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871.
Haith DA Lee PC Clark JM Roy GR Imboden MJ Walden RR 《Journal of environmental quality》2002,31(3):724-729
Pesticide volatilization models are typically based on equilibrium partitioning of the chemical into solid, liquid, and gaseous phases in the soil environment. In turf systems direct vaporization from vegetation surfaces is a more likely source, and it is difficult to apply equilibrium methods to plant material due to the uncertainties of solid-liquid-gas partitioning. An alternative approach is to assume that pesticide volatilization is governed by the same processes that affect water evaporation. A model was developed in which evapotranspiration values, as determined by the Penman equation, were adjusted to chemical vaporization using ratios of water and chemical saturated vapor pressures and latent heats of vaporization. The model also assumes first-order degradation of pesticide on turf vegetation over time. The model was tested by comparisons of predictions with measurements of volatilization for eight pesticides measured during 3 to 7 d in 11 field experiments. Measured volatilization fluxes ranged from 0.1 to 22% of applied chemical. Pesticides were divided into two groups based on saturated vapor pressures and organic C partition coefficients. One pesticide was selected from each group to calibrate the model's volatilization constant for the group, and the remaining pesticides were used for model testing. Testing results indicated that the model provides relatively conservative estimates of pesticide volatilization. Predicted mean losses exceeded observations by 20%, and the model explained 67% of the observed variation in volatilization fluxes. The model was most accurate for those chemicals that exhibited the largest volatilization losses. 相似文献
872.
Periyayya Uthirakumar Madhu Devendiran Subramaniyam Kalaiarasan Son Hoki Lee In-Hwan 《Environmental science and pollution research international》2021,28(6):6459-6469
Environmental Science and Pollution Research - A simple oxidation method for preparing CuO nanodisks on a flexible Cu sheet is presented. The crystal structure of as-prepared CuO nanodisks was... 相似文献
873.
Wen Huwei Lee Chien-Chiang Song Ziyu 《Environmental science and pollution research international》2021,28(39):54826-54841
Environmental Science and Pollution Research - Despite the increasing use of digital technology in industrial production, how industrial digitalization affects the environmental performance of... 相似文献
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Hsi-Hsien Yang Shao-Wei Luo Kuei-Ting Lee Jhin-Yan Wu Chun Wei Chang Pei Feng Chu 《Journal of the Air & Waste Management Association (1995)》2016,66(8):807-814
In this study, fine particulate matter (PM2.5) emitted from a municipal solid waste incinerator (MSWI) was collected using dilution sampling method. Chemical compositions of the collected PM2.5 samples, including carbon content, metal elements, and water-soluble ions, were analyzed. Traditional in-stack hot sampling was simultaneously conducted to compare the influences of dilution on PM2.5 emissions and the characteristics of the bonded chemical species. The results, established by a dilution sampling method, show that PM2.5 and total particulate matter (TPM) emission factors were 61.6 ± 4.52 and 66.1 ± 5.27 g ton-waste?1, respectively. The average ratio of PM2.5/TPM is 0.93, indicating that more than 90% of PM emission from the MSWI was fine particulate. The major chemical species in PM2.5 included organic carbon (OC), Cl?, NH4+, elemental carbon (EC) and Si, which account for 69.7% of PM2.5 mass. OC was from the unburned carbon in the exhaust, which adsorbed onto the particulate during the cooling process. High Cl? emission is primarily attributable to wastes containing plastic bags made of polyvinyl chloride, salt in kitchen refuse and waste biomass, and so on. Minor species that account for 0.01–1% of PM2.5 mass included SO42-, K+, Na, K, NO3?, Al, Ca2+, Zn, Ca, Cu, Fe, Pb, and Mg. The mean ratio of dilution method/in-stack hot method was 0.454. The contents of water-soluble ions (Cl?, SO42-, NO3?) were significantly enriched in PM2.5 via gas-to-particle conversion in the dilution process. Results indicate that in-stack hot sampling would underestimate levels of these species in PM2.5.Implications: PM2.5 samples from a municipal solid waste incinerator (MSWI) were collected simultaneously by a dilution sampling technique and a traditional in-stack method. PM2.5 emission factors and chemical speciation profiles were established. Dilution sampling provides more reliable data than in-stack hot sampling. The results can be applied to estimate the PM2.5 emission inventories of MSWI, and the source profile can be used for contribution estimate of chemical mass balance modeling. 相似文献
878.
The current conceptual hydrogeologic model established for source water to the Amargosa River was tested in order to help inform management decisions regarding the Amargosa River's Federal designation as Wild and Scenic through an Act of Congress. The limited availability of water in this region results in the critical need for effective management in the basin to maintain its Wild and Scenic attributes inclusive of habitat for several endangered and threatened species. The use of forensic tools and integration of multiple lines of geologic, hydrogeologic, geochemical, and stable isotopic evidence suggest that the simple historical model for primary groundwater transport through this region is incorrect and that a large supply of regional baseflow does not provide the hydrogeological foundation of the Amargosa River basin. Data collected is consistent with an alternative model requiring complex source mixing and shallow alluvial groundwater that supports river flow. This conclusion also suggests Wild and Scenic conditions in this basin are more precarious than previously understood. 相似文献
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Effects of acid and nitrogen depositions on soil microbial activities were studied in a laboratory-based experiment. Five treatments were added to forest soil for five weeks, and soil enzyme activities were determined along with chemical properties. There was little change in pH and nitrogen availability. Dehydrogenase, phosphatase and arylsulphatase activities were decreased by all the acidic treatments compared to the control, while urease activity was increased by the pH 4 treatment. at the same pH treatment, different nitric acid contents induced different urease activities. the results suggest that acid deposition would inhibit microbial activities and that more study is needed to elucidate the impact on nitrogen cycling in forests. 相似文献