TY - JOUR

T1 - Bioavailability of Antibiotics at Soil-Water Interfaces

T2 - A Comparison of Measured Activities and Equilibrium Partitioning Estimates

AU - Menz, Jakob

AU - Müller, Julia

AU - Olsson, Oliver

AU - Kümmerer, Klaus

PY - 2018/6/5

Y1 - 2018/6/5

N2 - There are growing concerns that antibiotic pollution impacts environmental microbiota and facilitates the propagation of antibiotic resistance. However, the prediction or analytical determination of bioavailable concentrations of antibiotics in soil is still subject to great uncertainty. Biological assays are increasingly recognized as valuable complementary tools that allow a more direct determination of the residual antibiotic activity. This study assessed the bioavailability of structurally diverse antibiotics at a soil-water interface applying activity-based analyses in conjunction with equilibrium partitioning (EqP) modeling. The activity against Gram-positive and Gram-negative bacteria of nine antibiotics from different classes was determined in the presence and absence of standard soil (LUFA St. 2.2). The addition of soil affected the activity of different antibiotics to highly varying degrees. Moreover, a highly significant correlation (p <0.0001) between the experimentally observed and the EqP-derived log EC50 (half-maximal effective concentration) values was observed. The innovative experimental design of this study provided new insights on the bioavailability of antibiotics at soil-water interfaces. EqP appears to be applicable to a broad range of antibiotics for the purpose of screening-level risk assessment. However, EqP estimates cannot replace soil-specific ecotoxicity testing in higher-tier assessments, since their accuracy is still compromised by a number of factors.

AB - There are growing concerns that antibiotic pollution impacts environmental microbiota and facilitates the propagation of antibiotic resistance. However, the prediction or analytical determination of bioavailable concentrations of antibiotics in soil is still subject to great uncertainty. Biological assays are increasingly recognized as valuable complementary tools that allow a more direct determination of the residual antibiotic activity. This study assessed the bioavailability of structurally diverse antibiotics at a soil-water interface applying activity-based analyses in conjunction with equilibrium partitioning (EqP) modeling. The activity against Gram-positive and Gram-negative bacteria of nine antibiotics from different classes was determined in the presence and absence of standard soil (LUFA St. 2.2). The addition of soil affected the activity of different antibiotics to highly varying degrees. Moreover, a highly significant correlation (p <0.0001) between the experimentally observed and the EqP-derived log EC50 (half-maximal effective concentration) values was observed. The innovative experimental design of this study provided new insights on the bioavailability of antibiotics at soil-water interfaces. EqP appears to be applicable to a broad range of antibiotics for the purpose of screening-level risk assessment. However, EqP estimates cannot replace soil-specific ecotoxicity testing in higher-tier assessments, since their accuracy is still compromised by a number of factors.

KW - Chemistry

UR - http://www.scopus.com/inward/record.url?scp=85048401105&partnerID=8YFLogxK

U2 - 10.1021/acs.est.7b06329

DO - 10.1021/acs.est.7b06329

M3 - Journal articles

C2 - 29630833

AN - SCOPUS:85048401105

VL - 52

SP - 6555

EP - 6564

JO - Environmental Science & Technology

JF - Environmental Science & Technology

SN - 0013-936X

IS - 11

ER -