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.

Community exposure to asbestos from a vermiculite exfoliation plant in NE Minneapolis.

Western Mineral Products/W. R. Grace operated a vermiculite plant in a mixed industrial/residential area of northeast Minneapolis from 1936 to 1989. The plant processed vermiculite ore contaminated with amphibole asbestos from a mine in Libby, MT. Air monitoring in the early 1970s found fiber concentrations in excess of 10 fibers per cubic centimeter of air (f/cc), indicating that worker exposure to asbestos was occasionally 100 times the current occupational standard. Residents of the surrounding community also had direct contact with vermiculite processing wastes (containing up to 10% amphibole asbestos) that were made freely available. Children played on waste piles and neighborhood residents hauled the wastes away for home use. In total, 259 contaminated residential properties have been found to date. Reported emission factors and plant process data were used as inputs to model airborne emissions from the plant over several operating scenarios using the U.S. Environmental Protection Agency (EPA) ISC-Prime model. Results estimate short-term air concentrations of asbestos fibers in residential areas nearest the plant may have at times exceeded current occupational standards. Exposure estimates for other pathways were derived primarily from assessments done in Libby by the U.S. EPA. The Northeast Minneapolis Community Vermiculite Investigation (NMCVI) was conducted by the Minnesota Department of Health to identify and characterize the exposures of a cohort of over 6000 people who live or lived in Northeast Minneapolis and may have been exposed to asbestos. This cohort is now being investigated in a respiratory health screening study conducted by the University of Minnesota and the Minnesota Department of Health.

Serotonin-containing neurons: their possible role in pain and analgesia.

Experimental evidence is reviewed showing that brain and spinal cord serotonergic neurons are involved in nociceptive responses, as well as in the analgesic effects of opiate narcotics. This evidence, based on studies employing pharmacological, surgical, electrophysiological, and dietary manipulations of central nervous system serotonergic neurotransmission, suggests that increases in the activity of brain and spinal cord serotonin neurons are associated with analgesia and enhanced antinociceptive drug potency, whereas decreases in the activities of these neurons correlate with hyperalgesia and diminished analgesic drug potency.

Radiographic evidence of nonoccupational asbestos exposure from processing Libby vermiculite in Minneapolis, Minnesota.

BACKGROUND: Community exposure to asbestos from contaminated vermiculite ore from Libby, Montana, occurred in many processing sites in the United States, including a densely populated urban residential neighborhood of Minneapolis, Minnesota. OBJECTIVE: We examined exposed community residents who never worked at the plant or never lived with a plant worker for radiographic evidence of lung changes consistent with asbestos exposure. METHODS: We obtained posteroanterior chest radiographs to identify the prevalence of pleural abnormalities consistent with pneumoconiosis, as determined by consensus of two National Institute for Occupational Safety and Health-certified B-reader radiologists. We estimated cumulative asbestos exposure (fibers per cubic centimeters × months) with air dispersion model data and activity-based modeled exposure estimates for vermiculite processing waste contact. We modeled associations between pleural abnormalities and asbestos exposure using multiple logistic regression to adjust for year of birth, sex, and potential occupational asbestos exposure. RESULTS: Radiographs were obtained for 461 participants. The prevalence of pleural abnormalities by B-reader consensus was 10.8%. A history of direct contact with the waste and ever playing in the waste piles was associated with pleural abnormalities {odds ratio [OR] 2.78 [95% confidence interval (CI): 1.26, 6.10] and 2.17 (95% CI: 0.99, 4.78), respectively, when adjusted for background exposure}. The regression coefficients for log-transformed measures (fibers per cubic centimeters × months) of background exposure and activity-based exposure were 0.322 (95% CI: 0.078, 0.567) and 0.063 (95% CI: -0.013, 0.139), respectively, when adjusted for each other, and 0.283 (95% CI: 0.104, 0.463) for cumulative exposure from all sources. CONCLUSION: These results support the hypothesis that community exposure to asbestos-contaminated vermiculite originating from Libby, Montana, is associated with measurable effects based on radiographic evidence.

Modeling community asbestos exposure near a vermiculite processing facility: Impact of human activities on cumulative exposure.

Contaminated vermiculite ore from Libby, Montana was processed in northeast Minneapolis from 1936 to 1989 in a densely populated urban residential neighborhood, resulting in non-occupational exposure scenarios from plant stack and fugitive emissions as well as from activity-based scenarios associated with use of the waste rock in the surrounding community. The objective of this analysis was to estimate potential cumulative asbestos exposure for all non-occupationally exposed members of this community. Questionnaire data from a neighborhood-exposure assessment ascertained frequency of potential contact with vermiculite processing waste. Monte Carlo simulation was used to develop exposure estimates based on activity-based concentration estimates and contact durations for four scenarios: S1, moved asbestos-contaminated waste; S2, used waste at home, on lawn or garden; S3, installed/removed vermiculite insulation; S4, played in or around waste piles at the plant. The simulation outputs were combined with air-dispersion model results to provide total cumulative asbestos exposure estimates for the cohort. Fiber emissions from the plant were the largest source of exposure for the majority of the cohort, with geometric mean cumulative exposures of 0.02 fibers/cc × month. The addition of S1, S2 and S3 did not significantly increase total cumulative exposure above background exposure estimates obtained from dispersion modeling. Activity-based exposures were a substantial contributor to the upper end of the exposure distribution: 90th percentile S4 exposure estimates are ∼10 times higher than exposures from plant emissions. Pile playing is the strongest source of asbestos exposure in this cohort, with other activity scenarios contributing less than from plant emissions.

Persistent neuropathy and hyperkeratosis from distant arsenic exposure.

The purpose of this case series is to assess long-term sequelae of arsenic exposure in a cohort acutely exposed to arsenic in drinking water from a well dug into a landfill containing arsenical pesticides. Ten of the 13 individuals (or next of kin) in the initial study agreed to participate in the follow-up study. Next of kin provided questionnaire data and released medical information on the three individuals who had died. The remaining seven cohort members were assessed by an interview, questionnaire, detailed physical examination and sensory nerve testing. Available medical records were obtained and reviewed. Sensory testing was performed using an automated electrodiagnostic sensory Nerve Conduction Threshold (sNCT) evaluation. Sensory complaints and electrodiagnostic findings consistent with polyneuropathy were found in a minority (3/7) of subjects 28 years after an acute toxic arsenic exposure. Two of the seven patients examined (1 of 3 with neuropathic findings) also had hyperkeratotic lesions consistent with arsenic toxicity and one of the patients had hyperpigmentation on their lower extremities possibly consistent with arsenic toxicity.