The influence of the scale of mining activity and mine site remediation on the contamination legacy of historical metal mining activity

Globally, thousands of kilometres of rivers are degraded due to the presence of elevated concentrations of potentially harmful elements (PHEs) sourced from historical metal mining activity. In many countries, the presence of contaminated water and river sediment creates a legal requirement to address such problems. Remediation of mining-associated point sources has often been focused upon improving river water quality; however, this study evaluates the contaminant legacy present within river sediments and attempts to assess the influence of the scale of mining activity and post-mining remediation upon the magnitude of PHE contamination found within contemporary river sediments. Data collected from four exemplar catchments indicates a strong relationship between the scale of historical mining, as measured by ore output, and maximum PHE enrichment factors, calculated versus environmental quality guidelines. The use of channel slope as a proxy measure for the degree of channel-floodplain coupling indicates that enrichment factors for PHEs in contemporary river sediments may also be the highest where channel-floodplain coupling is the greatest. Calculation of a metric score for mine remediation activity indicates no clear influence of the scale of remediation activity and PHE enrichment factors for river sediments. It is suggested that whilst exemplars of significant successes at improving post-remediation river water quality can be identified; river sediment quality is a much more long-lasting environmental problem. In addition, it is suggested that improvements to river sediment quality do not occur quickly or easily as a result of remediation actions focused a specific mining point sources. Data indicate that PHEs continue to be episodically dispersed through river catchments hundreds of years after the cessation of mining activity, especially during flood flows. The high PHE loads of flood sediments in mining-affected river catchments and the predicted changes to flood frequency, especially, in many river catchments, provides further evidence of the need to enact effective mine remediation strategies and to fully consider the role of river sediments in prolonging the environmental legacy of historical mine sites.     

Participation, Process Quality, and Performance of Marine Protected Areas in the Wider Caribbean

Throughout the wider Caribbean, marine protected areas (MPAs) are rapidly gaining momentum as a conservation tool, but management performance of existing MPAs is considered low. To enhance MPA management performance, stakeholders are increasingly being invited to discuss, debate, and develop rules about how people should interact with marine ecosystems. Using social and ecological data from a rapid assessment of 31 MPAs and their associated communities in the wider Caribbean, this study investigates stakeholder participation in MPA planning and management, and how participants' views of process quality relate to MPA performance. Findings indicate that (1) participants tended to be male, resource users, participate in community organizations, and have lived fewer years in the community associated with an MPA than non-participants; (2) simply participating was not associated with perceptions of the social and ecological performance of MPAs, however, perceptions of process quality were positively related to views of performance; and (3) resource users' perceptions of an MPA's ecological performance were likely shaped by a variety of factors. Conservation practitioners should be aware that participatory MPA processes are complex and require careful planning if they are to contribute positively to marine conservation efforts.     

Satellites viewing our world: The NASA landsat and the NOAA SMS/GOES

Thousands of individuals throughout the world are now users of satellite data. Hundreds of satellites have been launched—military, navigation, communications, educational, weather, and earth resources. One of the weather satellites (the SMS/GOES) and the NASA earth resources mapping satellite (Landsat) are the subjects of this article. Data from these systems have been highly cost beneficial, not only in the United States, but in developed and developing nations all over the globe as well. There is an increasing demand both for data and for training in data use.Data samples are shown and applications are discussed. Strong reference is made to the value of the digital computer in natural and man-made features mapping and monitoring. Procedures for acquiring NASA data are explained so that the reader may order data for his home region, or for other regions throughout the world which are of interest for their agriculture, forestry, hydrology, marine resources, geology, or land use. The cost of data is incredibly low; some products cost as little as three dollars.Also discussed are the remotely based data-collection platforms that acquire ground or water data daily and relay results to the NASA Landsat or to the NOAA SMS/GOES.     

Fluoride in drinking water: A survey of expert opinions

In recent years, public debate over the standard setting process related to fluoride in drinking water and the fiuoridation of water supplies has been steeped in much controversy. Discussion of such issues has been con strained by the limited consideration of options relevant to particular problems. To examine the responses to specific issues, we presented an analysis of the problem of excessive fluoride in drinking water to a group of 120 experts. Ninety-seven of the 120 responded to a detailed mail questionnaire distributed as part of a larger exploratory survey. Definite patterns in preferences were noted with certain aspects of the problem, although in some cases significant differences were found due to such factors as the institutional affiliation, residential status, and the length of professional experience of the participants. In general, our experts preferred immediate corrective action over extensive further research into the reduction of scientific uncertainties; were willing to take personal action to obtain fluoride-free water rather than wait for official action; preferred the supplier to fluoridate the supplies, if needed; and favoured a strong local control of such issues with consumers of public water systems and private well owners shouldering much of the financial responsibility. Preliminary results from such exploratory surveys can lead to insightful research hypotheses for further testing. Verification of such hypotheses by consumers, from areas with excessive fluoride in drinking water, is a valuable area for future research.     

