Water quality in a non-traditional off-stream polyethylene-lined reservoir

Annual water storage in a 5.3 ha, polyethylene-lined, off-stream irrigation reservoir in northern Alabama, USA, resulted in marked improvement in water quality. Results of three-year monitoring from June 1999 to May 2002 indicate that the relatively static conditions of the reservoir enhanced settling of suspended particles by 85% (from 14.4 to 2.1 mg TSS/L) that cleared the water and increased sunlight penetration. The organic and inorganic particles that settled to the bottom removed up to 88% of the nutrients and other chemical substances from the water. Nutrients remaining in the water column were rapidly assimilated by phytoplankton algae. With the basin sealed at the bottom and no runoff input there was limited opportunity for nutrients or other substances to enter the reservoir in quantities that would adversely affect water quality. Consequently, reservoir water was found to be of high quality and suitable as a raw water supply. Non-traditional, off-stream storage reservoirs such as described in this paper may be uniquely suited for agricultural irrigation and public water supply in regions such as southeastern US that experience relatively frequent drought conditions but have relatively abundant long-term annual rainfall.     

Nitrogen dynamics among cropland and riparian buffers: soil-landscape influences

Nitrate (NO3-) leaching to ground water poses water quality concerns in some settings. Riparian buffers have been advocated to reduce excess ground water NO3- concentrations. We characterized inorganic N in soil solution and shallow ground water for 16 paired cropland-riparian plots from 2003 to 2005. The sites were located at two private dairy farms in Central New York on silt and gravelly silt loam soils (Aeric Endoaqualfs, Fluvaquentic Endoaquepts, Fluvaquentic Eutrudepts, Glossaquic Hapludalfs, and Glossic Hapludalfs). It was hypothesized that cropland N inputs and soil-landscape variability would jointly affect NO3- leaching and transformations in ground water. Results showed that well and moderately well drained fields had consistently higher ground water NO3- compared to more imperfectly drained fields receiving comparable N inputs. Average 50-cm depth soil solution NO3- and ground water dissolved oxygen (DO) explained 64% of average cropland ground water NO3- variability. Cropland ground water with an average DO of <3 mg L(-1) tended to have <4 mg L(-1) of NO3- with a water table depth (WTD) of 相似文献   

Distribution and transportability of hexabromocyclododecane (HBCD) in the Asia-Pacific region using skipjack tuna as a bioindicator

The geographical distribution of hexabromocyclododecane (HBCD) was investigated through analysis of muscle tissue of skipjack tuna (Katsuwonus pelamis) collected from offshore waters of Asia-Pacific region (Japan, Taiwan, Philippines, Indonesia, Seychelles, Brazil, Japan Sea, East China Sea, South China Sea, Indian Ocean and North Pacific Ocean). HBCD was detected in almost all samples analyzed (<0.1 to 45 ng/g lipid weight basis), indicating widespread presence of this compound in the marine environment. Elevated concentrations of HBCD were found in skipjack tuna from areas around Japan, which have the larger modern industrial/urban societies, and implicated these areas as primary regional sources. All three individual HBCD isomers (alpha-, gamma- and beta-HBCD) were detected in almost all samples; the percentage contribution of the alpha-isomer to total HBCD increased with increasing latitude. The estimated empirical 1/2 distance for alpha-HBCD was 8500 km, which is one of the highest atmospheric transportability among various halogenated persistent organic pollutants (POPs).     

Air quality measurements for the aerosol research and inhalation epidemiology study

Measurements of pollutant gases, airborne particulate matter mass and composition, and meteorology have been made at a core site near downtown Atlanta, GA, since August 1998 in support of the Aerosol Research and Inhalation Epidemiology Study (ARIES). This site is one of eight in the Southeastern Aerosol Research and Characterization network. The measurement objective is to provide a long-term, multivariate dataset suitable for investigating statistical associations of respiratory and cardiovascular disease with airborne particulate matter composition, meteorology, and copollutant gases through epidemiologic modeling. Measurements are expected to continue through 2010. Ancillary multiyear measurements at additional sites in the Atlanta metropolitan area and in short-term exposure assessments have been used to estimate the exposure/measurement error associated with using data from a central site to approximate human exposures for the entire area. To date, 13-, 25-, and 53-month air quality datasets have been used in epidemiologic analyses.     

