Spatial Distribution and Temporal Trend in Concentration of Carbofuran,Diazinon and Chlorpyrifos Ethyl Residues in Sediment and Water in Lake Naivasha,Kenya

Chlorpyrifos ethyl was found to be widely distributed in water and sediment in Lake Naivasha. Higher levels were reported in sediment (11.2–30.0 ng g⁻¹ dry weight (dw) in wet season than in dry season (4.7–17.4 ng g⁻¹ dw). The mean concentration of chlorpyrifos ethyl in water in wet season ranged between 8.8 and 26.6 μg L⁻¹ and decreased to between below detection limit to 14.0 μg L⁻¹ in dry season. On average, higher concentrations of chlorpyrifos ethyl were observed in sediment than water samples. Statistical analysis revealed a significant difference in concentration between the seasons, and a significant interaction between seasons and mean concentrations at p ≤ 0.05. However, levels of diazinon and carbofuran were below the detection limit in all the samples analyzed. Notably, levels of chlorpyrifos ethyl were higher than the maximum allowable limits (0.1 μg L⁻¹) recommended by European Union for drinking water and general water quality criterion for protection of freshwater water organisms (0.083 μg L⁻¹).     

Body Residues and Responses of the Midge Chironomus riparius to Sediment-Associated 2,4,5-Trichlorophenol in Subchronic and Chronic Exposures

Subchronic and chronic toxicity of sediment-associated 2,4,5-trichlorophenol to the midge Chironomus riparius was determined by conducting a 10-day growth and a 50-day emergence tests with spiked lake sediment (nominal initial TCP concentrations were 25, 51, 101, 203, 304 and 405 μmol kg⁻¹ dry weight in the growth test and 25, 76, 152 and 304 μmol kg⁻¹ dry weight the emergence test). In addition, we measured the residue of chlorophenol in larval tissue and made an attempt to relate it with the observed adverse biological responses. The larvae were exposed individually to avoid density-dependent effects of mortality on food ration and growth of the surviving larvae. In the growth test, mortality was low at sediment concentrations ≤193 μmol TCP kg⁻¹, but it increased sharply at the higher concentrations being 37 and 94% at 334 and 441 μmol kg⁻¹ DW, respectively. The effect of sediment TCP concentration on larval mortality was highly significant (10-day LC50 337 μmol TCP kg⁻¹ dry sediment) in the growth test. In the emergence test, however, mortality was low (3–13%) at all concentrations. TCP did not affect larval growth at the concentrations used. The concentration of TCP in the whole larvae after the 10-day exposure was proportional to sediment concentration, being at highest 160 μmol kg⁻¹ fresh weight. When the average body residues of TCP were below 80 μmol kg⁻¹, mortality was low, but it increased when the body residue approached 100 μmol kg⁻¹. After the 10-day exposure, the body residue, at which 50% of the larvae survived (CBR50) was 113 μmol g⁻¹. TCP exposure accelerated larval development and the midges exposed to 171 and 324 μmol TCP kg⁻¹ emerged earlier than those in the other concentrations or in the control sediment. In natural environments, sediment-associated chlorophenolics are probably not a major environmental problem to benthic fauna because concentrations similar to that which we observed to cause adverse effects to C. riparius (>60 mg kg⁻¹ dry sediment) are rare. Received: 15 June 1998/Accepted: 5 January 1999     

