An integrated multivariate statistical approach for the evaluation of spatial variations in groundwater quality near an unlined landfill

Environmental Science and Pollution Research - Groundwater is a major resource for water supply in Canada, and 43 of 68 Saskatchewan municipalities rely on groundwater or combined groundwater and...     

Collaborative environmental planning in river management: an application of multicriteria decision analysis in the White River Watershed in Vermont

Multicriteria decision analysis (MCDA) provides a well-established family of decision tools to aid stakeholder groups in arriving at collective decisions. MCDA can also function as a framework for the social learning process, serving as an educational aid in decision problems characterized by a high level of public participation. In this paper, the framework and results of a structured decision process using the outranking MCDA methodology preference ranking organization method of enrichment evaluation (PROMETHEE) are presented. PROMETHEE is used to frame multi-stakeholder discussions of river management alternatives for the Upper White River of Central Vermont, in the northeastern United States. Stakeholders met over 10 months to create a shared vision of an ideal river and its services to communities, develop a list of criteria by which to evaluate river management alternatives, and elicit preferences to rank and compare individual and group preferences. The MCDA procedure helped to frame a group process that made stakeholder preferences explicit and substantive discussions about long-term river management possible.     

The acetochlor registration partnership surface water monitoring program for four corn herbicides

A surface drinking water monitoring program for four corn (Zea mays L.) herbicides was conducted during 1995-2001. Stratified random sampling was used to select 175 community water systems (CWSs) within a 12-state area, with an emphasis on the most vulnerable sites, based on corn intensity and watershed size. Finished drinking water was monitored at all sites, and raw water was monitored at many sites using activated carbon, which was shown capable of removing herbicides and their degradates from drinking water. Samples were collected biweekly from mid-March through the end of August, and twice during the off-season. The analytical method had a detection limit of 0.05 microg L(-1) for alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide] and 0.03 microg L(-1) for acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)-acetamide], atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide]. Of the 16528 drinking water samples analyzed, acetochlor, alachlor, atrazine, and metolachlor were detected in 19, 7, 87, and 53% of the samples, respectively. During 1999-2001, samples were also analyzed for the presence of six major degradates of the chloroacetanilide herbicides, which were detected more frequently than their parent compounds, despite having higher detection limits of 0.1 to 0.2 microg L(-1). Overall detection frequencies were correlated with product use and environmental fate characteristics. Reservoirs were particularly vulnerable to atrazine, which exceeded its 3 microg L(-1) maximum contaminant level at 25 such sites during 1995-1999. Acetochlor annualized mean concentrations (AMCs) did not exceed its mitigation trigger (2 microg L(-1)) at any site, and comparisons of observed levels with standard measures of human and ecological hazards indicate that it poses no significant risk to human health or the environment.     

Influence of flue-gas desulfurization systems on coal combustion by-product quality at kentucky power stations burning high-sulfur coal

Two Kentucky power plants burning similar blends of high-sulfur western Kentucky and southern Indiana coal provide a unique opportunity to examine the variations in coal combustion by-products due to differences in the method of wet flue-gas desulfurization (FGD). One plant employed carbide lime-based scrubbing for two units and a dual-alkali process for the third unit. The second plant employed a Mississippian limestone from Kentucky for all four units. This study provides an example of optical and SEM petrographic techniques, supplemented by chemical analyses, applied to the study of, at least from the geologic perspective, non-traditional materials. The coal sources comprise a blend of high volatile C and B bituminous, high vitrinite (85–90%, mmf), high-sulfur (> 3%, dry) coals. The fly ash is dominated by glassy phases (70–80%) with about 5–10% spinel (predominately magnetite), 3–10% quartz, and 4–10% isotropic coke comprising the remaining portion of the ash. SEM observations indicate that the glassy particles exhibit a bimodal size distribution with sub-micron glass spheres and a population of larger (several 10s of microns) spheres. The bottom ash has higher proportions of spinels and mullite, with negligible carbon forms, compared to the fly ash from the same units. Fly ashes were observed to be lower in Fe and higher in Al, Si, and S compared to the bottom ashes. Carbide lime, a by-product of acetylene manufacture, soda ash, and limestone were the reagents used in the flue-gas desulfurization processes. The primary FGD by-product is a calcium sulfite slurry which is vacuum filtered and mixed with fly ash and, usually, lime, to form a stable product for disposal. The FGD by-products have some potential, as yet unrealized, for utilization.     

