Development of an international standard for the determination of metals and metalloids in workplace air using ICP-AES: evaluation of sample dissolution procedures through an interlaboratory trial

Inductively coupled plasma atomic emission spectrometry (ICP-AES) is rapidly overtaking atomic absorption spectrometry (AAS) as the method of choice for the determination of toxic metals in workplace air. However, the few ICP-AES methods that have been published are not well characterised in terms of the effectiveness of the sample dissolution procedures described and their validation status. The International Standards Organization (ISO) is currently engaged in developing ISO 15202, which will describe a generic method for the determination of metals and metalloids in airborne particulate matter by ICP-AES. One part of the proposed standard deals with dissolution procedures. The ISO work has been supported by a project carried out in the authors' laboratory to identify, develop and validate sample dissolution procedures for inclusion in the proposed standard. This paper describes an interlaboratory comparison carried out to assess the performance of selected procedures using samples of airborne particulate matter collected on filters with a multiport sampler. Five dissolution procedures were tested. These included an ultrasonic agitation procedure, two hot-plate procedures (based upon NIOSH 7300 and OSHA ID 125G) and two microwave-assisted procedures (based upon EPA 3052). It was shown that the dissolution procedures selected for use in the trial and used internally at HSL generally gave equivalent performance. As expected, a wider spread of results was obtained by participants in the trial. More specifically, there exists some reservation regarding the ability of the ultrasonic and hot-plate procedures to attack fully on a consistent basis some resistant materials, e.g., chromium containing particulate matter. Above all, the trial demonstrated the usefulness of microwave-assisted dissolution procedures in a modern laboratory.     

Theory into Practice: Implementing Ecosystem Management Objectives in the USDA Forest Service

In the United States and around the world, scientists and practitioners have debated the definition and merits of ecosystem management as a new approach to natural resource management. While these debates continue, a growing number of organizations formally have adopted ecosystem management. However, adoption does not necessarily lead to successful implementation, and theories are not always put into practice. In this article, we examine how a leading natural resource agency, the United States Department of Agriculture Forest Service, has translated ecosystem management theory into concrete policy objectives and how successfully these objectives are perceived to be implemented throughout the national forest system. Through document analysis, interviews, and survey responses from 345 Forest Service managers (district rangers, forest supervisors, and regional foresters), we find that the agency has incorporated numerous ecosystem management components into its objectives. Agency managers perceive that the greatest attainment of such objectives is related to collaborative stewardship and integration of scientific information, areas in which the organization has considerable prior experience. The objectives perceived to be least attained are adaptive management and integration of social and economic information, areas requiring substantial new resources and a knowledge base not traditionally emphasized by natural resource managers. Overall, success in implementing ecosystem management objectives is linked to committed forest managers.     

Coral reef aerosol emissions in response to irradiance stress in the Great Barrier Reef,Australia

We investigate the correlation between stress-related compounds produced by corals of the Great Barrier Reef (GBR) and local atmospheric properties—an issue that goes to the core of the coral ecosystem’s ability to survive climate change. We relate the variability in a satellite decadal time series of fine-mode aerosol optical depth (AOD) to a coral stress metric, formulated as a function of irradiance, water clarity, and tide, at Heron Island in the southern GBR. We found that AOD was correlated with the coral stress metric, and the correlation increased at low wind speeds, when horizontal advection of air masses was low and the production of non-biogenic aerosols was minimal. We posit that coral reefs may be able to protect themselves from irradiance stress during calm weather by affecting the optical properties of the atmosphere and local incident solar radiation.     

Impacts of Variable Climate and Effluent Flows on the Transboundary Santa Cruz Aquifer

Assessing groundwater resources in the arid and semiarid borderlands of the United States and Mexico represents a challenge for land and water managers, particularly in the Transboundary Santa Cruz Aquifer (TSCA). Population growth, residential construction, and industrial activities have increased groundwater demand in the TSCA, in addition to wastewater treatment and sanitation demands. These activities, coupled with climate variability, influence the hydrology of the TSCA and emphasize the need for groundwater assessment tools for decision‐making purposes. This study assesses the impacts of changes in groundwater demand, effluent discharge, and climate uncertainties within the TSCA from downstream of the Nogales International Wastewater Treatment Plant to the northern boundary of the Santa Cruz Active Management Area. We use a conceptual water budget model to analyze the long‐term impact of the different components of potential recharge and water losses within the aquifer. Modeling results project a future that ranges from severe long‐term drying to positive wetting. This research improves the understanding of the impact of natural and anthropogenic variables on water sustainability, with an accessible methodology that can be globally applied.     

Catalyzing sustainable fisheries management through behavior change interventions

Small-scale fisheries are an important livelihood and primary protein source for coastal communities in many of the poorest regions in the world, yet many are overfished and thus require effective and scalable management solutions. Positive ecological and socioeconomic responses to management typically lag behind immediate costs borne by fishers from fishing pressure reductions necessary for fisheries recovery. These short-term costs challenge the long-term success of these interventions. However, social marketing may increase perceptions of management benefits before ecological and socioeconomic benefits are fully realized, driving new social norms and ultimately long-term sustainable behavior change. By conducting underwater visual surveys to quantify ecological conditions and by conducting household surveys with community members to quantify their perceptions of management support and socioeconomic conditions, we assessed the impact of a standardized small-scale fisheries management intervention that was implemented across 41 sites in Brazil, Indonesia, and the Philippines. The intervention combines TURF reserves (community-based territorial use rights for fishing coupled with no-take marine reserves) with locally tailored social-marketing behavior change campaigns. Leveraging data across 22 indicators and 4 survey types, along with data from 3 control sites, we found that ecological and socioeconomic impacts varied and that communities supported the intervention and were already changing their fishing practices. These results suggest that communities were developing new social norms and fishing more sustainably before long-term ecological and socioeconomic benefits of fisheries management materialized.     