Occurrence of Antifouling Biocides in Sediment and Green Mussels from Thailand

Various antifouling biocides were surveyed in sediment and green mussels (Perna viridis) from the coastal area of Thailand. The concentrations of butyltin (MBT), dibutyltin (DBT), and tiributyltin (TBT) in sediment from Thailand were in the range of 1–293 μg kg⁻¹ dry wt., 1–368 μg kg⁻¹ dry wt., and 2–1246 μg kg⁻¹ dry wt., respectively. A higher concentration of TBT was observed in industrial areas, where many tankers and cargo ships sail and moor. Phenyltin (PT) compounds were not detected in most of the sampling sites. The concentrations of MBT, DBT, and TBT in green mussels from Thailand were in the range of 8–20 μg kg⁻¹ wet wt., 4–9 μg kg⁻¹ wet wt., and 4–45 μg kg⁻¹ wet wt., respectively. The concentration of TBT was high in an area where aquaculture practice is common. The detection frequencies of TPT were low. Representative booster biocides were surveyed in sediment. The detection frequencies of Sea Nine 211 were low (2/13). Furthermore, Sea Nine 211 concentrations in the detected samples were at values near the detection limit (0.051–0.094 μg kg⁻¹ dry wt.). Diuron was detected at the highest level among the booster biocides in the range of 0.07–25 μg kg⁻¹ dry wt. Irgarol 1051 was detected in the range of 0.03–3.2 μg kg⁻¹ dry wt., and concentrations of the degradation product’s M1 were 0.03–4.9 μg kg⁻¹ dry wt. Diuron and Irgarol 1051 showed higher concentrations in industrial areas and fishery sites, respectively. Diuron was only detected among green mussels in the range of <0.64–9.6 μg kg⁻¹ wet wt. The lower ratio of Diuron and Irgarol 1051 for TBT concentration suggests that TBT is still being used in Thailand.     

Concentrations of Polybrominated Diphenyl Ethers in Sediments from Jukskei River,Gauteng, South Africa

This study determined concentration levels of polybrominated diphenyl ethers (PBDEs) in sediment samples collected from Jukskei River in South Africa. Final extracts, after concentration and dilution to 200 μL were analyzed by injecting 1 μL in the GC–ECD and GC–MS. Results obtained showed good recoveries (73%–114%, with RSD < 17%). The concentrations of ∑PBDEs in sediment for the seven sampling sites ranged from 0.92 to 6.76 ng g⁻¹ dry weight and total PBDEs with a total BDE sum of 23.85 ng g⁻¹ dry weights. Concentrations of PBDEs obtained in the present study are significantly lower than the values reported from developed countries.     

Estrogenic Activity in Water and Sediments of a French River: Contribution of Alkylphenols

Alkylphenols, known to possess estrogenic activity, have been found in the aquatic environment. In this study, we focused on the contribution of alkylphenols to total estrogenic activity in sediment and water extracts of French rivers. Four sites representing rural, agricultural, urban, and industrial watersheds were studied. The concentrations of alkylphenols in water and sediment were quantified by GC/MS. Estrogen-responsive reporter cell lines (MELN) have been used for investigating estrogenic activity at these sites. These observed activities were compared with activities mediated by known concentrations of alkylphenols. In water, the concentration of alkylphenols, from 0.06 to 0.550 μg · L⁻¹ and from < 0.001 μg · L⁻¹ to 0.077 μg · L⁻¹ for nonylphenols and 4t-octylphenol, respectively, were too low to contribute to the observed estrogenic activity. In sediment of the industrial, rural, and urban sites, the observed estrogenic activities could be explained in great part by the alkylphenol concentrations from 0.26 to 2.87 μg · g⁻¹ and from 0.005 μg · g⁻¹ to 0.49 μg · g⁻¹ for nonylphenols and 4t-octylphenol, respectively. In the agricultural site, the alkylphenols (0.022 μg · g⁻¹ of nonylphenols) poorly contribute to the observed estrogenic activity. Other compounds, such as natural and synthetic hormones, present in water and sediments could act additively in the overall activity. Received: 22 September 2001/Accepted: 24 July 2002     

Distribution and Enrichment of Silver and Cadmium in Coastal Sediments from Bahía Todos Santos, Baja California, México

Silver, cadmium and iron were studied in sediment from Bahia Todos Santos, Baja California, México during 2004. Results showed that the spatial distributions of these metals were very similar to that of organic carbon and fine grain size, with values increasing from the inner to the outer parts of the bay. High concentrations and enrichments of silver (0.051–0.071 μg g⁻¹ dry weight) and cadmium (1.9 μg g⁻¹ dry weight) in Bahía Todos Santos were associated to harbor dredging activities and to coastal upwelling, respectively. However, the distribution of silver and cadmium in most of the study area is controlled by grain size and organic carbon content.     

