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Acute hazards to young children from residential pesticide exposures.

OBJECTIVES: This study assessed acute hazards to young children from pesticides toxic enough to require child-resistant packaging. METHODS: The names of pesticides meeting acute toxicity criteria were ascertained from the Environmental Protection Agency. Poison Control Center reports identified children younger than 6 years who were exposed to these pesticides. Toxicity category, medical outcome, sex, and age were examined. RESULTS: A higher proportion of children with exposure to the more toxic products had serious medical outcomes. Children 2 years and younger were the predominant age group exposed. CONCLUSIONS: Protective measures--substituting less lethal pesticides, reducing the concentration of the active ingredients, and improving packaging and storage--are recommended.

Age Distribution↗

Regulating insect resistance management: the case of non-Bt corn refuges in the US.

In this paper, we analyze the insect resistance management (IRM) plan put in place by the US Environmental Protection Agency (EPA) to delay the evolution of resistance to Bt corn in natural populations of the European corn borer, Ostrinia nubilalis Hübner. This IRM plan is the most impressive mandatory IRM system ever developed. It forms a coherent whole and includes mandatory refuges, actions to increase growers' compliance and a program for monitoring the evolution of resistance. However, our analysis suggests that two components of this IRM plan are not entirely satisfactory: growers' compliance and monitoring of the evolution of resistance. Moreover, the implementation of these two components of IRM has been required of the registrants, whose incentives for IRM are probably lower than the social optimum. Our analysis suggests that alternatives to the IRM plan currently in place could improve these two components.

Animals↗

Hydrologic regionalisation impacts on wet-weather control selection.

Continuous simulation is performed using the US Environmental Protection Agency (USEPA) Storm Water Management Model (SWMM) to evaluate regional differences around the United States in hydrologic and water quality performance of wet-weather controls. Controls are characterised as being limited by peak inflow rate (i.e. any device with little or no storage, such as screens, filters and some proprietary devices) or by storage capacity (e.g., ponds, tanks). For flow-limited devices, results are presented in the form of percentage of annual runoff volume captured (passing through the device) for a given inflow capacity. For storage-limited devices, results are presented in two forms: percentage of annual runoff volume captured as a function of unit basin size and drawdown (drain) time, and as a percentage of total suspended solids captured, for the same two variables. Regional differences are apparent, driven mainly by variations in rainfall patterns around the country.

Demography↗

The medical waste audit. A framework for hospitals to appraise options and financial implications.

The generation, handling, and disposal of medical wastes involve virtually every department in the hospital. To enhance coordination, managers must comprehensively describe the total system and specify the roles of key functions and individuals. Hospitals produce about 77 percent of the approximately 500,000 tons of regulated medical waste produced annually in the United States. The amount produced by different hospitals varies, primarily because of differences in "waste-management practices." The Environmental Protection Agency is trying to develop a greater understanding of the types of medical wastes that are infectious, methods of transmission, and the likelihood of transmission in the handling and disposal of waste within the hospital environment. To ensure that medical waste is being handled and treated in the most cost-effective manner and with the least health risk to employees and the community, hospital administrators must undertake a comprehensive appraisal of the activities associated with the generation, handling, and disposal processes. A "medical waste audit" requires the following steps: Generation profile to identify origination points, categories or types of waste, and associated generation rates. Inventory of handling practices, including existing regulations, procedures and protocols, training programs, definitions regarding waste segregation, and documentation. Review of current disposal practices and existing and developing alternatives. Cost analysis

Accounting↗

Can varying concepts of susceptibility in risk assessment affect particulate matter standards?

