Identifying potential receptors and routes of contaminant exposure in the traditional territory of the Ouje-Bougoumou Cree: Land use and a geographical information system

Great concern has been raised with respect to the 13 traplines that constitute the traditional territory of the Ouje-Bougoumou Cree located in the James Bay region of northern Quebec, Canada, with respect to mine wastes originating from three local mines. As a result, an “Integrative Risk Assessment” was initiated consisting of three interrelated components: a comprehensive human health study, an assessment of the existing ecological/environmental database, and a land use/potential sites of concern study. In this paper, we document past and present land use in the traditional territory of the Ouje-Bougoumou Cree for 72 heads of households, including 13 tallymen, and use a Geographic Information System (GIS) to layer harvest/hunting and gathering/collecting data over known mining areas and potential sites of concern. In this way, potential receptors of contamination and routes of human exposure were identified. Areas of overlap with respect to land use activity and mining operations were relatively extensive for certain harvesting activities (e.g., beaver, Castor canadensis and various species of game birds), less so for fish harvesting (all species) and water collection, and relatively restrictive for large mammal harvesting and collection of firewood (and other collection activities). Potential receptors of contaminants associated with mining activity (e.g., fish and small mammals) and potential routes of exposure (e.g., ingestion of contaminated game and drinking of contaminated water) were identified.     

Export of nitrogen from catchments: a worldwide analysis

This study reviews nitrogen export rates from 946 rivers of the world to determine the influence of quantitative (runoff, rainfall, inhabitant density, catchment area, percentage of land use cover, airborne deposition, fertilizer input) and qualitative (dominant type of forest, occurrence of stagnant waterbodies, dominant land use, occurrence of point sources, runoff type) environmental factors on nitrogen fluxes. All fractions (total, nitrate, ammonia, dissolved organic and particulate organic) of nitrogen export showed a left-skewed distribution, which suggests a relatively pristine condition for most systems. Total nitrogen export showed the highest variability whereas total organic nitrogen export comprised the dominant fraction of export. Nitrogen export rates were only weakly explained by our qualitative and quantitative environmental variables. Our study suggests that the consideration of spatial and temporal scales is important for predicting nitrogen export rates using simple and easy-to-get environmental variables. Regionally based modelling approaches prove more useful than global-scale analyses.     

Metal concentrations and mobility in marine sediment and groundwater in coastal reclamation areas: a case study in Shenzhen, China

The concentrations of metals in the buried marine sediment and groundwater were differently affected by land reclamation. Nine metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in sediment and coastal groundwater from reclamation areas in Shenzhen were examined. The gradually decreased concentrations (V, Cr, Mn, Ni, Cu, Zn) in sediment and relatively higher concentrations (V, Cr, Mn, Co, Ni, Cu and Cd) in groundwater within reclamation areas were observed. The increase of V, Cr, Mn, Ni, Cu and Cd concentrations in groundwater within reclamation areas subsequently after land reclamation should be resulted from the mobilization of these metals accumulated in the sediment. These metals appear to be easily mobilized from solid phase to solution phase after reclamation. The physico-chemical changes such as reduction in pH and salinity in water environment induced by land reclamation appear to be responsible for metal mobility in the sediment-groundwater system.     

Can Basin Land Use Effects on Physical Characteristics of Streams Be Determined at Broad Geographic Scales?

The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional, land use would explain more of the variation in stream physical characteristics because environmental settings become more homogeneous. At a national scale, stepwise linear regression indicated that environmental setting was more important in explaining variability in stream physical characteristics. Although statistically discernible, the amount of variation explained by land use was not remarkable due to low partial correlations. At level II ecoregion spatial scales (southeastern USA plains, central USA plains, and a combination of the western Cordillera and the western interior basins and ranges), environmental setting variables were again more important predictors of stream physical characteristics, however, as the spatial scale decreased from national to regional, the portion of variability in stream physical characteristics explained by basin land use increased. Development of stream habitat indicators of land use will depend upon an understanding of relations between stream physical characteristics and environmental factors at multiple spatial scales. Smaller spatial scales will be necessary to reduce the confounding effects of variable environmental settings before the effects of land use can be reliably assessed.     

Influence of land tenure practices on artisanal mining activity in Ghana

This paper examines the issue of land tenure and how it influences artisanal and small-scale mining (ASM) activity in Ghana. Over the past few decades, attempts by governments in sub-Saharan Africa to regulate or formalize ASM as a result of the sector's increasing socio-economic and environmental importance have largely been unsuccessful. Even though mining laws have tended to vest all minerals in the state, increasing evidence suggests that mineral-rich lands for artisanal mining continue to be frequently traded between local landowners and miners or interested groups outside the official legal regime. This development, i.e. land trading for artisanal mining, contributes significantly towards proliferation of illegal ASM activity and hence potentially challenges attempts by governments and development partners to formalise the sector.     

Toward an improved legislative framework for China's land degradation control

The Chinese government has recently been attaching increasing importance to the application of effective legal tools to tackle land degradation (LD) issues. Based on the concept of sustainable development, China began developing and reaping the benefits of environmental and natural resources legislation including LD control regulations in the 1990s. In the past three years, some central‐western provinces in China have been implementing a “ People's Republic of China/Global Environment Facility (PRC/GEF ) Partnership on LD Control of Dryland Ecosystems”, which is based on an integrated ecosystem management (IEM) approach. IEM is designed to achieve a balanced, scientific and participatory approach to natural resources management, which creates the potential to improve the quality of Chinese environmental law and policy procedures. The paper studies the existing Chinese national laws and regulations pertinent to LD control within 9 areas covering land, desertification, soil erosion, grassland, forest, water, agriculture, wild animals and plants, and environment protection in detail, against IEM principles and basic legal elements. The main objective is to identify problems and provide feasible solutions and recommendations for the improvement of the existing laws and regulations. The authors conclude that the development of an improved national legislative framework is essential if LD control is to be successfully achieved. The paper is partly based on Component 1 — Improving Policies, Laws and Regulations for Land Degradation Control under PRC/GEF Partnership on Land Degradation in Dryland Ecosystems (TA 4357).     

