Environmental risk assessment: a critical approach of the European TGD in an in situ application.

The aim of this study was to test field relevance of the prospective methodology for the assessment of environmental risk described in the EU technical guidance document (TGD) [European Commission 2003. Technical guidance document in support of Commission Directive 93/67/EEC on Risk assessment for new notified substances and Commission Regulation (EC) No 1488/94 on Risk assessment for existing substances and Commission Directive (EC) 98/8 on biocides, second ed. European Commission, Luxembourg, Part 1, 2 and 3, 760 pp.]. To achieve this goal, an environmental risk assessment was performed according to the TGD for two major contaminants, atrazine and diuron, that are present in the Seine River estuary (France) and listed in the EU Water Framework Directive (Directive 2000/60/CE). Results showed that atrazine presented a source of risk in the upper- and mid-estuary throughout the 1993 and 1996 spring seasons. Diuron introduced a risk into the same areas throughout spring periods of 1993-2005. Results are discussed and some suggestions for a more realistic in situ risk assessment are given. For the computation of a more relevant PNEC for pesticides, their specific mode of action should be taken into consideration as well as ecotoxicological data on species endemic to the considered area.

Effects of ethylene glycol ethers on the reproduction of Ceriodaphnia dubia.

Seven-day static renewal tests with Ceriodaphnia dubia were used to document the chronic toxicity of ethylene glycol ethers and acetates to this invertebrate. The 7-d EC10 (effective concentrations inducing an inhibition of 10% of the reproduction of the tested organisms) values ranged from 0.06 to 1025 mg/l. While a survey of the literature showed that the acute toxicity of these chemicals appeared negligible, our results clearly revealed the potential chronic effects of some of them to this organism occupying an important trophic level in the aquatic ecosystems. The usefulness of this kind of test to better estimate the adverse effects of glycol ethers was stressed.

QSAR modeling of the adult and developmental toxicity of glycols, glycol ethers and xylenes to Hydra attenuata.

Autocorrelation descriptors encoding lipophilicity, molar refractivity, the H-bonding acceptor ability and H-bonding donor ability of the molecules were used to describe glycols, glycol ethers, and xylenes characterized by their adult and developmental toxicities to Hydra attenuata. A PLS regression analysis was employed to derive a QSAR model allowing to simulate both endpoints. Comparisons were made with classical regression analyses using the 1-octanol/water partition coefficient as molecular descriptor.

PLS-QSAR of the adult and developmental toxicity of chemicals to Hydra attenuata.

Autocorrelation descriptors encoding lipophilicity, molar refractivity, the H-bonding acceptor and donor ability of the molecules and also indicator variables were used to describe 30 organic chemicals characterized by their adult and developmental toxicities to Hydra attenuata. A PLS regression analysis was successfully employed to derive a QSAR model allowing the simulation of both endpoints. Comparisons were made with orthogonal regression analysis and different nonlinear regression analyses.

Two-step purification method of vitellogenin from three teleost fish species: rainbow trout (Oncorhynchus mykiss), gudgeon (Gobio gobio) and chub (Leuciscus cephalus).

A two-step purification protocol was developed to purify rainbow trout (Oncorhynchus mykiss) vitellogenin (Vtg) and was successfully applied to Vtg of chub (Leuciscus cephalus) and gudgeon (Gobio gobio). Capture and intermediate purification were performed by anion-exchange chromatography on a Resource Q column and a polishing step was performed by gel permeation chromatography on Superdex 200 column. This method is a rapid two-step purification procedure that gave a pure solution of Vtg as assessed by silver staining electrophoresis and immunochemical characterisation.

Uptake and elimination of lindane by Lymnaea palustris (Mollusca: Gastropoda): a pharmacokinetic approach.

The uptake and elimination of lindane by adult Lymnaea palustris (Müller) were studied using a static contamination system. First-order one- and two-compartment models were used to quantitatively describe these phenomena. The accumulation of residues was triphasic and the observed steady-state bioconcentration factor lay between 36.8 and 56.4 but did not significantly depend on the initial lindane concentration (6, 60, and 600 micrograms liter-1). Accumulation was inferior to that observed for other aquatic organisms and this was attributed to the relatively low lipid content of L. palustris tissues (mean of 0.81 +/- 0.17% of fresh weight). The transfer of snails to lindane-free water after 72 hr of exposure was followed by a biphasic elimination of residues with a half-life of 0.7 hr in the central compartment and of 130.2 hr in the peripheral compartment. Additional experiments showed that the residues enter the snails through the foot and are afterward stocked within the visceral mass which contains approximately three times more lipids than the foot (1.03 +/- 0.13% of fresh weight vs 0.37 +/- 0.03%).