1,721,056 research outputs found
Environmental exposure assessment
No full textEnvironmental exposure is usually assessed by evaluating the concentration of a specific chemical in the main environmental media (air, soil, water, sediment) and in biota as food source for other organisms (predators) by secondary poisoning. The study of exposure is complicated by the complexity of the many ecosystems to protect and the high number of chemicals that can be found in the environment. Exposure in the environment can be evaluated using monitoring data or predictive approaches, such as environmental fate models. When more details on organism uptake and levels are needed, specific bioaccumulation models can be used
Prediction of surface water input of chloridazon and chlorpyrifos from an agricultural watershed in Chile
No full textTwo compartmental fugacity-based models (Agrifug and SoilFug) for the prediction of pesticide runoff from agricultural fields were applied and experimentally validated in a river watershed, of about 106 km(2), in central Chile. Chloridazon and chlorpyrifos, two of the most widely used pesticides in the study area, were selected for their different physico-chemical properties, in order to test a range of environmental fate patterns by means of these models. Theoretical values were compared with analytical determinations in river water and soil and a goad predictive capability was found for both models, at least at the order of magnitude level. Value and limitations of the application of this approach at the basin scale and its usefulness for the management of pesticides are discussed
Predicting the contribution of a local emission source in mid-range transport of DDT and its deposition in terrestrial and aquatic ecosystems in Northern Italy
No full textA recently developed dynamic multiple box multimedia fate model (Gridded-SoilPlusVeg, or GSPV) was developed and implemented to account for the environmental variation and the effect of directional advective transport of chemicals towards different compartments and geographical locations. A chemical plant located in Pieve Vergonte in Ossola Valley produced and emitted DDTs for around 50 years. In the previous study the fate and transport of p,p’-DDT emitted from the chemical plant were evaluated in nearby areas (up to 12 km). In this paper, the GSPV model was run for p,p’-DDT from its production period and decades after the production stop in 1996 (a total of 100 years) for a much larger study area (40,000 km2) in order to evaluate the contribution of a local source on a larger scale. Additionally, the deposition fluxes into the lakes were calculated and were used as input into a dynamic fugacity-based aquatic model to calculate DDT concentration in water and sediments of three Prealpine lakes: Lake Maggiore, Lake Como and Lake Lugano. The results of the simulations were compared with the monitoring and literature data. The results obtained from GSPV allowed to estimate the atmospheric deposition fluxes and identify the role of this source for the regional scale contamination in terrestrial and aquatic ecosystems
Spatially resolved environmental fate models: A review
No full textSpatially resolved environmental models are important tools to introduce and highlight the spatial variability of the real world into modeling. Although various spatial models have been developed so far, yet the development and evaluation of these models remain a challenging task due to several difficulties related to model setup, computational cost, and obtaining high-resolution input data (e.g., monitoring and emission data). For example, atmospheric transport models can be used when high resolution predicted concentrations in atmospheric compartments are required, while spatial multimedia fate models may be preferred for regulatory risk assessment, life cycle impact assessment of chemicals, or when the partitioning of chemical substances in a multimedia environment is considered. The goal of this paper is to review and compare different spatially resolved environmental models, according to their spatial, temporal and chemical domains, with a closer insight into spatial multimedia fate models, to achieve a better understanding of their strengths and limitations. This review also points out several requirements for further improvement of existing models as well as for their integration
The effect of crop rotation on pesticide leaching in a regional pesticide risk assessment
No full textPlants radically change the mobility of PCBs in soil: Role of different species and soil conditions