The Clean Air Act mandates that sensitive subpopulations be considered in setting standards to protect the public's health. The purposes of this paper are to point out different conceptualizations of susceptibility, examine how it is approached in risk-related processes, and recommend ways it may be more explicitly framed for risk assessment and management purposes. We studied the traditional risk assessment paradigm, the U.S. Environmental Protection Agency (EPA) guidelines and revised PM standard, discussions from recent interdisciplinary meetings, and peer-reviewed literature. Areas of controversy include what factors intrinsic and extrinsic to the host should be incorporated in susceptibility, what health endpoints are of concern, whether susceptibility is deterministic or stochastic, and whether it should be defined on an individual or population scale. Recent discussions about susceptibility applied to PM indicate that it needs to be more clearly defined and evaluated for scientific and policy purposes. We conclude that varying concepts of susceptibility can affect risk-related processes such as PM standard setting. We recommend that susceptibility be clearly defined in the problem statement of risk assessments and be addressed in a specific subsection of risk characterization, integrating all susceptibility findings from the prior three steps in the risk assessment paradigm.

Air Pollution↗

Survey of trihalomethanes and other volatile chemical contaminants in processed foods by purge-and-trap capillary gas chromatography with mass selective detection.

A limited number of soft drinks, juices, beers, and waters from processed vegetables were analyzed for trihalomethanes (THMs), benzene, and toluene by a modified Environmental Protection Agency (EPA) Method 524.2. The THMs, which include chloroform, bromodichloromethane, dibromochloromethane, and bromoform, are reaction by-products of water disinfection by chlorination. EPA Method 524.2 is a purge-and-trap capillary gas chromatographic method based on mass spectrometric detection which identifies and simultaneously measures purgeable volatile organic compounds in drinking water. Chloroform was present at concentrations ranging from none detected to 94 ng/g in the 44 foods analyzed. Bromoform was not found in any of the products at a detection limit of 0.1 ng/g. Residue levels of the other THMs ranged from none detected to highs of 12 and 2 ng/g for bromodichloromethane and dibromochloromethane, respectively. Benzene residues were typically < 5 ng/g, except for 7 and 9 ng/g in 2 foods. Toluene residues were typically < or = 3 ng/g except for 23, 29, and 75 ng/g in 3 canned foods.

Benzene↗

Evaluation of reduced protocols for carcinogenicity testing of chemicals: report of a joint EPA/NIEHS workshop.

The current U.S. Environmental Protection Agency (EPA) and other national/international guidelines specify the use of two species and two sexes rodents (usually the rat and the mouse) for carcinogenicity testing of chemicals. In view of the enormous number of chemicals to be tested, the high cost of testing, and the large number of animals used in the present protocol, many academic, industrial, and government authorities are examining the possibility of using a reduced protocol (less than two species and two sexes of rodents) for carcinogenicity testing of chemicals. The use of a reduced protocol offers many advantages as well as some disadvantages. To pursue further the potential implications and impacts of using a reduced protocol for carcinogenicity testing on the processes of hazard identification and risk assessment, a workshop entitled "Evaluation of Reduced Protocols for Carcinogenicity Testing of Chemicals" was held at the Embassy Suites Hotel in Alexandria, Virginia on September 22 and 23, 1992. It was cosponsored by EPA's Office of Prevention, Pesticides and Toxic Substances (OPPTS) and the National Toxicology Program of the National Institutes of Environmental Health Sciences (NTP/NIEHS) and attended by more than 60 participants from government, industry, academia, and the general public. The Expert Consensus Panel and most of the participants supported the use of reduced protocols in carcinogenicity testing. However, it was recognized that reduced protocols may not be appropriate for the testing of all chemicals and that additional analyses/data may be needed for selection of the most appropriate reduced protocol for certain chemicals/chemical classes.

Animals↗

Factors in standardizing automated cholinesterase assays.

A scientific panel assembled by the U.S. Environmental Protection Agency (EPA) determined that variability in cholinesterase (ChE) activities in the agency's pesticide/animal study database likely was due to a lack of accepted guidelines for ChE methodology. A series of trials was held in which participating laboratories measured ChE activity in blood and brain samples from untreated and pesticide-treated rats using a colorimetric assay method. The degree of inhibition of ChE activity in plasma and brain samples compared to controls was consistent among most of the laboratories. The ChE activity in erythrocyte samples differed more between laboratories due to a high blank, low erythrocyte AChE activity and hemoglobin absorption at the wavelength of the assay. Strategies are suggested for minimizing the variability of ChE activity in hemoglobin-rich samples.

