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921.
Teuchies J de Deckere E Bervoets L Meynendonckx J van Regenmortel S Blust R Meire P 《Environmental pollution (Barking, Essex : 1987)》2008,155(1):20-30
A historical input of trace metals into tidal marshes fringing the river Scheldt may be a cause for concern. Nevertheless, the specific physicochemical form, rather than the total concentration, determines the ecotoxicological risk of metals in the soil. In this study the effect of tidal regime on the distribution of trace metals in different compartments of the soil was investigated. As, Cd, Cu and Zn concentrations in sediment, pore water and in roots were determined along a depth profile. Total sediment metal concentrations were similar at different sites, reflecting pollution history. Pore water metal concentrations were generally higher under less flooded conditions (mean is (2.32 ± 0.08) × 10−3 mg Cd L−1 and (1.53 ± 0.03) × 10−3 mg Cd L−1). Metal concentrations associated with roots (mean is 202.47 ± 2.83 mg Cd kg−1 and 69.39 ± 0.99 mg Cd kg−1) were up to 10 times higher than sediment (mean is 20.48 ± 0.19 mg Cd kg−1 and 20.42 ± 0.21 mg Cd kg−1) metal concentrations and higher under dryer conditions. Despite high metal concentrations associated with roots, the major part of the metals in the marsh soil is still associated with the sediment as the overall biomass of roots is small compared to the sediment. 相似文献
922.
Lethal and sublethal effects of the pyrethroid, bifenthrin, on grass shrimp (Palaemonetes pugio) and sheepshead minnow (Cyprinodon variegatus) 总被引:1,自引:0,他引:1
Harper HE Pennington PL Hoguet J Fulton MH 《Journal of environmental science and health. Part. B》2008,43(6):476-483
This study investigated the lethal and sublethal effects of the pyrethroid insecticide bifenthrin on adult and larval grass shrimp, Palaemonetes pugio, and adult sheepshead minnows, Cyprinodon variegatus. The effects were determined by conducting 96-h aqueous static renewal tests and 24-h static tests with sediment. Oxidative stress biomarkers, lipid peroxidation, glutathione, and catalase were also assessed. The 96-h aqueous LC50 value for adult shrimp was 0.020 microg/L (95% CI: 0.015-0.025 microg/L) and for larval shrimp was 0.013 microg/L (95% CI: 0.011-0.016 microg/L). The 96-h aqueous LC50 for adult sheepshead minnow was 19.806 microg/L (95% CI: 11.886-47.250 microg/L). The 24-h sediment LC50 for adult shrimp was 0.339 microg/L (95% CI: 0.291-0.381 microg/L) and for larval shrimp was 0.210 microg/L (95% CI: 0.096-0.393 microg/L). The oxidative stress assays showed some increasing trends toward physiological stress with increased bifenthrin concentrations but they were largely inconclusive. Given the sensitivity of grass shrimp to this compound in laboratory bioassays, additional work will be needed to determine if these exposure levels are environmentally relevant. 相似文献
923.
Hernández-Moreno D Soler-Rodríguez F Míguez-Santiyán MP Pérez-López M 《Journal of environmental science and health. Part. B》2008,43(5):395-404
The effect of a long-term exposure of tenchs to different concentrations (10 and 100 micro g/L) of the pesticide carbofuran has been evaluated. Microsomal hepatic cytochrome P450 subfamily 1A (CYP1A) and 3A (CYP3A) activities, as well as the phase II enzyme uridine diphospho-glucuronosyltransferase (UDPGT) activity were evaluated as adequate biomarkers of fish exposure to environmentally relevant concentrations of the pesticide carbofuran in freshwater ecosystems. A clear time-dependent inhibition of both CYP1A and UDPGT activities was observed in fish exposed to the highest dose of carbofuran with respect to controls, whereas in the case of CYP3A activity, values of exposed animals did not show a clear pattern of alteration during the experiment. The results of the present study demonstrated that hepatic CYP1A and UDPGT activities from tench could be considered as sensitive biomarkers for carbamate pesticides in polluted water, thus allowing future and ecologically relevant biomonitoring studies with this species. 相似文献
924.