The Influence of Diet on Mercury Intake by Little Tern Chicks

We assessed mercury levels in the feathers of little tern (Sternula albifrons) chicks from hatching to fledging and in their prey captured by adults in three main foraging habitats: lagoon, salinas, and adjacent sea. These data were used to model mercury concentration in chick feathers through food ingestion, in order to explore the effects that changes in diet would have on the mercury burden of chicks as they aged. The mercury concentration in feathers of chicks raised in sandy beaches was higher than in those raised in salinas. Lagoon prey had a significantly higher mercury concentration (0.18 ± 0.09 μg g⁻¹ dry weight [d.w.]) than prey from salinas and the adjacent sea (both 0.06 ± 0.03 μg g⁻¹ d.w.). In relation to prey species group, mercury content was significantly higher for bottom fish (0.17 ± 0.10 μg g⁻¹ d.w.) than for pelagic (0.08 ± 0.06 μg g⁻¹ d.w.), euryhaline fish (0.04 ± 0.02 μg g⁻¹ d.w.), and crustacea (0.08 ± 0.03 μg g⁻¹ d.w.). To understand the importance of mercury content of each prey group, we ran several theoretical scenarios assuming that chicks were fed on only one species at a time. Considering a diet restricted to lagoon (mostly benthic) prey, A- and B-chicks may encounter health problems with an excess of mercury. On the contrary, a diet restricted to marine (mostly pelagic) prey would decrease the mercury concentration in chick feathers; the fast growth rate and the related mercury dilution effect in little tern chicks seem to decrease mercury levels in their feathers. Our study supports the fact that marine pelagic prey are important for estuarine seabirds because they provide a food resource with lower contamination levels. This model may have a wider application in similar seabird species and coastal environments.     

Cadmium,Lead and Zinc Concentrations in Water,Sediment and Oyster (<Emphasis Type="Italic">Crassostrea virginica</Emphasis>) of San Andres Lagoon,Mexico

The spatial distribution of cadmium, lead and zinc concentrations in water, sediment and oysters from San Andres Lagoon was evaluated. Significantly higher cadmium (0.33 mg L⁻¹) and lead (0.70 mg L⁻¹) concentrations in water were observed in front of the mouth of Tigre river, whereas, zinc concentration (5.0 mg L⁻¹) was significantly higher in the south part of the lagoon. Similarly, lead and zinc values in sediment (1.01 and 9.29 μg g⁻¹, respectively) and oyster tissue (0.86 and 3.19 μg g⁻¹, respectively) were significantly higher in the south part of the lagoon. Levels of cadmium and lead in oyster tissue were positively related to those found in sediment. However, concerning zinc no evident relationship was found. Such differences in regression analyses may be explained by differential bioaccumulation of xenobiotic (cadmium, lead) and essential (zinc) metals.     

Accumulation of Lead,Zinc, and Cadmium in a Wild Population of <Emphasis Type="Italic">Clethrionomys glareolus</Emphasis> from an Abandoned Lead Mine

