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Smith P.G.,Stantec Consulting Ltd. | Boutin C.,Environment Canada | Knopper L.,Intrinsik Environmental Sciences Inc.
Archives of Environmental Contamination and Toxicology | Year: 2013

Vanadium concentrations in soil can be increased through anthropogenic inputs and can be harmful to plants. A Petri dish experiment was conducted to assess the effect of vanadium toxicity on the germination and survival of the garden lettuce, Lactuca sativa. A second study was conducted in a greenhouse to investigate the influence of species selection and nutrient concentration on the toxicity of vanadium pentoxide to plants. L. sativa and four non-crop native plant species, two grasses (Elymus virginicus and Panicum virgatum) and two broad-leaved species (Lycopus americanus and Prunella vulgaris) were selected. Artificial soil was used in both experiments, and a geometric progression of five vanadium concentrations plus controls was selected for the soil treatments. Results of the Petri dish experiment showed that seedling survival is a less sensitive end point than above-ground dry weight (DW) as measured in the greenhouse experiment. Nutrient level (100, 10, and 1 kg/ha) was found to strongly influence vanadium toxicity in the greenhouse study. At 100 kg/ha, plant tolerance to vanadium was greatest, as indicated by higher no-observed, lowest-observed, and percentage effect concentration values. Results showed that forbs (L. americanus and P. vulgaris) tended to be more sensitive than both the crop (L. sativa) and grasses (E. virginicus and P. virgatum) at high concentrations of vanadium. Soil concentrations resulting in a 25 % decrease in shoot DW were generally less than the Canadian soil quality guideline for vanadium, suggesting that 130 mg/kg may not be protective of the Canadian native plant species used in this study. © 2012 Her Majesty the Queen in Right of Canada. Source


Bacigalupo C.,Intrinsik Environmental Sciences Inc. | Hale B.,University of Guelph
Human and Ecological Risk Assessment | Year: 2011

Using publicly available data for contaminated sites, regression relationships between As or Pb concentrations in co-located soils and leaf, root, and fruit vegetables, were developed. The improvement of these regression relationships by additional independent variables known to influence bioavailability of these trace elements in soil (soil pH, available phosphorous, Fe oxide, total Fe, and organic carbon content) was tested. Soil pH, but not plant-available P, decreased unexplained variation in the model for As in leafy vegetables. Iron oxide concentration in soil reduced unexplained variability in As concentrations in root vegetables, but with a positive coefficient thus contradicting its anticipated role as a competitor for As uptake by plants. None of the soil characteristics beyond total Pb concentration reduced variability observed in Pb concentrations in leafy or root vegetables, and there was no model that predicted Pb concentrations in fruit. Predictions of tissue concentration from single-value Plant-Uptake Factors (PUFs) for As in leaf and root vegetables, and for Pb accumulation in root vegetables, deviated more from the observed values than predictions from the regression relationships. The FW PUF determined from this study was within an order of magnitude of that used by the United Kingdom for development of generic soil quality values. © Taylor & Francis Group, LLC. Source


Bacigalupo C.,Intrinsik Environmental Sciences Inc. | Hale B.,University of Guelph
Science of the Total Environment | Year: 2012

The consumption of home grown vegetables may represent a significant exposure pathway for arsenic (As) and lead (Pb) relative to direct incidental ingestion of soil, thus a probabilistic screening tool for estimating these exposures was developed using regression models relating co-located soil and home garden (HG) vegetable concentrations of Pb and As established from multiple independent studies and 2-dimensional Monte Carlo analyses. For high-quantity consumers of HG vegetables (i.e., the upper 95th percentile of consumers in the general population), the HG consumption pathway can be as significant as incidental soil and dust ingestion for inorganic As and, therefore, should be considered when developing generic health-based soil criteria in residential settings. Predicted Pb Hazard Quotient (HQ) estimates among young children resulting from HG consumption were 4- to 10-fold lower than exposures resulting from direct incidental soil and dust ingestion. The difference in soil/dust ingestion rates used to characterize young children (the 95th percentile of 202. mg/d) versus a lifetime residential receptor (the 95th percentile of 30. mg/d) was a primary factor contributing to the relative differences observed between HQ and incremental lifetime cancer risk (ILCR) resulting from these two exposure pathways for lead Pb and inorganic arsenic As, respectively. © 2012 Elsevier B.V. Source


