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Identification, Apportionment, and Photochemical Reactivity of Non-methane Hydrocarbon Sources in Busan, Korea Полный текст
2011
Choi, Eunhwa | Heo, Jong-Bae | Hopke, Philip K. | Jin, Byong-Bok | Yi, Seung-Muk
Hourly concentrations of non-methane hydrocarbons (NMHCs) recorded between June and August 2006, at two monitoring sites (Gijang and Jin) in Busan were analyzed to examine the characteristics and photochemical reactivity of NMHC sources. The two sites represent urban (Jin) and suburban (Gijang) Busan, which is a typical Korean city. Positive matrix factorization (PMF), applied to identify and apportion the sources of NMHCs, revealed nine sources for Gijang and ten sources for Jin. To explore the contribution of each NMHC source to ozone formation at the two sampling sites, the ozone formation potential was estimated for each source. The largest contributors to ozone formation were sources characterized by 1,2,3-trimethylbenzene (26.4%) at Gijang and by toluene, ethylbenzene, and xylenes (22.5%) at Jin, which were composed mostly of heavy hydrocarbons and aromatics. Secondary sources included two coating sources (20.9%, 12.2%) and vehicle exhaust (10.3%) at Gijang and a source represented by toluene (17.4%), vehicle exhaust (15.9%), and a coating-2 source (9.6%) at Jin. Conditional probability function (CPF) and potential source contribution function (PSCF) analysis methods were used to identify the directions of local sources and to locate potential source regions, respectively. The CPF and PSCF results agreed well for the majority of sources resolved by PMF and thus were very useful in identifying the major sources contributing to ozone formation at the two study sites.
Показать больше [+] Меньше [-]Vulnerability of Coastal Aquifers Due to Nutrient Pollution from Agriculture: Kalpitiya, Sri Lanka Полный текст
2011
Jayasingha, Pathmakumara | Pitawala, A. | Dharmagunawardhane, H. A.
This study focuses on spatial and temporal nutrient pollution of groundwater in the unconfined sandy aquifers of Kalpitiya peninsula, Sri Lanka, where agricultural activities are intense. The study covers two consecutive dry and rainy seasons during the period from 2008 to 2010. Nitrate is the dominant nutrient pollutant in groundwater. The values of Nitrate-N contents ranged from 0.60 to 212.40 mg/L in the dry seasons and 0.20–148.50 mg/L in rainy seasons. Phosphate in groundwater ranged from 0.20 to 5.70 mg/L in dry seasons and 0.04–10.35 mg/L with few exceptions in rainy seasons. About 50% of the studied water samples had Nitrate-N concentrations above WHO drinking water guideline values both in dry and rainy periods. These high concentrations were recorded from wells in agricultural lands. Although there is a slight decrease in the Nitrate-N concentrations at random in rainy seasons, an increasing trend of average concentrations became evident over the study period as a whole, probably indicating building up of Nitrate-N in groundwater in the vegetable growing areas. The spatial distribution of Nitrate-N too shows a good match of high Nitrate-N bearing zones with vegetable cultivated areas indicating intensive leaching from application of excessive chemical fertilizers. High Nitrate-N zones also showed fairly steady lateral distribution indicating slow lateral mobility of Nitrate-rich groundwater probably due to low hydraulic gradients. Low phosphate concentrations in both groundwater and surface soils either indicates their less use in the area or that the available phosphate is leached and removed from the aquifer water and (sandy) soil solutions and probably adsorbed in clayey deeper horizons. Low concentrations of major cations (especially K, Ca, and Na) indicate less impact on cation concentrations in groundwater by the fertilizer application or sea water intrusions/up-coning.
Показать больше [+] Меньше [-]Risk Assessment of Ingestion of Arsenic-Contaminated Water among Adults in Bandlaguda, India Полный текст
2011
Aneena S. Pokkamthanam | Anne M. Riederer | Raghupathy Anchala
Background. The Indian Government describes the Patancheru Industrial Development Area (IDA) near Hyderabad as a heavily polluted site. Previous studies show levels of arsenic in ground and surface water that exceed the national drinking water standard. Objectives. We conducted a pilot study to characterize potential non-cancer and cancer risks associated with ingesting arsenic-contaminated water by adult residents of Bandlaguda, a village in the Patancheru IDA. Methods. We used United States Environmental Protection Agency (USEPA) equations to calculate hazard quotients (for non-cancer outcomes) and excess cancer risks. Inputs included information on water sources and consumption that we collected from a representative sample of residents using a standardized questionnaire, and arsenic concentration data from a previous study. We calculated point estimates of risk and used @RISK software to conduct probabilistic simulations and perform sensitivity analyses. Results. In both the point and probabilistic analyses, the mean hazard quotients exceeded 1 for both men and women, indicating potentially elevated risk of non-cancer outcomes. Mean lifetime excess cancer risks using the USEPA default 70-year life expectancy were 0.01 (i.e., 1 in 100) for men and 0.006 (i.e., 6 in 1,000) for women. Mean excess risks using Indian life expectancies were 0.01 for men and 0.007 for women. Sensitivity analyses identified the reference dose and cancer slope factor as the most influential input variables. Conclusions. Our results show that arsenic in water consumed by Bandlaguda adults may be associated with both non-cancer and cancer risks. There is an urgent need to identify unsafe sources of drinking water in this community and educate residents on the hazards of using them.
