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81.
Fishes were collected at 16 sites within the three major river drainages (Delaware, Susquehanna, and Ohio) of Pennsylvania. Three species were evaluated for biomarkers of estrogenic/antiandrogenic exposure, including plasma vitellogenin and testicular oocytes in male fishes. Smallmouth bass Micropterus dolomieu, white sucker Catostomus commersonii, and redhorse sucker Moxostoma species were collected in the summer, a period of low flow and low reproductive activity. Smallmouth bass were the only species in which testicular oocytes were observed; however, measurable concentrations of plasma vitellogenin were found in male bass and white sucker. The percentage of male bass with testicular oocytes ranged from 10 to 100 %, with the highest prevalence and severity in bass collected in the Susquehanna drainage. The percentage of males with plasma vitellogenin ranged from 0 to 100 % in both bass and sucker. Biological findings were compared with chemical analyses of discrete water samples collected at the time of fish collections. Estrone concentrations correlated with testicular oocytes prevalence and severity and with the percentage of male bass with vitellogenin. No correlations were noted with the percentage of male sucker with vitellogenin and water chemical concentrations. The prevalence and severity of testicular oocytes in bass also correlated with the percent of agricultural land use in the watershed above a site. Two sites within the Susquehanna drainage and one in the Delaware were immediately downstream of wastewater treatment plants to compare results with upstream fish. The percentage of male bass with testicular oocytes was not consistently higher downstream; however, severity did tend to increase downstream.  相似文献   
82.
We reviewed published results to estimate no-till effects on SOC and denitrification in the Argentine Pampas and the potential of no-till to mitigate the global warming effect. On an equivalent mass basis, 42 paired data sets were used for SOC comparisons of no-till vs. plow till (moldboard plow or disk plow), 18 paired data for comparison of no-till vs. reduced till (chisel plow or harrow disk), and 20 paired data for comparison of plow till vs. reduced till. Twenty-six denitrification data sets were used for evaluation of tillage system and fertilization effects on N2O emission. Changes in SOC under no-till were not correlated to time since initiation of experiments. Averaged over years a 2.76 Mg ha(-1) SOC increase (P = 0.01) was observed in no-till systems compared with tilled systems, but no differences were detected between plow and reduced till. The SOC under tillage explained most of the SOC variation under no-till (R2= 0.94, P = 0.01). The model had a positive intercept and predicted a relatively higher increase of SOC in areas of low organic matter level. The conversion of the whole pampean cropping area to no-till would increase SOC by 74 Tg C, about twice the annual C emissions from fossil fuel consumption of Argentina. Emissions of N2O were greater under no-till with a mean increase of 1 kg N ha(-1) yr(-1) in denitrification rate for humid pampean scenarios. The increased emissions of N2O might overcome the mitigation potential of no-till due to C sequestration in about 35 yr, and therefore no-till might produce global warming.  相似文献   
83.
To fully utilize semipermeable membrane devices (SPMDs) as passive samplers in air monitoring, data are required to accurately estimate airborne concentrations of environmental contaminants. Limited uptake rate constants (kua) and no SPMD air partitioning coefficient (Ksa) existed for vapor-phase contaminants. This research was conducted to expand the existing body of kinetic data for SPMD air sampling by determining kua and Ksa for a number of airborne contaminants including the chemical classes: polycyclic aromatic hydrocarbons, organochlorine pesticides, brominated diphenyl ethers, phthalate esters, synthetic pyrethroids, and organophosphate/organosulfur pesticides. The kuas were obtained for 48 of 50 chemicals investigated and ranged from 0.03 to 3.07 m3 g?1 d?1. In cases where uptake was approaching equilibrium, Ksas were approximated. Ksa values (no units) were determined or estimated for 48 of the chemicals investigated and ranging from 3.84E+5 to 7.34E+7. This research utilized a test system (United States Patent 6,877,724 B1) which afforded the capability to generate and maintain constant concentrations of vapor-phase chemical mixtures. The test system and experimental design employed gave reproducible results during experimental runs spanning more than two years. This reproducibility was shown by obtaining mean kua values (n = 3) of anthracene and p,p′-DDE at 0.96 and 1.57 m3 g?1 d?1 with relative standard deviations of 8.4% and 8.6% respectively.  相似文献   
84.
Y. Ku  G. Alvarez 《Chemosphere》1982,11(1):41-46
N-Phenyl-β-naphthylamine, a widely used rubber antioxidant and antiozonant, was biotransformed into β-naphthylamine, a potent carcinogen, in a laboratory sewage sludge system. β-Naphthylamine appeared to accumulate in the aqueous phase of the system while the undegraded parent compound appeared to be associated with the sludge solids.  相似文献   
85.
Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of (14)C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% (14)CO(2) when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02.  相似文献   
86.
