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.     

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.     

Polybrominated diphenyl ethers (PBDE) in serum: findings from a US cohort of consumers of sport-caught fish

Polybrominated diphenyl ethers (PBDEs) have been used as flame retardants in foams, fabrics and plastics, and are common contaminants of household air and dust and bioaccumulate in wildlife, and are detectable in human tissues and in fish and animal food products. In the Great Lakes Basin sport fish consumption has been demonstrated to be an important source of PCB and DDE exposure. PBDEs are present in the same sport fish but prior to our study the contribution to human PBDE body burdens from Great Lakes sport fish consumption had not been investigated. This study was designed to assess PBDE, PCB and 1,1-bis(4-chlorophenyl)-2,2-dichloroethene (DDE) serum concentrations in an existing cohort of 508 frequent and infrequent consumers of sport-caught fish living in five Great Lake states. BDE congeners 47 and 99 were identified in the majority of blood samples, 98% and 62% respectively. summation operatorPBDE levels were positively associated with age, hours spent outdoors, DDE, summation operatorPCB, years of sportfish consumption, and catfish and shellfish intake, and negatively associated with income and recent weight loss. Other dietary components collected were not predictive of measured summation operatorPBDE levels. In multivariate models, summation operatorPBDE levels were positively associated with age, years consuming sport fish, shellfish meals, and computer use and negatively associated with recent weight loss. Having summation operatorPBDE levels in the highest quintile was independently associated with older age, male gender, consumption of catfish and shellfish, computer use and spending less time indoors. summation operatorPCB and DDE were strongly associated suggesting common exposure routes. The association between summation operatorPBDE and summation operatorPCB or DDE was much weaker and modeling suggested more diverse PBDE sources with few identified multi-contaminant-shared exposure routes. In our cohort Great Lakes sport fish consumption does not contribute strongly to PBDE exposure.     

A Benefit‐Cost Analysis of Total Maximum Daily Load Implementation1

Abstract: Total Maximum Daily Load (TMDL) implementation generates benefits and costs from water quality improvements, which are rarely quantified. This analysis examines a TMDL written to address bacteria and aquatic‐life‐use impairments on Abrams and Opequon Creeks in Virginia. Benefits were estimated using a contingent valuation survey of local residents. Costs were based on the number and type of best management practices (BMPs) necessary to achieve TMDL pollution reduction goals. BMPs were quantified using watershed‐scale water quality simulation models (Generalized Watershed Loading Function and Hydrological Simulation Program‐FORTRAN). Based on our projections, the costs to achieve TMDL induced pollution reduction goals outweigh the estimated benefits. Benefit‐cost ratios ranged between 0.1 and 0.3.     

Evaluation of alternative approaches for screening contaminated sediments and soils for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans

Traditional high resolution mass spectrometry (HRMS) analysis for polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) can be time consuming and expensive. Consequently, alternative methods are of great interest to regulatory agencies and others characterizing contaminated sites. One factor that hinders acceptance of alternative methods is a lack of performance information that assesses the alternative method's impacts on analytical results. The U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation Monitoring and Measurement Technologies Program (EPA SITE MMT) encourages the development and implementation of innovative and alternative monitoring methods by providing performance information on site characterization technologies. This paper presents a comparison of the results obtained from laboratory-based alternative approaches for screening sediment and soil samples for dioxin toxicity equivalents (TEQ(D/F)) to results obtained using traditional HRMS. The laboratory-based approaches included modifying the traditional HRMS analysis to make it more cost-effective (alternate 1613B), analyzing extracts that had been prepared for HRMS using low resolution mass spectrometry, and determining total organic carbon (TOC) content as an indicator of PCDD/F content. These comparisons demonstrated that TEQ(D/F) values generated using toxicity equivalency factors proposed by the World Health Organization in 1998 applied to alternate 1613B and LRMS analyses have a strong linear correlation to the TEQ(D/F) values derived in the same fashion from traditional HRMS analysis. These results would have placed >90% of the samples within the same concentration intervals using ranges of <0.05, 0.05-0.50, 0.50-5, and >5ng TEQ/g. Natural log transformed data for TOC had significantly weaker correlation to TEQ(D/F), indicating that TOC is not a reliable indicator of TEQ(D/F) concentrations.     