Determinants of brominated flame retardants in breast milk from a large scale Norwegian study

Brominated flame retardants (BFRs), particularly polybrominated diphenyl ethers (PBDEs), are widely present in human populations. In order to investigate human exposure pathways and associations with socioeconomic and lifestyle factors, 393 breast milk samples from mothers living in various regions throughout Norway were analyzed. Up to ten PBDE congeners were measured in all the samples, hexabromocyclododecane (HBCD) and BDE-209 in subsets of 310 and 46, respectively. The median concentrations of the sum of the seven most prominent PBDEs (BDE-28, 47, 99, 100, 153, 154 and 183), BDE-209 and HBCD were 2.1, 0.32 and 0.86 ng/g lipids, respectively. These concentrations are comparable to the levels generally observed in human populations in Europe. The frequency distributions were quite skewed with long tails towards higher concentrations. Maternal age, parity, education, having a cohabitant employed as electrician, and ventilation were factors significantly associated with some of the BFRs, although these factors only explained a small amount of the variability (R² 0.04–0.16). The mothers' diet was not found to influence the breast milk PBDE and HBCD levels. Our results show that sources other than the diet are important for the variability seen in breast milk BFR concentrations and that exposure from the indoor atmosphere should be emphasized in future studies.     

Low dose effects and non-monotonic dose responses for endocrine active chemicals: Science to practice workshop: Workshop summary

A workshop was held in Berlin September 12–14th 2012 to assess the state of the science of the data supporting low dose effects and non-monotonic dose responses (“low dose hypothesis”) for chemicals with endocrine activity (endocrine disrupting chemicals or EDCs). This workshop consisted of lectures to present the current state of the science of EDC action and also the risk assessment process. These lectures were followed by breakout sessions to integrate scientists from various backgrounds to discuss in an open and unbiased manner the data supporting the “low dose hypothesis”. While no consensus was reached the robust discussions were helpful to inform both basic scientists and risk assessors on all the issues. There were a number of important ideas developed to help continue the discussion and improve communication over the next few years.     

Sorption and predicted mobility of herbicides in Baltic soils

This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine approximately amitrole approximately simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log K(ow)) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides.     

Effects of residual antibiotics in groundwater on Salmonella typhimurium: changes in antibiotic resistance, in vivo and in vitro pathogenicity

An outbreak-causing strain of Salmonella enterica serovar Typhimurium was exposed to groundwater with residual antibiotics for up to four weeks. Representative concentrations (0.05, 1, and 100 μg L(-1)) of amoxicillin, tetracycline, and a mixture of several other antibiotics (1 μg L(-1) each) were spiked into artificially prepared groundwater (AGW). Antibiotic susceptibility analysis and the virulence response of stressed Salmonella were determined on a weekly basis by using human epithelial cells (HEp2) and soil nematodes (C. elegans). Results have shown that Salmonella typhimurium remains viable for long periods of exposure to antibiotic-supplemented groundwater; however, they failed to cultivate as an indication of a viable but nonculturable state. Prolonged antibiotics exposure did not induce any changes in the antibiotic susceptibility profile of the S. typhimurium strain used in this study. S. typhimurium exposed to 0.05 and 1 μg L(-1) amoxicillin, and 1 μg L(-1) tetracycline showed hyper-virulent profiles in both in vitro and in vivo virulence assays with the HEp2 cells and C. elegans respectively, most evident following 2nd and 3rd weeks of exposure.     

Mining and environmental change in Sierra Leone, West Africa: a remote sensing and hydrogeomorphological study

This paper evaluates the environmental changes in southwestern Sierra Leone, West Africa from rutile (titanium dioxide) between 1967 and 1995. Mining in peripheral parts of the world economy is a consequence of larger global economic interests. Historically, long-distance trade and export production of minerals and other natural resources primarily for the benefit of core countries are responsible for transforming the natural environment and landscapes of peripheral sectors of the world economy. Tracking environmental change in developing countries such as Sierra Leone is challenging because of financial and infrastructural constraints on the use of ground methods of evaluation and monitoring. Remote sensing data are invaluable in assessing the human dimensions of Land Use and Land Cover Change (LULCC) with implications for political ecology. Using available multi-date infrared Landsat images supplemented with field hydrological and biophysical data, we monitored the rapid temporal and spatial dynamic characteristic of mining areas in the study area with a focus on physical changes to the landscape. Reservoir construction for mining has caused flooding of alluvial lowlands, deforestation, and the creation of tailings and stockpiles over mined-out portions of the lease. Although the study was conducted at a local scale, it represents the broad, regional, past-to-present manner by which global economic interests exploit natural resources and impact the environment in distant places.