Dissipation of sulfosulfuron in water - bioaccumulation of residues in fish - LC-MS/MS-ESI identification and quantification of metabolites

Dissipation study of sulfosulfuron in natural water and its bioaccumulation in fish was conducted at 25+/-2 degrees C and at two different concentration levels 1mgl(-1) and 2mgl(-1). The dissipation data in water showed the DT50 and DT90 values 67-76 and 222-253 days and followed first order kinetics. Bioaccumulation of sulfosulfuron in fish was conducted under static conditions exposing the fish at one-tenth of sub-lethal concentration 9mgl(-1) and at double the concentration 18mgl(-1), for a period of 56 days. On different occasions fish samples were collected and analyzed. A HPLC-RF method was used for the quantification of sulfosulfuron and aminopyrimidine with the limit of quantification 0.001microg ml(-1). Results showed the accumulation of residues of sulfosulfuron in fish over the concentration range 0.009-0.496microg g(-1). Both in water and fish samples, identified the presence of metabolites aminopyrimidine, desmethyl sulfosulfuron, guanidine, sulfonamide, ethyl sulfone and rearranged amine. The formations of these metabolites are confirmed by LC-MS/MS analysis. An LC-MS/MS electro spray ionization technique was used for this purpose. One of the metabolite Aminopyrimidine was identified at higher concentration levels (0.01-0.1microg ml(-1)) when compared with other metabolites. Subsequently dissipation of aminopyrimidine in water and its bioaccumulation was also studied at the concentration level 1mgl(-1) and 2mgl(-1). The calculated DT50 and DT90 values are 66-68 days and 218-226 days, respectively. This followed first order kinetics. Three hundred days after the exposure complete demineralization was observed.     

Biochemical alterations in euryhaline fish, Oreochromis mossambicus exposed to sub-lethal concentrations of an organophosphorus insecticide, monocrotophos

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (1.15 mg l(-1)) of a organophosphorus insecticide, monocrotophos (MCP) for 30 days and allowed to recover for seven days. Alanine aminotransferase (ALAT), aspartate aminotransferase (AAT), acid phosphatase (AcP), alkaline phosphatase (ALP), glycogen, lactate dehydrogenase (LDH), Reduced glutathione (GSH), gluthathione-S-transferase (GST) and acetylcholinesterase (AChE), were assayed in plasma and different tissues at regular intervals of day -3, -7, -15, -30 and after recovery period of seven days. The ALAT and AAT activities were increased in plasma and kidney, where as liver and gill showed decrease. Increase in AcP and ALP activities were observed in plasma, gill and kidney, and reduction of 42% and 50% was observed in liver. Glycogen was depleted in plasma, liver and gill indicates of typical stress related response of the fish with pesticide. LDH activity was decreased in liver and muscle, indicating tissue damage and muscular harm, but a significant increase in LDH activity in gill and brain was observed. Depletion in GSH activity was observed in all the tissues, there by enhancing the lipid peroxidation resulting in cell damage. The induction in hepatic GST levels indicates the protection against the toxicity of xenobiotic-induced lipid peroxidation. There was a significant recovery in all the above biochemical parameters studied in plasma and different tissues, after seven days recovery period. These results revealed that MCP affects the intermediary metabolism of O. mossambicus and that the assayed enzymes can work as good biomarkers of organophosphorus contamination.     

Water quality and fish size affect toxicity of endosulfan, an organochlorine pesticide, to rainbow trout