Ou LT Thomas JE Allen LH Vu JC Dickson DW 《Journal of environmental science and health. Part. B》2008,43(5):376-381
The purpose of this study was to conduct a field study at a Florida field site on surface emissions and subsurface distribution of cis-and trans-1,3-dichloropropene (1,3-D) and chloropicrin (CP) in raised beds injected with Telone C35 with four replications. A total of 16 beds were applied with Telone C35 by chisel injection and covered with four different plastic films, 4 beds for each film. Each bed was installed with five 20-cm long soil pore air probes and a surface air collection pan at arbitrarily locations along the length of each bed for sampling soil pore air and surface air, respectively, for analysis of the three biologically active compounds, cis- and trans-1,3-D and CP. We found that average concentrations of the three compounds at 20-cm depth among the beds covered with four different plastic films generally were not statistically different. Among the four beds covered with the same plastic film, average concentrations of the three compounds were statistically different only in the four metallic PE covered beds at 5 and 24 hours after injection. Volatilization rates of the three compounds among the beds covered with four different plastic films, with the exception of CP at 48 hours after injection, were not statistically different. It appeared that initial upward diffusion and volatilization flux were influenced by solar radiation. Initial subsurface concentrations of the three compounds and volatilization flux, especially cis-1,3-D, were greater in the beds on the east side of the field than that in the beds on the west side of the field. Whether or not difference in initial subsurface concentrations of the compounds between east side beds and west side beds may influence fumigant efficacy remains to be determined. 相似文献
925.
Cáceres TP Megharaj M Naidu R 《Journal of environmental science and health. Part. B》2008,43(7):605-610
Fenamiphos (0-ethyl-0(3-methyl-4-methylthiophenyl)-isopropylamido-phosphate) is a widely used nematicide and insecticide in bowling greens and agriculture, but information on its sorption including its metabolites is limited. Hence, the sorption of fenamiphos (nematicide) and its major degradation products fenamiphos sulfoxide (FSO) and fenamiphos sulfone (FSO2) were determined in thirteen contrasting soils collected from Australia and Ecuador. The sorption coefficients (Kd) exhibited a wide range of variation from 2.48 to 14.94 L/Kg for fenamiphos; from 0 to 7.42 L/Kg for FSO and from 0 to 9.49 L/Kg for FSO2. The sorption affinity of the three compounds for all soils tested was as follows: fenamiphos > fenamiphos sulfone > fenamiphos sulfoxide. The results showed that the sorption of fenamiphos and its metabolites in some soils is very low, and in one case is nonexistant for the metabolites. This is of particular concern as due to its low sorption coefficient, the compound could easily migrate and contaminate water bodies. Fenamiphos and its oxidation products have been reported to be highly toxic to aquatic invertebrates and therefore, the information generated in this study assumes great importance in the risk assessment of fenamiphos and its metabolites in the environment. 相似文献
926.
Ureña-Amate MD Socías-Viciana MM González-Pradas E Cantos-Molina A Villafranca-Sánchez M López-Teruel C 《Journal of environmental science and health. Part. B》2008,43(2):141-150
The adsorption of chloridazon (5-amine-4-chloro-2-phenylpyridazin-3(2H)-one) on kerolite samples heated at 110 degrees C (K-110), 200 degrees C (K-200), 400 degrees C (K-400), 600 degrees C (K-600) and acid-treated with H(2)SO(4) solutions of two different concentrations (0.25 and 0.5 M) (K-0.25 and K-0.5, respectively) from pure water at 25 degrees C has been studied by using batch and column experiments. The adsorption experimental data points were fitted to the Freundlich equation in order to calculate the adsorption capacities (K(f)) of the samples; K(f) values ranged from 184.7 mg kg(-1) (K-0.5) up to 2253 mg kg(-1) (K-600). This indicated that the heat treatment given to the kerolite greatly increases its adsorption capacity for the herbicide whereas the acid treatment produces a clear decrease in the amount of chloridazon adsorbed. The removal efficiency (R) was also calculated; R values ranging from 52.8% (K-0.5) up to 88.3% (K-600). Thus, the results showed that the 600 degrees C heat-treated kerolite was more effective in relation to adsorption of chloridazon and it might be reasonably used in removing this herbicide from water. 相似文献
927.
Farenhorst A Londry KL Nahar N Gaultier J 《Journal of environmental science and health. Part. B》2008,43(2):113-119
This study was undertaken to assess 2,4-D mineralization in an undulating cultivated field, along a sloping transect (458 m to 442 m above sea level), as a function of soil type, soil microbial communities and the sorption of 2,4-D to soil. The 2,4-D soil sorption coefficient (Kd) ranged from 1.81 to 4.28 L kg(-1), the 2,4-D first-order mineralization rate constant (k) ranged from 0.04 to 0.13 day(-1) and the total amount of 2,4-D mineralized at 130 days (M(130)) ranged from 24 to 39%. Both k and M(130) were significantly negatively associated (or correlated) with soil organic carbon content (SOC) and Kd. Both k and M(130) were significantly associated with two fatty-acid methyl esters (FAME), i17:1 and a18, but not with twenty-two other individual FAME. Imperfectly drained soils (Gleyed Dark Grey Chernozems) in lower-slopes showed significantly lesser 2,4-D mineralization relative to well-drained soils (Orthic Dark Grey Chernozems) in mid- and upper-slopes. Well-drained soils had a greater potential for 2,4-D mineralization because of greater abundance and diversity of the microbial community in these soils. However, the reduced 2,4-D mineralization in imperfectly drained soils was predominantly because of their greater SOC and increased 2,4-D sorption, limiting the bioavailability of 2,4-D for degradation. The wide range of 2,4-D sorption and mineralization in this undulating cultivated field is comparable in magnitude and extent to the variability of 2,4-D sorption and mineralization observed at a regional scale in Manitoba. As such, in-field variations in SOC and the abundance and diversity of microbial communities are determining factors that require greater attention in assessing the risk of movement of 2,4-D by runoff, eroded soil and leaching. 相似文献
928.