Lead, zinc, and cadmium were determined in a range of tissues from wild populations of bank voles (Clethrionomys glareolus) trapped on an abandoned metalliferous mine site and a reference site. Estimated dietary intakes indicated that animals were exposed to elevated levels of all three metals at the mine site, and this was generally reflected in metal residues in body tissues. Lead concentrations were significantly higher in all tissues of animals from the mine compared to the reference site, while Cd was higher only in the kidney. There was evidence of age-accumulation (using total body weight as an index of age) of Cd in both the liver and kidney of mine site animals but no evidence of such accumulation of lead in bone. In contrast to Cd and Pb, Zn was lower in the tissues of mine site animals compared to the reference site. Based on critical tissue concentrations, the ecotoxicological risk to a wild population of bank voles (Clethrionomys glareolus), associated with total substrate levels of 1 μg g⁻¹ dry weight Cd and 700 μg g⁻¹ dry weight Zn at this mine site is negligible, but that associated with 4000 μg g⁻¹ dry weight Pb may be considered significant. Received: 28 January 2002/Accepted: 29 July 2002     

Intercomparison Studies on Distribution and Coassociations of Heavy Metals in Liver, Kidney, and Muscle of Harbor Porpoise, Phocoena phocoena, from Southern Baltic Sea and Coastal Waters of Denmark and Greenland

The concentrations of selected metals such as Cd, Pb, Cu, Zn, Cr, Ni, Mn, and Fe were determined in liver, kidney, and muscle of harbor porpoise (Phocoena phocoena) from three geographical regions, i.e., the Baltic Sea and Danish and Greenland coastal waters. The concentrations of Cd in liver and kidney increased with age of the specimens analyzed. Significant interspatial variations in both hepatic and renal levels of Cd were also observed. Average hepatic levels of Cd in Baltic, Danish, and Greenland specimens were (age range) 0.05–0.09, 0.12–0.25, and 20.6–51.6 μg g⁻¹ dry weight, respectively. Such values for renal Cd were as follows: 0.55–0.71, 0.14–1.84, and 0.55–94.3 μg g⁻¹ dry weight. In contrast to Cd, concentrations of Cu in the liver and kidney of specimens from Baltic, Danish, and Greenland areas did not indicate such great interspatial variability. The average hepatic values amounted to (age range) 14.1–15.5, 22.1–63.6, and 16.3–25.9 μg g⁻¹ dry weight, and kidney contained on the average 7.83–8.80, 11.7–16.2, and 11.1–15.7 μg Cu g⁻¹ dry weight, respectively. The higher levels of hepatic and renal Cd in Greenland specimens than in Baltic ones could be explained by different food composition in the area studied. Baltic porpoises mainly feed on fish (cod, plaice) containing extremely low levels of muscle Cd, but an important diet component of Greenlandic individuals is squid, characterized by elevated levels of Cd. Received: 22 May 2001/Accepted: 11 November 2001     

Fucus spp. as a Mercury Contamination Bioindicator in Costal Areas (Northwestern Portugal)

Mercury has been considered as one of the most important pollutants in coastal and estuarine areas. Efforts have been made to detect, as early as possible, the effects of this and other metals in several species. Macroalgae, particularly Fucus spp., have been widely used as biomonitors of metal pollution. In this study, three Fucus species (F. spiralis, F. vesiculosus and F. ceranoides) were collected from several sampling sites in Portugal. The concentrations of mercury were determined in three structural parts (holdfast, stipe and receptacles). Two different techniques were used to determine mercury concentrations. Almost all mercury concentrations (in sediments and in water) were below national and international standards. Mercury concentration in the specimens (0.012–0.061 μg g⁻¹ for receptacles, 0.028–0.221 μg g⁻¹ for stipe and 0.029–0.287 μg g⁻¹ for holdfast) was always higher that those obtained for the sediment (0.001–0.112 μg g⁻¹). With few exceptions the contrary was found for receptacles. In general, a good agreement between concentrations of mercury in sediment and Fucus was found. The results indicate that Fucus accumulate mercury and may be a suitable species for use in risk assessment for coast and estuarine areas, by providing valuable information regarding the levels of mercury that will be available for the consumers of Fucus spp.     