The acute toxicity of endosulfan in juvenile rainbow trout (Oncorhynchus mykiss, 10.61+/-1.69 g) was evaluated in glass aquaria under static conditions. Nominal concentrations of endosulfan in the toxicity test ranged from 1.3 microg l(-1) to 29 microg l(-1). The concentrations of endosulfan that killed 50% of the rainbow trout within 24-h (24-h LC50), 48-h LC50, 72-h LC50, and 96-h LC50 were 19.78, 8.89, 5.28, and 1.75 microg l(-1), respectively. None of the unexposed control fish died, and the first fish died 4 h after exposure to 26.3 microg l(-1) of endosulfan. Survival of fish was significantly increased with increasing fish size and decreased with decreased fish size at the same temperature (p<0.001). Temperature also had a significant effect on survival of fish. Alkalinity at levels above 20 mg l(-1) as CaCO3 significantly increased survival of fish at 19.78 microg l(-1) of endosulfan. Increasing alkalinity from 20 mg l(-1) as CaCO3 to 42 or higher concentrations tested in this study (121 mg l(-1) as CaCO3) significantly increased survival of fish (p<0.01). Total hardness ranging from 55 mg l(-1) as CaCO3 to 126 mg l(-1) as CaCO3 did not affect survival of fish exposed to endosulfan. Endosulfan toxicity was found to be irreversible when fish were exposed to minimum concentrations of endosulfan tested. Histologically, fish gills had lamellar edema, separation of epithelium from lamellae, lamellar fusion, and swelling of the epithelial cells. Melanomacrophage centers were scattered throughout the trunk kidney, head kidney, and spleen. The liver of endosulfan-exposed fish had severe focal necrosis. None of these lesions were seen in unexposed control fish. Results indicate that alkalinity, temperature, and fish size affect endosulfan toxicity of rainbow trout.     

Evaluation of impact of PAH on a tropical fish, Oreochromis mossambicus using multiple biomarkers

Treatment of the widely occurring tropical cichlid, Oreochromis mossambicus with a pure polycyclic aromatic hydrocarbon (PAH), phenanthrene, induced a concentration-dependant formation of the enzyme, 7-ethoxyresorufin-O-deethylase (EROD). Concomittant increase (65-669%) in the activity of sorbitol dehydrogenase in the serum (SSDH) occurring with EROD induction denoted liver cell damage, which was more severe in fish exposed to lower concentrations (0.4-4 microg g-1) of the chemical. In O. mossambicus exposed to 25% refinery effluent liver damage associated with cell death was indicated by the twin analyses of SSDH and liver somatic index. Cell injury appeared to have occurred at low PAH concentrations due to inadequately induced phase II-related detoxification of metabolites. This was indicated by the nearly 33% higher activity of hepatic glutathione S-transferase (GST) in fish exposed to higher PAH concentrations as compared to low-exposure animals. Tilapia such as O. mossambicus were found to be eminently suited for biomonitoring in tropical coastal waters. A combination of EROD and serum sorbitol dehydrogenase activity measurements serves as an excellent tool for biomonitoring sublethal effects of PAH pollution in fish.     

Copper modulates non-enzymatic antioxidants in the freshwater fish Channa punctata (Bloch) exposed to deltamethrin

The assessment of the ecotoxicological risks caused by pesticides to ecosystems are based on data on the toxicity and effects of pesticide preparations to non-target organisms like fish. Deltamethrin is a widely used pesticide based on pyrethroids, which is reported to be extremely toxic to fish species. Modulatory effect of copper pre-exposure (10 ppb) on deltamethrin (0.75 microg l-1)-induced oxidative stress was investigated in freshwater fish Channa punctata (Bloch). Non-enzymatic antioxidants were studied as biomarkers of exposure to deltamethrin and possible protection afforded by copper pre-exposure. Glutathione levels were reduced significantly (P<0.05) in liver of copper-acclimatized deltamethrin-exposed group when compared with deltamethrin-exposed groups. The total thiol levels of copper-acclimatized deltamethrin-exposed group was significantly lowered (P<0.01) in liver when compared with deltamethrin-exposed group, while non-protein thiol levels recorded a significant (P<0.01) increase in liver of copper-acclimatized deltamethrin-exposed group when compared with deltamethrin-exposed group. The lipid peroxidation levels of copper-acclimatized deltamethrin-exposed groups were significantly lowered (P<0.01) in liver when compared with deltamethrin-exposed group. Deltamethrin is known to induce toxic responses by generating reactive oxygen species and to neutralize its toxic effect various non-enzymatic antioxidants were found to be modulated thus implicating their role as biomarkers in pollution control programmes.     