Sulfide generation should be avoided during wastewater transportation. The efficiency of nitrate dosing for the inhibition of sulfide generation was evaluated during reclaimed wastewater transport with two nitrate doses, 2.5 and 5 mg/L nitrate-nitrogen (NO3-N). A calcium nitrate [Ca(NO3)2] solution was injected at the beginning of the 61-km-long gravity pipe, which is part of the Reclaimed Wastewater Reuse System of South Tenerife (Spain). During transportation, after dissolved oxygen depletion, a denitrification process took place. With the 5 mg/L NO3-N dose, nitrate was not completely removed at the end of the pipe, whereas with 2.5 mg/L NO3-N, a complete denitrification was achieved. Sulfide generation was completely inhibited with the 5 mg/L dose. However, with 2.5 mg/L, sulfide generation was not completely inhibited but delayed and minimized to a great extent. Denitrification was stoichiometrically limited by the availability in biodegradable matter. An empirical equation enables one to predict the nitrate concentration.  相似文献   
87.
During Late Proterozoic times, the Archaean Central African craton was affected by trough faulting which led to the formation of grabens, the Sangha aulacogen being the main structure of this type in the studied area. This transverse basin connects with other basins on the northern and south-western borders of the craton. During the Cryogenian, this network of basins was filled with fluvio-deltaic and lacustrine periglacial deposits. The glacio-eustatic transgression in Neoproterozoic III (end-Proterozoic) times flooded extensive areas of shelf on the northern edge of the craton, leading to the development of carbonate sedimentation in a broad outer shelf environment associated with nearshore barriers and evaporitic lagoons. These facies are similar to those developed in the West Congolian Schisto-calcaire (shale-limestone) ramp succession. The North-Central African ramp succession (sediment slope) contains an example of tidal rhythmites in vertical accretion, which occurs beneath the barrier deposits on the subtidal outer shelf. Mathematical analysis of the bedding pattern yields a period of 29–30 days for the lunar month, a result which is in agreement with astrophysical evidence for this epoch (i.e. 650 Ma ago). Major subsidence and seismic activity on this gently sloping platform, associated with the proximity of the Sangha aulacogen, caused the triggering of carbonate turbidites and mass flow deposits. The proliferation of microbial mats under euphotic conditions on an extensive shelf led to the build-up of a carbonate platform. During early Neoproterozoic III times, the West Congolian and North-Central African ramps prograded northwards and southwards, respectively, into the Sangha aulacogen. The sea at that time was restricted to a long graben-like basin, while a remaining area of marine sedimentation persisted into the Palaeozoic. Thus the pattern of end-Proterozoic carbonate sedimentation on the borders of the Central African craton can be interpreted in terms of an overall gently sloping ramp model with progradation converging towards the Sangha aulacogen.  相似文献   
88.
This study was carried out in male Wistar rats to determine the potential effects of chlorpyrifos (CHP) on oxidative stress, as was reported for organophosphorus (OP) pesticides. Following an acute, daily 3- or 14-day exposure with CHP at doses of 2.5, 5, or 25 mg kg?1 data showed significant increases in malondialdehyde levels at both exposure durations and at all doses, except for 2.5 mg kg?1, in hepatic and aorta, kidney, and plasma samples. The nitrites (NO) showed elevation at 25 mg kg?1 in aorta, at 3- and 14-day exposure, in hepatic tissue with all doses at 3-day exposure, but not at 14-day with a 5 mg kg?1 dose. In plasma, increases occurred only at 25 mg kg?1 at both exposure times, and in kidney at all doses and both exposure durations. Superoxide dismutase (SOD) enzyme activity in the aorta sample was statistically significant at all doses at 3 days and at 14 days, except at 2.5 mg kg?1; and in hepatic tissue only at 25 mg kg?1 dose at both durations. In plasma SOD activity was elevated at all doses at 3 days, but at 14 days only at 25 mg kg?1. Data suggests that oxidative stress may be involved in the effects of CHP on rats.  相似文献   
89.
PCB and PCT residues were measured in free‐living (FM) and cultivated mussels (CM) from ten sites in Galicia by gas chromatography with electron capture detector and capillary column. The level of PCB1260 and PCT5460 in FMs increases going from Muros‐Noya to Vigo estuarine bay. There was a trend of increase from north to south.  相似文献   
90.
The STRATEGY project (Sustainable Restoration and Long-Term Management of Contaminated Rural, Urban and Industrial Ecosystems) aimed to provide a holistic decision framework for the selection of optimal restoration strategies for the long-term sustainable management of contaminated areas in Western Europe. A critical evaluation was carried out of countermeasures and waste disposal options, from which compendia of state-of-the-art restoration methods were compiled. A decision support system capable of optimising spatially varying restoration strategies, that considered the level of averted dose, costs (including those of waste disposal) and environmental side effects was developed. Appropriate methods of estimating indirect costs associated with side effects and of communicating with stakeholders were identified. The importance of stakeholder consultation at a local level and of ensuring that any response is site and scenario specific were emphasised. A value matrix approach was suggested as a method of addressing social and ethical issues within the decision-making process, and was designed to be compatible with both the countermeasure compendia and the decision support system. The applicability and usefulness of STRATEGY outputs for food production systems in the medium to long term is assessed.  相似文献   
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