Probabilistic risk assessment of residential exposure to metal(loid)s in a mining impacted community.

The "Gold Country" region of California is impacted by legacy and active gold mines. Concomitantly, Gold Country has an increased rate of female breast cancer relative to the state average. Using community-based participatory research methods, 40 participants completed surveys and collected a total of 354 water, soil, home-grown foods, and dust samples from their homes, which we compared to state, federal, and international contamination standards for arsenic, cadmium, and lead. All soil samples exceeded U.S. EPA and California EPA soil standards for arsenic. When comparing other media to state, federal and international standards for arsenic, cadmium, and lead, 15 additional exceedances for indoor/outdoor dust, drinking water, and/or vegetable were documented. A probabilistic risk assessment was conducted to determine an adult female's exposure to arsenic, cadmium, and lead and estimated risk. Arsenic exposure, due largely to water (63.5 %) and homegrown food (33.3 %), presents carcinogenic risks in excess of the EPA recommended upper limit for contaminated sites (1 × 10-4) in 12.5 % of scenarios, and exceeds a risk level of 1 × 10-6 in 98.0 % of cases. Cadmium exposure results mainly from homegrown food consumption (83.7 %), and lead exposure results from a broader range of sources. This research indicates that rural areas in Gold Country face environmental exposures different than in urban areas. Exposure to arsenic in the female population of Gold Country may be driven by consumption of home-grown foods and water, and exposure to cadmium is driven by home-grown food intake. Since mining sites are of concern internationally, this risk assessment process and associated findings are significant and can be used to inform and tailor public health interventions. The weight of the evidence suggests that the arsenic exposure identified in this study could contribute to increases in the cancer rate among those living in Gold Country, California.

Environmental monitoring and exposure science dataset to calculate ingestion and inhalation of metal(loid)s through preschool gardening.

Metal(loid) contamination may pose an increased risk of exposure to children residing near legacy and active resource extraction sites. Children may be exposed to arsenic, cadmium, and/or lead by ingestion and/or inhalation while engaging in school or home outdoor activities via environmental media including water, soil, dust, and locally grown produce. It is thus critical to collect site-specific data to best assess these risks. This data article provides gastric and lung in-vitro bioaccessibility assay (IVBA) data, as well as environmental monitoring data for water, soil, dust, and garden produce collected from preschools (N = 4) in mining communities throughout Nevada County, California in 2018. Arsenic, cadmium, and lead concentrations in the aforementioned media and synthetic gastric and lung fluids were measured by inductively coupled plasma-mass spectrometry (ICP-MS). This dataset provides useful metal(loid) concentrations for future risk assessments for similar settings.

Ingestion and inhalation of metal(loid)s through preschool gardening: An exposure and risk assessment in legacy mining communities.

Children residing in mining towns are potentially disproportionately exposed to metal(loid)s via ingestion and dust inhalation, thus, increasing their exposure when engaging in school or home gardening or playing outside. This citizen science study assessed preschool children's potential arsenic (As), cadmium (Cd), and lead (Pb) exposure via locally grown produce, water, incidental soil ingestion, and dust inhalation at four sites. Participants were trained to properly collect water, soil, and vegetable samples from their preschools in Nevada County, California. As, Cd, and Pb concentrations in irrigation sources did not exceed the U.S. EPA's maximum contaminant and action levels. In general, garden and playground As and Pb soil concentrations exceeded the U.S. EPA Regional Screening Level, CalEPA Human Health Screening Level, and California Department of Toxic Substances Control Screening Level. In contrast, all Cd concentrations were below these recommended screening levels. Dust samples (<10 µm diameter) were generated from surface garden and playground soil collected at the preschools by a technique that simulated windblown dust. Soil and dust samples were then analyzed by in-vitro bioaccessibility assays using synthetic lung and gastric fluids to estimate the bioaccessible fraction of As, Cd, and Pb in the body. Metal(loid) exposure via grown produce revealed that lettuce, carrot, and cabbage grown in the preschool gardens accumulated a higher concentration of metal(loid) than those store-bought nation-wide. None of the vegetables exceeded the respective recommendation maximum levels for Cd and Pb set by the World Health Organization Codex Alimentarius Commission. The results of this study indicate that consumption of preschool-grown produce and incidental soil ingestion were major contributors to preschool-aged children's exposure to As, Cd, and Pb. Traditionally, this level of site- and age-specific assessment and analyses does not occur at contaminated sites. The results of this holistic risk assessment can inform future risk assessment and public health interventions related to childhood metal(loid) exposures.

Heavy Metals in California Women Living in a Gold Mining-Impacted Community.

Gold mining activities occurred throughout the foothills of the Sierra Nevada Mountains in California, leaving behind persistent toxic contaminants in the soil, dust, and water that include arsenic and cadmium. Despite a high level of concern among local residents about potential exposure and high breast cancer rates, no biomonitoring data has been collected to evaluate the levels of heavy metals. We conducted a study to characterize the urinary levels of heavy metals among women in this region by working with the community in Nevada County. Sixty women provided urine samples and completed a questionnaire. We examined levels of arsenic, cadmium, and other metals in relation to the length of residency in the area, age, dietary factors, recreational activities, and smoking. We compared urinary metal levels in participants to levels in the United States National Health and Nutrition Examination Survey (NHANES). Overall, study participants had higher urinary levels of arsenic than women in the national sample. Cadmium levels were similar to the national average, although they were elevated in women ≥35 years who had lived in the region for 10 years or more. Arsenic levels were higher among women who smoked, ate fish, ate home-grown produce, and who reported frequent hiking or trail running, although these differences were not statistically significant. This study established a successful community-research partnership, which facilitated community dialogue about possible human health consequences of living in a mining-impacted area.