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The objective of this study was to determine the levels of pesticides in the fishProchilodus costatuscaught in São Francisco River, one of most important rivers in Brazil. Thirty-six fish were captured in three different areas, and samples of the dorsal muscle and pooled viscera were collected for toxicological analysis. We evaluated the presence of 150 different classes of insecticides, fungicides, herbicides and acaricides by multiresidue analysis technique using liquid chromatography-tandem mass spectrometry (LC-MS/MS), with the limit of detection of 5 ppb. In this study, organophosphorus and carbamate pesticides were detected at the highest levels in the caught fish. Among the 41 organophosphorus pesticides surveyed, nine types were detected (chlorpyrifos, diazinon, dichlorvos, disulfoton, ethion, etrimfos, phosalone, phosmet and pyrazophos) in the muscle, viscera pool, or both in 22 (61.1%) fish. Sampled tissues of 20 (55.6%) fish exhibited at least one of the eight evaluated carbamate pesticides and their metabolites: aldicarb, aldicarb sulfoxide, carbaryl, carbofuran, carbosulfan, furathiocarb, methomyl and propoxur. Fungicides (carbendazim, benalaxyl, kresoxim-methyl, trifloxystrobin, pyraclostrobin and its metabolite BF 500 pyraclostrobin), herbicides (pyridate and fluasifopp-butyl), acaricide (propargite) and pyrethroid (flumethrin) were also detected. In conclusion,P. costatusfish caught in the São Francisco River contained residues of 17 different pesticides, in both muscles and the viscera pool, indicating heavy environmental contamination by pesticides in the study area. [ABSTRACT FROM AUTHOR]

Diazinon is an organophosphate pesticide widely used in agricultural areas (especially paddy fields) in Iran. Similar to other pesticides, diazinon may enter aquatic systems due to run-off and affect various organisms living in rivers and estuaries. Persian sturgeon Acipenser persicus is one of the most economically important species in the Caspian Sea, which enters Iranian rivers, such as the Sefidroud River, for breeding. Fish eggs hatch in the river and fingerlings migrate to the sea after a period of time. The International Sturgeon Research Institute in Rasht, Iran, produces and releases millions of fingerling sturgeons into the coastal area of the Caspian Sea annually and the fingerlings may thus be affected by this pesticide. This study was carried out to determine sublethal effects of diazinon on some hematological indices of Persian sturgeon under lab conditions. Fish were exposed to concentrations of 0, 0.01, 1.095 (0.25 LC50), 2.19 (0.5 LC50) or 3.285 ppm (0.75 LC50) diazinon and responses were studied after 12, 24 and 96 h. After 12 h exposure, the fingerlings exposed to 2.19 and 3.285 ppm revealed a series of abnormal responses such as muscle paralysis, change in gills and abdominal color, erratic swimming, rapid operculum movement, and loss of body balance. The exposed sturgeons also exhibited a significantly lower number of erythrocyte (RBC) and leukocyte count (WBC) after 24 and 96 h exposure. Similarly, after 96 h, there was a significant decrease in hematocrit (Htc). Results also revealed a decrease in lymphocyte numbers and an increase of meta neutrophils, band neutrophils and total neutrophils after 24 and 96 h diazinon. Data suggest that diazinon affects physiological and hematological functions of A. persicus, which may finally affect survival of the fish. Diazinon concentration of 0.01 ppm has been recorded in water of the Sefidroud River, where about five million Persian sturgeon fries are released annually by the Iranian department of fishery hatcheries. Since this level of pesticide was found to be toxic for fish fries, it is critical to avoid any toxic impact by regular monitoring of diazinon levels in the river water. [ABSTRACT FROM AUTHOR]

The effect of carbofuran, a carbamate pesticide, on the breeding performance of the freshwater fish Labeo rohita (Hamilton) has been investigated in the present study. Breeding of L. rohita was conducted after treatment with three sublethal concentrations, i.e. 0.06, 0.15 and 0.30 mg L-1 of carbofuran for 96 h. The present investigation showed that the number of total eggs and total amount of eggs (litre per kg body weight) decreased significantly (p < 0.01) at all concentrations of carbofuran in comparison to controls, while the reduction in fertilization percentage at all concentrations of carbofuran was not significantly different from controls. The reduction in hatching percentage, the expected number of hatchlings, and the expected number of hatched larvae were significantly (p < 0.01) different between treated and control groups at all carbofuran concentrations. No significant differences for the 96 h survivability of hatched larvae were reported at all concentrations of carbofuran. [ABSTRACT FROM AUTHOR]

