加州《Proposition 65》实施后美国和加州生物监测暴露趋势分析

有害化学品在美国商业中的普遍存在促使部分州制定法律以减少暴露，其中加州的《Proposition 65》（Prop 65）具有广泛影响力。该法案列出导致癌症、发育危害或生殖毒性的化学品，旨在减少企业对这些化学品的使用并降低消费者的暴露风险。然而，尚未明确Prop 65是否有效降低了公众对列入清单化学品的总体暴露水平。本文利用美国疾病控制与预防中心（CDC）国家生物监测数据，评估Prop 65对公众暴露的影响。我们分析了在Prop 65列入名单前后，从血液和尿液中检测的37种化学品（包括邻苯二甲酸酯、酚类、挥发性有机物、金属、多环芳烃和PFAS）的浓度变化，涉及的化学品中，有11种在列入前，11种在列入期间，4种在列入后，另有11种未列入但与列入的化学品密切相关。对于列入前后均有监测数据的化学品，我们采用差异中的差异模型（difference-in-differences）估算加州与非加州地区的浓度变化。使用分位数回归分析不同百分位点（25%、75%、95%）的暴露变化及地区差异。结果显示，无论是否列入Prop 65名单，全国范围内监测到的化学品浓度总体呈下降趋势。双酚A（BPA）的中位浓度在列入Prop 65后下降了15%，而非列入但相关的双酚S（BPS）浓度同期上升了20%，显示出化学品替代现象。加州居民的化学品暴露水平普遍低于其他地区。研究发现，科学和监管的关注增强以及公众对Prop 65有害影响的认知促使企业改变产品配方，减少了全国范围内的暴露。双酚类和部分邻苯二甲酸酯的变化提示制造商用未列入名单的化学品替代了列入名单的化学品，从而增加了对替代品的暴露。研究结果对制定减少有害暴露的政策、 biomonitoring 监测计划的优化以及理解影响化学暴露的监管和市场力量具有重要借鉴意义。https://doi.org/10.1289/EHP13956

The prevalence of toxic chemicals in US commerce has prompted some states to adopt laws to reduce exposure. One with broad reach is California's Proposition 65 (Prop 65), which established a list of chemicals that cause cancer, developmental harm, or reproductive toxicity. The law is intended to discourage businesses from using these chemicals and to minimize consumer exposure. However, a key question remains unanswered: Has Prop 65 reduced population-level exposure to the listed chemicals?We used national biomonitoring data from the Centers for Disease Control and Prevention (CDC) to evaluate the impact of Prop 65 on population-level exposures.We evaluated changes in blood and urine concentrations of 37 chemicals (including phthalates, phenols, VOCs, metals, PAHs, and PFAS), among US National Health and Nutrition Examination Survey (NHANES) participants in relation to the time of chemicals' Prop 65 listing. Of these, 11 were listed prior to, 11 during, and 4 after the biomonitoring period. The remaining 11 were not listed but were closely related to a Prop 65-listed chemical. Where biomonitoring data were available from before and after the date of Prop 65 listing, we estimated the change in concentrations over time for Californians compared with non-Californians, using a difference-in-differences model. We used quantile regression to estimate changes in exposure over time, as well as differences between Californians and non-Californians at the 25th, 75th, and 95th percentiles.We found that concentrations of biomonitored chemicals generally declined nationwide over time irrespective of their inclusion on the Prop 65 list. Median bisphenol A (BPA) concentrations decreased 15% after BPA's listing on Prop 65, whereas concentrations of the nonlisted but closely related bisphenol S (BPS) increased 20% over this same period, suggesting chemical substitution. Californians generally had lower levels of biomonitored chemicals than the rest of the US population.Our findings suggest that increased scientific and regulatory attention, as well as public awareness of the harms of Prop 65-listed chemicals, prompted changes in product formulations that reduced exposure to those chemicals nationwide. Trends in bisphenols and several phthalates suggest that manufacturers replaced some listed chemicals with closely related but unlisted chemicals, increasing exposure to the substitutes. Our findings have implications for the design of policies to reduce toxic exposures, biomonitoring programs to inform policy interventions, and future research into the regulatory and market forces that affect chemical exposure. https://doi.org/10.1289/EHP13956.