摘要

关于两种抗生素TOrCs，环丙沙星（CIP）和阿奇霉素（AZ）对陆地生物的生物利用度的信息受到严重限制，特别是在生物固体环境中。在涉及3H标记化合物的实验室培养研究中评估了两种陆生生物，蚯蚓和微生物对一系列环境相关浓度的生物固体携带的CIP和AZ的响应。蚯蚓评估基于蚯蚓亚慢性毒性试验（OCSPP 850.3100）。使用呼吸作用和逆转录酶定量PCR（mRNA）分析营养物（N和P）循环基因作为毒性标记来评估微生物影响。使用CaCl 2，甲醇：水的连续萃取和加速溶剂萃取以及使用薄层色谱分析来评估孵育期间的抗生素可提取性和稳定性。除连续提取外，子样品燃烧回收了几乎100％的添加抗生素。这两种化合物持续存在（估计半衰期≥3），但可萃取部分（特别是CIP）随时间降低。生物固体携带的抗生素都不会显着影响整体呼吸或N和P循环。微生物毒性反应微乎其微;氨氧化细菌基因的互补DNA（cDNA）浓度受到影响，但仅限于最初。同样，蚯蚓对生物固体携带的CIP和AZ的环境相关（和更高）浓度的毒性没有表现出明显的反应。然而，蚯蚓积累了两种化合物，并且在解冻的蠕虫中生物累积因子（BAF）值（基于干重）为~4（CIP）和~7（AZ），在未解冻的蠕虫中为~20（CIP和AZ）。微生物和蚯蚓的反应强烈地与目标TOrCs的“生物可接近”部分适度相关。结果表明，生物固体携带的CIP和AZ对陆地微生物和蚯蚓的毒性很小，但目标TOrC有可能进入生态食物网。

Information on bioavailability of two antibiotic TOrCs, ciprofloxacin (CIP) and azithromycin (AZ), to terrestrial organisms is severely limited, especially in the biosolids context. Responses of two terrestrial organisms, earthworms and microbes, to a range of environmentally relevant concentrations of biosolids-borne CIP and AZ were assessed in laboratory incubation studies involving 3H-labeled compounds. Earthworm assessments were based on the Earthworm Sub-chronic Toxicity Test (OCSPP 850.3100). Microbial impacts were assessed using respiration and reverse transcriptase-quantitative PCR (mRNA) analyses of nutrient (N and P) cycling genes as toxicity markers. Antibiotic extractability and stability during incubations were assessed using sequential extractions with CaCl2, methanol:water, and accelerated solvent extraction and analyses using thin layer chromatography. Subsample combustion, in addition to sequential extraction, recovered nearly 100% of the added antibiotic. The two compounds persisted (estimated half-lives ≥ 3 y), but extractable fractions (especially of CIP) decreased over time. Neither biosolids-borne antibiotic significantly impacted overall respiration or N and P cycling. Microbial toxicity responses were minimal; complementary DNA (cDNA) concentrations of ammonia oxidizing bacterial genes were affected, but only initially. Similarly, earthworms showed no apparent response related to toxicity to environmentally relevant (and much greater) concentrations of biosolids-borne CIP and AZ. Earthworms, however, accumulated both compounds, and the bioaccumulation factor (BAF) values (dry weight basis) were ~4 (CIP) and ~7 (AZ) in depurated worms and ~20 (CIP and AZ) in un-depurated worms. The microbial and earthworm responses strongly to moderately correlated with "bioaccessible" fractions of the target TOrCs. The results suggest that biosolids-borne CIP and AZ toxicity to terrestrial microbes and earthworms is minimal, but there is a potential for target TOrC entry into ecological food web.

https://www.ncbi.nlm.nih.gov/pubmed/30195128