No full textThe mobility of Polychlorinated Biphenyls (PCBs) in soil cultivated with different plant species was evaluated by means of a column experiment to investigate the specific plant influence on PCB environmental fate and the potential for leaching. The soil was collected at a National Relevance Site for remediation located in Northern Italy (SIN Brescia-Caffaro) and underwent a rhizoremediation treatment for 18 months with different plant species (Festuca arundinacea, Cucurbita pepo ssp pepo and Medicago sativa). The same but unplanted soil was also considered as control for comparison. The columns were leached with tap water and PCB concentrations were measured in the leachate after 7 days of soil/water contact. Soil previously cultivated with different plant species exhibited statistically different behavior in terms of chemical leaching among the different fractions. Total PCB bulk concentrations ranged from 24 to 219 ng/L. Leachate samples were enriched in tetra- to hepta-PCBs. While PCB concentrations in the dissolved phases varied within a factor of 2 between controls and treatments, PCB associated to particulate organic carbon (POC) differed by more than one order of magnitude. More specifically, Medicago sativa enriched the soil with POC doubling PCB leaching with respect to the other plant species and the unplanted controls
AGRO 76-FitoMarche: A tool to assess pesticide vulnerability maps and to estimate pesticide leaching in a stochastic way
No full textThe use of models to predict the behavior of agrochemicals has been promoted in the EU directive 91/414. A new software package to draw pesticide vulnerability maps has been developed. The tool links ESRI ArcGIS 9 with MACRO 5.0 in standalone software called FitoMarche and uses ArcObjects libraries as a middle tier. FitoMarche is easy-to-use software that allows the user to simulate pesticide behavior at different scales, depending on the detail of the input data, because part of the scenario data is taken from shape files and the rest is stored in an internal database. The tool requires shape files to describe the simulation area, the soil the land use, the rotations, and the climate. Moreover FitoMarche can be used to assess the pesticide fate using a probabilistic approach. In this case, the shape file does not contain real data but a grid where each polygon is identified by a different identification code
Estimating temporal and spatial levels of PAHs in air using rain samples and SPME analysis: Feasibility evaluation in an urban scenario
No full textThere is a growing interest in evaluating the role of concentration changes of contaminants in temporal and spatial gradients. This is often relevant for fast moving environmental phases such as air and water. In this paper, small volumes of rainwater were sampled as proxy for air concentrations of Polycyclic Aromatic Hydrocarbons (PAHs): rain was collected in three sampling sites (high traffic, restricted traffic and a low traffic zone) in Como. Solid phase micro extraction (SPME) was used for the extraction to reduce required sample volumes, allowing the acquisition of more samples in time. Rain samples highlighted a spatial and temporal variability along a traffic gradient in the Como city, especially for the most abundant PAH, e.g. phenanthrene. Air concentrations were then estimated from rain concentrations. The results show that this is a cheap and promising method, although requiring rainfall/snowfall conditions, that can be used to perform monitoring campaign of air concentrations at a higher temporal and spatial resolution than the adopted standard methods (e.g. high-volume air samplers). The results could be employed for evaluation of the exposure, emission profiles and calibration of fate models
PCBs and selected organochlorine compounds in Italian mountain air: the influence of altitude and forest ecosystem type RID E-3905-2010
No full textPassive air samplers (polyurethane foam disks) were deployed on an altitudinal transect in the rural Italian Alps to investigate the potential influence of forest cover on air concentrations. Samplers were exposed over two periods, each of several weeks, either in clearings or in forests. In the first period, there was high leaf coverage (high leaf area index, LAI); in the second, the LAI was low after the autumnal leaf fall. PCBs sequestered in the PUF generally declined with altitude, for example, in the clearings PCBs-28, 52, 90/101, 118, and 138, all showed statistically significant declines (p < 0.05). The mass of HCB sequestered increased with altitude, evidence of cold condensation. Ratios of the forest:clearing concentrations were calculated; this ratio expresses the filtering ability of forests to deplete air concentrations compared to the adjacent clearings. During the high LAI sampling period, these depletion factors ranged between 0.93 and 0.54 and were inversely correlated with temperature-corrected log K-OA. This relationship was not observed during the low LAI sampling period. The depletion factors were normalized using the LAI to give a density independent depletion factor (DIDF). The slopes of the correlations with KOA were comparable for broadleaf or coniferous forests at different altitudes, suggesting that leaf surfaces determine the exchanges with air. Broadleaf forests at 1000 and 1400 m showed similar behavior, while a conifer forest at 1800 m gave depletion factors which were higher by about a factor of 2. It is suggested that DIN can be used in regional environmental fate models to estimate the contribution of forests to contaminant fate
Caratterizzazione fitochimica e fisiologica in vitro di piante rigenerate da hairy roots
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