Investigation of acute toxicity of permethrin on guppies Poecilia reticulata

Permethrin, a synthetic pyrethroid pesticide and potential toxic pollutant contaminating aquatic ecosystems, was investigated in the present study for acute toxicity. Guppy fish (Poecilia reticulata) were selected for the bioassay experiments. The experiments were repeated 3 times and the 48-h LC(50) was determined for the guppies. The static test method of acute toxicity test was used. Water temperature was regulated at 20+/-1 degrees C. In addition, behavioral changes at each permethrin concentration were observed for the individual fish. Data obtained from the permethrin acute toxicity tests were evaluated using the probit analysis statistical method. The 48-h LC(50) value for guppy was estimated as 245.7 microg/l. Values in the range of 0.05-97.0 microg/l have been reported for various other fish species.     

Changes in plasma thyroid hormones and cortisol levels in crucian carp (Carassius auratus) exposed to the extracted microcystins

The endocrine response of crucian carp injected intraperitoneally with extracted microcystins (MC) was investigated in this study. Fish were injected intraperitoneally either with 0.75% NaCl (control) and Microcystis extract corresponding to 150 and 600 microg microcystins per kg body weight. The plasma levels of triiodothyronine (T(3)), thyroxine (T(4)), free triiodothyronine (FT(3)), free thyroxine (FT(4)), and cortisol were determined at 0, 1, 3, 12, 24, and 48h post-administration of MC-containing extract. Treated fish displayed abnormal behaviors, such as a startle response and disoriented swimming, as well as changes in ventilation rates. Plasma cortisol concentrations of fish in both dose groups significantly increased after administration of extracted MC and remained high throughout the experiment, which suggested that MC elicited a stress response in treated fish. The profiles of cortisol changes in treated fish appeared to be dose dependent, indicating that fish in the high dose group experienced greater MC-induced disturbance. Mortality occurred after 12h in the high dose group. Plasma levels of T(4), T(3), FT(4), and FT(3) did not vary significantly between the control fish. In contrast to this, fish exposed to MC-containing extract showed significant declines in T(3), FT(4), and FT(3) levels in a dose-dependent manner throughout the experiment. Plasma T(4) levels, however, did not vary significantly in the low dose group, whereas they decreased significantly at 48h post injection in the high dose group. This study demonstrates that administration of microcystins-containing extract causes a stress response and reduces the plasma levels of thyroid hormones in crucian carp. These results illustrate that microcystins exerted potent effects on the endocrine system of crucian carp, through activating their hypothalamus-pituitary- interrenal axis and disturbing thyroid function.     

Comparison of spray drift- and runoff-related input of azinphos-methyl and endosulfan from fruit orchards into the Lourens River, South Africa.

Spray drift and edge-of-field runoff are regarded as important routes of nonpoint-source pesticide input into aquatic surface waters, with current regulatory risk assessment in Europe focussing largely on spray drift. However, the two routes of entry had rarely been compared directly in the same catchment. To this end, the concentrations and loads of the current-use insecticides azinphos-methyl (AZP) and endosulfan (END) were monitored in the Lourens River, South Africa downstream of a 400-ha fruit orchard area during normal farming practice. Spray drift-related peak pesticide levels in the tributaries were in the range of 95th-percentiles of standard drift values according to regulatory risk assessment procedures. Resulting concentrations in Lourens River water samples (n = 3) at a discharge of 0.28 m3/s were as high as 0.04 +/- 0.01 microg/l AZP and 0.07 +/- 0.02 microg/l END. Pesticide levels at the same site during runoff following 3 storm events varying in rainfall between 6.8 and 18.4 mm/d (discharge: 7.5-22.4 m3/s) were considerably higher: by factors between 6 and 37 for AZP (0.26-1.5 microg/l) and between 2 and 41 for END (0.13-2.9 microg/l). Levels of pesticides associated with suspended particles were increased during runoff only up to 1247 microg/kg AZP and 12082 microg/kg END. A possible reason for the relative importance of runoff is that runoff largely integrates potential pesticide input over both time and space, because the prerequisites for the occurrence of runoff in terms of application and plot characteristics as well as meteorological conditions are far less specific than for spray drift. A probability analysis based on pesticide application patterns and 10-yr rainfall data indicates that the frequencies of rainfall events > or = 10 and > or = 15 mm/d are 3.4 and 1.7 per spraying season, respectively.     