Global warming contributions from wheat,sheep meat and wool production in Victoria,Australia – a life cycle assessment

This paper compares the life cycle global warming potential of three of Australia’s important agricultural production activities – the production of wheat, meat and wool in grazed subterranean clover (sub-clover) dominant pasture and mixed pasture (perennial ryegrass/phalaris/sub-clover/grass and cape weed) systems. Two major stages are presented in this life cycle assessment (LCA) analysis: pre-farm, and on-farm. The pre-farm stage includes greenhouse gas (GHG) emissions from agricultural machinery, fertilizer, and pesticide production and the emissions from the transportation of these inputs to paddock. The on-farm stage includes GHG emissions due to diesel use in on-farm transport and processing (e.g. seeding, spraying, harvesting, topdressing, sheep shearing), and non-CO₂ (nitrous oxide (N₂O), and methane (CH₄)) emissions from pastures and crop grazing of lambs.The functional unit of this life cycle analysis is the GHG emissions (carbon dioxide equivalents – CO₂ -e) from 1 kg of wheat, sheep meat and wool produced from sub-clover, wheat and mixed pasture plots. The GHG emissions (e.g. CO₂, N₂O and CH₄ emission) from the production, transportation and use of inputs (e.g. fertilizer, pesticide, farm machinery operation) during pre-farm and on-farm stages are also included. The life cycle GHG emissions of 1 kg of wool is significantly higher than that of wheat and sheep meat. The LCA analysis identified that the on-farm stage contributed the most significant portion of total GHG emissions from the production of wheat, sheep meat and wool. This LCA analysis also identified that CH₄ emissions from enteric methane production and from the decomposition of manure accounted for a significant portion of the total emissions from sub-clover and mixed pasture production, whilst N₂O emissions from the soil have been found to be the major source of GHG emissions from wheat production.     

Comparing Environmental Conditions Using Indicators of Pollution Hazard

/ Land use/land cover classifications for 1973 and 1991, derived from the interpretation of satellite imagery, are quantified on the basis of biophysical land units in a study area in southeastern Australia. Nutrient export potentials are estimated for each land unit based on their composition of land use/land cover classes. Spatial and temporal comparisons are made of the land units based on the calculated pollution hazard indicators to provide an insight into changes in the state of the environment and the regional significance of land use changes. For example, one ecosystem, unique to the study, showed a large increase in pollution hazard over the study period as a manifestation of an 11-fold rise in cleared area and an expansion of cropping activities. The benefits to environmental management in general are discussed.KEY WORDS: Land cover change; Nutrient export; Environmental condition; Pollution hazard; Agricultural pollution; Nonpoint source pollution; Diffuse pollution; Environmental degradation     

Response of “Alamo” switchgrass tissue chemistry and biomass to nitrogen fertilization in West Tennessee,USA

Switchgrass (Panicum virgatum) is a perennial, warm-season grass that has been identified as a potential biofuel feedstock over a large part of North America. We examined above- and belowground responses to nitrogen fertilization in “Alamo” switchgrass grown in West Tennessee, USA. The fertilizer study included a spring and fall sampling of 5-year old switchgrass grown under annual applications of 0, 67, and 202 kg N ha^?1 (as ammonium nitrate). Fertilization changed switchgrass biomass allocation as indicated by root:shoot ratios. End-of-growing season root:shoot ratios (mean ± SE) declined significantly (P ≤ 0.05) at the highest fertilizer nitrogen treatment (2.16 ± 0.08, 2.02 ± 0.18, and 0.88 ± 0.14, respectively, at 0, 67, and 202 kg N ha^?1). Fertilization also significantly increased above- and belowground nitrogen concentrations and decreased plant C:N ratios. Data are presented for coarse live roots, fine live roots, coarse dead roots, fine dead roots, and rhizomes. At the end of the growing season, there was more carbon and nitrogen stored in belowground biomass than aboveground biomass. Fertilization impacted switchgrass tissue chemistry and biomass allocation in ways that potentially impact soil carbon cycle processes and soil carbon storage.     

Dissolved organic matter mediated aquatic transport of chlorinated dioxins

The bioavailability and environmental fate of extremely hydrophobic environmental contaminants such as chlorinated dioxins is linked to their solubility characteristics in water. Solubilities of three chlorinated dioxins, viz., 1,2,3,7-T₄CDD, 1,2,3,4,7-P₅CDD, and 1,2,3,4,7,8-H₆CDD, were determined in pure water using a glass bead generator column technique, and their enhanced solubilities in the presence of several dissolved humic fractions quantified at 20, 30 and 40°C. The strengths of these interactions between chlorodioxins and the dissolved humic substances, viz., a fulvic acid, a humic acid, and Aldrich humic acid, were examined using simple thermodynamic calculations. A new partition/association coefficient, K_oc (mobile) is defined.     

A framework to assess regional environmental impacts of dedicated energy crop production

Numerous studies have evaluated air quality and greenhouse gas mitigation benefits of biomass energy systems, but the potential environmental impacts associated with large-scale changes in land-use patterns needed to produce energy crops have not been quantified. This paper presents a framework to assess the potential soil, water, and biodiversity impacts that may result from the large-scale production of dedicated energy crops. The framework incorporates producer economic decision models with environmental models to assess changes in land use patterns and to quantify the consequent environmental impacts. Economic and policy issues that will affect decisions to produce energy crops are discussed. The framework is used to evaluate erosion and chemical runoff in two Tennessee regions. The analysis shows that production of dedicated energy crops in place of conventional crops will significantly reduce erosion and chemical runoff.