Environmental health hazards are known to disproportionately burden marginalized communities. Agriculture, wastewater, and industrial waste contaminate surface and groundwater, used for drinking, with nitrates. High nitrate concentrations in drinking water have been linked to methemoglobinemia and, recently, thyroid cancer. With a large proportion of the nation's agriculture grown in California, thyroid cancer linked to nitrate water contamination is of concern. This research entailed geographic and statistical analysis of water, nitrate, health, and disadvantaged communities (DACs) in California. DACs are Californian defined areas that experience a combination of hardships from socioeconomic, health, and environmental fields. Our analysis of the California Cancer Registry and California Water Board's well data shows statistically significant correlation (p < 0.05) between nitrate contamination (wells >5 and 10 ppm NO₃-N per square mile and percentage of total wells) and thyroid cancer incidence. DACs had twice the rate of thyroid cancer compared with non-DACs, and higher numbers of nitrate-contaminated wells and hot spots compared with the state averages. Almost half (47%) of the Central Valley's area contained DACs and 27% of wells >10 ppm NO₃-N contaminants. Our study provides a method for other states and countries to conduct preliminary geospatial analysis between water contamination and health with open data. Maps and analysis from this research can inform the public, advocacy groups, and policy leaders of health-related concerns in relation to nitrate water contamination and environmental justice in California. DACs should be provided cost-effective drinking water monitoring and treatment, and governments should incentivize nitrate loading reductions in agriculture, industry, and wastewater. Future research is recommended with more localized, private health data on thyroid cancer incidence.

中文翻译：

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加利福尼亚州的水、健康和环境正义：硝酸盐污染和甲状腺癌的地理空间分析

众所周知，环境健康危害会给边缘化社区带来不成比例的负担。农业、废水和工业废物污染了用于饮用的地表水和地下水，其中含有硝酸盐。饮用水中的高硝酸盐浓度与高铁血红蛋白血症以及最近的甲状腺癌有关。由于美国大部分农业产自加利福尼亚州，因此与硝酸盐水污染相关的甲状腺癌令人担忧。这项研究需要对加利福尼亚州的水、硝酸盐、健康和弱势社区 (DAC) 进行地理和统计分析。DAC 是加州定义的地区，经历着社会经济、健康和环境领域的综合困难。我们对加州癌症登记处和加州水务局的水井数据进行的分析显示，硝酸盐污染（每平方英里>5 和 10 ppm NO 3 -N 的水井以及总水井的百分比）与甲状腺癌发病率之间存在统计显着相关性( _p  < 0.05 )。与非 DAC 相比，DAC 的甲状腺癌发病率是非 DAC 的两倍，受硝酸盐污染的井和热点数量也高于州平均水平。中央谷地区几乎一半 (47%) 的区域含有 DAC，27% 的井中 NO ₃ -N 污染物>10 ppm。我们的研究为其他州和国家提供了一种利用开放数据对水污染与健康进行初步地理空间分析的方法。这项研究的地图和分析可以让公众、倡导团体和政策领导人了解与加州硝酸盐水污染和环境正义相关的健康问题。应为 DAC 提供具有成本效益的饮用水监测和处理，政府应鼓励减少农业、工业和废水中的硝酸盐负荷。建议未来研究更多关于甲状腺癌发病率的本地化、私人健康数据。