Radionuclides (lead-210, polonium-210, thorium-230, and -232) and thorium and uranium in water, sediments, and fish from lakes near the city of Elliot Lake, Ontario, Canada

Radionuclides (210Pb, 210Po, 230Th, and 232Th) and chemical Th and U were measured in water, sediments, and fish tissues (bone, muscle, and gut contents of laketrout, Salvelinus namaycush, whitefish, Coregonus clupeaformis and Prosopium cylindraceum) from four lakes in a watershed affected by U mining and milling operations at Elliot Lake, Ontario, and from control lakes in an adjacent, non-industrialized, watershed. Radionuclide concentration ratios between tissue levels and sediment and water levels were calculated. Annual radionuclide intakes and resulting doses were estimated for humans consuming fish from the watershed. Bone 210Pb levels were higher (186 mBq g(-1) dry wt in laketrout and 230 mBq g(-1) dry wt in one lake whitefish) than in muscle (< 50 mBq g(-1) dry wt in all cases), and generally higher in fish from study lakes than from controls, but no consistent differences were observed among fish species. Similarly, 210Po levels were higher in bone (208 +/- 33 mBq g(-1), in laketrout) than muscle (maximum 26 +/- 4 mBq g(-1), in laketrout), and in study lake populations compared to controls. Laketrout 210Po bone concentrations were higher than previously reported in Canada. Levels of 230Th, 232Th, and Th were below detection limits (20 mBq g(-1), 0.05 microg g(-1)) in body tissues in all fish species. Bone levels of U (14.6 +/- 3.0 microg g(-1), in lake whitefish) were higher than in muscle (most < 0.05 microg g(-1), except 0.12 +/- 0.04 and 0.08 +/- 0.03 microg g(-1) in lake whitefish) in fish from waters affected by industrial activity. In control lakes, bone and muscle levels were lower and not significantly different from each other. Muscle levels did not vary consistently with location. Concentration of 210Pb and U was seen from water and 'gut' material (taken as a surrogate for diet) to bone in laketrout and whitefish, and of U from water to muscle in whitefish, but in no case from sediments to tissues. Human intakes of 210Pb, 210Po, 230Th, 232Th, and U from consuming one meal of fish (375 g) per week could, in aggregate, represent an annual effective dose < 15% of the public dose limit (5 mSv). Monitoring biota living near the decommissioned Elliot Lake U operations, especially of 210Pb levels in fish muscle, with further assessment of human doses attributable to local fish and other animals in the diet, should continue. Because radionuclide effects on fish health (and on other non-human organisms) are of increasing concern, neoplasms, malformations, and reproductive anomalies in local fish deserve examination.     

Persistent organochlorine pesticide residues in fish, sediments and water from Lake Bosomtwi, Ghana

Some organochlorine pesticide residues in tilapia fish (Tilapiazilli), sediment and water samples from Lake Bosomtwi (the largest natural lake in Ghana) were determined to find out the extent of pesticide contamination and accumulation in the lake. The extracted residues were analyzed on a micro-capillary gas chromatograph equipped with electron capture detector. DDE (p,p'-1,1-dichloro-2,2-bis-(4-chlorophenyl)ethylene) was the predominant residue in all the samples analyzed; detected in 82% of water samples, 98% of sediment samples and 58% of fish samples at concentrations of 0.061+/-0.03 ng g(-1), 8.342+/-2.96 ng g(-1) and 5.232+/-1.30 ng g(-1), respectively. DDT (p,p'-1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane) was detected in 78% at a mean concentration 0.012+/-0.62 ng g(-1) of water samples analyzed. The mean concentrations of DDT in sediments and fish were 4.41+/-1.54 ng g(-1) and 3.645+/-1.81 ng g(-1), respectively. The detection of lower levels of DDT than its metabolite, DDE, in the samples implies that the presence of these contaminants in the lake is as result of past usage of the pesticides.     

