Designing ambient particulate matter monitoring program for source apportionment study by receptor modeling

Particulate matter (PM) receptor modeling requires specific intensive input data that is always a challenge to produce cost effectively. A well-designed monitoring program is important to collect such PM ambient data in urban areas with diverse and densely distributed sources. This paper presents a general framework for designing such a monitoring program while emphasizing appropriate quality assurance and quality control elements that are particularly applicable where limited resources are available. Topics for discussion include selection of monitoring sites, sampling and analytical techniques, and the uncertainty estimation for ambient concentration input data. The design framework is illustrated by a case study of a monitoring program for PM source apportionment in the Bangkok Metropolitan Region in which 24-h fine and coarse PM samples were collected using two collocated dichotomous samplers. Comparison between black carbon measurements by Smoke Stain reflectometry and Thermal Optical Transmittance method is highlighted.     

Effects of radiative forcing by black carbon aerosol on spring rainfall decrease over Southeast Asia

The effects of black carbon (BC) aerosol radiative forcing on spring rainfall in Southeast Asia are studied using numerical simulations with the NASA finite-volume General Circulation Model (fvGCM) forced with monthly varying three-dimensional aerosol distributions from the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART).During the boreal spring, March–April–May (MAM), BC from local emissions accumulates over Southeast Asia. The BC aerosol layer, which extends from the surface to higher elevation above planetary boundary layer (PBL), absorbs solar radiation and heats the mid-troposphere through a semi-direct effect over regions of large aerosol optical thickness (AOT) and thereby significantly perturbs large-scale and meridional circulations. Results show that anomalous precipitation patterns and associated large-scale circulations induced by radiative forcing by BC aerosol can explain observed precipitation reductions, especially over Southeast Asia. Therefore, BC aerosol forcing may be one of the important factors affecting the spring rainfall trend over Southeast Asia.     

Indoor radon distribution of subway stations in a Korean major city

The overall survey on indoor radon concentration was conducted at all subway stations in a major city, Daejeon in the central part of Korea. It was quarterly performed from September 2007 to August 2008. The annual arithmetic mean of indoor radon concentration of all the stations was 34.1 ± 14.7 Bq m⁻³, and the range of values was from 9.4 to 98.2 Bq m⁻³. The radon concentrations in groundwater (average 31.0 ± 0.8 Bq m⁻³) were not significantly high in most stations, but the concentration (177.9 ± 2.3 Bq L⁻¹) of one station was over the level of 148 Bq L⁻¹ in drinking water proposed by U.S. EPA. Based on indoor survey results, the approximate average of the annual effective dose by radon inhalation to the employees and passengers were 0.24 mSv y⁻¹, and 0.02 mSv y⁻¹, respectively. Although the effective dose based on the UNSCEAR report was potentially estimated, for more accurate assessment, the additional survey on the influence by indoor radon will be necessary.     

Food security and seasonal climate information: Kenyan challenges

This article examines challenges to food security in areas especially vulnerable to the effects of climate variability and change, and the potential contribution of seasonal climate forecasting. Drawing on long-term study of the way environmental information is developed and circulates, and on recent fieldwork in Western Kenya, the article describes how climate variability exacerbates food insecurity; the kinds of climate information that are now being developed; and the kinds of technologies, organizations, and expertise that will be needed if new forms of climate information are to benefit vulnerable populations. Findings indicate that new forms of expertise need to be developed at all scales, and that linkage among stakeholders and between organizations functioning at different scales will be a considerable challenge.     

Supplementation of nitrocompounds in broiler diets: Effects on bird performance,ammonia volatilization and nitrogen retention in broiler manure

