In vitro genotoxicity of exhaust emissions of diesel and gasoline engine vehicles operated on a unified driving cycle

Acetone extracts of engine exhaust particulate matter (PM) and of vapor-phase semi-volatile organic compounds (SVOCs) collected from a set of 1998-2000 model year normal emitter diesel engine automobile or light trucks and from a set of 1982-1996 normal emitter gasoline engine automobiles or light trucks operated on the California Unified Driving Cycle at 22 [degree]C were assayed for in vitro genotoxic activities. Gasoline and diesel PM were comparably positive mutagens for Salmonella typhimurium strains YG1024 and YG1029 on a mass of PM extract basis with diesel higher on a mileage basis; gasoline SVOC was more active than diesel on an extracted-mass basis, with diesel SVOC more active on a mileage basis. For chromosomal damage indicated by micronucleus induction in Chinese hamster lung fibroblasts (V79 cells), diesel PM expressed about one-tenth that of gasoline PM on a mass of extract basis, but was comparably active on a mileage basis; diesel SVOC was inactive. For DNA damage in V79 cells indicated by the single cell gel electrophoresis (SCGE) assay, gasoline PM was positive while diesel PM was active at the higher doses; gasoline SVOC was active with toxicity preventing measurement at high doses, while diesel SVOC was inactive at all but the highest dose.     

Wilderness permit accuracy: Differences between reported and actual use

Wilderness permits are valuable tools for recording backcountry use patterns. They provide a valuable basis upon which management decisions are made. Unfortunately, significant inaccuracies in reporting permit data result from noncompliance, transmission errors, and changes in visitor plans. Data from Sequoia and Kings Canyon National Parks in California show that in 1978, 97 percent of the parties obtained wilderness permits. Changes in visitor plans resulted in an over-reporting of total persons by 8 percent and of visitor nights by 23 percent. The latter was due primarily to shortening of trip length. Over-reporting was greatest when permits were issued well in advance of the trip. Backcountry managers should be aware of possible inaccuracies in permit data and may want to adjust for them under certain circumstances.     

A case study of contaminants on military ranges: Camp Edwards, Massachusetts, USA

An extensive investigation at the Camp Edwards, Massachusetts Military Reservation (MMR) demonstrates that assessment of groundwater and soil contamination at military ranges can be limited primarily to explosive-related compounds such as RDX, HMX, perchlorate, TNT and their transformation products. A modified analytical method is recommended to expand the list of explosives and to improve the detection limits. Analyses of metals, VOCs, SVOCs, and TICs are unnecessary. Soil samples may require the analyses of PAHs and PCNs for burn areas. Camp Edwards, as one of the few military ranges that have been exhaustively investigated for contaminants, is an ideal point of departure for evaluating other ranges. The permeable site soils promote leaching of contaminants and inhibit biotic and abiotic transformations. Moreover, the site has experienced an unusual extent of activities in its more than ninety years of active use. The recommendations in this report are based on data obtained for more than 200 analytes from more than 15,000 environmental samples.     

Fate and transport of monoterpenes through soils. Part I. Prediction of temperature dependent soil fate model input-parameters

Monoterpenes are C10H(n)O(n') compounds of natural origin and are potentially environmentally safe substitutes for traditional pesticides. Still, an assessment of their environmental behaviour is required. As a first step in a theoretical study focussing on monoterpenes applied as pesticides to terrestrial environments, soil fate model input-parameters were determined for 20 monoterpenes with widely different structural characteristics. Input-parameters are the water solubility (S(W)), vapour pressure (P), n-octanol-water partition coefficient (K(OW)), atmospheric air and bulk water diffusion coefficients (D(A)air and D(W)water), first order biodegradation rate constants (k), and their temperature dependence. Values for these parameters were estimated or taken from previous experimental work. The quality of the estimations was discussed by focussing on their statistics and by comparison with available experimental data. From these properties, the air-water partition coefficient (K(AW), Henry's Law constant), the interface-water partition coefficient (K(IW)) and the organic matter-water partition coefficient (K(OM)) could be estimated with varying levels of accuracy. In general, little experimental data turned out to be available on biodegradation rate constants and on the temperature dependence of physico-chemical parameters.     