Показать больше [+] Меньше [-]Gorlovka Chemical Plant: Addressing a Piece of the Toxic Soviet Legacy Полный текст
2011
Andrew McCartor, JD | Ira P. May, BS
Background. The Gorlovka chemical plant is an abandoned industrial complex in the Donetsk region of Ukraine. The facility produced toxic mononitrochlorobenzene (MNCB) and explosive trinitrotoluene (TNT) until it was abruptly abandoned in 2001. The plant is now the subject of a cleanup project coordinated by a broad group of stakeholders, including the government of Ukraine, regional and municipal authorities, the international not-for-profit Blacksmith Institute, institutional and private sector donors, and local contractors. Objectives. Remediation efforts at the Gorlovka chemical plant complex aim to reduce environmental health risks to the local community by removing remaining stocks of MNCB and TNT, and analyzing soil and groundwater for potential contamination. Discussion. The Gorlovka Chemical Plant is one of many toxic sites left from Soviet industrial activities. Throughout Russia, Eastern Europe and Central Asia, former Soviet states are discovering and trying to deal with polluted sites that pose extraordinary risks to human health. Because many of these sites and facilities were secret under Soviet rule, the governments that emerged after the fall of the USSR are still not fully aware of the location and characteristics of sites within their borders. Conclusions. A successful remediation project at the Gorlovka Chemical Plant could serve as a model for future efforts to engage local, national and international stakeholders in the cleanup of complex legacy pollution sites in the former Soviet Union and around the world. Financial Disclosure. None reported
Показать больше [+] Меньше [-]Microbiological Quality and Antibiotic Resistance Analysis of a Brazilian Water Supply Source Полный текст
2011
da Silva, Trajano Felipe Barrabas Xavier | Ramos, Débora Toledo | Dziedzic, Maurício | de Oliveira, Cíntia Mara Ribas | de Vasconcelos, Eliane Carvalho
Water samples of the Passaúna River, Curitiba/Paraná (Brazil), were analyzed to determine total and thermotolerant coliform counts and Escherichia coli in order to provide information on human impacts on the water supply. Samples were collected and analyzed monthly, from March 2006 to February 2007, at five different locations along the river, and the multiple tube method was used to obtain total and thermotolerant coliform counts. The results varied from 130 MPN/100 mL to 1.6 × 106 MPN/100 mL for total coliforms, while for thermotolerant coliforms the variation was between 40 MPN/100 mL and 5 × 105 MPN/100 mL. The E. coli strains isolated from the samples were tested with 13 different antibiotics to determine their antibiotic resistance. The isolated strains were constantly sensitive to seven of the 13 antibiotics tested, and resistant to at least one of the other antibiotics. The results indicated that two factors could influence the increased contamination on this river, viz., seasonality parameters and domestic wastewater discharges. The determination of antibiotic resistance indices aimed to provide information on the anthropogenic influence. Only one of the locations investigated was considered critical due to the anthropogenic influence, with significant impacts from irregular domestic wastewater discharges.
Показать больше [+] Меньше [-]Population Density of Brown Trout (Salmo trutta) in Extremely Dilute Water Qualities in Mountain Lakes in Southwestern Norway Полный текст
2011
Enge, Espen | Kroglund, Frode
We have examined populations of brown trout in low-conductivity mountain lakes (5.0–13.7 μS/cm and 0.14–0.41 mg/l Ca) in southwestern Norway during the period 2000–2010. Inlets to the lakes were occasionally even more dilute (2007; conductivity = 2.9–4.8 μS/cm and Ca = 0.06–0.17 mg/l). The combination of pH and conductivity was the best predictor to fish status (CPUE), indicating that availability of essential ions was the primary restricting factor to fish populations in these extremely diluted water qualities. We suggest that conductivity <5 μS/cm is detrimental to early life stages of brown trout, and subsequently that there are lakes in these mountains having too low conductivity to support self-reproducing trout populations. Limited significance of alkalinity, Ca, Al, and color suggests that effects of ion deficit apparently overruled the effects of other parameters.
Показать больше [+] Меньше [-]UV-TiO2 Photocatalytic Degradation of Landfill Leachate Полный текст
2011
Jia, Chenzhong | Wang, Yanxin | Zhang, Caixiang | Qin, Qiaoyan
Mature landfill leachate contains some macromolecular organic substances that are resistant to biodegradation. The photocatalytic process helps to enhance biodegradability of landfill leachate. Batch experiments were employed to determine the optimum conditions for removal of organic matter by UV-TiO2 photocatalysis. Under optimum conditions, the removal of chemical oxygen demand (COD), dissolved organic carbon (DOC), biological oxygen demand (BOD), and color was determined. Moreover, gas chromatography coupled with mass spectrometry (GC/MS) was used to analyze the organic matter in the treated leachate before and after treatment by the photocatalysis. The experimental results indicated that the removal of COD, DOC, and color by UV-TiO2 photocatalysis could reach above 60%, 70% and 97%, respectively. Under optimal conditions, the ratio of biological oxygen demand (BOD)/chemical oxygen demand (COD) was elevated from 0.09 to 0.39, representing substantial improvement in biodegradability. GC/MS analysis revealed that 37 out of 72 kinds of organic pollutants in the leachate remained after 72 h treatment. Esters were produced during photocatalytic process and ketones, hydrocarbons, aromatic hydrocarbons, hydroxybenzenes, and acids were easier to be degraded during photocatalytic oxidation processes. The UV-TiO2 photocatalysis systems proposed may be a cost-effective approach for pre-treatment of landfill leachate.
