Lifetime Health Advisory Level Research Articles

Characteristics, pollution patterns and risks of Perfluoroalkyl substances in drinking water sources of Taiwan

Perfluoroalkyl substances (PFASs) are found globally in the environment, but for Taiwan there is a lack of studies on PFAS occurrence, source apportionment, and health risks in drinking water sources. We collected surface water samples from the Baoshan Reservoir of Taiwan and used Positive Matrix Factorization to attribute PFAS contaminants to possible sources. The health index (HI) was used to evaluate the health risk, which was then compared to various international advisory level guidelines. PFOA and PFOS were found to be the most predominant compounds, with concentrations averaging 20.2 ng/L and 16.7 ng/L, respectively. The joint contribution of domestic and commercial waste totaled 61.2% as the predominant source of pollution, followed by urban activities as a secondary source contributing 38.8%. Using the USEPA reference dose, a health risk analysis of Baoshan Reservoir drinking water did not reflect a formal high health risk (HI < 1.0), however potential risks to human health may be present since the sum of PFOA and PFOS (130 ng/L) exceeded the USEPA Lifetime Health Advisory level (70 ng/L). This investigation provides information and reference points for further reviews of PFAS presence in public water supplies.

Legacy and Emerging Perfluoroalkyl Substances Are Important Drinking Water Contaminants in the Cape Fear River Watershed of North Carolina

Long-chain per- and polyfluoroalkyl substances (PFASs) are being replaced by short-chain PFASs and fluorinated alternatives. For ten legacy PFASs and seven recently discovered perfluoroalkyl ether carboxylic acids (PFECAs), we report (1) their occurrence in the Cape Fear River (CFR) watershed, (2) their fate in water treatment processes, and (3) their adsorbability on powdered activated carbon (PAC). In the headwater region of the CFR basin, PFECAs were not detected in raw water of a drinking water treatment plant (DWTP), but concentrations of legacy PFASs were high. The U.S. Environmental Protection Agency’s lifetime health advisory level (70 ng/L) for perfluorooctanesulfonic acid and perfluorooctanoic acid (PFOA) was exceeded on 57 of 127 sampling days. In raw water of a DWTP downstream of a PFAS manufacturer, the mean concentration of perfluoro-2-propoxypropanoic acid (PFPrOPrA), a replacement for PFOA, was 631 ng/L (n = 37). Six other PFECAs were detected, with three exhibiting chromatographic peak ar...

Experimental design for one dimensional electrolytic reactive barrier for remediation of munition constituent in groundwater

A combination of direct electrochemical reduction and in situ alkaline hydrolysis has been proposed to decompose energetic contaminants such as 1,3,5-trinitroperhydro-1,3,5-triazine and 2,4,6-trinitrotoluene (RDX) in deep aquifers. This process utilizes natural groundwater convection to carry hydroxide produced by an upstream cathode to remove the contaminant at the cathode as well as in the pore water downstream as it migrates toward the anode. Laboratory evaluation incorporated fundamental principles of column design coupled with reactive contaminant modeling including electrokinetics transport. Batch and horizontal sand-packed column experiments included both alkaline hydrolysis and electrochemical treatment to determine RDX decomposition reaction rate coefficients. The sand packed columns simulated flow through a contaminated aquifer with a seepage velocity of 30.5cm/day. Techniques to monitor and record the transient electric potential, hydroxide transport and contaminant concentration within the column were developed. The average reaction rate coefficients for both the alkaline batch (0.0487h−1) and sand column (0.0466h−1) experiments estimated the distance between the cathode and anode required to decompose 0.5mg/L RDX to the USEPA drinking water lifetime Health Advisory level of 0.002mg/L to be 145 and 152cm.