Levels of organochlorine pesticides residues in dairy products in Kumasi, Ghana

Determination of six organochlorine pesticides, lindane, aldrin, dieldrin, endosulfan, dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethylene (DDE), residues were carried out on three dairy products sampled from six communities in the Kumasi metropolis in Ghana. Cheese samples were collected from three communities, (Tafo, Asawasi, and Aboabo), yoghurt samples from K-Poly and Ayeduasi while yoghurt and milk samples were collected from KNUST. Concentrations of DDT and DDE were, respectively, 42.17+/-6.00 microg kg(-1) and 31.50+/-3.44 microg kg(-1) in cheese sampled from Asawasi. Cheese samples from Tafo had an average DDT concentration of 298.57+/-28.02 microg kg(-1) while DDE concentration was 140.15+/-56.77 microg kg(-1). The highest average concentration of DDT in all the samples was 149.07 microg kg(-1) detected in cheese samples from Aboabo. Levels of DDT and its metabolite, DDE, in cheese from all the three sampling sites (Aboabo, Asawasi and Tafo) were well below the levels recommended by World Health Organisation (WHO). Mean concentration of DDT in fresh milk samples from KNUST was 12.53+/-1.61 microg kg(-1). As bioaccumulation of these residues is likely to pose problems in higher organisms, like human beings, there is the need for effective monitoring of these residues in the environment. This work, thus, seeks to provide information on levels of pesticide residues in dairy products that will assist in a scientific assessment of the impact of pesticides on public health, agriculture and the environment in Ghana.     

Bioaccumulation studies of organochlorinated pesticides in tissues of Cyprinus carpio

Freshwater fish Cyprinus carpio was selected for the study of bioaccumulation of organochlorinated pesticides in tissues like gills, muscle, intestine, kidney, and liver in a continuous fed system. The pesticides used were Aldrin, Dieldrin, BHC, and DDT. The bioaccumulation of Dieldrin was maximum of 85.0 microg g(-1) wet weight in liver tissue while minimum of 7.30 microg g(-1) wet weight for DDT at 30 days exposure time. Bioconcentration factor (BCF) has followed the same trend in liver tissue for Dieldrin and DDT. The rate of bioaccumulation was found to be maximum of 4.3879 microg g(-1) wet weight in liver tissue and minimum of 0.0021 microg g(-1) wet weight in gill tissue for 30 days exposure. As evidenced by the increasing values of BCF, pesticide uptake also showed increased trend with the increase in exposure time. A high correlation coefficient ranging between 0.7247 and 0.9616 between the pesticide concentration and exposure time was observed. Based on actual BCF values, log Kow were calculated and the values are well within the reported values of 6.5 indicating efficient relationship between BCF and log Kow because beyond the 6.5 the bioconcentration levels off.     

Water Quality of Medium Size Watercourse Under Baseflow Conditions: The Case Study of River Sutla in Croatia

The study on medium size river Sutla in Croatia indicated considerable water contamination at specific sites during the baseflow period, probably associated to low flow-rate (0.73-68.8 m3 s(-1)), and consequently low dilution capacity of this river. Various aspects of contamination were observed: increased conductivity to 1,000 microS cm(-1), decreased dissolved oxygen level to 50%, 4-5 degrees C increased water temperature, increased concentrations of several dissolved trace elements (e.g., maximal values of Li: 45.4 microg l(-1); Rb: 10.4 microg l(-1); Mo: 20.1 microg l(-1); Cd: 0.31 microg l(-1); Sn: 30.2 microg l(-1); Sb: 11.8 microg l(-1); Pb: 1.18 microg l(-1); Ti: 1.03 microg l(-1); Mn: 261.1 microg l(-1); and Fe: 80.5 microg l(-1)) and macro elements (e.g., maximal values of Na: 107.5 mg l(-1); and K: 17.3 mg l(-1)), as well as moderate or even critical fecal (E. coli: 4,888 MPN/100 ml; total coliforms: 45,307 MPN/100 ml; enterococci: 1,303 MPN/100 ml) and organic pollution (heterotrophic bacteria: 94,000 cfu/ml). Although metal concentrations still have not exceeded the limits considered as hazardous for aquatic life or eventually for human health, the observed prominent increases of both metal concentrations and bacterial counts in the river water should be considered as a warning and incentive to protect the small and medium size rivers from the future deterioration, as recommended by EU Water Framework Directive.     

