Adsorption, desorption, soil mobility and aqueous persistence of fensulfothion and its sulfide and sulfone metabolites

Soil/water interactions with the insecticide fensulfothion and its sulfide and sulfone metabolites and described. Adsorption to, and desorption from four soils were studied. There was a general inverse relationship between water solubilities of the three chemicals and their adsorption K values. Order of adsorption was f. sulfide greater than f. sulfone greater than fensulfothion. Adsorption K values correlated significantly with soil organic content. Desorption of fensulfothion and the sulfone were similar whereas the less soluble sulfide desorbed to a lesser extent. To facilitate comparison of desorption tendencies of the three compounds of desorption index was developed. Mobilities through the soils were directly related to the water solubilities of the three chemicals. Mobilities in decreasing order were - fensulfothion greater than f. sulfone greater than f. sulfide. Persistence of fensulfothion was similar in both sterile and non-sterile natural water - about 50% remaining at the end of the 16 wk experiment. Under reducing conditions fensulfothion disappeared from water in 8-12 wk with almost complete conversion to the sulfide.     

Population growth of the blackmargined aphid on pecan in the field

Caged populations of Monellia caryella (Fitch) were observed to condition pecan leaves throughout the season resulting in the leaves being unsuitable for subsequent colonization. Aphid populations were greatest (peak of 70 aphids/leaf) and occurred for a longer period (25 days) compared to late season activity (peak of 37 aphids/leaf, lasting 11 days) before conditioning occurred in closed cages. Intrinsic rates of increase per day or per degree-day declined during the season. Population growth was best described using an exponential increase equation compared to a logistic equation. These results indicated that as pecan leaves aged they were a poorer substrate for M. caryella and more easily made unsuitable for subsequent colonization.     

Fitness costs of dispersal in red foxes (Vulpes vulpes)

The costs of dispersal are an important factor promoting natal philopatry, thereby encouraging the formation of social groups. The red fox, Vulpes vulpes, exhibits a highly flexible social system and one that is thought to represent a possible stage in the evolution of more complex patterns of group-living. Although the potential benefits accruing to philopatric offspring have previously been studied in this species, the potential costs of dispersal have received less attention. We contrasted survival rates, nutritional status, injuries and reproductive output of dispersing and non-dispersing male and female foxes in an urban population to assess the relative costs of dispersal versus natal philopatry. Mortality rates were not significantly higher for dispersing foxes, either in the short- or long-term. There was no evidence of increased nutritional stress in dispersing individuals. Dispersing individuals did, however, exhibit greater levels of wounding, although this did not appear to affect survival. Dispersing females were more likely to miss a breeding opportunity early in their reproductive lifespan. In contrast, both dispersing and non-dispersing males were unlikely to breed in their first year. We conclude that the major fitness component in females affected by dispersing is age at first reproduction.     

Contamination from historic metal mines and the need for non-invasive remediation techniques: a case study from Southwest England

The UK is legally required by the EU Water Framework Directive (WFD) to improve the environmental quality of inland and coastal waters in the coming years. Historic metal mine sites are recognised as an important source of some of the elements on the WFD priority chemicals list. Despite their contamination potential, such sites are valued for their heritage and for other cultural and scientific reasons. Remediating historic mining areas to control the contamination of stream waters, whilst also preserving the integrity of the mine site, is a challenge but might be achieved by novel forms of remediation. In this study, we have carried out environmental monitoring at a historic, and culturally-sensitive, lead-silver mine site in southwest England and have undertaken a pilot experiment to investigate the potential for a novel, non-invasive remediation method at the site. Concentrations of Pb and Zn in mine spoil were clearly elevated with geometric mean concentrations of 6,888 and 710 microg g(-1), respectively. Mean concentrations of Pb in stream waters were between 21 and 54 microg l(-1), in exceedance of the WFD environmental quality standard (EQS) of 7.2 microg l(-1) (annual average). Mean Zn concentrations in water were between 30 and 97 microg l(-1), compared to the UK EQS of 66.5 microg l(-1) (average). Stream sediments within, and downstream from, the mining site were similarly elevated, indicating transport of mine waste particles into and within the stream. We undertook a simple trial to investigate the potential of hydroxyapatite, in the form of bonemeal, to passively remove the Pb and Zn, from the stream waters. After percolating through bonemeal in a leaching column, 96-99% of the dissolved Pb and Zn in stream water samples was removed.     

Agrochemical spray drift; assessment and mitigation--a review

During application of agrochemicals spray droplets can drift beyond the intended target to non-target receptors, including water, plants and animals. Factors affecting this spray drift include mode of application, droplet size, which can be modified by the nozzle types, formulation adjuvants, wind direction, wind speed, air stability, relative humidity, temperature and height of released spray relative to the crop canopy. The rate of fall of spray droplets depends upon the size of the droplets but is modified by entrainment in a mobile air mass and is also influenced by the rate of evaporation of the liquid constituting the aerosol. The longer the aerosol remains in the air before falling to the ground (or alternatively striking an object above ground) the greater the opportunity for it to be carried away from its intended target. In general, all size classes of droplets are capable of movement off target, but the smallest are likely to move the farthest before depositing on the ground or a non-target receptor. It is not possible to avoid spray drift completely but it can be minimized by using best-management practices. These include using appropriate nozzle types, shields, spray pressure, volumes per area sprayed, tractor speed and only spraying when climatic conditions are suitable. Field layout can also influence spray drift, whilst crop-free and spray-free buffer zones and windbreak crops can also have a mitigating effect. Various models are available to estimate the environmental exposure from spray drift at the time of application.     