Distribution of Heavy Metals in the Street Dusts and Soils of an Industrial City in Northern Spain

This study characterizes the elemental composition of street dust and soils in Avilés (N. Spain), a medium-size city of approximately eighty thousand inhabitants, where industrial activities and traffic strongly affect heavy metal distribution. A total of 112 samples of street dust were collected within a 7-km² area, encompassing residential and industrial sites (ferrous and non-ferrous plants). Elevated geometric mean concentrations of zinc (4,892 μg · g⁻¹), cadmium (22.3 μg · g⁻¹), and mercury (2.56 μg · g⁻¹) in street dust were found in samples located near industrial areas. Two types of anthropic influence were distinguishable: the first and most important one is that related to metallurgical activity and transportation of raw materials for local industries. Secondly, exhaust emissions from traffic are an important source of lead concentration in areas with high vehicular density (geometric mean: 514 μg · g⁻¹). The zinc content in the dust samples decreased with the distance from a zinc smelter located in the northern part of the city. The same trend was found for other elements in association with zinc in the raw materials used by the smelter, such as cadmium and mercury. A simultaneous research campaign of urban soils, that involved the collection of 40 samples from a 10-km² area, revealed geometric mean concentrations of 376 μg · g⁻¹ Zn, 2.16 μg · g⁻¹ Cd, 0.57 μg · g⁻¹ Hg, and 149 μg · g⁻¹ Pb, and distribution patterns almost identical to those found for street dust. Received: 22 January 2002/Accepted: 24 July 2002     

Potential Health Risk of Total Arsenic from Consumption of Farm Rice (Oryza sativa) from the Southern Caspian Sea Littoral and from Imported Rice in Iran

In this study, Arsenic (As) was measured in several varieties of imported and local cultivated rice. Soil samples collected from rice farms situated in south Caspian Sea (Iran) were also studied. The mean concentration of As in imported rice, local farmed rice and soil, were determined as 0.28, 0.39 and 3.80 μg g⁻¹ dry weight, respectively. Estimated daily intake of As through human consumption of imported and local produced rice was 0.77 and 1.074 μg day⁻¹ kg⁻¹ B.W., respectively. These values are much lower than the tolerable daily intakes estimated by JECFA. The As concentration in the soil (3.80 μg g⁻¹ dry) was below acceptable limit for agricultural soil of 20.0 mg kg⁻¹ as recommended by the European Community (EC). No correlation between the As concentrations in rice and soil samples was found (p > 0.05).     

Altered Growth and Metabolism of an Estuarine Shrimp (Palaemonetes pugio) During and After Metamorphosis onto Fenvalerate-Laden Sediment

Dry weight (W), carbon (C), nitrogen (N), and energy (E) (calculated) accumulation were measured in the estuarine grass shrimp, Palaemonetes pugio, throughout larval development and during the first 2 weeks as postlarvae in seawater over sediment containing the pyrethroid insecticide fenvalerate (SCF; nominal concentrations of 1, 10, and 100 μg fenvalerate kg⁻¹ sediment). The influence of fenvalerate-laden sediment on shrimp growth and utilization patterns of C, N, and E was dependent on fenvalerate concentration, age of shrimp, and whether shrimp were premetamorphic or postmetamorphic in development. The fenvalerate concentration in the sediment, which ultimately inhibited larval metamorphosis (100 μg fenvalerate kg⁻¹ sediment), significantly reduced W accumulation in developing larvae and in postlarvae growing on the sediment for an equivalent time. Accumulation of C, N, and E varied not only with concentration of SCF, but differed between pelagic larvae developing in water above SCF and newly settled postlarvae growing in direct contact with SCF. Larvae developing above ≥10 μg kg⁻¹ SCF contained significantly less N, while postlarval shrimp settling onto ≥10 μg kg⁻¹ SCF accumulated significantly less C and E. Measurable variations in growth and energy reserves of toxicant-sensitive life stages in response to environmentally realistic insecticide exposures have a direct link to ecological consequences of toxic stress and may be useful as biomarkers to diagnose early damage in estuarine populations. Received: 14 August 1997/Accepted: 7 April 1998     