A chemostat system for investigating pesticide biodegradation in continuous mixed bacteria cultures originating from surface water

To be able to predict the degradation (rate) of organic chemicals (e.g. pesticides) in the field, knowledge of the environmental conditions that are of influence on the degradation process are of importance. In the present study an experimental system is described which is used to study the degradation of organic pollutants in mixed bacteria cultures originating from surface water. With this system the degradation of compounds can be followed for relatively long experimental periods (months). In addition, it is possible to vary different environmental parameters in order to investigate their influences on the degradation of the chemical. These preliminary experiments show that growth and ‘composition’ of the bacteria culture have comparable patterns in parallel experiments. The first order degradation rate constant for the test compound dichloran, as calculated from these experiments under these circumstances, is about 0.002 h⁻¹.     

SUBJECTIVE DECISION-MAKING FOR URBAN WATER RESOURCES DEVELOPMENT1

ABSTRACT: Bayesian decision theory provides a procedure for the use of subjective data in a decision-making situation related to urban water resources development. This procedure is effectual in pursuing a set of goals and in transforming individual or group indecisiveness into satisfactory decisions. This approach is highlighted due to its capability to incorporate seemingly unquantifiable, abstract factors into the decision-making process. It is realized that the soliciting of expert and general public opinion is indispensable in making choices for the welfare of the general public from alternative courses of action under uncertainty. The analysis presented here considers engineering alternatives, quality, quantity, cost and the intangible public response in an integrated effort for the selection of optimum strategies in urban water resources development.     

Effect of field margins on moths depends on species mobility: Field-based evidence for landscape-scale conservation

Agri-environment schemes (AES) are widely used policy instruments intended to combat widespread biodiversity declines across agricultural landscapes. Here, using a light trapping and mark-release-recapture study at a field-scale on nine common and widespread larger moth species, we investigate the effect of wide field margins (a popular current scheme option) and the presence of hedgerow trees (a potential scheme option in England) on moth abundance. Of these, we show that wide field margins positively affected abundances, although species did not all respond in the same way. We demonstrate that this variation can be attributed to species-specific mobility characteristics. Those species for which the effect of wide margins was strongest covered shorter distances, and were more frequently recaptured at their site of first capture. This demonstrates that the standard, field-scale uptake of AES may be effective only for less mobile species. We discuss that a landscape-scale approach, in contrast, could deliver significant biodiversity gains, as our results indicate that such an approach (perhaps delivered through targeting farmers to join AES) would be effective for the majority of wider countryside species, irrespective of their mobility level.     

Functional response of sport divers to lobsters with application to fisheries management.

Fishery managers must understand the dynamics of fishers and their prey to successfully predict the outcome of management actions. We measured the impact of a two-day exclusively recreational fishery on Caribbean spiny lobster in the Florida Keys, USA, over large spatial scales (>100 km) and multiple years and used a theoretical, predator-prey functional response approach to identify whether or not sport diver catch rates were density-independent (type I) or density-dependent (type II or III functional response), and if catch rates were saturated (i.e., reached an asymptote) at relatively high lobster densities. We then describe how this predator-prey framework can be applied to fisheries management for spiny lobster and other species. In the lower Keys, divers exhibited a type-I functional response, whereby they removed a constant and relatively high proportion of lobsters (0.74-0.84) across all pre-fishing-season lobster densities. Diver fishing effort increased in a linear manner with lobster prey densities, as would be expected with a type-I functional response, and was an order of magnitude lower in the upper Keys than lower Keys. There were numerous instances in the upper Keys where the density of lobsters actually increased from before to after the fishing season, suggesting some type of "spill-in effect" from surrounding diver-disturbed areas. With the exception of isolated reefs in the upper Keys, the proportion of lobsters removed by divers was density independent (type-I functional response) and never reached saturation at natural lobster densities. Thus, recreational divers have a relatively simple predatory response to spiny lobster, whereby catch rates increase linearly with lobster density such that catch is a reliable indicator of abundance. Although diver predation is extremely high (approximately 80%), diver predation pressure is not expected to increase proportionally with a decline in lobster density (i.e., a depensatory response), which could exacerbate local extinction. Furthermore, management actions that reduce diver effort should have a concomitant and desired reduction in catch. The recreational diver-lobster predator-prey construct in this study provides a useful predictive framework to apply to both recreational and commercial fisheries, and on which to build as management actions are implemented.