Biological monitoring of chlorpyrifos exposure to rice farmers in Vietnam

Chlorpyrifos is the most common organophosphate insecticide registered for use in Vietnam and is widely used in agriculture, particularly rice farming. However, chlorpyrifos exposure to and adverse effects on farmers has not been evaluated. In this study, biological monitoring of chlorpyrifos exposure in a group of rice farmers was conducted after a typical application event using back-pack spraying.Urine samples (24 h) were collected from the rice farmers before and post insecticide application. Samples were analysed for 3,5,6-trichloropyridinol (TCP), the major urinary metabolite of chlorpyrifos, using an enzymatic pre-treatment before extraction followed by HPLC-MS/MS. Absorbed Daily Dose (ADD) of chlorpyrifos for farmers were then estimated from urinary TCP levels, expressed as μg g⁻¹ creatinine. The analytical method for urinary TCP had a low detection limit (0.6 μg L⁻¹), acceptable recovery values (80-114%), and low relative percentage differences in duplicate and repeated samples.Post-application chlorpyrifos ADD of farmers varied from 0.4 to 94.2 μg kg⁻¹ (body weight) d⁻¹ with a mean of 19.4 μg kg⁻¹ d⁻¹ which was approximately 80-fold higher than the mean baseline exposure level (0.24 μg kg⁻¹ d⁻¹). Hazard Quotients (ratio of the mean ADD for rice farmers to acute oral reference dose) calculated using acute oral reference doses recommended by United States and Australian agencies varied from 2.1 (Australian NRA), 4.2 (US EPA) to 6.9 (ATSDR).Biological monitoring using HPLC-MS/MS analysis of urinary TCP (24 h) was found to be an effective method for measuring chlorpyrifos exposure among farmers. This case study found that Vietnamese rice farmers had relatively high exposures to chlorpyrifos after application, which were likely to have adverse health effects.     

Bioaccumulation of butyltins and liver damage in the demersal fish Cathorops spixii (Siluriformes,Ariidae)

The toxicity of butyltin compounds (BTs), mainly tributyltin (TBT), has been reported in different organisms. However, such an analysis in fish after field exposure with reference to the related biomarkers has not been commonly observed in the literature. This study presents the uptake of BTs in the liver of a neotropical marine catfish Cathorops spixii in Paranagua Bay, an important estuarine system located in southern Brazil. Two different areas, close to and distant from the harbor, were used for chemical analysis evaluation of hepatotoxicity through genetic, enzymatic, and histopathological biomarkers. The presence of polycyclic aromatic hydrocarbons in bile was also considered as a biomarker. The results showed a significant relationship between TBT levels and the inhibition of biotransformation enzymes and high occurrence of melanomacrophages in fish collected close to the harbor site. These effects were linked to the absence of TBT metabolites in the liver. In the second site, the presence of DBT was associated with an increase in EROD and GST activity. The larger amount of DNA damage as well as the highest oxidative stress was noted in fish from the less TBT-polluted area, where DBT and bile PAHs occurred. These findings showed different impact levels due to or increased by the chronic exposure of biota to BTs.     

Kinetics of the oxidation of sucralose and related carbohydrates by ferrate(VI)

The kinetics of the oxidation of sucralose, an emerging contaminant, and related monosaccharides and disaccharides by ferrate(VI) (Fe(VI)) were studied as a function of pH (6.5-10.1) at 25°C. Reducing sugars (glucose, fructose, and maltose) reacted faster with Fe(VI) than did the non-reducing sugar sucrose or its chlorinated derivative, sucralose. Second-order rate constants of the reactions of Fe(VI) with sucralose and disaccharides decreased with an increase in pH. The pH dependence was modeled by considering the reactivity of species of Fe(VI), (HFeO(4)(-) and FeO(4)(2-)) with the studied substrates. Second-order rate constants for the reaction of Fe(VI) with monosaccharides displayed an unusual variation with pH and were explained by considering the involvement of hydroxide in catalyzing the ring opening of the cyclic form of the carbohydrate at increased pH. The rate constants for the reactions of carbohydrates with Fe(VI) were compared with those for other oxidant species used in water treatment and were briefly discussed.     

