Ecological Risk Assessment of Amoxicillin, Enrofloxacin, and Neomycin: Are Their Current Levels in the Freshwater Environment Safe?

Abstract

Veterinary pharmaceuticals may cause unexpected adverse effects on non-target aquatic species. While these pharmaceuticals were previously identified as priority compounds in ambient water, their ecological risks are relatively unknown. In this study, a series of chronic toxicity tests were conducted for these pharmaceuticals using algae, two cladocerans, and a fish. After a 21-d exposure to amoxicillin, enrofloxacin, and neomycin, no observed effect concentration (NOEC) for the reproduction of Daphnia magna was detected at 27.2, 3.3, and 0.15 mg/L, respectively. For the survival of juvenile Oryzias latipes following the 40-d exposure, NOEC was found at 21.8, 3.2, and 0.87 mg/L, respectively. Based on the results of the chronic toxicity tests and those reported in the literature, predicted no-effect concentrations (PNECs) were determined at 0.078, 4.9, and 3.0 µg/L for amoxicillin, enrofloxacin, and neomycin, respectively. Their hazard quotients (HQs) were less than 1 at their average levels of occurrence in ambient freshwater. However, HQs based on the maximum detected levels of amoxicillin and enrofloxacin were determined at 21.2 and 6.1, respectively, suggesting potential ecological risks. As the potential ecological risks of these veterinary pharmaceuticals at heavily contaminated sites cannot be ignored, hotspot delineation and its management are required.

Heterogeneous Photocatalysis of Amoxicillin under Natural Conditions and High-Intensity Light: Fate, Transformation, and Mineralogical Impacts

“…Pharmaceuticals in the environment are a recurring problem that threatens human health and ecosystem balance due to their widespread availability. Pharmaceuticals are designed for specific therapeutic functions and may cause unexpected physiological effects on non-target species [ 1 ]. The potential consequences of these compounds in the environment have to be considered seriously, and growing attention has been directed to pharmaceuticals in ecological systems.…”

“…Given that only about 25% of antibiotics are effectively used in aquaculture, the animal body poorly absorbs most antibiotics, and 30–90% of antibiotics are excreted via urine and feces into the environment. Consequently, antibiotics are frequently detected in surface water, groundwater, soils, and sediments [ 1 , 6 , 7 ].…”

“…This drug is widely used in veterinary practices and can reach the environment primarily via aquaculture, livestock breeding, or human and veterinary excretion. It has been used extensively for disease control and livestock feed for several decades due to its excellent therapeutic value [ 1 , 4 , 7 , 8 ]. As a result, livestock agriculture is considered a significant source of amoxicillin pollution.…”

“…Conversely, the reported amoxicillin concentrations in wastewater are at low levels [ 10 , 11 ]. Previous reports indicate that the environmental concentrations of amoxicillin are typically low in raw sewage, which can vary from several ng L −1 to μg L −1 [ 1 , 9 , 12 , 13 ], except some rare cases showed mg L −1 levels [ 12 ]. The infrequent detection of amoxicillin may be explained by a short retention time of amoxicillin in the environment due to the highly reactive β-lactam ring, which can be broken under environmental conditions and transformed into different products [ 4 , 6 , 9 – 11 , 14 ].…”

Detection of Antibacterial Residues in Nile Tilapia Oreochromis niloticus (L.) in the Shatt Al-Arab river, Southern Iraq

“…In the surface waters of these countries with concentrations ranging from less than 1 ng L -1 to hundreds of µg L -1 . Lee et al (2021) evaluated the environmental risks of the antibiotics Amoxicillin, Enrofloxacin, Neomycin on the aquatic environment, where the study conducted a series of toxicity tests for these antibiotics on algae and bacteria, The results indicated that Amoxicillin and Enrofloxacin are antibacterial that cause great concerns for the environment, and that more efforts, studies and investigations are needed to investigate the environmental consequences caused by both antibiotics. As for the antibiotic Neomycin, where the study confirmed that the environment in the surrounding waters must be monitored before it can properly describe its environmental risks.…”