A study was conducted to evaluate the effects of dietary nitrocompounds on bird performance, ammonia volatilization, and changes in manure nitrogen (N). A total of 200 one-day-old male chicks (Cobb 500) were used for this study. The chicks were raised in electrically heated battery brooders for 18 days. On day 1, birds were allocated into five treatment groups with four replicated pens: (T1) control, a corn and soybean meal diet (3,100 kcal kg^?1 metabolizable energy (ME) and 21% Crude Protein (CP)); (T2) 16.7 mg kg^?1 nitroethanol (NEL); (T3) 33.3 mg kg^?1 NEL; (T4) 16.7 mg kg^?1 nitropropanol (NPL); and (T5) 33.3 mg kg^?1 NPL. The body weight gain, feed intake and feed efficiency were measured on days 7, 14 and 18. Volatized ammonia (VA) and other N forms were measured at collection and following 2 weeks of incubation at 30°C. Broiler growth was not adversely affected by the nitrocompounds at concentrations up to 33.3 mg kg^?1. The results show that initial manure pH was reduced by adding nitroethanol (NEL) and nitropropanol (NPL) to the diet by 0.2 and 0.5 pH units, respectively. Total VA after 2 weeks was unaffected by dietary treatment. The amounts of uric acid decomposed and ammonia produced were closely balanced in the control sample. However, this balance was significantly different among the manures produced by birds receiving nitrocompound treatments. The inclusion of NEL and NPL resulted in the presence of measurable amounts of Xanthine not found in the control group. This study indicates that supplementation of nitroethanol or nitropropanol into broiler diets up to 33.3 mg kg^?1 influences uric acid degradation and ammonia production in broiler manure while maintaining optimal growth performance.     

1H-NMR-based metabolomic study on toxicity of methomyl and methidathion in fish

A ¹H-nuclear magnetic resonance (NMR) spectroscopy with multivariate analysis was applied to detect the toxicity of antiacetylcholinesterase insecticides, methomyl (methyl (1E)-N-(methylcarbamoyloxy)ethanimidothioate) and methidathion (3-(dimethoxyphosphinothioyl sulfanylmethyl)-5-methoxy-1,3,4-thiadiazol-2-one), using zebrafish (Danio rerio) and Chinese bleak (Aphyocypris chinensis). Generally, methomyl and methidathion have been believed not to highly accumulate in fish tissues. However, these pesticides showed their toxicity by altering patterns of whole-body metabolites in neurotransmitter balance, energy metabolism, oxidative stress, and muscle maintenance in low concentrations. We used Pearson correlation analysis to contextualize the metabolic markers in pesticide treated groups. We observed that the positive correlations of choline with acetate and betaine in untreated control were shifted to null correlations showing acetylcholinesterase specific toxicity. This research demonstrated the applicability and potential of NMR metabolomics in detecting toxic effects of insecticide with a modicum of concentrations in aquatic environment.     

Effect of incineration on the removal of key offensive odorants released from a landfill leachate treatment station (LLTS)

As a basic means to control odorants released from a landfill leachate treatment station (LLTS), effluents venting from this station were treated via incineration with methane rich landfill gas (at 750 °C). A list of the key offensive odorants covering 22 chemicals was measured by collecting those gas samples both before and after the treatment. Upon incineration, the concentration levels of most odorants decreased drastically below threshold levels. The sum of odorant intensities (SOIs), if compared between before and after incineration, decreased from 6.94 (intolerable level) to 3.45 (distinct level). The results indicate that the thermal incineration method can be used as a highly efficient tool to remove most common odorants (e.g., reduced sulfur species), while it is not so for certain volatile species (e.g., carbonyls, fatty acids, etc.).     

Enzymatic and microbial transformation assays for the evaluation of the environmental fate of diclofenac and its metabolites

Diclofenac has been of environmental concern due to the potential harmful effects on non-target organisms at environmentally relevant concentrations. In this study, we evaluated the transformation kinetics of diclofenac and its two major metabolites in two laboratory-scale experiments: the transformation of diclofenac in the presence of rat liver S9 fraction with co-factors, and the transformation of diclofenac, 4′-hydroxy-diclofenac and diclofenac β-O-acyl glucuronide in the inoculum used for the OECD 301C ready-biodegradability test. 4′-Hydroxy-diclofenac was identified as the major phase I metabolite and diclofenac β-O-acyl glucuronide was identified as the major phase II metabolite in the S9 assay. Transformation of diclofenac in the microbial degradation test did not occur significantly for 28 d, whereas 4′-hydroxy-diclofenac degraded slowly, indicating that the biological removal of diclofenac is not likely to occur in conventional STPs unless sorptive removal is significant. However, diclofenac β-O-acyl glucuronide deconjugated to form equimolar diclofenac within 7 d, in the microbial degradation test. The mixture of diclofenac and its two metabolites, formed after incubating diclofenac in S9 medium for 2 h, was spiked in the inoculum to link both assays. The concentrations of diclofenac and its metabolites, measured over time, agreed well with predicted values, using rate parameters obtained from independent experiments. The results show that phase II metabolites generated in mammals may deconjugate easily in conventional STPs to form a parent compound and that these processes should be considered during the environmental monitoring and risk assessment of diclofenac.