Acetylcholinesterase↗

Reducing the risks from radon.

The U.S. Environmental Protection Agency estimates that residential radon levels in the United States lead to approximately 13,600 lung cancer deaths per year. To address this problem, the Agency has identified three program initiatives that can provide substantial reductions in the public's risks: (1) public information activities that urge the public to test for radon and reduce elevated concentrations in existing homes, (2) new construction standards to reduce radon entry, and (3) radon testing and mitigation during real estate transactions. This paper analyzes the costs and risk reductions that could result from the implementation of these major initiatives, showing how all three elements cost-effectively protect the public's health.

Construction Materials↗

An evaluation of the urban stormwater pollutant removal efficiency of catch basin inserts.

In a storm sewer system, the catch basin is the interface between surface runoff and the sewer. Responding to the need to improve the quality of stormwater from urban areas and transportation facilities, and spurred by Phase I and II Stormwater Rules from the U.S. Environmental Protection Agency, several companies market catch basin inserts as best management practices for urban water quality management. However, little data have been collected under controlled tests that indicate the pollutant removal efficiency of these inserts when the inflow is near what can be expected to occur in the field. A stormwater simulator was constructed to test inserts under controlled and replicable conditions. The inserts were tested for removal efficiency of total suspended solids (TSS) and total petroleum hydrocarbons (TPH) at an inflow rate of 757 to 814 L/min, with influent pollutant concentrations of 225 mg/L TSS and 30 mg/L TPH. These conditions are similar to stormwater runoff from small commercial sites in the southeastern United States. Results from the tests indicate that at the test flowrate and pollutant concentration, average TSS removal efficiencies ranged from 11 to 42% and, for TPH, the removal efficiency ranged from 10 to 19%.

Drainage, Sanitary↗

Probabilistic risk assessment of cotton pyrethroids: IV. Landscape-level exposure characterization.

Aquatic exposure arising from the use of pyrethroid insecticides on cotton in the United States was estimated as part of an extensive pyrethroid aquatic risk assessment. The exposure analysis was based on the standard U.S. Environmental Protection Agency tier II regulatory scenario for cotton, which assumes a 1-ha pond surrounded by 10 ha of treated crop, with high levels of runoff, erosion, and drift entering the pond. This regulatory scenario was modified to include simplified landscape-level information on the proximity of cotton to ponds derived from a remote sensing study. This scenario also accounts for the no-spray buffers between pyrethroid applications and surface waters mandated on all cotton pyrethroid labels (which differentiate applications made by air and by ground-based equipment), and for the percentage of cotton area that is treated with pyrethroids. Incorporation of these landscape-level factors into the analysis reduced the predicted aquatic exposure concentrations approximately 50- to 100-fold. Because many other conservative assumptions in the original tier II exposure analysis were not revised, the modified exposure predictions are still overestimates of true field exposure concentrations.

Animals↗

Toxicity equivalency factors for PCBs?

In December 1990 the U.S. Environmental Protection Agency sponsored a workshop to discuss the applicability of an interim "toxicity equivalency factor" (TEF) approach to assessing risks posed by exposures to complex mixtures of polychlorinated biphenyls (PCBs). The group concluded that application of the TEF approach to PCBs would be less straightforward than it was in the case of chlorinated dibenzo-p-dioxins and dibenzofurans (CDDs/CDFs). It appears that "dioxin"-like properties of some PCB congeners are amenable to a TEF treatment that is compatible with that used for CDDs/CDFs. Such a scheme also seems to have utility in assessing risks to wildlife. Other non-"dioxin"-like toxic endpoints (e.g., neurotoxicity) appear to have a different structure-activity-related mechanism-of-action that requires a separate TEF scheme. The workshop identified data gaps in toxicology and analytical chemistry that hinder adoption of proposed TEF schemes for PCBs at this time.

