Effects of river water and salinity on the toxicity of deltamethrin to freshwater shrimp, cladoceran, and fish

Deltamethrin is a pyrethroid insecticide used extensively to control invertebrate pests on cotton and other crops. It is acutely toxic to nontarget aquatic organisms, but existing toxicity data are mostly from toxicity tests using purified laboratory water that differs greatly from the turbid, high-conductivity rivers in the cotton-growing regions of Australia. The aim of this study was to determine whether the water quality variables conductivity, suspended particles, and dissolved organic matter alter the toxicity of deltamethrin to freshwater crustaceans and a fish. We tested three Australian native species: a cladoceran (Ceriodaphnia cf. dubia), a freshwater shrimp (Paratya australiensis), and larvae of the eastern rainbow fish (Melanotaenia duboulayi). Conductivity of the test solutions ranged from 200 to 750 μS/cm, but such changes did not modify the toxicity of deltamethrin to any of the test species. However, the toxicity of deltamethrin to C. cf. dubia and P. australiensis in river water was significantly decreased (1.8-fold to 6.3-fold reduction) compared to that in laboratory water. Variability in the toxicity data limited our ability to detect differences between laboratory and river water for M. duboulayi. Despite reductions in toxicity in natural waters, deltamethrin remained highly toxic [all L(E)C50 values <0.26 μg/L] to all organisms tested; thus, further investigation of the hazard of deltamethrin is warranted. © 2008 Springer Science+Business Media, LLC

Identification strategy for unknown pollutants using high-resolution mass spectrometry: Androgen-disrupting compounds identified through effect-directed analysis

Effect-directed analysis has been applied to a river sediment sample of concern to identify the compounds responsible for the observed effects in an in vitro (anti-)androgenicity assay. For identification after non-target analysis performed on a high-resolution LTQ-Orbitrap, we developed a de novo identification strategy including physico-chemical parameters derived from the effect-directed analysis approach. With this identification strategy, we were able to handle the immense amount of data produced by non-target accurate mass analysis. The effect-directed analysis approach, together with the identification strategy, led to the successful identification of eight androgen-disrupting compounds belonging to very diverse compound classes: an oxygenated polyaromatic hydrocarbon, organophosphates, musks, and steroids. This is one of the first studies in the field of environmental analysis dealing with the difficult task of handling the large amount of data produced from non-target analysis. The combination of bioassay activity assessment, accurate mass measurement, and the identification and confirmation strategy is a promising approach for future identification of environmental key toxicants that are not included as priority pollutants in monitoring programs

Environmental occurrence, analysis, and toxicology of toxaphene compounds.

Toxaphene production, in quantities similar to those of polychlorinated biphenyls, has resulted in high toxaphene levels in fish from the Great Lakes and in Arctic marine mammals (up to 10 and 16 microg g-1 lipid). Because of the large variabiliity in total toxaphene data, few reliable conclusions can be drawn about trends or geographic differences in toxaphene concentrations. New developments in mass spectrometric detection using either negative chemical ionization or electron impact modes as well as in multidimensional gas chromatography recently have led researchers to suggest congener-specific approaches. Recently, several nomenclature systems have been developed for toxaphene compounds. Although all systems have specific advantages and limitations, it is suggested that an international body such as the International Union of Pure and Applied Chemistry make an attempt to obtain uniformity in the literature. Toxicologic information on individual chlorobornanes is scarce, but some reports have recently appeared. Neurotoxic effects of toxaphene exposure such as those on behavior and learning have been reported. Technical toxaphene and some individual congeners were found to be weakly estrogenic in in vitro test systems; no evidence for endocrine effects in vivo has been reported. In vitro studies show technical toxaphene and toxaphene congeners to be mutagenic. However, in vivo studies have not shown genotoxicity; therefore, a nongenotoxic mechanism is proposed. Nevertheless, toxaphene is believed to present a potential carcinogenic risk to humans. Until now, only Germany has established a legal tolerance level for toxaphene--0.1 mg kg-1 wet weight for fish

