Risk factors for Cryptosporidium contamination in Minnesota public supply wells.

In a recent monitoring study of Minnesota's public supply wells, Cryptosporidium was commonly detected with 40% of the wells having at least one detection. Risk factors for Cryptosporidium occurrence in drinking water supply wells, beyond surface water influence, remain poorly understood. To address this gap, physical and chemical factors were assessed as potential predictors of Cryptosporidium occurrence in 135 public supply wells in Minnesota. Univariable analysis, regression techniques, and classification trees were used to analyze the data. Many variables were identified as significant risk factors in univariable analysis and several remained significant throughout the succeeding analysis techniques. These factors fell into general categories of well use and construction, aquifer characteristics, and connectedness to the land surface, well capture zones, and land use therein, existence of potential contaminant sources within 200-feet of the well, and variability in the chemical and isotopic parameters measured during the study. These risk categories, and the specific variables and threshold values we have identified, can help guide future research on factors influencing Cryptosporidium contamination of wells and can be used by environmental health programs to develop risk-based sampling plans and design interventions that reduce associated health risks.

Potential for Manganese-Induced Neurologic Harm to Formula-Fed Infants: A Risk Assessment of Total Oral Exposure.

BACKGROUND: High oral exposure and biological vulnerabilities may put formula-fed infants at risk for manganese-induced neurotoxicity. OBJECTIVES: We sought to characterize manganese concentrations in public drinking water and prepared infant formulas commonly purchased in the United States, integrate information from these sources into a health risk assessment specific to formula-fed infants, and examine whether households that receive water with elevated manganese concentrations avoid or treat the water, which has implications for formula preparation. METHODS: Manganese was measured in 27 infant formulas and nearly all Minnesota community public water systems (CPWS). The risk assessment produced central tendency and upper-end exposure estimates that were compared to a neonatal animal-based health reference dose (RfD) and considered possible differences in bioavailability. A survey study assessed esthetic concerns, treatment, and use of water in a Twin Cities community with various levels of manganese in drinking water. RESULTS: Ten percent of CPWSs were estimated to exceed the EPA health advisory level of 300 µg/L. Manganese concentrations in formula ranged from 69.8 to 741 µg/L, with amino acid>soy>cow's milk formula concentrations. Central tendency estimates of soy and amino acid formula reconstituted with water at the CPWS 95th percentile manganese concentration exceeded the neonatal-based RfD. Upper-end estimates of manganese intake from formula alone, independent of any water contribution, equaled or exceeded the neonatal-based RfD. In the survey study, we observed increased awareness of esthetic issues and water avoidance at higher manganese concentrations, but these concentrations were not a reliable consumption deterrent, as the majority of households with inside tap drinking water results above 300 µg/L reported drinking the water. DISCUSSION: Excessive exposure to manganese early in life can have long-lasting neurological impacts. This assessment underscores the potential for manganese overexposure in formula-fed infants. U.S. agencies that regulate formula and drinking water must work collaboratively to assess and mitigate potential risks. https://doi.org/10.1289/EHP7901.

Microbial pathogens and contaminants of emerging concern in groundwater at an urban subsurface stormwater infiltration site.

Urban stormwater may contain a variety of pollutants, including viruses and other pathogens, and contaminants of emerging concern (pharmaceuticals, artificial sweeteners, and personal care products). In vulnerable geologic settings, the potential exists for these contaminants to reach underlying aquifers and contaminate drinking water wells. Viruses and other pathogens, as well as other contaminants of emerging concern, were measured in stormwater and groundwater at an urban site containing a stormwater cistern and related subsurface infiltration gallery, three shallow lysimeter wells, and a monitoring well. Five of 12 microbial targets were detected more than once across the eight rounds of sampling and at multiple sampling points, with human-specific Bacteroides detected most frequently. The microbial and chemical contaminants present in urban stormwater were much lower in the water table monitoring well than the vadose zone lysimeters. There may be numerous causes for these reductions, but they are most likely related to transit across fine-grained sediments that separate the water table from the vadose zone at this location. Precipitation amount prior to sample collection was significantly associated with microbial load. A significant relation between microbial load and chloride-bromide ratio was also observed. The reduction in number and concentrations of contaminants found in the monitoring well indicates that although geologically sensitive aquifers receiving urban stormwater effluent in the subsurface may be prone to contamination, those with a protective cap of fine-grained sediments are less vulnerable. These results can inform stormwater infiltration guidance relative to drinking water wells, with an emphasis on restricting infiltration near water supply wells finished in geologically sensitive aquifers to reduce public health risks.

