School of Planning, Architecture and Civil Engineering, The Queen's University of Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, Northern Ireland, United Kingdom.
Environmental Protection Agency, Richview, Clonskeagh, Dublin 14, Ireland; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland.
Sci Total Environ. 2016 Jan 15;541:949-956. doi: 10.1016/j.scitotenv.2015.09.071. Epub 2015 Nov 11.
Diverse land use activities can elevate risk of microbiological contamination entering stream headwaters. Spatially distributed water quality monitoring carried out across a 17 km(2) agricultural catchment aimed to characterize microbiological contamination reaching surface water and investigate whether winter agricultural land use restrictions proved effective in addressing water quality degradation. Combined flow and concentration data revealed no significant difference in fecal indicator organism (FIO) fluxes in base flow samples collected during the open and prohibited periods for spreading organic fertilizer, while relative concentrations of Escherichia coli, fecal streptococci and sulfite reducing bacteria indicated consistently fresh fecal pollution reached aquatic receptors during both periods. Microbial source tracking, employing Bacteroides 16S rRNA gene markers, demonstrated a dominance of bovine fecal waste in river water samples upstream of a wastewater treatment plant discharge during open periods. This contrasted with responses during prohibited periods where human-derived signatures dominated. Differences in microbiological signature, when viewed with hydrological data, suggested that increasing groundwater levels restricted vertical infiltration of effluent from on-site wastewater treatment systems and diverted it to drains and surface water. Study results reflect seasonality of contaminant inputs, while suggesting winter land use restrictions can be effective in limiting impacts of agricultural wastes to base flow water quality.
多样化的土地利用活动会增加微生物污染进入溪流源头的风险。在一个 17 平方公里的农业流域内进行的空间分布水质监测旨在描述进入地表水的微生物污染情况，并调查冬季农业土地利用限制措施是否能有效解决水质下降问题。结合流量和浓度数据，发现在开放和禁止施有机肥期间，基流样本中的粪大肠菌群通量没有显著差异，而大肠杆菌、粪链球菌和亚硫酸盐还原菌的相对浓度表明，在这两个时期，水生受体都持续受到新鲜粪便污染。微生物源追踪技术利用 Bacteroides 16S rRNA 基因标记物表明，在污水处理厂排放口上游的河水样本中，牛的粪便废物占主导地位。这与禁止施有机肥期间的情况形成对比，当时人类来源的特征占主导地位。从水文数据来看，微生物特征的差异表明，地下水位的升高限制了现场污水处理系统的废水垂直渗透，并将其转移到排水渠和地表水。研究结果反映了污染物输入的季节性，同时表明冬季土地利用限制措施可有效限制农业废物对基流水质的影响。