Agricultural pesticide residues in farm ditches of the Lower Fraser Valley, British Columbia, Canada

Transient and permanent farm ditches flowing to the Lower Fraser River tributary fish streams of British Columbia, Canada, were sampled at several locations in 2003-2004 to determine the occurrence and concentration of residues of selected pesticides, their transformation products, and soluble/extractable Cu++ ions. Of the 43 compounds analyzed, 28 and 22 pesticides were detected in transient farm ditch water and sediments, respectively. About 34% fewer pesticides, however, were found in both matrices of permanent farm ditches. Average concentrations (microg L(-1)) of those most frequently detected in permanent farm ditch water were atrazine (0.20), alpha -chlordane (0.06), desethylatrazine (0.13), diazinon (0.55), dieldrin (0.28), endosulfan sulfate (0.16), glyphosate (6), metalaxyl (0.27); and soluble Cu++ ions (25). Those most often found in ditch sediments (microg kg(-1)) were aminomethylphosphonic acid (AMPA) (2,300), 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT) (250), endosulfan sulfate (500), glyphosate (1,225); and extractable Cu++ ions (58,000). The risk potential of these pesticide residues to non-target aquatic organisms inhabiting Fraser River tributary fish streams contiguous to permanent farm ditches is evaluated and discussed.     

Factors influencing the total mercury and methyl mercury in the hair of the fishermen of Kuwait

Total and methyl mercury (MeHg) levels in the hair of fishermen are described anticipating that they represent the critical group for dietary exposure. One-hundred human hair samples were collected from fishermen (Egyptians: age range 25-60), living in Doha Fishing Village, Kuwait. Thirty-five additional samples were taken from a control group working in a local construction company (age range 26-35). Overall mean concentrations in the hair of the population of fishermen are 4.181+/-3.220 and 4.025+/-3.130 microg g(-1) for total and MeHg, respectively. The equivalent values for the control are 2.617+/-1.404 and 2.556+/-1.391 microg g(-1) for total and MeHg, respectively. MeHg concentrations are strongly correlated to those of total Hg ( [Formula: see text], [Formula: see text] ) and MeHg concentrations in human hair are unrelated to age and duration of residence in Kuwait but show a positive correlation with the quantity of fish consumed. Levels of Hg in hair also show a tendency to increase in those who prefer to eat the entire fish, including the heads. In general, the concentrations of total and MeHg in fishermens' hair are twice the WHO 'normal' level (2.0 microg g(-1)) but are still less than the WHO threshold level (10.0 microg g(-1)). The results also show that grey hair contains undetectable amounts of Hg and therefore does not reflect individual exposure to this contaminant.     

Investigation of acute toxicity of beta-cypermethrin on guppies Poecilia reticulata

Beta-cypermethrin, a synthetic pyrethroid pesticide and potential toxic pollutant, contaminating aquatic ecosystems was investigated in the present study for acute toxicity. Guppy fish (Poecilia reticulata) was selected for the bioassay experiments. The experiments were repeated three times and the 48-h LC50 was determined for the guppies. The static test method of acute toxicity test was used. Water temperature was regulated at 22 +/- 1 degrees C. In addition, behavioral changes at each beta-cypermethrin concentration were observed for the individual fish. Data obtained from the beta-cypermethrin acute toxicity tests were evaluated using the probit analysis statistical method. The 48-h LC50 value for guppy was estimated as 21.4 microg/l.     