Can Aggregated Restaurant Inspection Data Help Us Understand Why Individual Foodborne Illness Outbreaks Occur?

ABSTRACT: Restaurant inspections seek to identify and correct risk factors for foodborne illness, but restaurant inspection data are not typically used more broadly as a food safety surveillance tool. In 2015, there was an outbreak of Salmonella serotype Newport infections associated with multiple restaurants in a chain (chain A), primarily in Minnesota. The outbreak was associated with tomatoes that were likely contaminated at the point of production. The objective of this study was to demonstrate the potential usefulness of aggregated restaurant inspection data in aiding individual outbreak investigations. Reports of the last inspection for all chain A restaurants that preceded the first reported case meal date in the outbreak were obtained from local health departments and the Minnesota Department of Health. Ordinal logistic regression was used to assess differences in risk factor and good retail practice violation categories and specific violations in restaurants with zero cases (nonoutbreak restaurants) (n = 25), one to two cases (n = 16), and at least three cases (n = 13). For restaurants with a "protection from contamination" violation in the routine inspection that preceded the outbreak, the proportional odds ratio for outbreak level was 4.92 (95% confidence interval: 1.57, 15.39; P = 0.01). These findings suggest that food handling practices in the outbreak restaurants may have increased contamination of foods through cross-contamination, which in turn increased transmission at outbreak restaurants. These data suggest that aggregated data from routine inspection reports can provide useful information to aid in outbreak investigations and other foodborne illness surveillance and prevention activities.

Biomonitoring programs in Michigan, Minnesota and New York to assess human exposure to Great Lakes contaminants.

Over the past century, industrialization and urban practices have resulted in the contamination of the Great Lakes ecosystem-the world's largest surface freshwater system-that provides drinking water and recreation to more than 40 million residents. In 2010, the Great Lakes Restoration Initiative was launched to accelerate efforts to protect and restore the Great Lakes and surrounding areas. Funded by GLRI, the Agency for Toxic Substances and Disease Registry initiated the Biomonitoring of Great Lakes Populations (BGLP) program. The objective of the program is to assess human exposure to legacy and emerging contaminants in the Great Lakes by measuring the body burden of contaminants in potentially susceptible populations. The BGLP program consists of a series of cross-sectional studies carried out collaboratively with states that are funded through ATSDR. The first BGLP Program (BGLP-I) began in 2010 and was completed in September 2015 through cooperative agreements with state health departments in Michigan, Minnesota, and New York. The three state programs targeted susceptible adult populations living in designated areas of contamination. Contaminants measured in all populations include mercury, lead, mirex, hexachlorobenzene, dichlorodiphenyltrichloroethane, and selected polychlorinated biphenyl congeners. In addition, some chemicals of emerging concern, such as per- and polyfluoroalkyl substances, were measured in several populations. The biomonitoring results helped guide public health actions to mitigate chemical exposures in these vulnerable Great Lakes populations. We provide an overview of the BGLP-I program's study populations, designs, and general methods. This overview provides a lead-in for subsequent manuscripts that present human biomonitoring data for legacy and emerging contaminants in culturally diverse susceptible populations-i.e., shoreline anglers, sport anglers, American Indians, and Burmese immigrants-residing in seven areas of concern.

Does soil track-in contribute to house dust concentrations of perfluoroalkyl acids (PFAAs) in areas affected by soil or water contamination?

The Minnesota Department of Health measured levels of perfluoroalkyl acids (PFAAs) in house dust at homes in communities impacted by PFAA-contaminated soil and drinking water to determine whether PFAAs in soil outside the home are associated with concentrations in dust. House dust samples from both interior living spaces and entryways to the yard were collected and analyzed separately based on the presumption that PFAAs in entryway dust may better reflect "track-in" of PFAAs into the home from contaminated soil or lawns irrigated with contaminated water. PFAA detections and concentrations in living rooms were significantly higher compared to entryways; and concentrations in both sampling locations were higher than corresponding soil concentrations, suggesting that interior sources were the main contributors to PFAAs in house dust. PFAA dust concentrations in entryways were significantly associated with living room dust levels for all analytes except PFBA. Relationships between entryway dust and soil were only seen for one PFAA (PFOA). However, median concentrations of PFOA in entryway and living room dust were 35 and 70 times higher (respectively) than in soil, which highlights the lack of importance of PFAA soil track-in as a contributor to dust concentration in this setting. Due to the small sample size, larger scale studies are needed to further assess the potential for migration of PFAA contaminated soil to indoor dust.