Effects of doping amounts of potassium ferricyanide with titanium dioxide and calcination durations on visible-light degradation of pharmaceuticals

Acetaminophen (ACT) is one of the most frequently detected pharmaceuticals in aqueous environments, and treatment of ACT were generally carried out by photocatalytic degradations under high energy UV irradiation. In this study, potassium ferricyanide was utilized as a quadruple-elemental dopant in a TiO₂ photocatalyst in order to enhance its visible-light activity. Two critical parameters (amounts of dopants and durations of calcination) of the synthesis of the photocatalyst by a sol–gel method were systematically evaluated. Crystal structure of the doping TiO₂ was examined by X-ray diffraction while the effects of the two parameters on the photocatalytic activity were elucidated by various characterizations. Increasing the amount of dopant or the duration of calcination red-shifted the UV–vis DRS of the doped TiO₂. The estimated band gap energy of the doped TiO₂ decreased slightly as the amount of dopant increased, but it increased as the duration of calcination increased. The FT-IR yielded characteristic peaks that revealed the effects of the two parameters, whereas the SEM images revealed the morphological evolutions of each effect. The photocatalyst, synthesized at optimum conditions was able to remove 99.1 % acetaminophen with rate constant of 7.9 × 10⁻³ min⁻¹, which was 4.88 times greater than virgin TiO₂. In general, this study not only optimized synthetic conditions of the new visible-light active photocatalyst for ACT degradation but also presented characterizations conducted by SEM, XRD, UV–vis DRS, and FTIR to elucidate the relationship between modified structure and the photocatalytic activity.

Effects of doping amounts of K₃[Fe(CN)₆] and calcunation duration on visible light absorbance of TiO₂ photocatalysts

     

From wetland to farm and back again: phosphorus dynamics of a proposed restoration project

We studied the phosphorus dynamics in a former wetland, which had been converted to a celery farm, and now consists of two shallow, flooded ponds that are being proposed for aquatic habitat restoration. However, like many agricultural areas, this site is plagued by phosphorus legacy issues. Proposed restoration includes hydrologic reconnection of these ponds to its adjacent stream, which are now isolated from one another by an earthen berm, to create a wetland complex. One of the two flooded ponds was partially dredged, whereas the other one has remained undredged. Water column, sediment pore water, and sediment total phosphorus concentrations were significantly greater in the undredged pond compared to the dredged pond, but in both cases phosphorus levels in the water columns (mean TP 929 vs. 133 μg/L in undredged vs. dredged ponds, respectively) would exacerbate downstream water quality issues if hydrologic reconnection occurred without first addressing the phosphorus issue. Sediment isotherm and maximum sorption data indicated that the sediments are close to phosphorus saturation in the undredged pond; simulated dredging of the cores revealed that exposure of deeper sediment layers would increase sorption capacity. Pore water SRP concentrations increased with sediment depth and were significantly greater in the undredged vs. dredged pond at both the 1–4-cm depth (2249 vs. 112 μg/L) and 14–17-cm depth (5506 vs. 222 μg/L). This study provides a framework for other projects that need to balance the competing demands of habitat restoration vs. water quality when restoring wetlands that have been converted to agricultural production.

     

Residues of organochlorine pesticides and PCBs in some Brazilian municipal solid waste compost

Persistent organic pollutants (POPs), organochlorine pesticides and polychlorinated biphenyls (PCBs), listed as per the Stockholm Convention (α -HCH, β -HCH, γ -HCH, p,p′-DDT, o,p′-DDT, p,p′-DDD, p,p′-DDE, aldrin, endrin, dieldrin, PCBs 28, 52, 118, 138, 153, and 180), were analyzed in municipal solid waste (MSW) compost samples from three different Brazilian composting plants located in three São Paulo State cities: Araras, Araraquara and São Paulo (Vila Leopoldinha). Quantitative and qualitative analyses were carried out using gas chromatography electron capture detection (GC-ECD) and gas chromatography mass spectrometry (GC-MS) (Ion Trap, electron impact ionization), respectively. The samples were analyzed in triplicate and the target POPs were not detected by GC-ECD. Twelve pollutants were identified in two samples when qualitative analysis (GC-MS) was used (β -HCH, γ -HCH, p,p′-DDT, o,p′-DDT, p,p′-DDD, and p,p′-DDE, PCBs 28, 118, 138, 153 and 180). The composting process has advantages such as urban solid waste reduction and landfill life-span increase, however the MSW compost quality, which can be utilized for agricultural purposes, should be evaluated and be controlled. This kind of study is the first step in making available information to answer questions regarding MSW compost for sustainable agricultural use, such as the pollutants accumulation in soil and in groundwater, and plants uptake.     