Organochlorine residues in roof timbers and possible implications for bats

In Britain, many species of bat regularly use buildings as roosts. DDT, DDE, dieldrin (HEOD) and gamma-HCH (lindane) have been detected in carcasses of bats that had died a short while before they were found. Roof timbers may be a source of this contamination. This study reports concentrations of organochlorines in (i) roof timbers known to have been treated in the past (spot samples; n - 17) and (ii) timbers before and after treatment with commercial permethrin formulations (pre-treatment and post-treatment samples, n = 11). Gamma-HCH was detected in 13 spot samples and HEOD in 6. Where present, mean (+/-1 SE) concentrations in wood were 15.6+/-6.5 microg g-1 WW (n = 13) and 25.0+/-11.8 microg g-1 WW (n = 6), respectively. DDT was not detected in any spot samples, but permethrin was detected in four (1264+/-567 microg g(-1) WW) samples, but not in the corresponding pre-treatment samples; in one other pair of samples, concentrations of gamma-HCH increased from 74 to 2468 microg g-1 WW after treatment. Both DDT and HEOD occurred in low (<2 microg g-1 WW) concentrations in five post-treatment samples and in one and zero pre-treatment samples, respectively; the highest dieldrin concentration measured was 30.9 microg g-1 WW. Permethrin was not detectable in any pre-treatment samples but was present in ten post-treatment samples in concentrations ranging from 93 to 2995 microg g-1 WW. The spot results suggest that low concentrations of organochlorines can persist in treated roof timbers for at least 13 years post-treatment. Occasionally, these pesticide residues in timber may be of sufficient magnitude to result in bats absorbing a substantial proportion of a lethal dose. Results also suggest that there is organochlorine contamination of permethrin formulations and that the solvents used in new applications of pesticide may re-mobilise organochlorines already present in wood.     

Evaluation of pesticides and metals in fish of the Dniester River, Moldova

The Dniester River is one of the largest rivers in Eastern Europe and receives input from numerous anthropogenic activities. In October 2001, fish samples (Abramis brama, Rutilus rutilus heckeli, Perca fluviatilis, Chondrostoma nasus, Carassius auratus gibelio, and Cyprinus carpio) were collected and analyzed for metals and various pesticides. Maximum total DDT pesticide concentrations were between 27.7 and 34.2 ng/g wet weight in muscles and gonads, respectively. DDE isomers comprised up to 70% of total DDT measurement in fish tissues, indicating historical rather than recent DDT pollution. Chlordane and lindane were also detected in amounts up to 37 and 76 ng/g wet weight in gonads, respectively. Among organophosphorous pesticides, malathion showed extremely high concentrations--3 microg/g wet weight in muscles and 46 microg/g wet weight in gonads, indicating recent exposure. Copper concentrations in muscles (1.8-7.2 microg/g) exceeded Threshold Effect Concentrations for copper in fish. Detection of high concentrations of malathion and copper in fish tissues indicated potential anthropogenic stress for more sensitive aquatic biota, likely from agricultural sources in the Dniester River.     

Increased formation of carcinogenic PAH metabolites in fish promoted by nitrite

Nitrite (NO(2)(-)), a highly reactive chemical species, accumulates in coastal waters as a result of pollution with nitrogenous waste and/or an imbalance in the bacterial processes of nitrification and denitrification. The present study probed the impact of nitrite (NO(2)(-)) on the metabolism of polycyclic aromatic hydrocarbons (PAHs) in fish. In a laboratory experiment, exposure of euryhaline fish, Oreochromis mossambicus to industrial effluents containing PAHs in the presence of NO(2)(-) enhanced the cytochrome P450-dependent biotransformation activity determined as 7-ethoxyresorufin-O-deethylase (EROD), by nearly 36% compared to the value observed in the absence of NO(2)(-) (50.2 +/- 6.74 pmol resorufin min(-1) g(-1) liver). Fixed wavelength fluorescence measurements in bile revealed maximum enhancement to have occurred in the metabolites of benzo[a]pyrene, a carcinogenic PAH. Lasting, sublethal physiological deterioration was apparent in fish exposed simultaneously to an oil refinery effluent and NO(2)(-), from the unremittingly decreasing liver somatic index, even after the withdrawal of the contaminants.