of bioturbating animals and possibly other processes that increase the influx of oxygenated seawater into the sediments. Our findings support the move towards an ecosystem approach for environmental management.

The Distribution of Copper in Saronicos Gulf after the Operation of the Wastewater Treatment Plant of Psitalia

The establishment of the Wastewater Treatment Plant of Athens is considered as the main factor contributing to the improvement of water quality and recovery of the marine ecosystem in Saronicos gulf as it removes significant percentage of pollutants entering the gulf, including heavy metals. The comparison of concentrations of dissolved and particulate copper during 1993, 1994 (before the operation of the plant) and 1998, 1999 and 2000 (after the beginning of the operation) revealed that some changes in the distribution of copper occurred because of this major change concerning the pollution sources of the gulf. The effects are both direct, like the increased concentrations in the sediments near Psitalia and the slight decrease of mean values of dissolved copper and indirect, associated with the decrease of dissolved oxygen in the deep water of the western basin, i.e. the decrease of dissolved copper in this layer and the increase of copper concentrations in surface sediments. The general conclusion of this study is that the overall picture of copper pollution of the gulf has differentiated but not radically changed.

Validating the use of embryonic fish otoliths as recorders of sublethal exposure to copper in estuarine sediments

In this study we explore the use of fish otoliths (‘earbones’) as a tool for detecting exposure to heavy metals in sediments. Because otoliths are metabolically inert and incorporate chemical impurities during growth, they can potentially provide a more permanent record of pollutant exposure history in aquatic environments than soft tissues. To validate this technique we cultured embryos of a native Australian fish, the common Galaxias (Galaxias maculatus), in the laboratory on sediments spiked with copper in a concentration gradient. Our aims were to test whether exposure to copper contaminated sediments is recorded in the otoliths of embryos and determine over what range in concentrations we can detect differences in exposure. We found elevated copper levels in otoliths of embryos exposed to high copper concentrations in sediments, suggesting that otoliths can be used as a tool to track a history of exposure to elevated copper levels in the environment.

Effects of season and altitude on copper and zinc concentrations in benthos (Chironomids and Gammarids) and sediment

Concentration of heavy metals in aquatic ecosystems is considered as an important environmantal issue. In this study, the Namrood River located in Firoozkooh (Tehran province, Iran) was assessed for the existence of heavy metals. The Namrood river is situated by the main road being by pollutants from tourism and recreational centers, gas stations, sewage of villages, agricultural wastewater and fish culture effluent. The water is extremely contaminated in some parts and possibly contains heavy metals. In the present study, two stations up- and downstream were determined to sample the sediments and Chironomidae and Gammarus pluex in both cold and warm seasons of the year (middle of March and middle of August). The copper and zinc were measured in sediment and benthos. The results showed that copper and zinc concentrations ranged 0.170-0.966 and 0.187-3.846 ppm, respectively. Sediments of the upstream station had the highest copper concentration among the samples in both cold and warm seasons of the year.

Copper, lead and cadmium concentrations in surface water, sediment and fish, C. Carpio, samples from Lake Naivasha: effect of recent anthropogenic activities

Following recent concerns of chemical pollution around Lake Naivasha, especially originating from recent agricultural activities in the catchment, samples of water, sediments, and fish Common carp (Cyprinus carpio) were collected from the Hippo Point, Kasarani, Mouth of Malewa River, Mouth of Karati River, Crescent Island, Sher Karuturi Discharge outlet and Oserian Bay for analysis of Cu, Cd and Pb by FAAS. The mean heavy metal levels ranged from 5.12–58.11 (Pb), 1.06–1.73 (Cd), and <0.03–2.29 (Cu) mg/kg wet weight in C. carpio muscle, <100–179.83 (Pb), <10.00–10.06 (Cd) and <30.00–32.33 (Cu) μg/L in surface water, and 17.11–53.07 (Pb), 1.18–5.58 (Cd) and 3.00–8.48 (Cu) mg/kg dry weight in sediment and showed a wide variation within and between samples with relatively high concentrations in sediments and fish muscle tissues. The results indicate that Lake Naivasha, in some parts, is polluted with these heavy metals of which relatively higher concentrations are found at the discharge outlets near Sher Karuturi and Oserian Bay. This indicates possible contribution from surrounding horticultural/floricultural activities and the Mouths of the Rivers Malewa and Karati which flow from it’s upper catchment.

