The acute toxicity of chlorobenzenes for earthworms (Eisenia andrei) in different exposure systems

Earthworms (Eisenia andrei) were exposed to different concentrations of two chlorobenzenes (1,2,3-trichloro- and pentachlorobenzene) using different routes of administration: in water, in soil, via food and on filter paper. Except for the contact paper toxicity test, lethal body burdens (LBBs) measured in these different exposure systems were similar for the same test chemical. LBBs for 1,2,3-trichlorobenzene varied between 0.44 and 2.1 μmol/g and for pentachlorobenzene between 1.29 and 2.34 μmol/g. These values correspond with literature data for fish. For 1,4-dichloro- and 1,2,3,4-tetrachlorobenzene LBBs measured with the contact paper toxicity test were 0.33 and 3.2 μmol/g, respectively. Exposure to hexachlorobenzene and hexabromobenzene using the contact toxicity test did not result in death within 48 hours.     

Little effect of excessive biofouling on the uptake of organic contaminants by semipermeable membrane devices

The effects of water flow rate and antifouling agents on the extent of biofouling and on the uptake of non-polar organic contaminants by semipermeable membrane devices (SPMDs) were studied during four field experiments in the Western Wadden Sea. Biofouling densities on the sampler surface ranged from 0.3 to 16 g dry weight dm⁻². Water sampling rates were estimated from the dissipation rates of performance reference compounds (PRCs). The antifouling agents Irgarol and capsaicin (33 mg per ml triolein) had no noticeable effect on the extent of fouling, and caused only a 5–10% increase in the absorbed amounts. Enhanced flow rates had only a minimal effect on the amount of biofouling, but caused the water sampling rates to increase by a factor of 1.2–2. Increases in PRC-derived sampling rates were reflected by increases in the absorbed amounts for compounds that were in the linear uptake stage of the sampling process. The results imply (1) that extreme biofouling does not always result in reduced sampling rates, (2) that extreme biofouling does not preclude the existence of flow effects on the sampling rates, and (3) that differences in uptake rates are quantitatively reflected by the dissipation rates of PRCs.     

Polycyclic aromatic hydrocarbons and hydroxylated metabolites in the muscle tissue of Eurasian perch (Perca fluviatilis) through dietary exposure during a 56-day period

Eurasian perch (Perca fluviatilis) was exposed trophically to phenanthrene, pyrene and benzo[a]pyrene. Accumulation kinetics in the muscle tissue of parent PAHs and hydroxylated metabolites were established for 56 days at 3 levels of exposure (0, 100 and 500 μg/kg BW). Benzo[a]pyrene and 3-hydroxy-benzo[a]pyrene were not detected in the muscles. During exposure, there was an increase in phenanthrene, pyrene and their hydroxylated metabolites in the muscle tissue. Low transfer to muscle tissue was observed at equilibrium for phenanthrene (4.4 ± 0.6% and 2.7 ± 0.8%) and pyrene (1.0 ± 0.2% and 0.33 ± 0.09%), depending on the concentrations in the spiked feed.     

Pesticide pressure and fish farming in barrage pond in northeastern France. Part III: how management can affect pesticide profiles in edible fish?

Purpose

The quality of fish produced in ponds needs to be ensured. Indeed, pond is often strongly connected to an agricultural watershed, and pesticides are a main health and environmental issue of concern. In this context, the purpose of this study is to highlight the management practices which could impact the pesticide contamination profiles in edible fish and to give recommendations for better practices.

Methods

A principal component analysis, coupled to a hierarchical cluster analysis, was performed to evaluate temporal evolution of contamination profiles and to assess variability among fish species and among sites according to watershed characteristics. The explicative variables correspond to muscular concentrations of pesticides (azoxystrobin, clomazone, diflufenican, carbendazim, isoproturon, metazachlor, napropamid) in three species of fish (Perca fluviatilis, Cyprinus carpio and Rutilus rutilus), caught in five ponds during two sampling campaigns. Management data are added variables in order to discuss about parameters suspected to be implicated in the contamination profiles recorded.