Aneja VP Arya SP Kim DS Rumsey IC Arkinson HL Semunegus H Bajwa KS Dickey DA Stefanski LA Todd L Mottus K Robarge WP Williams CM 《Journal of the Air & Waste Management Association (1995)》2008,58(9):1130-1144
Ammonia (NH3) fluxes from waste treatment lagoons and barns at two conventional swine farms in eastern North Carolina were measured. The waste treatment lagoon data were analyzed to elucidate the temporal (seasonal and diurnal) variability and to derive regression relationships between NH3 flux and lagoon temperature, pH and ammonium content of the lagoon, and the most relevant meteorological parameters. NH3 fluxes were measured at various sampling locations on the lagoons by a flowthrough dynamic chamber system interfaced to an environmentally controlled mobile laboratory. Two sets of open-path Fourier transform infrared (FTIR) spectrometers were also used to measure NH3 concentrations for estimating NH3 emissions from the animal housing units (barns) at the lagoon and spray technology (LST) sites. Two different types of ventilation systems were used at the two farms. Moore farm used fan ventilation, and Stokes farm used natural ventilation. The early fall and winter season intensive measurement campaigns were conducted during September 9 to October 11, 2002 (lagoon temperature ranged from 21.2 to 33.6 degrees C) and January 6 to February 2, 2003 (lagoon temperature ranged from 1.7 to 12 degrees C), respectively. Significant differences in seasonal NH3 fluxes from the waste treatment lagoons were found at both farms. Typical diurnal variation of NH3 flux with its maximum value in the afternoon was observed during both experimental periods. Exponentially increasing flux with increasing surface lagoon temperature was observed, and a linear regression relationship between logarithm of NH3 flux and lagoon surface temperature (T1) was obtained. Correlations between lagoon NH3 flux and chemical parameters, such as pH, total Kjeldahl nitrogen (TKN), and total ammoniacal nitrogen (TAN) were found to be statistically insignificant or weak. In addition to lagoon surface temperature, the difference (D) between air temperature and the lagoon surface temperature was also found to influence the NH3 flux, especially when D > 0 (i.e., air hotter than lagoon). This hot-air effect is included in the statistical-observational model obtained in this study, which was used further in the companion study (Part II), to compare the emissions from potential environmental superior technologies to evaluate the effectiveness of each technology. 相似文献
929.
George P. Ingersoll M. Alisa Mast Donald H. Campbell David W. Clow Leora Nanus John T. Turk 《Atmospheric environment (Oxford, England : 1994)》2008,42(24):6098-6113
Seasonal snowpack chemistry data from the Rocky Mountain region of the US was examined to identify long-term trends in concentration and chemical deposition in snow and in snow-water equivalent. For the period 1993–2004, comparisons of trends were made between 54 Rocky Mountain Snowpack sites and 16 National Atmospheric Deposition Program wetfall sites located nearby in the region. The region was divided into three subregions: Northern, Central, and Southern. A non-parametric correlation method known as the Regional Kendall Test was used. This technique collectively computed the slope, direction, and probability of trend for several sites at once in each of the Northern, Central, and Southern Rockies subregions. Seasonal Kendall tests were used to evaluate trends at individual sites.Significant trends occurred during the period in wetfall and snowpack concentrations and deposition, and in precipitation. For the comparison, trends in concentrations of ammonium, nitrate, and sulfate for the two networks were in fair agreement. In several cases, increases in ammonium and nitrate concentrations, and decreases in sulfate concentrations for both wetfall and snowpack were consistent in the three subregions. However, deposition patterns between wetfall and snowpack more often were opposite, particularly for ammonium and nitrate. Decreases in ammonium and nitrate deposition in wetfall in the central and southern rockies subregions mostly were moderately significant (p<0.11) in constrast to highly significant increases in snowpack (p<0.02). These opposite trends likely are explained by different rates of declining precipitation during the recent drought (1999–2004) and increasing concentration. Furthermore, dry deposition was an important factor in total deposition of nitrogen in the region. Sulfate deposition decreased with moderate to high significance in all three subregions in both wetfall and snowpack. Precipitation trends consistently were downward and significant for wetfall, snowpack, and snow-telemetry data for the central and southern rockies subregions (p<0.03), while no trends were noted for the Northern Rockies subregion. 相似文献
930.