Organochlorine pesticides and polychlorinated biphenyls (PCBs) in eggs of red-legged frogs (Rana aurora) and northwestern salamanders (Ambystoma gracile) in an agricultural landscape

Organochlorine pesticides were widely used in the past in Sumas Prairie, British Columbia, Canada. In the 1990s, the hatching success of amphibians from agricultural sites was significantly depressed in the Sumas Prairie compared to reference sites. Therefore, in this study, organochlorine pesticides and polychlorinated biphenyls (PCBs) were measured in eggs of red-legged frogs (Rana aurora) and northwestern salamanders (Ambystoma gracile) from the Sumas Prairie. Egg masses were sampled from three agricultural sites that were exposed to agricultural runoff, and three reference sites that had lower agricultural runoff exposures. Not only was there little difference in contamination between agricultural and reference sites, but the levels of pesticides and PCBs found were lower than the concentrations reported to cause developmental or behavioural problems in amphibians.     

Loss of PM2.5 nitrate from filter samples in central California

Evaporative loss of particulate matter (with aerodynamic diameter < 2.5 microm, [PM2.5]) ammonium nitrate from quartz-fiber filters during aerosol sampling was evaluated from December 3, 1999, through February 3, 2001, at two urban (Fresno and Bakersfield) and three nonurban (Bethel Island, Sierra Nevada Foothills, and Angiola) sites in central California. Compared with total particulate nitrate, evaporative nitrate losses ranged from < 10% during cold months to > 80% during warm months. In agreement with theory, evaporative loss from quartz-fiber filters in nitric acid denuded samplers is controlled by the ambient nitric acid-to-particulate nitrate ratio, which is determined mainly by ambient temperature. Accurate estimation of nitrate volatilization requires a detailed thermodynamic model and comprehensive chemical measurements. For the 14-month average of PM2.5 acquired on Teflon-membrane filters, measured PM2.5 mass was 8-16% lower than actual PM2.5 mass owing to nitrate volatilization. For 24-hr samples, measured PM2.5 was as much as 32-44% lower than actual PM2.5 at three California Central Valley locations.     

Direct-push geochemical profiling for assessment of inorganic chemical heterogeneity in aquifers

Discrete-depth sampling of inorganic groundwater chemistry is essential for a variety of site characterization activities. Although the mobility and rapid sampling capabilities of direct-push techniques have led to their widespread use for evaluating the distribution of organic contaminants, complementary methods for the characterization of spatial variations in geochemical conditions have not been developed. In this study, a direct-push-based approach for high-resolution inorganic chemical profiling was developed at a site where sharp chemical contrasts and iron-reducing conditions had previously been observed. Existing multilevel samplers (MLSs) that span a fining-upward alluvial sequence were used for comparison with the direct-push profiling. Chemical profiles obtained with a conventional direct-push exposed-screen sampler differed from those obtained with an adjacent MLS because of sampler reactivity and mixing with water from previous sampling levels. The sampler was modified by replacing steel sampling components with stainless-steel and heat-treated parts, and adding an adapter that prevents mixing. Profiles obtained with the modified approach were in excellent agreement with those obtained from an adjacent MLS for all constituents and parameters monitored (Cl, NO(3), Fe, Mn, DO, ORP, specific conductance and pH). Interpretations of site redox conditions based on field-measured parameters were supported by laboratory analysis of dissolved Fe. The discrete-depth capability of this approach allows inorganic chemical variations to be described at a level of detail that has rarely been possible. When combined with the mobility afforded by direct-push rigs and on-site methods of chemical analysis, the new approach is well suited for a variety of interactive site-characterization endeavors.     

A review of perceived diversity in teams: Does how members perceive their team's composition affect team processes and outcomes?

In this paper, we review the growing literature on perceived diversity in teams. We aim to clarify the construct of perceived diversity and organize the findings in this emergent line of research. To do so, we develop a framework integrating research emerging on perceived diversity from across several different research fields. We propose that the nature of perceived diversity and its effects can be best understood by identifying the focal point of the diversity perceptions being studied: perceptions of self‐to‐team dissimilarity, of subgroup splits, and of group heterogeneity. Our review concludes that perceived self‐to‐team dissimilarity and perceived subgroup splits mostly have been linked to negative effects for individuals and groups, whereas perceived group heterogeneity has been shown to exert both positive and negative effects on group outcomes. Our review also draws attention to the problem that research on perceived diversity varies not only in definitions and conceptualizations, but also in the methodological approaches towards operationalizing perceived diversity. We conclude by discussing potential areas for future research. Copyright © 2014 John Wiley & Sons, Ltd.     