Development and evaluation of GIS-based ArcPRZM-3 system for spatial modeling of groundwater vulnerability to pesticide contamination

The objectives of this study were to develop and evaluate a GIS-based modeling system called ArcPRZM-3 for spatial modeling of pesticide leaching potential from soil surface towards groundwater. The ArcPRZM-3 was developed by coupling a commonly used FORTRAN-based Pesticide Root Zone Model version 3 (PRZM-3) with user-friendly input and output interfaces through links to GIS using customized programming. A Visual PRZM-3 interface simplifies the entry of model inputs and links to the databases of crops, soils, and pesticides. The ArcPRZM-3 produces user-friendly outputs from the PRZM-3 batch simulations in the form of tables, charts, and maps. The Visual PRZM-3 can be used to run a single simulation for site-specific studies or simultaneous multiple simulations for spatial distributed modeling. The ArcPRZM-3 was applied to simulate maximum dissolved bentazon concentration at 0.75 m soil depth for a period of 2 years. These simulation results were used to develop a health risk map for Woodruff County, Arkansas, based on the U.S. Environmental Protection Agency's Lifetime Health Advisory Level (USEPA-LHA) of bentazon in drinking water. The ArcPRZM-3 was evaluated by comparing the bentazon detection data from monitoring wells from the same area with the predicted bentazon health risk map. The results showed that 100% of the wells where bentazon was detected were within the high risk category based on the ArcPRZM-3 predictions. However, uncertainty in the ArcPRZM-3 model and the timing of groundwater well monitoring could both complicate the interpretations of the ArcPRZM-3 simulation results.

Herbicide dynamics in the Bogue Phalia watershed in the Yazoo River basin of Mississippi

A two-year surface water reconnaissance of the Bogue Phalia and its tributaries was conducted in 1997 and 1998. Cyanazine and metolachlor in surface water samples were quantified using enzyme-linked immunosorbent assays (ELISA). Cyanazine and metolachlor were detected in 101 and 132 of 160 samples, respectively. Cyanazine concentrations ranged from 0.1 to 2.2 g L−1and exceeded the U.S. Environmental Protection Agency (EPA) lifetime health advisory level (HAL) of 1 g L−1in eight samples. However, concentrations never exceeded the HAL for shorter exposure times. Metolachlor concentrations never reached the lifetime HAL of 100 g L−1. Metolachlor concentrations ranged from 0.1 to 20.6 g L−1. Metolachlor was detected more frequently and found to be more persistent throughout the growing season than was cyanazine. Higher cyanazine and metolachlor concentrations were detected at sampling dates that coincided with herbicide applications. One of the Bogue Phalia's tributaries, Clear Creek, was found to be a point-source of cyanazine for the watershed.

Water manganese exposure and children's intellectual function in Araihazar, Bangladesh.

Exposure to manganese via inhalation has long been known to elicit neurotoxicity in adults, but little is known about possible consequences of exposure via drinking water. In this study, we report results of a cross-sectional investigation of intellectual function in 142 10-year-old children in Araihazar, Bangladesh, who had been consuming tube-well water with an average concentration of 793 μg Mn/L and 3 μg arsenic/L. Children and mothers came to our field clinic, where children received a medical examination in which weight, height, and head circumference were measured. Children’s intellectual function was assessed on tests drawn from the Wechsler Intelligence Scale for Children, version III, by summing weighted items across domains to create Verbal, Performance, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and creatinine and were asked to provide blood samples for measuring blood lead, As, Mn, and hemoglobin concentrations. After adjustment for sociodemographic covariates, water Mn was associated with reduced Full-Scale, Performance, and Verbal raw scores, in a dose–response fashion; the low level of As in water had no effect. In the United States, roughly 6% of domestic household wells have Mn concentrations that exceed 300 μg Mn/L, the current U.S. Environmental Protection Agency lifetime health advisory level. We conclude that in both Bangladesh and the United States, some children are at risk for Mn-induced neurotoxicity.

Monitoring Groundwater for Pesticides at Selected Mixing/Loading Sites in Arkansas