Effect of the Pittsburgh Air Pollution Episode upon Pulmonary Function in School Children

Due to increasing atmospheric concentrations of participates, five of Allegheny County’s seven monitoring areas were placed on first stage air pollution alert by November 18,1975. The Liberty Borough area reached second stage alert, and then emergency stage the morning of November 19. An investigation was mounted to determine whether these emergency levels of par-ticulates had an effect upon the pulmonary function of school children sufficiently severe that it would require several days for pulmonary function to return to normal. Beginning November 20 in two schools and November 21 in four additional schools, the three-quarter second forced expiratory volume (FEV.75) and the forced vital capacity (FVC) of approximately 270 parochial school children in fourth, fifth, and sixth grades were tested daily through November 26. Two schools, approximately 80 children, were in control areas; the remaining children were exposed to high or very high levels of particulate air pollution with significant levels of sulfur oxides. If a severe effect of pollution on pulmonary function occurred, one would expect daily measurements to tend upward in children in the four schools in polluted areas and to remain more or less steady in the two control areas. Analyses of the data yielded no indications of such an effect of air pollution upon the lung function of the school children studied. Pulmonary function values declined very slightly in all six schools over the study period. Unexplained variability over a weekend was observed.     

EPA SITE Demonstration of the International Waste Technologies/Geo-Con In Situ Stabilization/Solidification Process

This paper presents an EPA evaluation of the first field demonstration of an in situ stabilization/solidification process for contaminated soil under the EPA Superfund Innovative Technology Evaluation (SITE) program. Demonstration of this process was a joint effort of two vendors: ? International Waste Technologies (IWT) of Wichita, Kansas, who provided the treatment process, specifically the proprietary additive called HWT-20, and

? Geo-Con, Inc., of Pittsburgh, Pennsylvania, who provided both engineering and hardware for the in situ soil treatment.

The field demonstration took place in April, 1988 at a site in Hialeah, Florida, contaminated mainly with polychlorinated biphenyls (PCBs). EPA tested the soil before and after treatment and the EPA evaluation of this process is based on results from this testing. A year later, in April 1989, EPA tested again the treated soil and results of that testing were compared to those of the demonstration. Results of the EPA evaluation of the IWT process, the Geo-Con performance, and treatment costs are discussed separately.     

Secondhand smoke exposure is associated with smoke-free laws but not urban/rural status

The objective was to determine secondhand smoke (SHS) exposure with and without smoke-free laws in urban and rural communities. The research hypothesis was that SHS exposure in public places could be improved by smoke-free law regardless of urban and rural status. Indoor air quality in hospitality venues was assessed in 53 communities (16 urban and 37 rural) before smoke-free laws; 12 communities passed smoke-free laws during the study period. Real-time measurements of particulate matter with 2.5 µm aerodynamic diameter or smaller (PM_2.5) were taken 657 times from 586 distinct venues; about 71 venues had both pre- and post-law measurements. Predictors of log-transformed PM_2.5 level were determined using multilevel modeling. With covariates of county-level percent minority population, percent with at least high school education, adult smoking rate, and venue-level smoker density, indoor air quality was associated with smoke-free policy status and venue type and their interaction. The geometric means for restaurants, bars, and other public places in communities without smoke-free policies were 22, 63, and 25 times higher than in those with smoke-free laws, respectively. Indoor air quality was not associated with urban status of venue, and none of the interactions involving urban status were significant. SHS exposure in public places did not differ by urban/rural status. Indoor air quality was associated with smoke-free law status and venue type.

Implications:?This study analyzed 657 measurements of indoor PM_2.5 level in 53 communities in Kentucky, USA. Although indoor air quality in public places was associated with smoke-free policy status and venue type, it did not differ by urban and rural status. The finding supports the idea that population in rural communities can be protected with smoke-free policy. Therefore, it is critical to implement smoke-free policy in rural communities as well as urban areas.     

Environmental controls on denitrifying communities and denitrification rates: insights from molecular methods.

The advent of molecular techniques has improved our understanding of the microbial communities responsible for denitrification and is beginning to address their role in controlling denitrification processes. There is a large diversity of bacteria, archaea, and fungi capable of denitrification, and their community composition is structured by long-term environmental drivers. The range of temperature and moisture conditions, substrate availability, competition, and disturbances have long-lasting legacies on denitrifier community structure. These communities may differ in physiology, environmental tolerances to pH and O2, growth rate, and enzyme kinetics. Although factors such as O2, pH, C availability, and NO3- pools affect instantaneous rates, these drivers act through the biotic community. This review summarizes the results of molecular investigations of denitrifier communities in natural environments and provides a framework for developing future research for addressing connections between denitrifier community structure and function.