Recent advances and future directions in soils and sediments research

In 2010, the Journal of Soils and Sediments (JSS) reached a milestone: its 10th anniversary. This prompted us to think about where the academic community has come in its understanding of the behaviour of soils and sediments within landscapes. The rapid growth of the journal and the number of papers published in it, and other related journals, suggests, probably correctly, that there is much interest in the topics of soils and sediments. In the January 2011 editorial (Xu and Owens 2011), we presented an overview of some of the main developments in the past 10 years and provided some future directions of JSS for 2011 and beyond. In that editorial we indicated that a more comprehensive editorial would be published in the journal on the recent advances and future directions of soils and sediments research. The following sections are presented to fulfill this commitment and start a dialogue with the journal subject editors, authors and readers in these important areas of soils and sediments research. The dawn of the next decade of JSS is a good time to reflect on progress to-date and, more importantly, to consider where research needs to go in the years ahead; a time of rapid environment change, a time of rapid population growth, and a time when society is increasingly looking to science to provide the understanding (and solutions) to the problems that we face.No Full Tex

Trophic magnification of organic chemicals: A global synthesis

Production of organic chemicals (OCs) is increasing exponentially, and some OCs biomagnify through food webs to potentially toxic levels. Biomagnification under field conditions is best described by trophic magnification factors (TMFs; per trophic level change in log-concentration of a chemical) which have been measured for more than two decades. Syntheses of TMF behavior relative to chemical traits and ecosystem properties are lacking. We analyzed >1500 TMFs to identify OCs predisposed to biomagnify and to assess ecosystem vulnerability. The highest TMFs were for OCs that are slowly metabolized by animals (metabolic rate kM 0.2 day-1). This probabilistic model provides a new global tool for screening existing and new OCs for their biomagnification potential.No Full Tex

Does lake size affect concentrations of atmospherically derived polychlorinated biphenyls in water, sediment, zooplankton, and fish?

Concentrations of 90 polychlorinated biphenyl (PCB) congeners were determined in water, surface sediment, zooplankton, and fish collected from eight remote lakes in northwestern Ontario. The lakes vary in surface area from 0.2 to 4848 km2 and receive PCBs only from atmospheric deposition. Systematic differences with lake size in concentrations of Sigma PCBs or in congener distributions were not detected in any of the sample sets, except sediment. Concentrations of Sigma PCBs in surface sediments increased in the largest lakes when expressed on an organic carbon basis because carbon content decreased with lake size. In general, there were few strong correlations among PCB concentrations in water, sediment, or biota and physical, chemical, or biotic conditions at the time of sampling. There was no strong biomagnification of PCBs up the food chain from plankton to piscivorous fish. The results of this study are surprising because many factors that are thought to affect PCB dynamics and bioaccumulation varied systematically with lake size (water temperature, dissolved organic carbon concentrations, particle residence times, food chain length, algal productivity). </jats:p

Trends of Chlorinated Organic Contaminants in Great Lakes Trout and Walleye from 1970 to 1998

Levels of chlorinated organic contaminants in predator fish have been monitored annually in each of the Great Lakes since the 1970s. This article updates earlier reports with data from 1991 to 1998 for lake trout ( Salvelinus namaycush ) and (Lake Erie only) walleye ( Sander vitreus ) to provide a record that now extends nearly 30 years. Whole fish were analyzed for a number of industrial contaminants and pesticides, including polychlorinated biphenyls (PCBs), dichloro-diphenyl-trichloroethane (DDT), dieldrin, toxaphene, and mirex, and contaminant trends were quantified using multicompartment models. As in the past, fish from Lakes Michigan, Ontario, and Huron have the highest levels of PCBs, DDT, and dieldrin; Superior has the highest levels of toxaphene; and Ontario has the highest levels of mirex. In the period after curtailment of chemical use, concentrations rapidly decreased, represented by relatively short half-lives from approximately 1 to 9 years. Although trends depend on both the contaminant and the lake, in many cases the rate of decline has been decreasing, and concentrations are gradually approaching an irreducible concentration. For dioxin-like PCBs, levels have not been decreasing during the most recent 5-year period (1994 to 1998). In some cases, the year-to-year variation in contaminant levels is large, mainly because of food-web dynamics. Although this variation sometimes obscures long-term trends, the general pattern of a rapid decrease followed by slowing or leveling-off of the downward trend seems consistent across the Great Lakes, and future improvements of the magnitude seen in the 1970s and early 1980s likely will take much longer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48086/1/244_2005_Article_1007.pd