Influence of input uncertainty on prediction of within-field pesticide leaching risks

Previous research has suggested that pesticide losses at the field scale can be dominated by a small proportion of the field area. The objective of this study was to investigate whether site-specific applications (i.e. avoiding high-risk areas) at the field scale can contribute to a reduction of pesticide leaching despite uncertainty in the underlying model-based leaching risk map. Using a meta-model of the dual-permeability model MACRO, the annual average pesticide leaching concentrations were estimated for 162 sample sites on a 47 ha field. The procedure was repeated for different scenarios describing different patterns of spatial variation of degradation half-lives and the partition coefficient to soil organic carbon. To account for interpolation uncertainty, maps of predicted pesticide leaching risk were produced by the method of sequential Gaussian simulation. The results of the case study show that larger reductions of predicted leaching were achieved by site-specific application than by that of a comparable uniform dose reduction. Hence, site-specific-applications may be a feasible method to reduce pesticide leaching at the field-scale providing that the model approach gives reasonable estimates of the spatial pattern of pesticide leaching.     

Empirical realised niche models for British coastal plant species

Coastal environments host plant taxa adapted to a wide range of salinity conditions. Salinity, along with other abiotic variables, constrains the distribution of coastal plants in predictable ways, with relatively few taxa adapted to the most saline conditions. However, few attempts have been made to quantify these relationships to create niche models for coastal plants. Quantification of the effects of salinity, and other abiotic variables, on coastal plants is essential to predict the responses of coastal ecosystems to external drivers such as sea level rise. We constructed niche models for 132 coastal plant taxa in Great Britain based on eight abiotic variables. Paired measurements of vegetation composition and abiotic variables are rare in coastal habitats so four of the variables were defined using community mean values for Ellenberg indicators, i.e. scores assigned according to the typical alkalinity, fertility, moisture availability and salinity of sites where a species occurs. The remaining variables were the canopy height, annual precipitation, and maximum and minimum temperatures. Salinity and moisture indicator scores were significant terms in over 80 % of models, suggesting the distributions of most coastal species are at least partly determined by these variables. When the models were used to predict species occurrence against an independent dataset 64 % of models gave moderate to good predictions of species occurrence. This indicates that most models had successfully captured the key determinants of the niche. The models could potentially be applied to predict changes to habitats and species-dependent ecosystem services in response to rising sea levels.     

Strategies for improving human health in contaminated situations: a review of past,present and possible future approaches

Strategies for improving human health in contaminated situations have traditionally been based on restricting emissions, remedial reduction of exposure and, where appropriate and possible, medical reconnaissance of efficacy. We review these and the broader aspects of general public health approaches, including necessary understanding of epidemiology and the wider social context, before considering a specific local case study involving health issues associated with chromium-contaminated land and its remediation in an area of urban regeneration. The impact of remediation upon the common good, in its broadest environmental, health and socio-economic sense, including enhanced opportunities for members of the community to take personal responsibility for health-improving activities, should be taken into account in addition to conventional theoretical assessments and practical measurements of relief from environmental risk. Rapidly emerging toxicogenomic technologies may have a role to play in informing future risk assessment and remediation approaches in contaminated situations, although the ethical challenges of using personal genetic information could well be considerable.     

A simple method for predicting the consequences of land management in urban habitats

Land management in urban areas is characterized by the diversity of its goals and its physical expression in the landscape, as well as by the frequency and often rapidity of change. Deliberate or accidental landscape alterations lead to changes in habitat, some of which may be viewed as environmentally beneficial, others as detrimental. Evaluating what is there and how changes may fit into the landscape context is therefore essential if informed land-management decisions are to be made. The method presented here uses a simple ecological evaluation technique, employing a restricted number of evaluation criteria, to gather a spatially complete data set. A geographical information system (GIS) is then used to combine the resulting scores into a habitat value index (HVI). Using examples from Wolverhampton in the United Kingdom, existing real-world data are then applied to land-management scenarios to predict probable landscape ecological consequences of habitat alteration. The method provides an ecologically relevant, spatially complete evaluation of a large, diverse area in a short period of time. This means that contextual effects of land-management decisions can be quickly visualized and remedial or mitigating measures incorporated at an early stage without the requirement for complex modeling and prior to the detailed ecological survey. The strengths of the method lie in providing a detailed information baseline that evaluates all habitats, not just the traditional “quality” habitats, in a manner that is accessible to all potential users—from interested individuals to professional planners.     

Radioactivity in environmental samples: Calibration standards measurement methods,quality assurance,and data analysis

The numerous environmental radioactivity measurements made by and for the U.S. Environmental Protection Agency (U.S. EPA) include measurements on samples of water, urine, food, milk, and air filters. Calibration standards are listed which are available in the form of water solutions and soils for a wide range of radionuclides. Method validation procedures for U.S. EPA approval include protocol development and single-laboratory and multiple-laboratory evaluation for precision and accuracy. Interlaboratory comparison studies are conducted for both cross-check and performance evaluation samples and involve 295 federal, state, and local laboratories. For water samples, 80%–90% of the participating laboratories are within the control limits for most of the radionuclides measured; however, some problem areas exist, especially for radium-228 and strontium-89 and -90. For milk and food samples, more than 90% of the laboratories are within control limits for cobalt-60 and cesium-137 but some problems exist for the measurement of strontium-90, iodine-131, and potassium-40. For tritium, 91% of the laboratories are within the control limit for water samples and 87% are within the control limits for the urine samples. The laboratory performance for air filter samples shows some problems for gross beta, strontium-90 and cesium-137 measurements.