Department of Ecology and Evolutionary Biology, Yale College, New Haven, Connecticut, USA.
Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, USA.
Environ Health Perspect. 2018 Jun 27;126(6):067008. doi: 10.1289/EHP2663. eCollection 2018 Jun.
Hydraulically fractured wells produce 2-14 million liters of wastewater, which may contain toxic and radioactive compounds. The wastewater is predominantly disposed of using Class II injection wells.
Our objective was to evaluate the relationship between sociodemographic characteristics and injection well locations in Ohio.
Using state and federal data sources, we classified Ohio census block groups by presence of injection wells, number of hydraulically fractured wells, sociodemographic factors (median household income, % white, population density, % ≥high school education, median age, voter turnout), and geographic information (land area, water area, situated over shale). We modeled the odds of having at least one injection well within a block group with respect to all covariates using three multivariable models incorporating different spatial components to account for similarities in neighboring block groups.
In bivariate analyses, block groups with injection wells (=156) compared with those without (=9,049) had lower population density (71 vs. 2,210 people/mi or 27 vs. 854 people/km), larger median area (43.5 vs. 1.35 km), higher median age (42.8 vs. 40.2 y), and higher % white (98.1% vs. 92.1%). After adjustment using a spatial logistic regression model, the odds of a block group containing an injection well were 16% lower per $10,000 increase in median income [odds ratio(OR)=0.837; 95% credible interval (CI): 0.719, 0.961] and 97% lower per 1,000 people/mi (or per 386 people/km) increase (OR=0.030; 95% CI=0.008, 0.072). Block groups on shale and those containing fewer hydraulically fractured wells were more likely to include an injection well. Percentage white, median age, % ≥high school education, and % voter turnout were not significant predictors of injection well presence.
In Ohio, injection wells were inversely associated with block groups' median incomes after adjusting for other sociodemographic and geographic variables. Research is needed to determine whether residents in census blocks with injection wells face increased risk of chemical exposures or adverse health outcomes. https://doi.org/10.1289/EHP2663.
水力压裂井会产生 200 万至 1400 万升废水，其中可能含有有毒和放射性化合物。这些废水主要通过 II 类注入井进行处理。
我们的目的是评估俄亥俄州社会人口特征与注入井位置之间的关系。
我们使用州和联邦数据源，根据注入井的存在、水力压裂井的数量、社会人口因素（家庭收入中位数、白人比例、人口密度、高中以上学历比例、人口中位数年龄、投票率）以及地理信息（土地面积、水域面积、所处页岩位置）对俄亥俄州的普查街区组进行分类。我们使用三种多变量模型，根据所有协变量，针对每个街区组至少有一个注入井的情况进行建模，这些模型包含不同的空间成分，以说明相邻街区组之间的相似性。
在单变量分析中，与没有注入井的街区组（=9049）相比，有注入井的街区组（=156）的人口密度更低（71 人/英里或 27 人/平方公里，而 2210 人/英里或 854 人/平方公里），面积中位数更大（43.5 平方公里或 1.35 平方公里），人口中位数年龄更高（42.8 岁或 40.2 岁），白人比例更高（98.1%或 92.1%）。在使用空间逻辑回归模型进行调整后，街区组中每增加 10000 美元的中位数收入，注入井的可能性就会降低 16%[优势比（OR）=0.837；95%置信区间（CI）：0.719，0.961]，每增加 1000 人/英里（或每增加 386 人/平方公里），注入井的可能性就会降低 97%（OR=0.030；95%CI=0.008，0.072）。位于页岩上的街区组和水力压裂井数量较少的街区组更有可能包含注入井。白人比例、人口中位数年龄、高中以上学历比例和投票率不是注入井存在的显著预测因素。
在俄亥俄州，在调整其他社会人口和地理变量后，注入井与街区组的中位数收入呈负相关。需要研究居民在有注入井的普查区块中是否面临更高的化学暴露或不良健康结果风险。https://doi.org/10.1289/EHP2663.