Hemocytic Lysosome Response in the Snail Helix aspersa After Exposure to the Fungicide Copper Oxychloride

This study investigated the use of lysosomal responses of hemocytes of the common garden snail, Helix aspersa, as biomarker of stress due to exposure to the fungicide copper oxychloride. The neutral red retention (NRR) time assay was employed for this purpose. Two groups of snails were exposed to 80 μg g⁻¹ and 240 μg g⁻¹ copper oxychloride in their food, respectively, for a period of 6 weeks. They were compared with a control group to which no copper oxychloride was added. The two groups exposed to the fungicide exhibited significantly higher (p < 0.001) whole body copper concentrations (200.85 ± 53.5 and 272.24 ± 67.15 μg g⁻¹ dry mass, respectively), and significantly shorter (p < 0.001) NRR times (10.22 ± 3.53 and 2.67 ± 2.83 min, respectively), after 6 weeks, compared to the control group (67.85 ± 31.08 μg g⁻¹ dry mass and 24.44 ± 8.35 min). In both exposure groups NRR times became progressively shorter as body copper concentrations increased over time. Thus, both exposure concentration and exposure time of copper oxychloride were shown to be important factors influencing lysosomal responses (and therefore NRR times) of H. aspersa hemocytes. It was concluded that these responses in this species, as measured by the NRR time assay, could be considered a useful cellular biomarker of stress resulting from exposure to copper oxychloride. Received: 8 December 1999/Accepted: 31 May 2000     

Assessment of Antifouling Biocides Contaminations in Maizuru Bay, Japan

The concentrations of organotin compounds in the aquatic environment of Maizuru Bay and their spatial distribution are discussed. The concentrations of tributyltin (TBT) compounds in water samples ranged from 0.001 to 0.002 μg l⁻¹, and monobutyltin compounds were the dominant species among the butyltin compounds. TBT concentrations in Maizuru Bay are low compared with other coastal waters of Japan. Drastic differences in TBT concentrations were not observed among the Maizuru Bay sites. Phenyltin compounds were not detected in the water samples. Concentrations of TBT and triphenyltin (TPT) in sediment from Maizuru Bay ranged, respectively, from 0.9 to 11 μg kg⁻¹, from 0.2 to 17 μg kg⁻¹ dry weight (dw). TBT concentrations in Maizuru Bay were lower than those in other coastal areas of Japan. TPT concentrations were greater than TBT concentrations in the fishing port. The concentrations of TBT and TPT in blue mussels (M. galloprovincialis) from Maizuru Bay were in the range of 2.4 to 9.3 μg kg⁻¹ and 0.2–13 μg kg⁻¹ wet weight (ww), respectively. A tolerable average residue level (TARL) was estimated at 74.8 μg kg⁻¹ from a tolerable daily intake (TDI) of 0.25 bis(tributyltin)oxide μg kg⁻¹ body weight day⁻¹. TBT concentrations detected in blue mussel samples were lower than the TARL values. The acceptable concentration of TPT, which were calculated using acceptable daily intake instead of TDI, was 127 μg kg⁻¹. Concentrations of TPT in blue mussel samples were also lower than the TARL. TBT compounds in blue mussel samples were at similar levels among the various sampling sites, indicating that TBT is not currently being used in ship hull paints; the ratios of degradation products of TBT and TPT were greater than those of the parent compounds. Concentrations of alternative biocides in water samples were also investigated in the bay. Although Sea-Nine 211, M1, and Pyrithiones were not detected, Diuron and Irgarol 1051 were detected at 0.010–0.257 and at 0.002–0.018 μg l⁻¹, respectively. Concentrations of Diuron were great in the shipping route and near the shipyard, whereas the concentration of Irgarol 1051 was great at the fishing port. Concentrations of Diuron and Irgarol 1051 in sediment from Maizuru Bay ranged, respectively, from <0.08 to 12, from <0.08 to 9.8 μg kg⁻¹ dw, respectively. Despite being a semi-enclosed bay, we found that sediment in Maizuru Bay is not contaminated by alternative biocides to the degree found in other coastal areas. Copper concentrations of sediment were at ordinary levels, and those of blue mussels were slightly lower than those reported previously in other coastal areas of Japan. In both the sediment and blue mussels, there was no correlation between the presence of copper and antifouling biocides.     

