ecological risk assessment.xlsx

To examine the residues and distributions of tetracycline antibiotics in Weihe basin, SPE-UPLC (solid phase extraction-ultra performance liquid chromatography) was employed to analyze the Oxytetracycline (OTC), Chlortetracycline (CTC) and Minocycline (MC) of 41 surface water and 35 sediment samples collected from main streams, tributaries and main sewage outlets. The Results showed that (1) The order of residual levels of tetracycline antibiotics in water and sediment from high to low was following: OTC>CTC>MC. The concentrations of OTC in water and sediment were in the range of 1.56-87.89 ng/L and 6.13-45.38 ng/g (mean value of 16.13 ng/L and 20.60 ng/g), respectively; while CTC was 1.07-26.78 ng/L and 6.17-32.29 ng/g (mean value of 4.96 ng/L and 14.48 ng/g), respectively; and MC was 0.28-12.35 ng/L and 4.80-29.74 ng/g (mean value of 1.70 ng/L and 12.96 ng/g), respectively. There were maximum concentrations in all sewage outlets. Compared with other areas in China, tetracyclines residues in Weihe basin was at a medium level; (2) In spatial distribution, the levels of tetracyclines in water and sediment from the middle and upper reaches were higher than the lower reaches. Meanwhile, the sewage outfalls and livestock farm waste water discharge were main sources of tetracycline antibiotics in Weihe basin; (3) Ecological risk assessment revealed that in main streams and tributaries, OTC and CTC may be at low ecological risk level; while in sewage outfalls, they may be at medium ecological risk level.