Patterns of Predation Risk and Survival of Bird Nests in a Chilean Agricultural Landscape

Abstract: We used experimental nests baited with California Quail (  Callipepla californica ) eggs or clay eggs to examine relative risks of nest predation in an agricultural landscape and in two large forest preserves in a south-temperate rainforest in Chile. The most common predators, as identified by marks on clay eggs, were a caracara (   Milvago chimango ), a blackbird ( Curaeus curaeus ), and rodents. Nest losses from predation were similar in large and small forest patches and lower in patches than in extensive forest. In general, predation risk was higher (and nest survival therefore lower) on forest edges than in forest interior, in short-grass pasture than in tall-grass pasture, in narrow corridors than in wide corridors, and on visible nests than on concealed nests. High predation risks in pasture habitat tended to increase the risk of nest predation in adjacent forest edges. For open-cup nesters, the risk of nest predation was relatively high in the present agricultural landscape, indicating that much of the available wooded habitat (  forest edges, narrow corridors) offers poor nesting habitat, although it may be suitable for foraging and traveling. The numerous bird-plant mutualisms in this landscape may be at risk if nesting success of the principal mutualists is consistently low.     

Improving Peer Review of Listings and Recovery Plans under the Endangered Species Act

Abstract: We discuss several challenges encountered in peer review of Endangered Species Act listings and recovery plans, with particular attention to Meffe et al.'s (1998) statement on independent scientific review in natural resource management. First, Endangered Species Act listing documents and recovery plans pose a diverse array of scientific questions, and we suggest that overall effectiveness of peer review may be increased by segregating the critical issues and identifying specific reviewers for each issue. Some scientific reviewers may be unfamiliar with the decision standards prescribed by the Endangered Species Act and implementing policies. Unnecessary confusion could be prevented by providing reviewers with information about these standards and by requesting that reviewers clearly differentiate their assessment of decisions that must be based on available information from recommendations for future research. Short review periods constitute another constraint on careful review, but tight deadlines are fairly intractable in the context of the Endangered Species Act. We suggest that short time frames could be partially ameliorated by narrowing the scope of issues to be treated by each reviewer, and we discuss the issue of providing monetary compensation for efficient review. Finally, Endangered Species Act listing decisions and recovery planning may profit from more frequent peer review of intermediate analyses that precede publication of formal proposals or complete plans.     

Contaminant exposure in outmigrant juvenile salmon from Pacific Northwest estuaries of the United States

To better understand the dynamics of contaminant uptake in outmigrant juvenile salmon in the Pacific Northwest, concentrations of polychlorinated biphenyls (PCBs), DDTs, polycylic aromatic hydrocarbons (PAHs) and organochlorine pesticides were measured in tissues and prey of juvenile chinook and coho salmon from several estuaries and hatcheries in the US Pacific Northwest. PCBs, DDTs, and PAHs were found in tissues (whole bodies or bile) and stomach contents of chinook and coho salmon sampled from all estuaries, as well as in chinook salmon from hatcheries. Organochlorine pesticides were detected less frequently. Of the two species sampled, chinook salmon had the highest whole body contaminant concentrations, typically 2--5 times higher than coho salmon from the same sites. In comparison to estuarine chinook salmon, body burdens of PCBs and DDTs in hatchery chinook were relatively high, in part because of the high lipid content of the hatchery fish. Concentrations of PCBs were highest in chinook salmon from the Duwamish Estuary, the Columbia River and Yaquina Bay, exceeding the NOAA Fisheries' estimated threshold for adverse health effects of 2400 ng/g lipid. Concentrations of DDTs were especially high in juvenile chinook salmon from the Columbia River and Nisqually Estuary; concentrations of PAH metabolites in bile were highest in chinook salmon from the Duwamish Estuary and Grays Harbor. Juvenile chinook salmon are likely absorbing some contaminants during estuarine residence through their prey, as PCBs, PAHs, and DDTs were consistently present in stomach contents, at concentrations significantly correlated with contaminant body burdens in fish from the same sites.     

Effects of Exposure Conditions on Antioxidant Depletion,Tensile Strength,and Creep Modulus of Corrugated HDPE Pipes Made With or Without Recycled Resins

Journal of Polymers and the Environment - The service lifetime of corrugated high-density polyethylene (HDPE) pipes used in transportation infrastructure applications has been the subject of...