Copper and Lead Concentrations in Water, Sediments, and Tissues of Asian Clams (Corbicula sp.) in Bung Boraphet Reservoir in Northern Thailand (2008)

Bung Boraphet is the largest freshwater reservoir in Thailand. This study examined the accumulation of copper (Cu) and lead (Pb) in water, sediment and tissues of Asian clams (Corbicula sp.) within Bung Boraphet to assess the possible polluting effect of soil erosion and the dissolution of water soluble salts from the Nan River. Samples were collected from 12 study sites within Bung Boraphet between February and December 2008. The physicochemical parameters of the water including temperature, pH, turbidity, ammonia nitrogen, nitrate nitrogen, orthophosphates, biochemical oxygen demand, dissolved oxygen, Cu, and Pb were measured. The water in Bung Boraphet was found to be medium clean according to the surface water quality standard of Thailand. The levels of Cu and Pb in the water were low but heavy metals were detected at higher levels in the sediment and tissues of Corbicula sp. In the near future, management practices and regulator approaches for Cu and Pb contamination will be needed to protect the water in Bung Boraphet.

The Importance of Phosphorus and Copper Carryover in Pond Sediments for Juvenile Percid Survival, Growth, and Yield

AbstractOver‐fertilization with phosphorus and carryover copper residual in the sediment from copper sulfate treatment in double‐cropped ponds were suspected as the primary causes of low larval percid survival in coolwater aquaculture ponds. Consequently, in this study, we compared saugeye (male sauger Sander canadensis × female walleye S. vitreus) survival, growth, and yield among ponds that were single‐cropped with only saugeyes in the spring during the previous two consecutive years (SS ponds) and ponds that were double‐cropped (with saugeye culture in the spring and channel catfish Ictalurus punctatus culture in the summer) during the previous two consecutive years (DD ponds). We also compared sediment phosphorus (soluble reactive phosphorus [SRP] and total phosphorus [TP]), sediment copper concentrations, phytoplankton biomass, and zooplankton biomass. Fish survival (number harvested) and fish yield (mass harvested) were significantly lower in DD ponds than in SS ponds in 2001 but were similar in 2002 (a year of wide temperature fluctuation early in the production season). Sediment analyses revealed that DD ponds had significantly lower SRP and TP but higher copper concentrations than did SS ponds. A detailed study done in 2002 revealed that individual length and wet weight of percids were significantly higher in the SS ponds than in DD ponds; phytoplankton biomass was similar in both sets of ponds, while zooplankton biomass was significantly lower in DD ponds. These results suggest that residual materials used in double‐cropped channel catfish ponds may negatively affect subsequent years' percid culture.

Sudbury Sediments Revisited: Evaluating Limnological Recovery in a Multiple-Stressor Environment

Paleolimnological techniques were utilized to determine whether diatom and scaled chrysophyte assemblages in Daisy, Swan, and Tilton lakes (Sudbury, Ontario) have recovered toward their preimpact conditions as a result of reduced inputs of anthropogenic pollutants (SO 4 2− and metals) or whether other environmental stressors have affected recovery trajectories. In addition, geochemical analysis was used to track trends in sedimentary nickel and copper concentrations through time. Preindustrial algal assemblages were primarily dominated by circumneutral to alkaline and pH-indifferent taxa. However, with the onset of open-pit roasting and smelting operations, there was a stratigraphic shift toward acid-tolerant species. With wide-scale smelter emission reductions commencing in the 1970s, scaled chrysophyte assemblages in Swan and Daisy lakes have started to show signs of biological recovery in ∼1984 and ∼1991, respectively. Although the scaled chrysophyte assemblage in Tilton Lake has not recovered toward the predisturbance assemblage, the decline in acidophilic taxa and increase in circumneutral taxa in recently deposited lake sediments indicate that the community is responding to increased lake water pH. Conversely, diatom assemblages within each of the study lakes have not begun to recover, despite well-documented chemical recovery. It is suspected that biological recovery in Sudbury area lakes may be impeded by other environmental stressors such as climate warming. Copper and nickel concentrations in lake sediments increased with the onset of mining activities and subsequently declined with emission controls. However, metal concentrations in lake sediments remain elevated compared to preindustrial concentrations. Together, biological and geochemical evidence demonstrates the clear environmental benefits associated with smelter emission controls.