Garron C.,Environment Canada | Knopper L.D.,Intrinsik Environmental Sciences Inc. | Ernst W.R.,Environment Canada | Mineau P.,Environment Canada
Archives of Environmental Contamination and Toxicology | Year: 2012

Chlorothalonil, a broad-spectrum nonsystemic foliar fungicide, is one of the most extensively used pesticide active ingredients on Prince Edward Island, Canada, for blight control on potatoes. In ambient air-sampling programs conducted in 1998 and 1999 and from 2002 to 2004, chlorothalonil was measured in 97% of air samples collected. It is known to produce severe eye and skin irritation, is cytogenic and is considered a possible human carcinogen by the United States Environmental Protection Agency and the International Agency for Research on Cancer. Inhalation studies that quantify chlorothalonil subchronic effects (e.g., genotoxicity) are lacking. The purpose of this study was to assess the possible genotoxic potential of chlorothalonil under field conditions by using the alkaline comet assay to assess DNA damage in CD-1 mice. Mice were selected as a surrogate species for wild small mammals (e.g., meadow voles, deer mice) known to inhabit areas adjacent to potato fields. Mice were placed at three locations downwind of a chlorothalonil application (0, 30, and 100 m) and at one up-wind control location at least 30 m from the field. Downwind mice were exposed to drift throughout the spray period (approximately 30 min) and for an additional hour after spraying. Air samples were collected during the spray trials (before, during, and after spraying) using high-volume polyurethane foam and PM 2.5 air samplers. Pesticide deposits were measured using 20 × 25 cm glass-fibre filters. After exposure, blood was collected from each mouse, and DNA strand breaks in white blood cells measured using comet assay. Results suggest that metrics of DNA damage [tail length (TL), percent DNA in tail] were not significantly related to total air chlorothalonil concentration from the three spray trials (r 2 = 0.000, P = 0.907 for TL; r 2 = 0.001, P = 0.874 for percent DNA). In addition, no significant difference in DNA damage was observed between exposed (at 0 m) and control animals (P = 0.357 for TL; P = 0.958 for percent DNA). Based on these results it can be concluded that wild small mammals living beside fields sprayed with chlorothalonil are at no greater risk of exposure-related DNA damage than conspecifics from unexposed areas. © 2011 Springer Science+Business Media, LLC. Source


Hull R.N.,Intrinsik Environmental Sciences Inc. | Luoma S.N.,University of California at Davis | Bayne B.A.,AECOM Technology Corporation | Iliff J.,National Oceanic and Atmospheric Administration | And 4 more authors.
Integrated Environmental Assessment and Management | Year: 2016

Ecosystem restoration planning near the beginning of the site assessment and management process ("early integration") involves consideration of restoration goals from the outset in developing solutions for contaminated ecosystems. There are limitations to integration that stem from institutional barriers, few successful precedents, and limited availability of guidance. Challenges occur in integrating expertise from various disciplines and multiple, sometimes divergent interests and goals. The more complex process can result in timing, capacity, communication, and collaboration challenges. On the other hand, integrating the 2 approaches presents new and creative opportunities. For example, integration allows early planning for expanding ecosystem services on or near contaminated lands or waters that might otherwise have been unaddressed by remediation alone. Integrated plans can explicitly pursue ecosystem services that have market value, which can add to funds for long-term monitoring and management. Early integration presents opportunities for improved and productive collaboration and coordination between ecosystem restoration and contaminant assessment and management. Examples exist where early integration facilitates liability resolution and generates positive public relations. Restoration planning and implementation before the completion of the contaminated site assessment, remediation, or management process ("early restoration") can facilitate coordination with offsite restoration options and a regional approach to restoration of contaminated environments. Integration of performance monitoring, for both remedial and restoration actions, can save resources and expand the interpretive power of results. Early integration may aid experimentation, which may be more feasible on contaminated lands than in many other situations. The potential application of concepts and tools from adaptive management is discussed as a way of avoiding pitfalls and achieving benefits in early integration. In any case, there will be challenges with early integration of restoration concepts for contaminated ecosystems, but the benefits are likely to outweigh them. © 2016 SETAC. Source

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