1 Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University , Boston, Massachusetts, USA.
2 Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts, USA.
Environ Health Perspect. 2019 Jun;127(6):67006. doi: 10.1289/EHP4093. Epub 2019 Jun 6.
Between 2013 and 2015, concentrations of poly- and perfluoroalkyl substances (PFAS) in public drinking water supplies serving at least six million individuals exceeded the level set forth in the health advisory established by the U.S. Environmental Protection Agency. Other than data reported for contaminated sites, no systematic or prospective data exist on the relative source contribution (RSC) of drinking water to human PFAS exposures.
This study estimates the RSC of tap water to overall PFAS exposure among members of the general U.S.
We measured concentrations of 15 PFAS in home tap water samples collected in 1989-1990 from 225 participants in a nationwide prospective cohort of U.S. women: the Nurses' Health Study (NHS). We used a one-compartment toxicokinetic model to estimate plasma concentrations corresponding to tap water intake of PFAS. We compared modeled results with measured plasma PFAS concentrations among a subset of 110 NHS participants.
Tap water perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) were statistically significant predictors of plasma concentrations among individuals who consumed [Formula: see text] cups of tap water per day. Modeled median contributions of tap water to measured plasma concentrations were: PFOA 12% (95% probability interval 11%-14%), PFNA 13% (8.7%-21%), linear perfluorooctanesulfonic acid (nPFOS) 2.2% (2.0%-2.5%), branched perfluorooctanesulfonic acid (brPFOS) 3.0% (2.5%-3.2%), and perfluorohexanesulfonic acid (PFHxS) 34% (29%-39%). In five locations, comparisons of PFASs in community tap water collected in the period 2013-2016 with samples from 1989-1990 indicated increases in quantifiable PFAS and extractable organic fluorine (a proxy for unquantified PFAS).
Our results for 1989-1990 compare well with the default RSC of 20% used in risk assessments for legacy PFAS by many agencies. Future evaluation of drinking water exposures should incorporate emerging PFAS. https://doi.org/10.1289/EHP4093.
2013 年至 2015 年间，至少有 600 万人使用的公共饮用水供应中的多氟和全氟烷基物质 (PFAS) 浓度超过了美国环境保护署制定的健康咨询设定的水平。除了受污染地点报告的数据外，没有关于饮用水对人类 PFAS 暴露相对源贡献 (RSC) 的系统或前瞻性数据。
本研究估计全美国普通人群中自来水中 PFAS 暴露的 RSC。
我们测量了 1989-1990 年间来自全美国妇女的一项全国前瞻性队列研究——护士健康研究 (NHS) 中 225 名参与者家中自来水中 15 种 PFAS 的浓度。我们使用一个单室毒代动力学模型来估计与每天饮用[Formula: see text]杯水的 PFAS 摄入相对应的血浆浓度。我们比较了模型结果与 110 名 NHS 参与者中的一部分人的血浆 PFAS 浓度。
自来水中的全氟辛酸 (PFOA) 和全氟壬酸 (PFNA) 是每天饮用[Formula: see text]杯水的个体血浆浓度的统计学显著预测因子。模型中自来水中对测量血浆浓度的中位贡献分别为：PFOA 为 12%（95%概率区间为 11%-14%），PFNA 为 13%（8.7%-21%），线性全氟辛烷磺酸 (nPFOS) 为 2.2%（2.0%-2.5%），支链全氟辛烷磺酸 (brPFOS) 为 3.0%（2.5%-3.2%），以及全氟己烷磺酸 (PFHxS) 为 34%（29%-39%）。在五个地点，2013-2016 年采集的社区自来水中的 PFAS 与 1989-1990 年的样本进行比较，结果表明可量化的 PFAS 和可提取有机氟（不可量化的 PFAS 的代理）增加。
我们对 1989-1990 年的数据的结果与许多机构对遗留 PFAS 进行风险评估时使用的默认 RSC 20% 相比表现良好。未来对饮用水暴露的评估应纳入新兴的 PFAS。https://doi.org/10.1289/EHP4093.
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