Rapid assessment of environmental health risks posed by mining operations in low- and middle-income countries: selected case studies

Previous studies have evaluated associated health risks and human exposure pathways at mining sites. Others have provided estimates of the scale of the issue based in part on surveys. However, a global census of mining-related hazardous waste sites has been lacking. The Toxic Sites Identification Program (TSIP) implemented by Blacksmith Institute (New York, NY, USA) since 2009 is an ongoing effort to catalogue a wide range of chemically contaminated sites with a potential human health risk (Ericson et al., Environ Monit Assess doi:10.1007/s 10661-012-2665-2, 2012). The TSIP utilizes a rapid assessment instrument, the Initial Site Screening (ISS), to quickly and affordably identify key site criteria including human exposure pathways, estimated populations at risk, and sampling information. The resulting ISS allows for comparison between sites exhibiting different contaminants and pollution sources. This paper explores the results of a subset of ISSs completed at 131 artisanal and small-scale gold mining areas and 275 industrial mining and ore processing sites in 45 countries. The authors show that the ISS captures key data points, allowing for prioritization of sites for further investigation or remedial activity.     

Comparison of biotic and abiotic treatment approaches for co-mingled perchlorate, nitrate, and nitramine explosives in groundwater

Biological and abiotic approaches for treating co-mingled perchlorate, nitrate, and nitramine explosives in groundwater were compared in microcosm and column studies. In microcosms, microscale zero-valent iron (mZVI), nanoscale zero-valent iron (nZVI), and nickel catalyzed the reduction of RDX and HMX from initial concentrations of 9 and 1 mg/L, respectively, to below detection (0.02 mg/L), within 2 h. The mZVI and nZVI also degraded nitrate (3 mg/L) to below 0.4 mg/L, but none of the metal catalysts were observed to appreciably reduce perchlorate ( approximately 5 mg/L) in microcosms. Perchlorate losses were observed after approximately 2 months in columns of aquifer solids treated with mZVI, but this decline appears to be the result of biodegradation rather than abiotic reduction. An emulsified vegetable oil substrate was observed to effectively promote the biological reduction of nitrate, RDX and perchlorate in microcosms, and all four target contaminants in the flow-through columns. Nitrate and perchlorate were biodegraded most rapidly, followed by RDX and then HMX, although the rates of biological reduction for the nitramine explosives were appreciably slower than observed for mZVI or nickel. A model was developed to compare contaminant degradation mechanisms and rates between the biotic and abiotic treatments.     

Does cannibalism in Spodoptera frugiperda (Lepidoptera: Noctuidae) reduce the risk of predation?

The incidence of cannibalism of larval Spodoptera frugiperda (Lepidoptera: Noctuidae) on maize under field conditions was investigated using field cages. Cannibalism was found to account for approximately 40% mortality when maize plants were infested with two or four fourth-instar larvae over a 3-day period. Field trials examined the effect of larval density on the prevalence of natural enemies of S. frugiperda. The abundance of predators (earwigs, staphylinids, other predatory beetles, and Chrysoperla spp.) was significantly greater on maize plants with higher levels of larval feeding damage, while the relationship between predator abundance and number of S. frugiperda larvae per plant was less clear. As larval damage is probably a more reliable indicator of previous larval density than numbers collected at an evaluation, this indicates that predation risk will be greater for larvae living in large groups. Parasitism accounted for 7.1% mortality of larvae in sorghum, and involved six species of Hymenoptera and Tachinidae. There was no effect of larval density or within-plant distribution on the probability of larval attack by parasitoids. The selective benefits of cannibalism, in relation to the risk of predation and parasitism, are discussed. Received: 23 March 2000 / Accepted: 24 June 2000     

Passing the Panda Standard: A TAD Off the Mark?

Tilapia, a tropical freshwater fish native to Africa, is an increasingly important global food commodity. The World Wide Fund for Nature (WWF), a major environmental nongovernmental organization, has established stakeholder dialogues to formulate farm certification standards that promote “responsible” culture practices. As a preface to its “tilapia aquaculture dialogue,” the WWF for Nature commissioned a review of potential certification issues, later published as a peer-reviewed article. This article contends that both the review and the draft certification standards subsequently developed fail to adequately integrate critical factors governing the relative sustainability of tilapia production and thereby miss more significant issues related to resource-use efficiency and the appropriation of ecosystem space and services. This raises a distinct possibility that subsequent certification will promote intensive systems of tilapia production that are far less ecologically benign than existing widely practiced semi-intensive alternatives. Given the likely future significance of this emergent standard, it is contended that a more holistic approach to certification is essential.     

Forest Value Orientations in Australia: An Application of Computer Content Analysis

This article explores the expression of three forest value orientations that emerged from an analysis of Australian news media discourse about the management of Australian native forests from August 1, 1997 through December 31, 2004. Computer-coded content analysis was used to measure and track the relative importance of commodity, ecological and moral/spiritual/aesthetic forest value orientations. The number of expressions of these forest value orientations followed major events in forest management and policy, with peaks corresponding to finalization of Regional Forest Agreements and conflicts over forest management. Over the time period analyzed, the relative share of commodity value orientation decreased and the shares of the ecological and moral/spiritual/aesthetic value orientations increased. The shifts in forest value orientations highlight the need for native forests to be managed for multiple values and the need for continued monitoring of forest values. Research carried out while employed by the Bureau of Rural Sciences, Department of Agriculture, Fisheries, Forestry, Canberra, Australia.     