Total Mercury Concentrations in Lakes and Fish of Western Maryland, USA

The purpose of this study was to quantify total mercury concentrations in three species of fish in three lakes of western Maryland: Piney Creek reservoir, Deep Creek Lake, and Lake Habeeb. We measured total mercury concentrations in water from each lake and muscle tissue from 119 fish collected in fall 2000: 15 largemouth bass (Micropterus salmoides), 15 yellow perch (Perca flavescens), and 15 bluegill (Lepomis macrochirus) from the Piney Creek reservoir; 15 largemouth bass, 15 yellow perch, and 14 bluegill from Deep Creek Lake; and 15 largemouth bass and 15 bluegill from Lake Habeeb. Average total mercury concentrations (± SD) in surface waters were 0.96 ± 0.03 ng L⁻¹ for the Piney Creek reservoir, 0.56 ± 0.07 ng L⁻¹ for Deep Creek Lake, and 0.40 ± 0.05 ng L⁻¹ for Lake Habeeb. These water quality differences were sometimes reflected in the total mercury concentration in fish muscle tissue. Total mercury concentrations in bluegill (0.05 ± 0.02 μg g⁻¹) and largemouth bass (0.10 ± 0.03 μg g⁻¹) from Lake Habeeb were significantly (p < 0.001) lower than the total mercury concentrations in bluegill and largemouth bass from the Piney Creek reservoir (bluegill: 0.13 ± 0.04 μg g⁻¹ and largemouth bass: 0.37 ± 0.18 μg g⁻¹) and Deep Creek Lake (bluegill: 0.11 ± 0.04 μg g⁻¹ and largemouth bass: 0.30 ± 0.09 μg g⁻¹). Yellow perch from the Piney Creek reservoir had significantly higher total mercury concentrations than yellow perch from Deep Creek Lake (0.20 ± 0.08 μg g⁻¹ versus 0.13 ± 0.04 μg g⁻¹). In contrast, total mercury concentrations in largemouth bass from the Piney Creek reservoir and Deep Creek Lake were not significantly different. With the exception of largemouth bass from Lake Habeeb and yellow perch from Deep Creek Lake, there were relatively strong (r ² > 0.39–0.79) log-log relationships between the size (weight and length) of the fish and total mercury concentrations in muscle tissue. The largest largemouth bass (> 800 g and > 38 cm) from both Deep Creek Lake and the Piney Creek reservoir had total mercury concentrations that exceeded the consumption advisory of 0.5 μg g⁻¹ that is used by many states and Canada. In contrast, total mercury concentrations in largemouth bass from Lake Habeeb did not exceed this consumption advisory. Our results suggest that fish consumption advisories are needed for largemouth bass in the Piney Creek reservoir and Deep Creek Lake. Received: 8 August 2001/Accepted: 1 December 2001     

Temporal Variation of Metals in Water,Sediment and Tissues of the European Chup (<Emphasis Type="Italic">Squalius cephalus</Emphasis> L.)