Benzofurans↗

A river water quality model integrated with a web-based geographic information system.

Scientists often use mathematical models to assess river water quality. However, the application of the models in environmental management and risk assessment is quite limited because of the difficulty of preparing input data and interpreting model output. This paper presents a study that links ArcIMS, a Web-based Geographic Information System (GIS) software to ROUT, a national and regional scale river model which evolved from the US Environmental Protection Agency's Water Use Improvement and Impairment Model, to create a WWW-GIS-based river simulation model called GIS-ROUT. GIS-ROUT is used to predict chemical concentrations in perennially flowing rivers throughout the continental United States that receive discharges from more than 10,000 publicly owned wastewater treatment plants (WWTPs). The WWTP chemical loadings are calculated from per capita per day disposal of product ingredients and the population served by each plant. Each WWTP, containing data on treatment type and influent and effluent flows, is spatially associated with a specific receiving river segment. Based on user defined treatment-type removal rates for a particular chemical, an effluent concentration for each WWTP is calculated and used as input to the river model. Over 360,000 km of rivers are modeled, incorporating dilution and first order loss of the chemical in each river segment. The integration of spatial data, GIS, the WWW, and modeling in GIS-ROUT makes it possible to organize and analyze data spatially, and view results on interactive maps as well as tables and distribution charts. The integration allows scientists and managers in different locations to coordinate and share their estimations for environmental exposure and risk assessments.

Geographic Information Systems↗

Analysis of flour and food samples for cry9C from bioengineered corn.

StarLink corn is a variety of yellow corn that has been genetically modified by the insertion of an altered cry9C gene into the plant genome. resulting in expression of the insecticidal Cry9C protein. The U.S. Environmental Protection Agency has approved StarLink corn for use in animal feed but not in food intended for human consumption. Therefore, under the U.S. Food, Drug, and Cosmetic Act, any food intended for human consumption in which the presence of StarLink corn is indicated by the presence of either the Cry9C protein or the cry9C gene would be considered adulterated. Extraction and PCR-based methods were used to detect the presence of the cry9C DNA initially in corn flour and corn meal, and then these methods were extended to the analysis of processed corn products, including taco shells, cereals, baby foods, party snacks, and chips, for the presence of this modified genetic material. In a survey of 63 products, the cry9C transgene was detected in 4 taco shells.

Bacillus thuringiensis Toxins↗

Survey of lead exposure around a closed lead smelter.

OBJECTIVE: To test the hypothesis that elevated lead in soil is positively correlated with blood lead (BPb) levels in children in an urban population surrounding a closed lead smelter, a US Environmental Protection Agency Superfund clean-up site was surveyed. METHOD: A total of 827 volunteers including 490 children under 6 years of age participated. A questionnaire was administered. Blood lead was determined as was lead content of samples of house dust, soil, paint, and water of the participants' homes. RESULTS: The arithmetic mean venous BPb in 490 children between 6 and 72 months of age was 6.9 micrograms/dL (0.33 mumol/L) range 0.7 to 40.2 micrograms/dL (0.03 to 1.94 mumol/L). The BPb of 78 (16%) children in this group was > or = 10 micrograms/dL (0.48 mumol/L). Based on multiple regression modeling, lead in house dust accounted for 18% of the variance in BPb. Lead in paint together with the condition of the house were the main contributors to the dust lead variance (26%) with soil lead accounting for an additional 6%. Lead in paint alone accounted for 3% of the BPb variance. Lead in paint together with the condition of the house accounted for 12% of BPb variance, and lead in soil accounted for an additional 3%. Factors other than environmental lead such as education of parents, household income, and behavior were associated with BPb levels. CONCLUSIONS: The mean BPb in children was below the present level of concern of the Centers for Disease Control and Prevention. Children with BPb of > or = 10 micrograms/L (0.48 mumol/L) tended to live in poorly maintained older houses. Based on these findings lead in soil and paint in well-maintained homes contributed little to the lead exposure of children.

