RESUMO
Here, we detail arsenic (As) and lead (Pb) concentrations in community science generated rooftop harvested rainwater data from Project Harvest (PH), a co-created community science study, and National Atmospheric Deposition Program (NADP) National Trends Network wet-deposition AZ samples as analyzed by Palawat et al. [1]. 577 field samples were collected in PH and 78 field samples were collected by NADP. All samples were analyzed via inductively coupled plasma mass spectrometry (ICP-MS) for dissolved metal(loid)s including As and Pb by the Arizona Laboratory for Emerging Contaminants after 0.45 um filtration and acidification. Method limits of detection (MLOD) were assessed and sample concentrations above MLODs were considered detects. Summary statistics and box and whisker plots were generated to assess variables of interest such as community and sampling window. Finally, As and Pb data is provided for potential reuse; the data can be used to assess contamination of harvested rainwater in AZ and to inform community use of natural resources.
RESUMO
As climate change exacerbates water scarcity, rainwater harvesting for household irrigation and gardening becomes an increasingly common practice. However, the use and quality of harvested rainwater are not well studied, and the potential pollutant exposures associated with its use are generally unknown. There are currently no federal standards in the United States to assess metal(loid)s in harvested rainwater. Project Harvest, a community science research project, was created to address this knowledge gap and study the quality of harvested rainwater, primarily used for irrigation, in four environmental justice communities in Arizona, USA. Community scientists collected 577 unique rooftop harvested rainwater samples from 2017 to 2020, which were analyzed for metal(loid)s, where arsenic (As) concentrations ranged from 0.108 to 120 µg L-1 and lead (Pb) concentrations ranged from 0.013 to 350 µg L-1 and compared to relevant federal/state standards/recommendations. Community As and Pb concentrations decreased as: Hayden/Winkelman > Tucson > Globe/Miami > Dewey-Humboldt. Linear mixed models were used to analyze rooftop harvested rainwater data and results indicated that concentrations of As and Pb in the summer monsoon were significantly greater than winter; and contamination was significantly greater closer to extractive industrial sites in three of the four study communities (ASARCO Hayden Plant Superfund Alternative site in Hayden/Winkelman, Davis-Monthan United States Air Force Base in Tucson - Pb only, and Freeport McMoRan Copper and Gold Mine in Globe/Miami). Based on models, infrastructure such as proximity to roadway, roof material, presence of a cistern screen, and first-flush systems were not significant with respect to As and Pb when controlling for relevant spatiotemporal variables; whereas, cistern age was associated with Pb concentrations. These results however, indicate that concentrations vary seasonally and by proximity to industrial activity, not by decisions made regarding collection system infrastructures at the individual home level. This study shows that generally, individuals are not responsible for environmental contamination of rooftop harvested rainwater, rather activities and decisions of government and corporate industries control contaminant release.
