No abstract

Predicting fish acute toxicity of chemicals in vitro is an attractive alternative method to the conventional approach using juvenile and adult fish. The rainbow trout ( Oncorhynchus mykiss ) cell line assay with RTgill-W1 cells has been designed for this purpose. It quantifies cell viability using fluorescent measurements for metabolic activity, cell- and lysosomal-membrane integrity on the same set of cells. Results from over 70 organic chemicals attest to the high predictive capacity of this test. We here report on the repeatability (intralaboratory variability) and reproducibility (interlaboratory variability) of the RTgill-W1 cell line assay in a round-robin study focusing on 6 test chemicals involving 6 laboratories from the industrial and academic sector. All participating laboratories were able to establish the assay according to preset quality criteria even though, apart from the lead laboratory, none had previously worked with the RTgill-W1 cell line. Concentration-response modeling, based on either nominal or geometric mean-derived measured concentrations, yielded effect concentrations (EC 50 ) that spanned approximately 4 orders of magnitude over the chemical range, covering all fish acute toxicity categories. Coefficients of variation for intralaboratory and interlaboratory variability for the average of the 3 fluorescent cell viability measurements were 15.5% and 30.8%, respectively, which is comparable to other fish-derived, small-scale bioassays. This study therefore underlines the robustness of the RTgill-W1 cell line assay and its accurate performance when carried out by operators in different laboratory settings.

Permanent fish cell lines constitute a promising complement or substitute for fish in the environmental risk assessment of chemicals. We demonstrate the potential of a set of cell lines originating from rainbow trout ( Oncorhynchus mykiss) to aid in the prediction of chemical bioaccumulation in fish, using benzo[ a]pyrene (BaP) as a model chemical. We selected three cell lines from different tissues to more fully account for whole-body biotransformation in vivo: the RTL-W1 cell line, representing the liver as major site of biotransformation, and the RTgill-W1 (gill) and RTgutGC (intestine) cell lines, as important environment-organism interfaces, which likely influence chemical uptake. All three cell lines were found to effectively biotransform BaP. However, rates of in vitro clearance differed, with the RTL-W1 cell line being most efficient, followed by RTgutGC. Co-exposures with α-naphthoflavone as potent inhibitor of biotransformation, assessment of CYP1A catalytic activity, and the progression of cellular toxicity upon prolonged BaP exposure revealed that BaP is handled differently in the RTgill-W1 compared to the other two cell lines. Application of the cell-line-derived in vitro clearance rates into a physiology-based toxicokinetic model predicted a BaP bioconcentration factor (BCF) of 909-1057 compared to 920 reported for rainbow trout in vivo.

No abstract

No abstract

No abstract

The eomparison of a fish stoeking experiment in a Swiss mountain lake (Lake Laiozza) with results obtained in a South Norwegian lake (Lake Liervatn) revealed eontradictory results as to the toxieity ofthe respeetive acid water. This, even though the pH, aluminium eoneentration, conduetivity, and ionie composition ofthe two lakes proved to be almost identical. Lake Liervatn water was less toxie and had a substantially higher NaCI eoncentration. In order to answer the question whether NaCI eould have a mitigating effeet on pHaluminium toxicity to fish, experiments were performed in the laboratory using "Synthetic Laiozza", a media made up from deionized water and salts added aeeording to the eoneentrations found in Lake Laiozza. Synthetic Laiozza was then enriehed with 0, 0.125, 0.25, 0.5, and 4.0 meq NaCI per liter media.The addition ofO, 0.125, 0.25 and 0.5 meq NaCI/L had no significant effect on the survival time ofthe fish (all MT 50'S laying between 16 and 23 hours), whereas the addition of 4.0 meq NaCI/L resulted in langer survival of the fish i.e. MT50 = 85 hours. The analyses of plasma eleetrolytes on the other hand, revealed a progressive reduction in electrolyte loss with inereasing ambient NaCI eoneentration.KEY WORDS: Aluminium, toxieity, mitigation, ionoregulation, NaCl, brown trout, gills, eleetrothermieal atomie absorption speetrometry (ETAAS). INTRODUCTIONOne and two year old brown trout (Salmo trutta fario) were stoeked in the ehronically acid Lake Laiozza, a poorly buffered mountain lake in the alps of southern Switzerland. This lake water (labile-Al =41-52 J-lg AI/L, 0.5 mg Ca/L, 0.09 mg Na/L.Conductivity 7 J-lS/cm, and pH 5.37 ±0.22) proved to be acutely toxie to both age c1asses (MT50 = 37 hours for one year old fish and 39 hours for the two year old fish respectively The comparison of a fish stocking experiment in a Swiss mountain lake (Lake Laiozza) with results obtained in a South Norwegian lake (Lake Liervatn) revealed contradictory results as to the toxicity ofthe respective acid water. This, even though the pH, aluminium concentration, conductivity, and ionic composition of the two lakes proved to be almost identical. Lake Liervatn water was less toxic and had a substantially higher NaCI concentration. In order to answer the question whether NaCl could have a mitigating effect on pHaluminium toxicity to fish, experiments were performed in the laboratory using "Synthetic Laiozza", a media made up from deionized water and salts added according to the concentrations found in Lake Laiozza. Synthetic Laiozza was then enriched with 0, 0.125, 0.25, 0.5, and 4.0 meq NaCI per !iter media. The addition of 0, 0.125, 0.25 and 0.5 meq NaCI/L had no significant effect on the survival time of the fish (all MT 50'S laying between 16 and 23 hours), whereas the addition of 4.0 meq NaCI/L resulted in longer survival of the fish i.e. MT50 = 85 hours. The analyses of plasma electrolytes on the other hand, revealed a progressive reduction in electrolyte loss with increasing ambient NaCl concentration.

No abstract