Temporal and Spatial Variations of Copper, Cadmium, Lead, and Zinc in Ten Mile Creek in South Florida, USA

Lead (Pb), zinc (Zn), copper (Cu), and cadmium (Cd) often seriously deteriorate water quality. Spatial and temporal fluctuations of the metal concentrations in the Ten Mile Creek (Florida) (TMC) were monitored on a weekly basis at 7 sampling sites, from June 2005 to September 2007. River sediment samples were also collected from these sites in April, June, and October 2006 and January 2007, and analyzed for water, Mehlich 1 (M1), and Mehlich 3 (M3)-extractable metals (Mehlich, 1953, 1984), to examine the role of sediments as sources or sinks of the metals. The concentrations of lead, zinc, copper, and cadmium in the water samples were <detection limit (DL)-309, < DL-102, < DL-106, and < DL-15.7 microg/L, respectively. Even though median concentrations of lead (<DL), zinc (6.45 microg/L), copper (2.53 microg/L), and cadmium (<DL) were lower than their respective U.S. Environmental Protection Agency (Washington, D.C.) limits for freshwater (2.5 microg/L for lead, 120 microg/L for zinc, 9.0 microg/L for copper, and 0.25 microg/L for cadmium), pulse concentrations of the metals significantly exceeded these limits. Correlations of lead, zinc, copper, and cadmium concentrations in the TMC to other environmental factors, including the results of principal component analysis, suggest that there are different sources of metals. These sources include surface runoff from agricultural lands or urban wastewater, geological backgrounds, and tidal flow. Water-, M1-, and M3-extractable lead, zinc, copper, and cadmium concentrations in river sediments indicate the possibility that river sediment serves as an internal source of the metals for the TMC. This hypothesis was supported by positive correlations between concentrations of copper, lead, and zinc in the river water and their respective water-extractable concentrations in the sediments.

Aquatic risk assessment of copper in freshwater and saltwater ecosystems of South Florida

A screening-level aquatic risk assessment was conducted for copper in south Florida's freshwater and saltwater environments. Risk was quantified by comparing the overlap between the probability distributions of copper exposure from surface water and sediment with the probability distributions of effects data obtained from laboratory studies. Copper concentrations in surface water and sediment in south Florida were summarized by county. For surface water, the highest concentrations of copper were found in Martin and St. Lucie counties for freshwater and saltwater, respectively. From the exposure probability distributions, the 90th centile values were estimated at 14.0 microg/L and 15.4 microg/L in freshwater and saltwater, respectively. Copper concentrations in sediment were evaluated from a probability distribution of predicted pore water concentrations. The 90th centile values of pore water concentrations from freshwater sediments ranged from 5.0 microg/L in Palm Beach County to 71.7 microg/L in Broward County. In saltwater sediments, the 90th centile values for pore water ranged from 26.1 microg/L in St. Lucie County to 27.3 microg/L in Miami-Dade County. Ecological effects data were obtained for acute and chronic copper effects in freshwater and saltwater. The 10th centile values for acute effects data were 21.2 microg/L and 9.8 microg/L for freshwater and saltwater species, respectively. For chronic effects, the 10th centile values were 3.8 microg/L and 3.9 microg/L for freshwater and saltwater species, respectively. The risk of acute copper exposure in surface water was generally low; however, the potential for ecological risk from chronic copper exposure was low to high in several counties including Lee, Martin, and St. Lucie counties. The risk of acute copper exposure in porewater from freshwater sediments also was low with the exception of St. Lucie and Broward counties. However, porewater from saltwater sediments posed a significant acute risk in Miami-Dade and St. Lucie counties. In porewater from freshwater and saltwater sediments chronic risk was high in counties with sufficient data available to calculate risk estimates.