Assessment of rainwater volatile organic carbon in southeastern North Carolina,USA

Extensive production of ethanol and vehicular use of this biofuel have recently been suggested as possible sources of elevated volatile organic carbon (VOC) in rain in Brazil (Campos, M.L.A.M., Nogueira, R.F.P., Dametto, P.R., Francisco, J.G., Coelho, C.H., 2007. Dissolved organic carbon in rainwater: glassware decontamination and sample preservation and volatile organic carbon. Atmos. Environ. 41, 8924–8931; Coelho, C.H., Francisco, J.G., Nogueira, R.F.P., Campos, M.L.A.M., 2008. Dissolved organic carbon in rainwater from areas heavily impacted by sugar cane burning. Atmos. Environ. 42, 7115–7121). Furthermore, these studies suggested that the global flux of rainwater dissolved organic carbon (DOC) may be underestimated since most DOC analytical methods do not measure VOC. The current study examined rain VOC in Wilmington, North Carolina USA in order to assess the importance of rain VOC in a location that does not have the unique conditions of ethanol production and usage found in Brazil. VOC was observed in one of six whole rain events analyzed in the current study. This event had an air mass back trajectory that originated over the Midwestern USA, the primary region where ethanol is produced and used as fuel. The other five storms which had no influence from the central US prior to arrival at the rain collection site had non-detectable VOC suggesting that air mass back trajectory has a dramatic impact on the VOC content of rainwater. VOC was also observed in the initial 1 mm of rain from two of these events but was not detectable in the whole event samples suggesting VOC is efficiently washed out of the atmosphere and is not rapidly resupplied in rainwater at this location. Considering the results of the previous Brazilian studies and the current study, and the likelihood of increased global production and consumption of ethanol based biofuels, it is imperative that future measurements of rainwater DOC include measurement of VOC. Monitoring changes in the VOC contribution to rain DOC will provide an assessment of the impact of increased ethanol biofuel usage on rainwater composition and allow for future refinements of global rainwater DOC flux estimates.     

Residences with anomalous soil concentrations of dioxin-like compounds in two communities in Michigan, USA: a case study

Most contamination of residential property soil with dioxin-like compounds occurs as a result of proximity to industrial activity that produces such compounds and, outside the industrially impacted zone, the soil concentrations are at background levels. However, as part of the University of Michigan Dioxin Exposure Study, residential properties in the lower peninsula of Michigan, USA, were identified that were located far enough from known sources of these compounds that the soil concentrations should have been at background levels and yet the toxic equivalent (TEQ) of some properties' soil was greater than 2.5 standard deviations above the mean background level. In the three cases presented here from Midland/Saginaw Counties, the anomalously high-TEQ values were primarily due to the presence of polychlorinated dibenzofurans. Based on interviews with the residents and a comparison of soil congener profiles, it was deduced that these values resulted from anthropogenic soil movement from historically contaminated areas. In the cases from Jackson/Calhoun Counties, the unusually high-TEQ values were primarily due to polychlorinated biphenyls. In the case profiled here, it appears that the soil became contaminated through sandblasting to remove paint from the swimming pool. This study identified two mechanisms for soil contamination outside zones of industrial impact; thus, an assumption of background levels of soil contamination outside industrial zones may not be valid.     

Weighing empirical and hypothetical evidence for assessing potential invasive species range limits: a review of the case of Burmese pythons in the USA

Range expansion potential is an important consideration for prioritizing management actions against an invasive species. Understanding the potential for range expansion by invasive reptiles such as the Burmese python can be challenging, because the lack of knowledge on fundamental physiological and behavioral constraints initially forces reliance on modeling to predict hypothetical invasive range potential. Hypothetical predictions for Burmese python range limits in the USA have been highly divergent, from only extreme South Florida and the extreme southern Gulf edge of Texas to a broad swath over the southern third of the continental USA. Empirical observations on python thermal tolerances and behavioral abilities to cope with more temperate temperatures became evident during a cold spell in December 2009–January 2010. We review and highlight important considerations for improving invasive range estimation methodology, deciding between competing range predictions, and the importance of having, and applying, empirical data to aid in decision making.     

Polycyclic aromatic hydrocarbons affect survival and development of common snapping turtle (Chelydra serpentina) embryos and hatchlings

Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds found in the John Heinz National Wildlife Refuge in Philadelphia, Pennsylvania. We assessed the impact of PAHs and crude oil on snapping turtle development and behavior by exposing snapping turtle eggs from the Refuge and from three clean reference sites to individual PAHs or a crude oil mixture at stage 9 of embryonic development. Exposure to PAHs had a significant effect on survival rates in embryos from one clean reference site, but not in embryos from the other sites. There was a positive linear relationship between level of exposure to PAHs and severity of deformities in embryos collected from two of the clean reference sites. Neither righting response nor upper temperature tolerance (critical thermal maximum, CTM) of snapping turtle hatchlings with no or minor deformities was significantly affected by exposure to PAHs.     

