DiMIZA : a dispersion modeling based impact zone assessment of mercury (Hg) emissions from coal-fired power plants and risk evaluation for inhalation exposure

Coal-fired combined heat and power plants (CHPPs) serving large districts are among the major sources of mercury (Hg) emissions globally, including Central Asia. Most CHPPs reside on the outskirts of urban areas, thus creating risk zones. The impact of atmospheric Hg levels on health is complex to establish due to the site-specific nature of the relationship between CHPP emissions and hotspots (i.e., localized areas where Hg concentrations greatly exceed its background value). However, a methodological identification of "emission impact zones" for atmospheric Hg emissions from CHPPs with potential adverse public health outcomes has not yet been fully studied. The present work suggests an easy-to-use and cost-free impact zone identification method based on HYSPLIT dispersion modeling for atmospheric Hg emissions from CHPPs. The dispersion modeling based impact zone assessment, DiMIZA, merges short-term dispersion runs (e.g., hourly) into long-term emission impacts (e.g., yearly), which allows to identify the source impact zones. To perform a case study using the suggested method, a CHPP plant in Nur-Sultan (capital of Kazakhstan) was selected. First, traditional ad-hoc measurements were performed to identify the level of dispersions at ground level in different atmospheric stability characteristics. Then, HYSPLIT dispersion model was run for the same days and times of those particular periods when the field measurements were performed. The model results were evaluated via a comparison with the ground measurements and assessed for their atmospheric stability and diel conditions. Due to different emission loads in heating and non-heating periods, two separate pairs of impact zone maps were generated, and public Hg exposure health risks (acute and chronic) were assessed

Trends in Pesticide Concentrations in Streams of the Western United States, 1993-20051

Trends in pesticide concentrations for 15 streams in California, Oregon, Washington, and Idaho were determined for the organophosphate insecticides chlorpyrifos and diazinon and the herbicides atrazine, s-ethyl diproplythiocarbamate (EPTC), metolachlor, simazine, and trifluralin. A parametric regression model was used to account for flow, seasonality, and antecedent hydrologic conditions and thereby estimate trends in pesticide concentrations in streams arising from changes in use amount and application method in their associated catchments. Decreasing trends most often were observed for diazinon, and reflect the shift to alternative pesticides by farmers, commercial applicators, and homeowners because of use restrictions and product cancelation. Consistent trends were observed for several herbicides, including upward trends in simazine at urban-influenced sites from 2000 to 2005, and downward trends in atrazine and EPTC at agricultural sites from the mid-1990s to 2005. The model provided additional information about pesticide occurrence and transport in the modeled streams. Two examples are presented and briefly discussed: (1) timing of peak concentrations for individual compounds varied greatly across this geographic gradient because of different application periods and the effects of local rain patterns, irrigation, and soil drainage and (2) reconstructions of continuous diazinon concentrations at sites in California are used to evaluate compliance with total maximum daily load targets

Phytotoxicity, cytotoxicity and genotoxicity evaluation of organic and inorganic pollutants rich tannery wastewater from a Common Effluent Treatment Plant (CETP) in Unnao district, India using Vigna radiata and Allium cepa

The leather industry is a major source of environmental pollution in India. The wastewater generated by leather industries contains very high pollution parameters due to the presence of a complex mixture of organic and inorganic pollutants even after the treatment at a Common Effluent Treatment Plant (CETP) and disturbs the ecological flora and fauna. The nature, characteristics and toxicity of CETP treated wastewater is yet to be fully elucidated. Thus, this study aims to characterize and evaluate the toxicity of CETP treated tannery wastewater collected from the Unnao district of Uttar Pradesh, India. In addition to measuring the physico-chemical parameters, the residual organic pollutants was identified by GC-MS analysis and phytotoxicity, cytotoxicity and genotoxicity of the treated wastewater was evaluated using Vigna radiata L. and Allium cepa L. Results showed that the treated wastewater contained very high pollution parameters (TDS 3850mg/L, BOD 680mg/L, COD-1300mg/L). GC-MS analysis revealed the presence of various types of residual organic pollutants including benzoic acid, 3-[4,-(T-butyl) Phenyl] furan-2-5-dione, benzeneacetamide, resorcinol, dibutyl phthalate, and benzene-1,2,4-triol. Further, toxicological studies showed the phytotoxic nature of the wastewater as it inhibited seed germination in V. radiata L. and root growth of A. cepa. Genotoxicity was evidenced in the root tip cell of A. cepa where chromosomal aberrations (stickiness, chromosome loss, C-mitosis, and vagrant chromosome) and nuclear abnormalities like micronucleated and binucleated cells were observed. Thus, results suggested that it is not safe to discharge these wastewater into the environment

Human exposure to hydrogen sulphide concentrations near wastewater treatment plants

The hydrogen sulphide (H2S) levels from wastewater treatment plants (WWTPs) in Curitiba, Brazil have been quantified for the first time. H2S generated by anaerobic decomposition of organic matter in WWTPs is a cause for concern because it is an air pollutant, which can cause eye and respiratory irritation, headaches, and nausea. Considering the requirement for WWTPs in all communities, it is necessary to assess the concentrations and effects of gases such as H2S on populations living and/or working near WWTPs. The primary objective of this study was to evaluate the indoor and outdoor concentration of H2S in the neighbourhood of two WWTPs located in Curitiba, as well as its human health impacts. Between August 2013 and March 2014 eight sampling campaigns were performed using passive samplers and the analyses were carried out by spectrophotometry, presenting mean concentrations ranging from 0.14 to 32 μg m− 3. Eleven points at WWTP-A reported H2S average concentrations above the WHO recommendation of 10 μg m− 3, and 15 points above the US EPA guideline of 2 μg m− 3. At WWTP-B the H2S concentration was above US EPA guideline at all the sampling points. The I/O ratio on the different sampling sites showed accumulation of indoor H2S in some instances and result in exacerbating the exposure of the residents. The highest H2S concentrations were recorded during the summer in houses located closest to the sewage treatment stations, and towards the main wind direction, showing the importance of these factors when planning a WWTP. Lifetime risk assessments of hydrogen sulphide exposure showed a significant non-carcinogenic adverse health risk for local residents and workers, especially those close to anaerobic WWTPs. The data indicated that WWTPs operated under these conditions should be recognized as a significant air pollution source, putting local populations at risk