4非癌症人类健康效应的风险阈值是等于,当暴露等于参考剂量(RFD)时。癌症效应的阈值是终身过剩的癌症风险为1x10-6,即,当寿命平均每日剂量导致高于背景癌症发病率的每百万次癌症病例时。5 Though EPA Method 1633 recommends that laboratories develop their own limit of quantification (LOQ) and method detection limit (MDL) when measuring PFAS in sewage sludge, most laboratories running this method achieve LOQs and MDLs of 1 ppb or lower for PFOA and PFOS ( se e https://www.epa.gov/cwa-方法/CWA分析方法和聚氟烷基 - 溶剂 - 替代pfas)。