Attractancy evaluation of ceralure‐B1 isomer via field captures of mediterranean fruit flies (Diptera: Tephritidae)

Abstract

Commercially prepared ceralure‐B1, an attractant for the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), was evaluated in trapping tests by comparison with commercial ceralure and trimedlure. Jackson traps were used for medfly captures. The residual ceralure‐B1, ceralure, and trimedlure contents of aged dispensers were determined. The results of this study show that male medfly captures from traps with ceralure‐B1 were as high or higher than male medfly captures from traps with twice the quantity of ceralure or trimedlure. The use of regioselectively synthesized ceralure‐B1, enriched in B1, as a source of a more potent attractant than commercial ceralure and as a more persistent male medfly attractant than trimedlure is reported.     

Optimizing line intercept sampling and estimation for feral swine damage levels in ecologically sensitive wetland plant communities

Ecological sampling can be labor intensive, and logistically impractical in certain environments. We optimize line intercept sampling and compare estimation methods for assessing feral swine damage within fragile wetland ecosystems in Florida. Sensitive wetland sites, and the swine damage within them, were mapped using GPS technology. Evenly spaced parallel transect lines were simulated across a digital map of each site. The length of each transect and total swine damage under each transect were measured and percent swine damage within each site was estimated by two methods. The total length method (TLM) combined all transects as a single long transect, dividing the sum of all damage lengths across all transects by the combined length of all transect lines. The equal weight method (EWM) calculated the damage proportion for each transect line and averaged these proportions across all transects. Estimation was evaluated using transect spacings of 1, 3, 5, 10, 15, and 20 m. Based on relative root mean squared error and relative bias measures, the TLM produced higher quality estimates than EWM at all transect spacings. Estimation quality decreased as transect spacing increased, especially for TLM. Estimation quality also increased as the true proportion of swine damage increased. Diminishing improvements in estimation quality as transect spacings decreased suggested 5 m as an optimal tradeoff between estimation quality and labor. An inter-transect spacing of 5 m with TLM estimation appeared an optimal starting point when designing a plan for estimating swine damage, with practical, logistical, economic considerations determining final design details.     

Estimation of primary drainage three-phase relative permeability for organic liquid transport in the vadose zone

The modeling of transport of organic liquid contaminants through the vadose zone often requires three-phase relative permeabilities. Since these are difficult to measure, predictive models are usually used. The objective of this study is to assess the ability of eight common models to predict the drainage relative permeability to oil in a three-phase system (water-oil-air). A comparison of the models' estimates using data set from Oak [Oak, M.J., 1990. Three-phase relative permeability of water-wet Berea. In: Seventh Symposium on Enhanced Oil Recovery, Paper SPE/Doe 20183. Tulsa, OK, April 22-25] showed that they provide very different predictions for the same system. The goodness of the models does not increase with the amount of data or computation that the models require. Also, the calculations showed how different interpretations of the models and of the terminology associated with them can significantly impact the predictions. Thus, considerable error may be introduced into the simulations of organic liquid transport in the vadose zone depending on the selection and interpretation of the three-phase relative permeability model.     

Risk assessment of the use of PAS100 green composts in sheep and cattle production in Scotland

A generalized quantitative risk assessment for the use of source-segregated green waste (SSGW) compost use in livestock production is presented. This assessment focussed on potential risks associated with a specific product, PAS100 compost that meets the UK publicly available specification 100 and represents the majority of compost available for use in extensive Scottish livestock systems. A hazard screening approach was used to identify all potentially hazardous agents present in compost. A total of 497 potentially hazardous agents were screened, with 147 finally put forward for quantitative risk assessment. Scenarios modelled in the assessment included surface application of compost to grazing land and also incorporation into soil and subsequent uptake by fodder crops. Risk estimates were compared to those associated with six comparator materials, including various sludges, slurries and farm yard manures. Overall, five potentially hazardous agents (PCB28, PCB138, PCB153, 1,2,3,4,6,7,8-HpCDD, Clopyralid) returned a hazard quotient >1 but within margins of uncertainty, indicating that further investigation may be required. Within the limitations of available information, SSGW compost was found to pose less risk to grazing livestock, or the environment, than other commonly-used soil amendments. While this assessment relates to a specific product/standard used in the UK, the methodology could easily be applied to other composts/products/situations. Therefore these results have wider applicability.