Toxicity tests using adult specimens of Jenynsia multidentata were carried out during 96 hours in order to determine the lethal concentration (LC50) of endosulfan. Histological alterations were determined in gills and liver. Gill damage was quantified as secondary lamellae thickness. The 96 hr LC50 values were significantly different between males (0.719 μ g.L- 1) and females (1.317 μg.L- 1). The sex difference was attributed to the dimorphism in the lipid content in females (2.16%) and males (1.79%). Histological alterations in gills included hypertrophy and lifting of the epithelium of the secondary lamellae and aneurisms. These alterations caused a significant increase of the secondary lamellae thickness in treatment versus control fish. Finally, reversible histological alterations (such as hydropic degeneration and dilation of sinusoids) were observed in the liver of exposed fish as well as an irreversible change such as necrosis at the highest concentrations. [ABSTRACT FROM AUTHOR]

The Grenland fjords, southern Norway, have been heavily contaminated by dibenzo- p -dioxins and dibenzofurans (dioxins) over decades through inputs from a magnesium smelter. Despite radically decreased inputs since 1990, there are still high levels of dioxins in both biotic and abiotic components of the fjords. The aim of the study was to establish whether biomarkers’ responses in three fish species, Atlantic cod ( Gadus morhua L.), sea-trout (anadromous brown trout, Salmo trutta L.) and flounder ( Platichthys flesus L.), could be used to discern the effects in the most contaminated ecosystem, Frierfjord, from the effects in the adjacent, less-contaminated ecosystem, Eidangerfjord. Biomarker responses clearly indicated that the three fish species were affected by dioxin exposure. Phase I responses in cod and trout could be used to differentiate exposure in the two fjord ecosystems. Phase II responses (glutathione S -transferase) in cod and trout similarly indicated a higher dioxin exposure in Frierfjord compared with Eidangerfjord. Results for glutathione S -transferase and glutathione reductase indicated different exposure levels in the two fjords, but also showed seasonal variability, and the results highlighted the need for baseline data for these biomarkers. [ABSTRACT FROM AUTHOR]

Accumulation, distribution and metabolism of ring labelled, 14C-1,1,1, - trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) in a model marine aquatic ecosystem consisting of sea water, sediment, oysters (Isognomonon alatus) and Humbug fish (Dascillus aruanus) were studied in the laboratory. 14C-p,p'-DDT distributes rapidly in the ecosystem immediately after application on the water surface with reduction of its concentration in the water phase from 1.18 ng g-1 to 0.71 ng g-1 after 2 hours and an increase in its content in the sediment and oysters. The bioconcentration factor reached a maximum of 19 103 in oysters, and 1657 in Humbug fish after 24 hours. The sediment concentration reached 117 ng g-1 after 168 hours from start of application. A peak bioconcentration factor of 111 103 was calculated after 120 hours when 0.24 mg kg-1 of 14C-p,p'-DDT was maintained through dosing every 24 hours with 0.002 mg kg-1 of a mixture of labelled and non-labelled pesticide. The rate of depuration of accumulated 14C-p,p'-DDT sediment residues was up to 78.3% after 24 hours while oysters lost only 14.0% during the same period. The loss in Humbug fish was only 22.2% in three days. Volatilisation and sorption losses from seawater alone (without sediment/biota) were found to be very high in the range of 73.8 - 91.5% over 24 h for p,p'-DDT in aerated and non-aerated ecosystem. Gas chromatograph and TLC analysis of water, sediment and oyster samples revealed presence of p,p'-DDT and substantial amounts of p,p'-DDE and p,p'-DDD three days after pesticide dosage. [ABSTRACT FROM AUTHOR]

The concentrations of organochlorine residues of lindane, aldrin, ∞- endosulfan, dieldrin, endrin, p,p'-DDE, p,p'-DDD and p,p'-DDT in samples of seawater, sediment, fish and seaweed from different locations along the coast of Kenya are discussed in relation to the geographical location of the sampling sites and potential sources of residue over a period of two years. All sediment samples were found to contain very low levels of organic carbon except those sampled from Sabaki River that had high (4.7%) organic carbon due to greater primary activity. Most of the pesticides residues (112 samples analysed in 1997 and 258 analysed in 1998/99) were detected in fish, water, sediments and seaweed. The concentration of some residues was higher during the wet season than the dry season in 1997, but no marked seasonal variation was observed in 1998/99. Lindane, aldrin, p,p'-DDT and p,p'-DDE were the most frequently observed residues in all samples while ∞-endosulfan, dieldrin, p,p'-DDD and endrin were either present in low concentrations or absent in most samples. Water samples had the lowest concentrations of residues (range 0.503 - 9.025 ng g-1). Sediments had the second highest levels of pesticides residues with a range of 0.584 - 59.00 ng g-1 while fish lipid content had the highest levels of residues in 1989/99 with p,p'-DDT concentration of 1011 ng g-1 and 418 ng g-1 p,p'-DDD in Siganus rivulatus. [ABSTRACT FROM AUTHOR]