Screening organic chemicals in commerce for emissions in the context of environmental and human exposure

Quantitative knowledge of organic chemical release into the environment is essential to understand and predict human exposure as well as to develop rational control strategies for any substances of concern. While significant efforts have been invested to characterize and screen organic chemicals for hazardous properties, relatively less effort has been directed toward estimating emissions and hence also risks. Here, a rapid throughput method to estimate emissions of discrete organic chemicals in commerce has been developed, applied and evaluated to support screening studies aimed at ranking and identifying chemicals of potential concern. The method builds upon information in the European Union Technical Guidance Document and utilizes information on quantities in commerce (production and/or import rates), chemical function (use patterns) and physical-chemical properties to estimate emissions to air, soil and water within the OECD for five stages of the chemical life-cycle. The method is applied to 16,029 discrete substances (identified by CAS numbers) from five national and international high production volume lists. As access to consistent input data remains fragmented or even impossible, particular attention is given to estimating, evaluating and discussing uncertainties in the resulting emission scenarios. The uncertainty for individual substances typically spans 3 to 4 orders of magnitude for this initial tier screening method. Information on uncertainties in emissions is useful as any screening or categorization methods which solely rely on threshold values are at risk of leading to a significant number of either false positives or false negatives. A limited evaluation of the screening method's estimates for a sub-set of about 100 substances, compared against independent and more detailed emission scenarios presented in various European Risk Assessment Reports, highlights that up-to-date and accurate information on quantities in commerce as well as a detailed breakdown on chemical function are critically needed for developing more realistic emission scenarios.     

Changes in area and number of nature reserves in China

Nature reserves (NR) are the cornerstone of biodiversity conservation. Over the past 60 years, the rapid expansion of NRs in China, one of the world's megadiverse countries, has played a critical role in slowing biodiversity loss. We examined the changes in the number and area of China's NRs from 1956 to 2014 and analyzed the effect of economic development on the expansion of China's NRs from 2005 to 2014 with linear models. Despite a continuing increase in the number of NRs, the total area of China's NRs decreased by 3% from 2007 to 2014. This loss resulted from downsizing and degazettement of existing NRs and a slowdown in the establishment of new ones. Nature reserves in regions with rapid economic development exhibited a greater decrease in area, suggesting that downsizing and degazettement of NRs are closely related to the intensifying competition between economic growth and conservation. For example, boundary adjustments to national NRs, the most strictly protected NRs, along the coast of China's Yellow Sea, a global biodiversity hotspot with a fast-growing economy, resulted in the loss of one-third of the total area. One of the most important ecosystems in these NRs, tidal wetlands, decreased by 27.8% because of boundary adjustments and by 25.2% because of land reclamation. Our results suggest conservation achievement, in terms of both area and quality, are declining at least in some regions in the Chinese NR estate. Although the designation of protected areas that are primarily managed for sustainable use has increased rapidly in recent years in China, we propose that NRs with biodiversity conservation as their main function should not be replaced or weakened.     

Water column use and forage strategies of female southern elephant seals from Marion Island

The at-sea behaviour of marine top predators provides valuable insights into the distribution of prey species and strategies used by predators to exploit patchily distributed resources. We describe the water column usage and dive strategies of female southern elephant seals from Marion Island tracked between 2004 and 2008. Dives representing increases in forage effort were identified using a method that combines dive type analyses and the calculation of relative amounts of time that animals spend in the bottom phases of dives. Results from this analysis indicate that female elephant seals from Marion Island tend to display lower levels of forage effort closer to the island and display intensive opportunistic forage bouts that occur at a minimum distance of approximately 215 km from the island. Females from Marion Island dived deeper and for longer periods of time, compared to females from other populations. Most animals displayed positive diel vertical migration, evidently foraging pelagically on vertically migrating prey. A few animals displayed periods of reverse (negative) diel vertical migration, however, diving to deeper depths at night, compared to daytime. This behaviour is difficult to explain and prey species targeted during such periods unknown. Our results illustrate plasticity in foraging behaviour of southern elephant seals, as well as inter-population differences in forage strategies.     

Analysis of the key intermediates of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) in groundwater: occurrence, stability and preservation

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a widely used explosive that is present in soils at a number of military sites, including training and testing ranges. Because of its relatively weak adsorption to soil, RDX frequently migrates through the unsaturated zone and causes groundwater contamination. In the environment, RDX can transform to produce mono-, di-, and tri-nitroso derivatives (MNX, DNX, and TNX) and the ring cleavage products methylenedinitramine (MEDINA) and 4-nitro-2,4-diazabutanal (NDAB). The present study was undertaken to analyze RDX and its products in groundwater samples taken from various US military sites. The stability of some of the common transformation intermediates of RDX, including the nitroso derivatives, NDAB and MEDINA, under typical conditions in a groundwater aquifer is not well understood, and appropriate preservation methods for these compounds have not been established. Therefore, we studied the inherent stability of these compounds in deionized water and in groundwater, and evaluated various preservation techniques, including adjustment of pH, temperature, and salinity. NDAB and nitroso derivatives were stable under typical ambient environmental conditions, but MEDINA was highly unstable. The addition of sea salts (10% w/v) was found to stabilize MEDINA when the samples were stored at 4 °C. Using appropriate preservation techniques, we detected nitroso derivatives and NDAB, but no MEDINA, at some of the sites investigated. Stabilizing RDX intermediate products in field samples to allow detection is important because the presence of any of these chemicals can indicate past contamination by RDX and provide insight into the occurrence of in situ natural attenuation.