Child, Preschool↗

The future of benefit-cost analyses of the Clean Air Act.

This review examines the first two studies conducted pursuant to a Congressional mandate that the U.S. Environmental Protection Agency analyze the effects of the Clean Air Act on the "public health, economy, and the environment of the United States." While these studies indicate that overall, the nation received good value for the resources it invested in improving air quality over the past three decades, we don't know if even higher value could have been obtained by changing or eliminating certain potentially inefficient elements. The review focuses on the critical policy and technical choices made in the analyses, including the selection of the appropriate baseline and the level of disaggregation for the studies. It is proposed that a potential third analysis focus on potential new policies not yet mandated by law or regulation. It is also proposed that the next study fill in key information gaps, expand the benefit categories, and incorporate new research on topics such as mortality and morbidity benefits, cost uncertainties, and others.

Air Pollution↗

A survey and analysis of states' methodologies for deriving drinking water guidelines for chemical contaminants.

Data from a national survey questionnaire regarding the development of guidelines for chemical contaminants in drinking water were collected from all 50 states. Twenty-three states develop at least some of their own guidelines; the other 27 states rely on guidelines previously developed by the U.S. Environmental Protection Agency (USEPA) or by other states. States which derive guidelines generally employ toxicological criteria and risk assessment methodologies developed by the USEPA. Fourteen of the twenty-three states that develop their own guidelines depend on cancer potency factors derived by the USEPA to establish risk-based concentrations for carcinogens. Most of the states develop guidelines based on preventing possible excess cancer risk greater than one in one million. Seventeen of these twenty-three states rely on oral reference doses (RfDs) to derive guidelines for noncarcinogens. Examination and clarification of the states' approaches to guideline derivation reveal that although similar risk assessment techniques are generally employed, differences in assumptions, chemical classifications, and uncertainty factors may lead to variation in resultant guidance levels. Improved communication and coordination between states and the federal government may help reduce the variations and inconsistencies among the states in establishing drinking water guidelines for chemical contaminants.

Carcinogens↗

Laboratory evaluation of amalgam separators.

BACKGROUND: Amalgam in dental wastewater is receiving increasing scrutiny from regulators because of national, state and local initiatives to reduce or virtually eliminate the discharge of mercury and mercury-containing items into the environment. Amalgam separators are considered to be one means of reducing the amount of amalgam that dental offices discharge into sewers. The purpose of this study was to evaluate the amalgam removal efficiency of commercially available amalgam separators and the total mercury concentration in the effluent from laboratory testing. METHODS: The authors evaluated the amalgam removal efficiency of 12 amalgam separators according to International Organization for Standardization, or ISO, Standard 11143 for Amalgam Separators. Total mercury concentration in the effluent was calculated using the mass of amalgam particles larger than 1.2 micrometers and the volume of effluent, together with U.S. Environmental Protection Agency, or EPA, Method 245.1 for amalgam particles smaller than 1.2 microm. Total dissolved mercury also was determined. RESULTS: The results show that all 12 amalgam separators exceeded the ISO 11143 requirement of 95 percent amalgam removal efficiency. Statistical differences were found in the efficiencies of the separators. Both the total mercury concentration and total dissolved mercury concentration in the effluent demonstrated large variations. CONCLUSIONS AND CLINICAL IMPLICATIONS: This laboratory evaluation shows that amalgam separators removed at least 96.09 percent of the amalgam in samples with particle-size distribution as specified in ISO 11143. Total mercury concentration and total dissolved mercury concentration in the effluent varied widely for each amalgam separator. Additional research is needed to develop test methods to evaluate the efficiency of amalgam separators in removing small amalgam particles, colloidal amalgam particles and ionic mercury in solution.

Dental Amalgam↗