Role of complex organic arsenicals in food in aggregate exposure to arsenic

For much of the world''s population, food is the major source of exposure to arsenic. Exposure to this non-essential metalloid at relatively low levels may be linked to a wide range of adverse health effects. Thus, evaluating foods as sources of exposure to arsenic is important in assessing risk and developing strategies that protect public health. Although most emphasis has been placed on inorganic arsenic as human carcinogen and toxicant, an array of arsenic-containing species are found in plants and animals used as foods. Here, we 2evaluate the contribution of complex organic arsenicals (arsenosugars, arsenolipids, and trimethylarsonium compounds) that are found in foods and consider their origins, metabolism, and potential toxicity. Commonalities in the metabolism of arsenosugars and arsenolipids lead to the production of di-methylated arsenicals which are known to exert many toxic effects. Evaluating foods as sources of exposure to these complex organic arsenicals and understanding the formation of reactive metabolites may be critical in assessing their contribution to aggregate exposure to arsenic.     

Acute toxicity of chlorpyrifos and carbosulfan to glochidia of the freshwater mussel Hyriopsis bialata Simpson, 1900

Environmental Science and Pollution Research - The acute toxicity of carbosulfan and chlorpyrifos in formulated pesticides to glochidia (larvae) of the freshwater mussel (Hyriopsis bialata Simpson,...     

The population biology of the living coelacanth studied over 21 years

Between 1986 and 2009 nine submersible and remote-operated vehicle expeditions were carried out to study the population biology of the coelacanth Latimeria chalumnae in the Comoro Islands, located in the western Indian Ocean. Latimeria live in large overlapping home ranges that can be occupied for as long as 21 years. Most individuals are confined to relatively small home ranges, resting in the same caves during the day. One hundred and forty five coelacanths are individually known, and we estimate the total population size of Grande Comore as approximately 300–400 adult individuals. The local population inhabiting a census area along an 8-km section of coastline remained stable for at least 18 years. Using LASER-assisted observations, we recorded length frequencies between 100 and 200 cm total length and did not encounter smaller-bodied individuals (<100 cm total length). It appears that coelacanth recruitment in the observation areas occur mainly by immigrating adults. We estimate that the mean numbers of deaths and newcomers are 3–4 individuals per year, suggesting that longevity may exceed 100 years. The domestic fishery represents a threat to the long-term survival of coelacanths in the study area. Recent changes in the local fishery include a decrease in the abundance of the un-motorized canoes associated with exploitation of coelacanths and an increase in motorized canoes. Exploitation rates have fallen in recent years, and by 2000, had fallen to lowest ever reported. Finally, future fishery developments are discussed.     

Contaminated land clean-up using composted wastes and impacts of VOCs on land

This paper describes experiments that demonstrate the effects and potential for remediation of a former steelworks site in Wales polluted with polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Under field conditions, PAH-contaminated soil was composted in-vessel, with or without organic feedstocks, receiving forced aeration for 80 days followed by 4 months maturation. Treatments compared PAH removal in contaminated soil to contaminated soil mixed with three different organic waste mixes after composting and after composts were spread to land. After composting, PAH concentrations declined in all treatments, by up to 38%. Sixteen months after the composts were landspread and vegetation was established, only those containing contaminated soil with organic additions exhibited further PAH removal, by up to 29%. Composting resulted in a decline in the relative concentration of small PAHs, whereas the landspreading-vegetation phase saw a decline in the relative concentration of medium PAHs in two of the three composts exhibiting PAH removal. Under controlled glasshouse conditions, vegetated soil columns of differing depths were exposed to VOCs from beneath. VOC vapour affected both shoot and root growth and soil microbial activity; effects varied with distance from the VOC source. This work demonstrated that on-site remediation of aged PAH-contaminated land can be successfully initiated by in-vessel co-composting followed by land spreading and vegetation, within a practical timeframe.     

An evaluation of fishery co-management experience in an Amazonian black-water river (Unini River,Amazon, Brazil)

We evaluated the implementation of a fishing agreement, which was created by negotiation among all users of the resources as a co-management strategy because its definition was a result of meetings between all users of the resources. The fishing agreement was implemented in Unini River, a tributary of the right bank of Negro River. Our approach was based on the perception of the people who live in that area, called ribeirinhos. The management strategy was based on spatial distribution of the different types of fishing. We used two logistic regression models to identify the variables which are important to determine the previous concordance and satisfaction with the agreement. First, we analyzed the initial effort to implement the agreement. The variable that influenced the decision of support for the agreement and satisfaction with the results of agreement in both models was the distance from the interviewee’s residence to the sport fishing area. The results showed that the perception of improvement in well-being of the communities and structured social organization are crucial for the success of the co-management strategy.