Effects of instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, Georgia

Data from the U.S. Environmental Protection Agency Air Quality System, the Southeastern Aerosol Research and Characterization database, and the Assessment of Spatial Aerosol Composition in Atlanta database for 1999 through 2002 have been used to characterize error associated with instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, GA. These data are being used in time series epidemiologic studies in which associations of acute respiratory and cardiovascular health outcomes and daily ambient air pollutant levels are assessed. Modified semivariograms are used to quantify the effects of instrument precision and spatial variability on the assessment of daily metrics of ambient gaseous pollutants (SO2, CO, NOx, and O3) and fine particulate matter ([PM2.5] PM2.5 mass, sulfate, nitrate, ammonium, elemental carbon [EC], and organic carbon [OC]). Variation because of instrument imprecision represented 7-40% of the temporal variation in the daily pollutant measures and was largest for the PM2.5 EC and OC. Spatial variability was greatest for primary pollutants (SO2, CO, NOx, and EC). Population-weighted variation in daily ambient air pollutant levels because of both instrument imprecision and spatial variability ranged from 20% of the temporal variation for O3 to 70% of the temporal variation for SO2 and EC. Wind     

Synthesis and application of titanium dioxide photocatalysis for energy,decontamination and viral disinfection: a review

Environmental Chemistry Letters - Global pollution is calling for advanced methods to remove contaminants from water and wastewater, such as&nbsp;TiO2-assisted photocatalysis.&nbsp; The...     

The viticultural system and climate change: coping with long-term trends in temperature and rainfall in Roussillon,France

Mediterranean viticulture could suffer from hotter and drier growing seasons over the coming decades. The present article focuses on the wine-producing area Côtes-du-Roussillon-Villages near Perpignan, in southern France. We used observational daily data (1925–2010) from Perpignan weather station and daily outputs (2001–2060) of the regional climate model ARPEGE-RETIC-V4 from Météo-France with scenarios A2, A1B and B1, to assess the exposure of the regional wine system to changes in temperature and precipitation, both in the recent past and the coming decades (1925–2060). Temperatures during the growing season and summer temperature extremes have been increasing continuously since the mid-1980s and are projected to increase faster from the mid-2040s. Precipitation is highly variable and very low in summer, and projections suggest greater uncertainty, and more extreme drought events could be expected. The analysis of climate data was complemented by thirty-two in-depth interviews with local actors of the wine industry to assess the impacts of climate change on their activities and potential adaptive options. Producers reported negative impacts of recent changes in climate in conjunction with a difficult economic situation. Analyses of historical, social and economic backgrounds are important to fully conceptualize the nature and extent of climate change risks in the region. This case study provides important insights into the roles of non-climatic factors in the generation of vulnerability for Mediterranean agricultural systems facing rapid climate change.     

A probabilistic hazard and risk assessment of exposure to metals and organohalogens associated with a traditional diet in the Indigenous communities of Eeyou Istchee (northern Quebec,Canada)

Environmental Science and Pollution Research - Hunting, trapping, and fishing are part of an Indigenous lifestyle in subarctic Canada. However, this lifestyle may be a route of exposure to...     

A model of fishing vessel accident probability

Problem: Commercial fishing is one of the least safe occupations. Method: The researchers develop a fishing vessel accident probability model for fishing areas off the northeastern United States using logit regression and daily data from 1981 to 1993. Results: The results indicate that fishing vessel accident probability declined over the study period. Higher wind speed is associated with greater accident probability. Medium-size vessels have the highest accident probability, while small vessels have the lowest. Within the study region, accident probability is lower in the southwestern section than in the northeastern section. Accidents are likely to occur closer to shore than offshore. Accident probability is lowest in spring. Impact on Industry: The probability model is an important building block in development and quantitative assessment of management mechanisms related to safety in the commercial fishing industry.     

Chlorinated Solvent Treatment Wetland

A first‐of‐its‐kind wetland restoration project was completed in October 2000 to treat trichloroethene‐(TCE‐)impacted groundwater from a former manufacturing facility prior to discharge into a highly valued recreational surface water body in the upper Midwest. This article summarizes the design, construction, operation, and effectiveness of the restored wetland. The groundwater‐surface water discharge zone at the site was restored as a wetland to improve the natural degradation of TCE and subsequent degradation by‐products. For the past 11 years, the treatment wetland performance was evaluated by monitoring the wetland vegetation, wetland hydraulics, and water chemistry. Water quality data have been used to assess the wetland geochemistry, TCE and TCE‐degradation by‐product concentrations within the wetland, and the surface water quality immediately downgradient of the wetland. The treatment wetland has been performing according to design, with TCE and TCE‐degradation by‐products not exceeding surface water criteria. The monitoring results show that TCE and TCE‐degradation by‐products are entering the treatment wetland via natural hydraulic gradients and that the geochemistry of the wetland supports both reductive dechlorination (anaerobic degradation) and cometabolic degradation (aerobic degradation) of TCE and TCE‐degradation by‐products: cis‐ and trans‐1,2‐dichloroethene and vinyl chloride. © 2013 Wiley Periodicals, Inc.