Chlordecone is a toxic organochlorine insecticide that was used in banana plantations until 1993 in the French West Indies. This study aimed at assessing the potential of near infrared reflectance spectroscopy (NIRS) for determining chlordecone content in Andosols, Nitisols and Ferralsols from Martinique. Using partial least square regression, chlordecone content conventionally determined through gas chromatography-mass spectrometry could be correctly predicted by NIRS (Q² = 0.75, R² = 0.82 for the total set), especially for samples with chlordecone content <12 mg kg⁻¹ or when the sample set was rather homogeneous (Q² = 0.91, R² = 0.82 for the Andosols). Conventional measures and NIRS predictions were poorly correlated for chlordecone content >12 mg kg⁻¹, nevertheless ca. 80% samples were correctly predicted when the set was divided into three or four classes of chlordecone content. Thus NIRS could be considered a time- and cost-effective method for characterising soil contamination by chlordecone. Soil content in chlordecone, an organochlorine insecticide, can be determined time- and cost-effectively using near infrared reflectance spectroscopy (NIRS).

This study discusses the operating variables for removal of metals from soils using EDTA, including the type of EDTA, reaction time, solution pH, dose, temperature, agitation, ultrasound and number of extractions. For As, Cd, Cu, Pb and Zn, the removal efficiency order was: H4-EDTA > Na2EDTA > (NH4)2EDTA. At low EDTA concentrations the removal increased progressively with increasing dose while above 0.4 mmol/g only small increases in extraction efficiency were observed. EDTA induced a two-step process including a rapid desorption within the first hour, and a gradual release in the following hours. The extraction efficiency of metals decreased with increasing pH in the range of 2-10. Consecutive extractions using low concentrations were more effective than a single extraction with concentrated EDTA if the same dose of EDTA was used. Consecutive extractions using low concentrations are more effective than a single extraction with concentrated EDTA if the same dose of EDTA is used.

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC50) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands.

Concentrations of organic contaminants in common productive soils based on the total soil mass give a misleading account of actual contamination effects. This is attributed to the fact that productive soils are essentially water-saturated, with the result that the soil uptake of organic compounds occurs principally by partition into the soil organic matter (SOM). This report illustrates that the soil contamination intensity of a compound is governed by the concentration in the SOM (Com) rather than by the concentration in whole soil (Cs). Supporting data consist of the measured levels and toxicities of many pesticides in soils of widely differing SOM contents and the related levels in in-situ crops that defy explanation by the Cs values. This SOM-based index is timely needed for evaluating the contamination effects of food crops grown in different soils and for establishing a dependable priority ranking for intended remediation of numerous contamination sites. The concentration of an organic compound in soil based on the entire soil mass is not a proper measure of its contamination intensity.

In this study, we report that silver ions (Ag+) from the oxidative dissolution of silver engineered nanoparticles (Ag-ENs) determined the EN toxicity to the marine diatom Thalassiosira weissflogii. Most of the Ag-ENs formed non-toxic aggregates (>0.22 μm) in seawater. When the free Ag+ concentration ([Ag+]F) was greatly reduced by diafiltration or thiol complexation, no toxicity was observed, even though the Ag-ENs were better dispersed in the presence of thiols with up to 1.08 x 10⁻⁵ M Ag-ENs found in the <0.22 μm fraction, which are orders of magnitude higher than predicted for the natural aquatic environment. The secretion of polysaccharide-rich algal exopolymeric substances (EPS) significantly increased at increasing [Ag+]F. Both dissolved and particulate polysaccharide concentrations were higher for nutrient-limited cells, coinciding with their higher Ag+ tolerance, suggesting that EPS may be involved in Ag+ detoxification. Ag-ENs were found to only have indirect toxic effects on marine phytoplankton as a result of their rapid Ag+ release.

Organic phosphorus (P) fractions in surface sediments from a large shallow, eutrophic Lake Taihu, China, were extracted with 0.1 M NaOH after pre-treatment of the sediments with a solution composed of 0.1 M EDTA and 2% (w/v) Na₂S₂O₄. Composition of organic P in the extracts was then characterized by ³¹P nuclear magnetic resonance spectroscopy (³¹P NMR). Several P species, including phosphonates, orthophosphate, orthophosphate monoesters, phospholipids, DNA, pyrophosphate and polyphosphate, were detected in the NaOH extracts. The proportion of extracted organic P to total P in sediments was negatively correlated with total P in the water column, as were the proportions for orthophosphate monoesters and DNA. This implies that the majority of organic P in surface sediments is likely stabilized in some way, and does not directly contribute to the internal loading of P from sediments. Organic phosphorus species in surface sediments of Lake Taihu.