The aim of this study was to analyze seasonal variation of levels of Chromium (Cr), Manganese (Mn), Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Lead (Pb) in water, sediment and tissues of Squalius cephalus (L., 1758) taken from five different stations chosen at Yamula Dam Lake (Kayseri, Turkey). Concentrations of metals were generally sorted as water<tissue<sediment. The highest concentration of metals in water was observed in the samples taken in the summer (Mn, 1.04 ± 0.15 mg L⁻¹; Ni, 0.42 ± 0.12 mg L⁻¹; Cu, 1.25 ± 0.88 mg L⁻¹; Zn, 3.61 ± 1.53 mg L⁻¹; Pb, 0.58 ± 0.09 mg L⁻¹). While the highest Zn (24.85 ± 21.82 μg g⁻¹) and Pb (10.89 ± 4.2 μg g⁻¹) concentrations in sediment were observed in the winter samples, the highest Mn concentration (167.2 ± 99.37 μg g⁻¹) was observed in the summer. Cd pollution was determined in sediment according to international criteria. The highest metal concentration in tissues was generally observed in the liver and the other tissues; following liver were gills and muscles. In liver tissues, while the highest accumulation of Zn (110.34 ± 13.1) and Mn (22.5 ± 14.85 μg g⁻¹), which are essential for the body, were observed in the winter, Pb (22.58 ± 7.83 μg g⁻¹) and Cd (11.77 ± 7.83 μg g⁻¹), which are toxic, were found to be higher in the summer. Also, concentrations of Mn, Cd and Pb in muscle tissues were found to be above the limits permitted.     

Accumulation of Microcystins in Nile Tilapia, <Emphasis Type="Italic">Oreochromis niloticus</Emphasis> L., and Effects of a Complex Cyanobacterial Bloom on the Dietetic Quality of Muscles

The aim of this study was to investigate the kinetics of accumulation and elimination of microcystins in the tissues of Nile tilapia (Oreochromis niloticus) and to evaluate the effect of cyanobacterial exposure on fish muscle quality (levels of total fat and ash, protein, dry matter and the composition of saturated, monounsaturated and polyunsaturated fatty acids). Fish were exposed for 28 days to a natural cyanobacterial bloom with total microcystin concentration around 1,200 μg g⁻¹ biomass dry weight. The hepatopancreas accumulated microcystins up to 350 ng g⁻¹ fresh weight, but concentrations in muscle were generally below the detection limit (2 ng g⁻¹ fresh weight). Following the exposure, fish were moved to the clean water, but only minor microcystin removal from the hepatopancreas was observed during a 4 week depuration period. Exposures of tilapia to the complex cyanobacterial bloom had only minor and temporary impacts on the investigated parameters of dietetic quality.     

Historical Distribution of PCDDs, PCDFs, and Coplanar PCBs in Sediment Core of Ariake Bay, Japan

Persistent organic pollutants, particularly polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (co-PCBs) and toxic equivalent quantity (pg TEQ g⁻¹) were determined in sediment samples collected from Ariake Bay, Japan. The total concentration of PCDDs/DFs in surface sediment of the Yabe River (17,000 pg g⁻¹ dry wt) was approximately 2.5-fold higher than that of the Chikugo River (7,000 pg g⁻¹ dry wt) which has the highest flow amount of about 40% inputting to the northern Bay. The congener profile suggested that dioxin sources could be close to the study area. The PCDDs concentration (12,000 pg g⁻¹ dry wt) in the sediment layer, which was corresponding to the 1960s, was reflected on the pentachlorophenol (PCP) contamination occurring at that time in Ariake Bay. The reflecting of PCP in the sediment core was significantly considered by hierarchical cluster analysis. Based on isomer-specific analysis, the tetrachlorodibenzo-p-dioxin composition showed a gradual increase from 1978–1982 toward the surface, indicating that the pollution source at that period might be more influenced by chloronitrofen than PCP. This fact was supported, based on the ratio of ΣPCDD to ΣPCDF concentration. The PCDDs/DFs-derived TEQ contributed more than 90% of the ΣTEQ (PCDDs/DFs and co-PCBs) in all the detected sediment layers. The contribution of PCBs to the total TEQ was low; however, an increasing historical trend of concentration was clearly observed.