Intensive Livestock Production Causing Antibiotic Pollution in the Yinma River of Northeast China

Hanyu Ju,Jiquan Zhang,Guangxin Zhang,Y Xu,Sijia Li

doi:10.3390/w11102006

Abstract

Antibiotics are increasingly used in livestock production in rural China, raising concerns over pollution and health risk in countryside waterways. The Yinma River Basin in China’s far northeast is an agriculture-dominated area mixed with a densely populated province capitol city, providing a suitable area for investigating the influence of a typical land use mix in Northeast China on riverine antibiotic levels and transport. In this study, we sampled water along the Yinma River from upstream to downstream in a wet and a dry season and analyzed the samples for two popularly used antibiotics, ciprofloxacin (CIP) and norfloxacin (NOR). The goal of the study was to determine the spatiotemporal distribution of the antibiotics in Yinma’s two tributaries, Yitong and Yinma, which drain intensive livestock production land, and to elucidate which environmental and social factors influence the distribution of antibiotics in the cold and low mountainous areas. Water sample collection and instream measurements on dissolved oxygen and other ambient conditions were conducted at 17 locations along the Yinma and Yitong tributaries in August 2015 (wet season) and November 2015 (dry season). In addition to determining CIP and NOR levels, water samples were also analyzed for dissolved organic carbon (DOC), ammonia (NH3), and free chlorine. We found a significantly higher level of NOR when compared to CIP, indicating greater use of the first in livestock production. The level of both antibiotics was higher in the wet season (NOR: 61.063 ± 13.856 ng L−1; CIP: 3.453 ± 0.979 ng L−1) than in the dry season (57.435 ± 14.841 ng L−1; 3.091 ± 0.824 ng L−1), suggesting higher runoff of the antibiotics from the drainage area during the raining season. The level of antibiotics was higher in rural areas, especially forested and wetland areas where livestock typically graze, as well as in the lower river basin. However, the health risk of antibiotics is determined by the physical condition and lifestyle of the residents in the river basin, hence showing a higher vulnerability of the urban area than the rural area.

Highlights

Large amounts of antibiotics are being used in agriculture as growth promoters [1,2].Especially, antibiotics are widely used in livestock production and aquaculture in the form of animal feed additives to prevent the occurrence of animal diseases [3,4]
This study found the presence of two antibiotics, ciprofloxacin and norfloxacin, in waterways of a headwater area in Northeast China, indicating the effect of intensive livestock production on water quality and health risk
Rainfall can cause a higher level of pollution of both antibiotics across the river basin, while topography and land use contribute to the spatial distribution of the antibiotics

Summary

Introduction

Large amounts of antibiotics are being used in agriculture as growth promoters [1,2].Especially, antibiotics are widely used in livestock production and aquaculture in the form of animal feed additives to prevent the occurrence of animal diseases [3,4]. Water 2019, 11, 2006 used in humans are excreted with urine and feces [5,6], reaching urban sewage treatment plants and rivers by soil leaching, where they may escape degradation and can contaminate waste, surface, and groundwater [7]. Several studies [7,11,12] indicated that the main source of antibiotic pollution in the river basins of northern China came from livestock production, aquaculture, sewage discharge, and wastewater treatment plant drainage. Antibiotics can enter the natural environment through metabolites, surface runoff, soil leaching, and illegal dumping [13,14]. Studies have shown that domestic sewage can contain a large number of pharmaceutical residues, which are discharged into waterways in a river basin [6]. The typical sources of antibiotics in the river basin have been identified, the distribution of antibiotics under the influence of a dominant factor has not been studied in depth

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