Introduction The effect of oceanic CO₂ sequestration was examined exposing a deep-sea bacterium identified as Vibrio alginolyticus (9NA) to elevated levels of carbon dioxide and monitoring its growth at 2,750 psi (1,846 m depth). Findings The wild-type strain of 9NA could not grow in acidified marine broth below a pH of 5. The pH of marine broth did not drop below this level until at least 20.8 mM of CO₂ was injected into the medium. 9NA did not grow at this CO₂ concentration or higher concentrations (31.2 and 41.6 mM) for at least 72 h. Carbon dioxide at 10.4 mM also inhibited growth, but the bacterium was able to recover and grow. Exposure to CO₂ caused the cell to undergo a morphological change and form a dimple-like structure. The membrane was also damaged but with no protein leakage.

Background, aim, and scope Impacts on the reproductive health of wild fish are thought to be suitable early-warning tools indicating contamination of surface waters with endocrine-disrupting compounds. Ecotoxicological assessment of these field observations depends on the availability of reliable biomarkers to enable a discrimination of natural variations of reproductive functions from anthropogenic impacts. Materials and methods Roach and perch were caught at eight sampling sites by electrofishing twice a year in summer (July-September) and late autumn/winter (November-December) over a 2-year period. The sites are characterized by different degrees of anthropogenic impact and are situated within the greater Upper Rhine catchment. Age growths, parasitization and gonadal histology of more than 3,000 fish were examined. Results The two dominant fish species in German surface waters perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) differ considerably regarding their suitability for biomonitoring. Even in pristine habitats, perch show several variants of sex differentiation in terms of (1) the time of first sexual maturation, (2) the course of seasonal gonadal recrudescence, and (3) the occurrence of heterologous germ cells (testes ova). A statistically significant elevated proportion of males were observed in fish obtained from a TBT-contaminated marina and suppression of gonadal ripening was observed in females caught in a sewage-contaminated brook. Both effects appear to be due to chemical contamination. The only “natural” alteration of sex differentiation in roach was related to parasitization with Ligula intestinalis (Eucestoda, Pseudophyllidea). Other deviations from the normal pattern of sex differentiation were (1) suppression of ovarian ripening and (2) asynchronic seasonal gonadal recrudescence. These are strong indicators of an anthropogenically induced impact on reproductive health. Feminization phenomena were not observed at either the individual or the population level. Discussion Interpretation of field monitoring results concerning reproductive health requires large numbers of samples and detailed knowledge of the natural plasticity of sex differentiation in the species under investigation. A better understanding of the mechanisms underlying the plasticity of sex differentiation in perch is indispensable to enable perch to be used as a bioindicator. Conclusions Deviation from the strict and probably endogenous control of sex differentiation in roach is a strong and unequivocal warning signal. Recommendations and perspectives The subject of fish monitoring should be addressed in the context of a broader spectrum of potential risks. Seasonal and ontogenetic integrity of gonadal development and recrudescence are potent biomarkers, provided the natural process is well documented for the species under investigation.

The introduction of glyphosate-tolerant (GT) crops is expected to mitigate the environmental contamination by herbicides because glyphosate is less persistent and toxic than the herbicides used on non-GT crops. Here, we compared the environmental balances of herbicide applications for both crop types in three French field trials. The dynamic of herbicides and their metabolites in soil, groundwater and air was simulated with PRZM model and compared to field measurements. The associated impacts were aggregated with toxicity potentials calculated with the fate and exposure model USES for several environmental endpoints. The impacts of GT systems were lower than those of non-GT systems, but the accumulation in soils of one glyphosate metabolite (aminomethylphosphonic acid) questions the sustainability of GT systems. The magnitude of the impacts depends on the rates and frequency of glyphosate application being highest for GT maize monoculture and lowest for combination of GT oilseed rape and non-GT sugarbeet crops. The impacts of herbicide applications on glyphosate-tolerant crops could be higher than expected due to the accumulation of a metabolite of glyphosate in soils.

There is currently a lack of ecotoxicity tests adapted to earthworm species of higher ecological relevance and whose endpoints could be directly related to their ecological role in the soil. We propose a new and relatively simple ecotoxicity test based on the estimation of cast production (CP) by Lumbricus terrestris under laboratory conditions. CP was found to be linearly correlated to earthworm biomass and to be greatly influenced by soil water content. Azinphos-methyl had no effect on CP at all the concentrations tested. Significant decreases were observed at the normal application rate for other pesticides with (imidacloprid, carbaryl, methomyl) or without (ethyl-parathion and chlorpyrifos-ethyl) a clear concentration–effect response. For the highest concentration tested, reduction in CP varied between 35 and 67%. CP is straightforward and rapidly measured and ecologically meaningful. We thus believe it to be of great use as an endpoint in ecotoxicity testing.

An increasing amount of scientific information is available on water pollution and its effect. Water pollution management for pollution control seldom considers the scientific information. The main objective of this paper is to review the water pollution management in Bangkok and link the entire process to the cause and effects of water pollution. Existing approaches for water pollution control primarily focuses on enforcing various standards. Respective local authorities in Bangkok have also set their own surface water quality requirement. However, the entire management approach requires further analysis in line with the present situation. This paper attempts to review the entire management approach and suggests reduction strategies, control measures/treatment systems and some preferred solutions to the water pollution management. It also covers other important measures for control. The conclusion proposes some policy recommendations on reducing pollution through effect management approach.

We present here the effects of ambient ozone (O3)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O3 treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O3 (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated ci/ca ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1, 5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O3 tolerance and might be interpreted as part of Aleppo pine acclimation response to O3.

In Réunion Island, expanding human populations, urbanization and agriculture during the last 50 years have all contributed to a steady increase in the level of nitrates in drinking water. Various nitrate point sources are responsible for the nitrate contamination around the island including chemical fertilizers, animal effluent applied to pasture and crops, and urban waste such as sewage and domestic waste water. In terms of agricultural fertilizers, pig effluent is the most widely used, but the cumulative effects of slurry applications on soil water and groundwater are unknown. Our objectives were (1) to characterize and follow in situ the fate of nitrogen through the subsurface after application of pig effluent onto a cultivated soil using stable nitrate isotopes, 15N and 18O, and (2) to compare the isotopic signatures of Réunion Island's principal aquifers with results from the experimental site to infer potential contamination sources. The study was conducted on an experimental field site planted with maize in the western part of Réunion Island during the rainy season. A control site with no fertilizer application to the maize was compared with the investigation site which had pig effluent applied once a year. The site which had pig effluent applied over one year had an average maximum surface soil water 15N-NO-3 value of +9.0% at 0.45 m depth. This signature was significantly more enriched in 15N than the corresponding subsurface soil water 15N-NO? 3 value of +3.8%_ at 10 m depth. The control site average maximum surface soil water 15N-NO? 3 value of +3.6%_ at 0.45 m is similar to the subsurface pig effluent application plot. This indicates that nitrates derived from pig effluent have not reached 10 m depth in the subsurface, even though over the last 18 months this site was subjected to two effluent applications, each around 200 kg N ha?1, and more than 1900 mm of rain, more than half of which drains directly into the root zone. This slow migration shows that mobilization of nitrates through cultivated soil can take many tens of years before infiltrating and contaminating the saturated zone situated at several tens, and in places, hundreds of meters depth. On an island-wide scale, an isotopic assessment of nitrates from the experimental site's soil water and other drinking water wells highlights a nitrogenous contaminations derived primarily from urban and/or agriculture via effluent application. (Résumé d'auteur)