Transpiration and Root Development of Urban Trees in Structural Soil Stormwater Reservoirs

Stormwater management that relies on ecosystem processes, such as tree canopy interception and rhizosphere biology, can be difficult to achieve in built environments because urban land is costly and urban soil inhospitable to vegetation. Yet such systems offer a potentially valuable tool for achieving both sustainable urban forests and stormwater management. We evaluated tree water uptake and root distribution in a novel stormwater mitigation facility that integrates trees directly into detention reservoirs under pavement. The system relies on structural soils: highly porous engineered mixes designed to support tree root growth and pavement. To evaluate tree performance under the peculiar conditions of such a stormwater detention reservoir (i.e., periodically inundated), we grew green ash (Fraxinus pennsylvanica Marsh.) and swamp white oak (Quercus bicolor Willd.) in either CUSoil or a Carolina Stalite-based mix subjected to three simulated below-system infiltration rates for two growing seasons. Infiltration rate affected both transpiration and rooting depth. In a factorial experiment with ash, rooting depth always increased with infiltration rate for Stalite, but this relation was less consistent for CUSoil. Slow-drainage rates reduced transpiration and restricted rooting depth for both species and soils, and trunk growth was restricted for oak, which grew the most in moderate infiltration. Transpiration rates under slow infiltration were 55% (oak) and 70% (ash) of the most rapidly transpiring treatment (moderate for oak and rapid for ash). We conclude this system is feasible and provides another tool to address runoff that integrates the function of urban green spaces with other urban needs.     

Limitations in the use of potassium dichromate as a blood preservative for the analysis of organohalogenated compounds: two month results

For analysis of organochlorine contaminants in human tissue, the "gold standard" for preservation, storage, and shipping is usually freezing. However, this method can be difficult, if samples are taken in remote areas, and costly, when the samples must be shipped on dry ice. Therefore, a more simple and cost effective method of preservation is essential for remote field work. Potassium dichromate (K(2)Cr(2)O(7)) has been successfully employed in the preservation of human and cows' milk as well as chicken eggs. Our previous studies described the use of potassium dichromate for preservation of whole blood for analysis of dioxins, dibenzofurans, and PCBs. Potassium dichromate was found to successfully preserve blood at room temperature for 34 d with no significant differences in the measured concentrations of chemical contaminants or blood lipid level when compared to frozen samples. However, in a follow-up study, 3 months and 6 months of potassium dichromate preservation proved inadequate to preserve the samples for organic pollutant analysis. We noted that the lipid portion of the blood in the chemically preserved samples was declining in level or degrading, while the persistent organic pollutants remained intact at the same levels on a whole weight basis. To narrow down the window of efficacy for the use of potassium dichromate to preserve blood samples for analysis, the present study compared chemical preservation to freezing for an intermediate time period, 2 months. Similar to our previous findings at 3 and 6 months, at 2 months significant lipid degradation was observed in the chemically preserved samples. Chemically preserved samples had significantly higher levels of organochlorine contaminants (dioxins, dibenzofurans, and PCBs) when measured on a blood lipid basis but not on a wet weight basis compared to frozen samples. While 2 months of potassium dichromate preservation was not useful for obtaining accurate measure of dioxins, furans, and PCBs on a lipid basis, previous studies found this method of preservation to be useful for at least one month (Schecter, A., Pavuk, M., P?pke, O., Malisch, R., 2004. The use of potassium dichromate and ethyl alcohol as blood preservatives for analysis of organochlorine contaminants. Chemosphere 57, 1-7). However blood stored at -70 degrees C and at 22 degrees C with potassium dichromate gave similar results when expressed on a wet weight basis.     

Results of Community Deliberation About Social Impacts of Ecological Restoration: Comparing Public Input of Self-Selected Versus Actively Engaged Community Members

Participatory processes for obtaining residents' input about community impacts of proposed environmental management actions have long raised concerns about who participates in public involvement efforts and whose interests they represent. This study explored methods of broad-based involvement and the role of deliberation in social impact assessment. Interactive community forums were conducted in 27 communities to solicit public input on proposed alternatives for recovering wild salmon in the Pacific Northwest US. Individuals identified by fellow residents as most active and involved in community affairs ("AE residents") were invited to participate in deliberations about likely social impacts of proposed engineering and ecological actions such as dam removal. Judgments of these AE participants about community impacts were compared with the judgments of residents motivated to attend a forum out of personal interest, who were designated as self-selected ("SS") participants. While the magnitude of impacts rated by SS participants across all communities differed significantly from AE participants' ratings, in-depth analysis of results from two community case studies found that both AE and SS participants identified a large and diverse set of unique impacts, as well as many of the same kinds of impacts. Thus, inclusion of both kinds of residents resulted in a greater range of impacts for consideration in the environmental impact study. The case study results also found that the extent to which similar kinds of impacts are specified by AE and SS group members can differ by type of community. Study results caution against simplistic conclusions drawn from this approach to community-wide public participation. Nonetheless, the results affirm that deliberative methods for community-based impact assessment involving both AE and SS residents can provide a more complete picture of perceived impacts of proposed restoration activities.