Occurrence of perfluoroalkyl substances (PFAS) in garden produce at homes with a history of PFAS-contaminated drinking water.

The decades-long disposal of manufacturing waste containing perfluoroalkyl substances (PFAS) in landfills resulted in contamination of groundwater serving as the drinking water supply for the eastern Twin Cities metropolitan region. While measures were taken to reduce the levels of PFAS in the drinking water, questions remained about possible non-drinking water pathways of exposure in these communities. The Minnesota Department of Health (MDH) investigated whether PFAS in water used for yard and garden irrigation results in elevated concentrations of PFAS in soil and home-grown produce. In 2010, samples of outdoor tap water, garden soil, and garden produce were collected at homes impacted by the contamination and analyzed for several PFAS. Perfluorobutanoic acid (PFBA) was the primary PFAS present in water, followed by perfluoropentanoic acid (PFPeA). Although PFBA, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were present in 100% of soil samples at higher concentrations compared to other PFAS, only PFBA was readily translocated to plants. Significant determinants of PFBA concentration in produce were the amount of PFBA applied to the garden via watering and the type of produce tested. Results from this real-world study are consistent with experimental findings that short-chain PFAS have the highest potential to translocate to and bioaccumulate in edible plants. These findings are globally relevant, as short-chain PFAS serve as commercial substitutes for longer-chain compounds and are increasingly detected in water due to their relatively high solubility and mobility.

Estimating absorbed dose of pesticides in a field setting using biomonitoring data and pharmacokinetic models.

Linking biomarker data to pharmacokinetic (PK) models permits comparison of absorbed dose with a toxicological benchmark, which is an important step to understanding the health implications of pesticide exposure. The purpose of this analysis was to evaluate the feasibility of reconstructing the absorbed dose of two pesticides using PK models developed from biomarker data in a study of occupational application of these compounds. Twenty-four-hour urine samples were collected from farmers 24 h before through 96 h after a typical application of chlorpyrifos or 2,4-D. PK models were used to link the amounts found in urine samples to absorbed dose. Modeled total body dose estimates (in micrograms) were compared to measured dose from time 0-96 h. Despite the complexities surrounding the interpretation of biomonitoring data from a field setting, the models developed as part of this analysis accurately estimated the absorbed dose of 2,4-D and chlorpyrifos when collection of urine samples was largely complete. Over half of the farmers were excluded from modeling due to suspected noncompliance with urine collection or confounding exposure events, which highlights the importance of these issues for designing and interpreting biomonitoring data in future studies. Further evaluation of PK models in scenarios using single void samples is warranted for improving field-based dose assessments.

Agreement of pesticide biomarkers between morning void and 24-h urine samples from farmers and their children.

In pesticide biomonitoring studies, researchers typically collect either single voids or daily (24-h) urine samples. Collection of 24-h urine samples is considered the "gold-standard", but this method places a high burden on study volunteers, requires greater resources, and may result in misclassification of exposure or underestimation of dose due to noncompliance with urine collection protocols. To evaluate the potential measurement error introduced by single void samples, we present an analysis of exposure and dose for two commonly used pesticides based on single morning void (MV) and 24-h urine collections in farmers and farm children. The agreement between the MV concentration and its corresponding 24-h concentration was analyzed using simple graphical and statistical techniques and risk assessment methodology. A consistent bias towards overprediction of pesticide concentration was found among the MVs, likely in large part due to the pharmacokinetic time course of the analytes in urine. These results suggest that the use of single voids can either over- or under-estimate daily exposure if recent pesticide applications have occurred. This held true for both farmers as well as farm children, who were not directly exposed to the applications. As a result, single void samples influenced the number of children exposed to chlorpyrifos whose daily dose estimates were above levels of toxicologic significance. In populations where fluctuations in pesticide exposure are expected (e.g., farm families), the pharmacokinetics of the pesticide and the timing of exposure events and urine collection must be understood when relying on single voids as a surrogate for longer time-frames of exposure.