Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, United States of America.
Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, United States of America.
Sci Total Environ. 2019 Feb 15;651(Pt 2):3151-3160. doi: 10.1016/j.scitotenv.2018.10.194. Epub 2018 Oct 15.
Ciprofloxacin (CIP) and azithromycin (AZ) are commonly prescribed antibiotics for various infections in humans and are frequently detected in biosolids. Ecological and human health risks from biosolids-borne CIP and AZ are not well understood, but necessary for formulating policies on safe use and management of biosolids. A tiered integrated risk assessment (IRA), based on the World Health Organization (WHO) framework and the USEPA Part 503 Biosolids Rule, was conducted to assess human and ecological health risks from biosolids-borne CIP and AZ. The IRA utilized the hazard quotient (HQ) approach to evaluate risks to various receptors of concern (including humans, animals, and birds) in sixteen exposure pathways and three conservative biosolids land application scenarios. The scenarios consisted of (i) single-heavy (100 Mg ha) land application of biosolids containing 95th percentile concentrations of CIP or AZ (USEPA, 2009), (ii) long-term (annual for 40-y) land application of biosolids containing typical (median; USEPA, 2009) CIP or AZ concentrations, and (iii) long-term (annual for 40-y) land application of biosolids containing the 95th percentile concentrations of CIP or AZ. The unrealistically conservative screening level (Tier 1) assessment identified three pathways of potential concern: biosolids → soil → plant (CIP); biosolids → soil → soil organism (CIP and AZ); and biosolids → soil → soil organism → predator (CIP and AZ). Subsequent tier (refined; more realistic) assessments and pollutant limits (calculated based on the USEPA Part 503 Biosolids Rule) suggested negligible human and ecological health risks from biosolids-borne CIP and AZ under real-world biosolids application scenarios. Pollutant concentration limits were 12 mg CIP kg and 2.2 mg AZ kg; suggesting that pollutant load tracking is not needed for the majority (75% for CIP and 90% for AZ) of USA biosolids. Biosolids-borne antibiotic resistance (currently not addressed in any risk assessment model) is the principal uncertainty limiting risk assessment of biosolids-borne antibiotics including CIP and AZ.
环丙沙星（CIP）和阿奇霉素（AZ）是人类常用的抗生素，常用于治疗各种感染，并且经常在生物固体中被检测到。生物固体中 CIP 和 AZ 带来的生态和人类健康风险尚未得到充分了解，但制定生物固体安全使用和管理政策时需要考虑这些风险。本研究采用基于世界卫生组织（WHO）框架和美国环保署（USEPA）第 503 号生物固体法规的分层综合风险评估（IRA）方法，评估生物固体中 CIP 和 AZ 对人类和生态健康的风险。IRA 利用危害商数（HQ）方法，评估了十六种暴露途径和三种保守的生物固体土地应用情景中各种关注受体（包括人类、动物和鸟类）的风险。这三种情景分别为：（i）单重负荷（100 Mg ha）土地应用含有 95%百分位浓度 CIP 或 AZ 的生物固体（USEPA，2009 年）；（ii）长期（40 年每年）土地应用含有 CIP 或 AZ 典型（中位数；USEPA，2009 年）浓度的生物固体；（iii）长期（40 年每年）土地应用含有 95%百分位浓度 CIP 或 AZ 的生物固体。不切实际的保守筛选水平（第 1 层）评估确定了三个潜在关注途径：生物固体→土壤→植物（CIP）；生物固体→土壤→土壤生物（CIP 和 AZ）；以及生物固体→土壤→土壤生物→捕食者（CIP 和 AZ）。随后的第 2 层（精细化；更现实）评估和污染物限量（根据美国环保署第 503 号生物固体法规计算）表明，在实际的生物固体应用情景下，生物固体中 CIP 和 AZ 对人类和生态健康的风险可忽略不计。污染物浓度限量分别为 12mg CIP kg 和 2.2mg AZ kg；这表明对于大多数（CIP 为 75%，AZ 为 90%）美国生物固体来说，不需要跟踪污染物负荷。生物固体中抗生素抗性（目前任何风险评估模型都未涉及）是限制生物固体中抗生素（包括 CIP 和 AZ）风险评估的主要不确定性。