Sustainability of wastewater treatment technologies

A set of indicators that incorporate environmental, societal, and economic sustainability were developed and used to investigate the sustainability of different wastewater treatment technologies, for plant capacities of <5 million gallons per day (MGD) or 18.9 x 10(3) cubic meters (m(3)/day). The technologies evaluated were mechanical (i.e., activated sludge with secondary treatment), lagoon (facultative, anaerobic, and aerobic), and land treatment systems (e.g., slow rate irrigation, rapid infiltration, and overland flow). The economic indicators selected were capital, operation and management, and user costs because they determine the economic affordability of a particular technology to a community. Environmental indicators include energy use, because it indirectly measures resource utilization, and performance of the technology in removing conventional wastewater constituents such as biochemical oxygen demand, ammonia nitrogen, phosphorus, and pathogens. These indicators also determine the reuse potential of the treated wastewater. Societal indicators capture cultural acceptance of the technology through public participation and also measure whether there is improvement in the community from the specific technology through increased job opportunities, better education, or an improved local environment. While selection of a set of indicators is dependent on the geographic and demographic context of a particular community, the overall results of this study show that there are varying degrees of sustainability with each treatment technology.     

A methodology of characterizing status and trend of land changes in oases: a case study of Sangong River watershed, Xinjiang, China

Land change is often studied with Markov models to develop a probability transition matrix. The existing methods dependent on such matrixes cannot effectively characterize some important aspects associated with land change such as status, direction, trend and regional variations. This study presents mathematical models to quantify these elements, defining unbalanced, quasi-balanced and balanced status, one- and two-way transitions and the rising or falling trends. Using these models and remote-sensing imageries, the landscape was studied for a case area, the oasis of Sangong River in Xinjiang, Northwest China where typical arid conditions prevail. Land expansion and contraction among various land types and for the entire oasis were analyzed for the periods of 1978-1987, 1978-1998 and 1987-1998. The changes were closely related to a strong economic growth after the land-reform campaign and adoption of the market economy in China in the 1980s to early 1990s, a process not strictly Markovian that requires stationarity and randomness. Information on land-change status and trend is important for a better understanding of the underlying driving processes but also for land-use planning and decision-making.     

Land use change and population growth in the Morobe Province of Papua New Guinea between 1975 and 2000

The relation between human population growth and land use change is much debated. Here we present a case study from Papua New Guinea where the population has increased from 2.3 million in 1975 to 5.2 million in 2000. Since 85% of the population relies on subsistence agriculture, population growth affects agricultural land use. We assessed land use change in the Morobe province (33,933 km2) using topographic maps of 1975 and Landsat TM images of 1990 and 2000. Between 1975 and 2000, agricultural land use increased by 58% and population grew by 99%. Most new agricultural land was taken from primary forest and the forest area decreased from 9.8 ha person(-1) in 1975 to 4.4 ha person(-1) in 2000. Total population change and total land use change were strongly correlated. Most of the agricultural land use change occurred on Inceptisols in areas with high rainfall (>2500 mm year(-1)) on moderate to very steep slopes (10-56%). Agricultural land use changes in logged-over areas were in the vicinity of populated places (villages), and in close proximity to road access. There was considerable variation between the districts but districts with higher population growth also had larger increases in agricultural areas. It is concluded that in the absence of improved farming systems the current trend of increased agriculture with rapid population growth is likely to continue.     

Quantitative Identification of Disturbance Thresholds in Support of Aquatic Resource Management

The identification of disturbance thresholds is important for many aspects of aquatic resource management, including the establishment of regulatory criteria and the identification of stream reference conditions. A number of quantitative or model-based approaches can be used to identify disturbance thresholds, including nonparametric deviance reduction (NDR), piecewise regression (PR), Bayesian changepoint (BCP), quantile piecewise constant (QPC), and quantile piecewise linear (QPL) approaches. These methods differ in their assumptions regarding the nature of the disturbance-response variable relationship, which can make selecting among the approaches difficult for those unfamiliar with the methods. We first provide an overview of each of the aforementioned approaches for identifying disturbance thresholds, including the types of data for which the approaches are intended. We then compare threshold estimates from each of these approaches to evaluate their robustness using both simulated and empirical datasets. We found that most of the approaches were accurate in estimating thresholds for datasets with drastic changes in responses variable at the disturbance threshold. Conversely, only the PR and QPL approaches performed well for datasets with conditional mean or upper boundary changes in response variables at the disturbance threshold. The most robust threshold identification approach appeared to be the QPL approach; this method provided relatively accurate threshold estimates for most of the evaluated datasets. Because accuracy of disturbance threshold estimates can be affected by a number of factors, we recommend that several steps be followed when attempting to identify disturbance thresholds. These steps include plotting and visually inspecting the disturbance-response data, hypothesizing what mechanisms likely generate the observed pattern in the disturbance-response data, and plotting the estimated threshold in relation to the disturbance-response data to ensure the appropriateness of the threshold estimate.