Leisure/Labor Tradeoffs: The Backward-Bending Labor Supply in Fisheries

Economists have understood that the open-access nature of fishing grounds can cause the long-run fishery supply to bend backward. There is also increasing speculation that fishermen respond to falling output price either by increasing or decreasing effort, depending on the circumstances. This suggests a short-run backward-bending supply of fishing labor. A dynamic, utility-theoretic model of fishermen's behavior is developed to address this possibility. The model highlights both contemporaneous and intertemporal trade-offs between labor and leisure. The model is tested and the results indicate that the short-run labor supply in fisheries may exhibit backward-bending properties. In addition, changes in current prices may trigger changes in expectations of future prices, causing potentially greater counterintuitive behavior. These results challenge many traditional regulatory strategies (e.g., output taxes) that address problems of open access.     

Comparative assessment of municipal wastewater disposal methods in southeast Florida.

A comparative assessment of the risks of three effluent disposal alternatives currently available to wastewater utilities in Southeast Florida is presented in this paper. The alternatives are: deep well injection and ocean outfalls following secondary treatment, and surface water (canal) discharges following secondary wastewater treatment, filtration and nutrient removal. Water quality data, relative to disposal of wastewater treatment plant effluent were gathered, along with water quality data on the receiving waters, from utilities. Comparisons and conclusions regarding potential health concerns associated with the three disposal alternatives are presented. The results indicated that health risks associated with deep wells were generally lower than those of the other two alternatives. The proximity of injection wells to aquifer storage and recovery wells was a determining factor relative to injection well risk. Urban ecological risks were also indicated to be lower, though impacts of urban water use/reuse to the Everglades were not studied. Additional data collection and analysis were recommended to understand the effects of wastewater management on the cycling of water, nutrients and other constituents on southeast Florida. In particular, it was recommended that monitoring of effluents for nitrosamines and pharmaceutically active substances be implemented on a broad scale.     

Prevalence and perspectives of illegal trade in cacti and succulent plants in the collector community

Although illegal wildlife trade (IWT) represents a serious threat to biodiversity, research into the prevalence of illegal plant collection and trade remains scarce. Because cacti and succulents are heavily threatened by overcollection for often illegal, international ornamental trade, we surveyed 441 members of the cacti and succulent hobbyist collector community with a mixed quantitative and qualitative approach. We sought to understand collector perspectives on the Convention on the International Trade in Endangered Species of Wild Flora and Fauna (CITES) and on the threats IWT poses to cactus and succulent conservation. Most respondents (74% of 401 respondents) stated that illegal collection in cacti and succulents represents a “very serious problem” and that the problem of wild plant collection is increasing (72% of 319 respondents). Most forms of illegal collection and trade were seen as very unacceptable by respondents. Self-reported noncompliance with CITES rules was uncommon (11.2% of 418 respondents); it remains a persistent problem in parts of the cacti and succulent hobbyist community. People engaging in rule breaking, such as transporting plants without required CITES documents, generally did so knowingly. Although 60.6% of 381 respondents regarded CITES as a very important tool for conservation, sentiment toward CITES and its efficacy in helping species conservation was mixed. Collectors in our survey saw themselves as potentially playing important roles in cactus and succulent conservation, but this potential resource remains largely untapped. Our results suggest the need for enhanced consultation with stakeholders in CITES decision-making. For challenging subjects like IWT, developing evidence-based responses demands deep interdisciplinary engagement, including assessing the conservation impact of species listings on CITES appendices.