Although the use of tributyltin in antifouling paints has been banned, this compound is still a serious pollutant of the marine environment. This paper describes a unique study in which European flounder (Platichthys flesus) were chronically (8 months) exposed to bis(tri-n-butyltin)oxide (TBTO) in the water under controlled laboratory conditions. Residue levels in selected tissues (liver, muscle) and general health status indices were measured and the effects on several organs (gills, liver, mesonephros, ovary/ testis, spleen, and gastrointestinal tract) were examined histopathologically. Additionally, morphometric analysis of the thymus was performed. The major finding is that exposure of flounder to 5 mg TBTO/l over a period of 8 months, resulting in body burdens comparable to high field levels, induced significant reduction of thymus volume, possibly affecting immunocompetence of the animals. Chronic exposure of European flounder to tributyltin is therefore likely to affect the general health status of this species in heavily polluted aquatic environments.

A database has been developed that demonstrates experimental evidence of hormesis. It includes information from a broad range of biological models, including plants, and information on study design, dose-response features, and physical/chemical properties of the agents. An assessment of plant hormetic dose responses is presented based on greater than 3000 plant endpoints. Plant hormetic dose responses were observed for numerous endpoints including disease incidence, reproductive indices, mutagenic endpoints, various metabolic parameters, developmental processes, and a range of growth indicators. Quantitative features of these dose responses typically display a maximum stimulatory response less than two-fold greater than controls and a width of the stimulatory response usually less than 10-fold in dose range. The database establishes that hormetic dose responses commonly occur in plants, are broadly generalizable, and have quantitative features similar to hormetic dose responses found for animals. Hormesis commonly occurs within plant species.

The study was prompted to characterize the B-type esterase activities in the terrestrial snail Xeropicta derbentina and to evaluate its sensitivity to organophosphorus and carbamate pesticides. Specific cholinesterase and carboxylesterase activities were mainly obtained with acetylthiocholine (Km = 77.2 mM; Vmax = 38.2 mU/mg protein) and 1-naphthyl acetate (Km = 222 mM, Vmax = 1095 mU/mg protein) substrates, respectively. Acetylcholinesterase activity was concentration-dependently inhibited by chlorpyrifos-oxon, dichlorvos, carbaryl and carbofuran (IC50 = 1.35 x 10-5-3.80 x 10-8 M). The organophosphate-inhibited acetylcholinesterase activity was reactivated in the presence of pyridine-2-aldoxime methochloride. Carboxylesterase activity was inhibited by organophosphorus insecticides (IC50 = 1.20 x 10-5-2.98 x 10-8 M) but not by carbamates. B-esterase-specific differences in the inhibition by organophosphates and carbamates are discussed with respect to the buffering capacity of the carboxylesterase to reduce pesticide toxicity. These results suggest that B-type esterases in X. derbentina are suitable biomarkers of pesticide exposure and that this snail could be used as sentinel species in field monitoring of Mediterranean climate regions. Characterization of the B-type esterases in the terrestrial snail Xeropicta derbentina in order to evaluate pesticide exposure.

Trifolium repens and Lolium perenne were exposed as both monocultures and two-species mixtures to an episodic rural ozone regime in large, well-watered containers within solardomes for 12 weeks. There were reductions in biomass for T. repens, but not L. perenne, and the proportion of T. repens decreased in ozone-exposed mixtures compared to the control. In addition, leaf biomass of T. repens was maintained at the expense of biomass partitioning to the stolons. The decreased growth corresponded with decreased photosynthetic capacity for T. repens, however, by the end of the exposure there was also decreased photosynthetic capacity of L. perenne, a species previously considered insensitive to ozone. The observed decreases in photosynthetic efficiency and capacity in elevated ozone indicate that the ability of such ubiquitous vegetation to act as a sink for atmospheric carbon may be reduced in future climates. Ozone causes changes in biomass partitioning, and photosynthetic efficiency and capacity that could decrease the ability of plants to act as a carbon sink.