Показать больше [+] Меньше [-]Removal of Cyanide in Ni(II)–Cyanide, Ni(II)–Cyanide–EDTA, and Electroplating Rinse Wastewater by Ferrate(VI) Полный текст
2011
Osathaphan, Khemarath | Tiyanont, Patarawan | Yngard, Ria A. | Sharma, Virender K.
Cyanide is found as free cyanide and metal–cyanide complexes in metal finishing rinse wastewaters. Experiments were performed to seek removal of cyanide in Ni(II)–cyanide and Ni(II)–cyanide–ethylenediaminetetraacetate (EDTA) solutions by the environmentally friendly oxidant, ferrate(VI) (FeO4 2−, Fe(VI)) as a function of pH (8.0–11.0). Incomplete removal of cyanide in Ni(II)–cyanide solutions (≤60%) was observed at the studied pH range. However, cyanide removal efficiency approached to 100% in Ni(II)–cyanide–EDTA solutions. Formation of Ni(II)–cyanide and Ni(II)–EDTA complexes and relative rates of the reactions of Fe(VI) with various species (water, cyanide, Ni(II)–cyanide, and EDTA) present in solutions were responsible for the variation in removal efficiencies in mixtures at various pH. The oxidation of cyanide by Fe(VI) produced cyanate. Tests using electroplating rinse wastewaters demonstrated that Fe(VI) was highly effective in removing cyanide.
Показать больше [+] Меньше [-]Fate of Heavy Metals in an Urban Natural Wetland: The Nyabugogo Swamp (Rwanda) Полный текст
2011
Sekomo, Christian B. | Nkuranga, Egide | Rousseau, Diederik P. L. | Lens, P. N. L. (Piet N. L)
The Nyabugogo natural wetland (Kigali City, Rwanda) receives all kinds of untreated wastewaters, including those from industrial areas. This study monitored heavy metal concentrations (Cd, Cr, Cu, Pb, and Zn) in all environmental compartments of the swamp: water and sediment, the dominant plant species Cyperus papyrus, and fish (Clarias sp. and Oreochromis sp.) and Oligochaetes. Cr, Cu, and Zn concentrations in the water were generally below the WHO (2008) drinking water standards, whereas Cd and Pb were consistently above these limits. Except Cd, all metal concentrations were below the threshold levels for irrigation. The highest metal accumulation occurred in the sediment with up to 4.2 mg/kg for Cd, 68 mg/kg for Cu, 58.3 mg/kg for Pb, and 188.0 mg/kg for Zn, followed by accumulation in the roots of C. papyrus with up to 4.2 mg/kg for Cd, 45.8 mg/kg for Cr, 29.7 mg/kg for Cu, and 56.1 mg/kg for Pb. Except Cu and Zn, other heavy metal (Cd, Cr, and Pb) concentrations were high in Clarias sp., Oreochromis sp., and Oligochaetes. Therefore, there is a human health concern for people using water and products from the swamp.
Показать больше [+] Меньше [-]Manure as a Source of Antibiotic-Resistant Escherichia coli and Enterococci: a Case Study of a Wisconsin, USA Family Dairy Farm Полный текст
2011
Walczak, Jacob J. | Xu, Shangping
The spread of antibiotic-resistant bacteria in the environment is raising serious public health concerns, and manure is being increasingly recognized as a major source of antibiotic-resistant bacteria. In this research, we isolated Escherichia coli and enterococci from manure produced in a Wisconsin, USA family dairy farm to determine their resistance to six representative antibiotics. The average densities for E. coli and enterococci were 6.37(±4.38)â×â107 colony formation units (CFU)âg−1 and 1.60(±1.57)â×â104 CFU g−1, respectively. The E. coli isolates were found to be resistant to cephalothin, ampicillin, tetracycline, and erythromycin. In addition to these four antibiotics, the Enterococcus isolates were also resistant to gentamicin and ciprofloxacin. Additionally, we examined the survival and growth of E. coli and enterococci in dairy manure over a period of ~3 days. While the densities of enterococci remained stable over the study period, the concentrations of E. coli on average increased by 1.5 log10 units. Further tests of the bacterial antibiotic resistance over time showed no significant changes in the prevalence of antibiotic resistance. This result indicated that slightly aged manure could represent a larger source of antibiotic-resistant E. coli than fresh manure and the accumulation of antibiotic-resistant E. coli and enterococci in the agricultural fields must be accounted for in the modeling of the spread of antibiotic-resistant bacteria in the environment.
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