Results

This work shows that high amounts of pesticides applied, short crop rotation durations and bare soil practices led to contamination of sediments and fish and were associated to a “bad” management of watershed. Breeding fish that had low masses and establishing the fishing period at the end of winter seemed to be “bad” management of pond. Aggravating topological parameters were big watershed coupled to small pond and high proportions of sand soils in the watershed.

Conclusions

Reducing amounts of pesticide used (e.g. policy agency plans, farmer acceptance), favouring long-term rotations and inter-cultures, adapting pond creation and fish farming practices to watershed management and topography all could reduce pesticide levels in edible fish and contribute to a better sustainability of the extensive fish farming in pond.     

Bioavailability in soil or sediment: exposure of different organisms and approaches to study it

Soil and benthic organisms may be exposed to contaminants via different routes: (pore) water, soil or sediment, and food. Depuration of the contaminant from the organisms may take place via the same routes and, additionally, via biotransformation, reproduction, etc. Whereas uptake from and depuration to water can be predicted well, predictions for soil or sediment are less accurate. One of the reasons may be the reduced bioavailability of the contaminant in the soil or sediment. In biomimetic approaches, such as solid phase micro-extraction (SPME) or measurements with C18-discs, the freely dissolved concentration in the (pore) water is determined. The SPME-fiber or C18-disc may serve as a surrogate organism, but sometimes underestimates, and sometimes overestimates bioavailability. The soil (or sediment) availability ratio (SARA) method, that uses organisms to study the uptake of freshly added and 'aged' chemicals, is proposed to study the magnitude of the reduction in bioavailability. SARA also includes the organism-specific exposure and depuration routes.     

Disposition, elimination and enzyme induction of 1,2,3,7,8-PnCDD, 1,2,3,6,7,8-HxCDD and 2,3,4,7,8-PnCDF in the liver of the mouse after a single oral dose

The disposition, elimination and cytochrome P450 related enzyme induction of 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PnCDD), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD) and 2,3,4,7,8-pentachlorodibenzofuran (PnCDF) were studied in the liver of the male C57BL/6 mouse. Elimination of all compounds from the liver followed first-order kinetics. Half-lives for PnCDD, HxCDD and PnCDF were 15, 52 and 65 days respectively. 7-Ethoxyresorufin-O-deethylation (EROD) activity in the livers of the treated animals showed a good correlation with the liver tissue concentrations but the slopes of these liver concentration-response curves were not equal for all three compounds.     

Habitat-induced changes in song consistency affect perception of social status in male chickadees

The ability of male black-capped chickadees to maintain consistent internal structure between successive iterations of their songs is affected by both their social rank and the quality of their habitat. Lab studies reveal that female chickadees discriminate between songs of dominant and subordinate males, which vary in acoustic structure. We investigate whether males also rely on acoustic structure to assess rival quality during agonistic interactions, and whether habitat-induced differences in song consistency affect the perception of male rank. We conducted a playback experiment to simulate territorial intrusions by dominant, stimuli males into the territories of dominant, subject males; stimuli males were recorded either in low-quality (young forest) or high-quality (mature forest) habitats. Stimuli from low-quality habitat had lower song consistency than those from high-quality habitats, despite being recorded from males of equivalent social rank. Subject males for playbacks (also socially dominant males) were chosen from either habitat type. Subject males in mature forest responded less to young-forest stimuli compared to mature-forest stimuli, despite the stimuli in both cases being recorded from dominant males. Conversely, male subjects in young forest did not differentiate between stimuli, but their response to both stimuli was lower than that of mature-forest subject males to mature-forest stimuli. We demonstrate that the ability to maintain internal song structure in the black-capped chickadee constitutes a signal that appears to be used by males to assess the level of threat of intruders, and that this perception is affected by habitat from which the stimulus males were recorded.