Groundwater monitoring studies have been conducted in recent years to survey contamination due to pesticides, yet few have addressed wells where pesticides are mixed, loaded, or rinsed. Beginning in 1990, a monitoring study conducted over a 2-year period included five collections at each of 16 mixer/loader locations to assess any pesticide and nitrate contamination. At sites in 11 counties, samples for pesticide analysis were extracted with solid-phase extraction (SPE) disks. Samples were screened using gas chromatography-electron capture detection (ECD) and high-performance liquid chromatography−UV detection (LCUV) for 17 pesticides commonly used in Arkansas. Detections were confirmed by gas chromatography−mass spectroscopy (MS) or co-chromatography. Fourteen samples revealed atrazine (1 detection), cyanazine (4), parathion-methyl (2), metolachlor (2), norflurazon (1), pendimethalin (1), propanil (2), or trifluralin (1) at eight locations during the 2-year study. Two detections of parathion-methyl and one detection of trifluralin were above the Lifetime Health Advisory Level (LHAL) of 2 μg L-1. Data suggested a high correlation between pesticide used and pesticide detected at sites sampled. Three wells contained NO3-N concentrations of 10 mg L-1 or higher, but these did not correlate with pesticide concentrations. The pesticide's proximity to the wells during mixing, rinsing, or loading was considered to be a greater influence on temporary contamination of groundwater than chemical or site-specific characteristics.

Atrazine Exposures through Drinking Water: Exposure Assessments for Ohio, Illinois, And Iowa

A systematic exposure assessment process has been developed for evaluating and describing the distribution, within large populations, of human exposures through drinking water to substances of potential health concern. This process involves dividing the population into groups of known size, within which the drinking water exposure is the same or similar, and estimating the exposure concentration for each group based on the best available data. Using this process, assessments of human exposures to atrazine though drinking water have been carried out for the populations of the states of Ohio, Illinois, and Iowa. The assessments indicate that atrazine exposure through drinking water does not represent a significant human health threat based on the current understanding of atrazine toxicity. Exposures to atrazine above the lifetime health advisory level of 3.0 ppb do not exceed 0.25% of the assessed population in any of the three states, and between 94% and 99% of the assessed populations have exposure concentrations less than 1 ppb.

Managing pesticides for crop production and water quality protection: practical grower guides

A decision aid has been developed for use by farmers and other pesticides users that permits the selection of pesticides on the basis of water quality impact in addition to efficacy and cost as is tradionally done. This ‘kitchen table’ decision aid uses information on environmental fate and toxicity of pesticides, soil leaching potential or run-off ratings in combination with pest management guidelines to make site-specific selections that minimize the potential impacts of pesticide use on water quality. Pesticide properties used include the sorption coefficint ( K oc), degradation half-life, lifetime health advisory level (HAL), and aquatic toxicity. The first two properties are used to derive a relative leaching potential index, RLPI, and a relative run-off potential index, RRPI, for each pesticide. Site-specific soil ratings for pesticides leaching and run-off, provided by the US Department of Agriculture Soil Conservation Service, are matched with these indices and toxicity values via a table of selection criteria. A pesticide selection worksheet is provided to organize the necessary information to make an informed decision. This decision aid assists the pesticide user in understanding the water quality impacts of alternative pesticide selection. Thse grower guides are customized to individual crops. They include a table of pesticides registered for use on the crop, organized by major use category (herbicides, insecticides, nematicides, fungicides, and soil fumigants). Within categories, trade names, common names, application type (soil vs. foliar), K oc, RLPI, RRPI, HAL, and aquatic toxicity are listed. These grower guides can easily be adapted for use in other states or countries. This technology will not only help agricultural and urban pesticide users select pesticides with less water quality impact, but will also aid regulatory agencies in developing meaningful groundwater protection plans, and hopefully will result in more equitable public policy decisions.

Site-Specific Pesticide Recommendations: The Final Step in Environmental Impact Prevention

A screening procedure to minimize adverse water quality impacts of pesticide application is presented that matches pesticide parameters to site-specific soil ratings. The pesticide parameters include a Relative Leaching Potential Index (RLPI), a Relative Runoff Potential Index (RRPI), the U.S. Environ. Prot. Agency (USEPA) lifetime health advisory level (HAL), and aquatic toxicity (LC50). Criteria used in developing soil ratings are described. Pesticide selection is accomplished by matching pesticide parameters values for the array of pesticides that control the pest of interest to soil ratings at the application site using selection criteria. A worksheet is presented to facilitate organization of information for the selection procedure and to serve as a record of the pesticide applicator's decision. The linking of an environmental fate model to a geographic information system (GIS) to create thematic maps of pesticide leaching potentials in terms of probability of exceeding the HAL in groundwater is described. A cost vs. groundwater hazard index frontier is described that suggests a method to assess the economic consequences of alternative pesticide selections.