西江流域地表水微生物污染定量源解析

Quantitative source analysis of microorganism pollution in the surface water in Xijiang River Basin

水体微生物污染标记物的源强特征是定量解析微生物污染来源的关键.应用实时荧光定量PCR(qPCR)技术分别对人源(qHS601F/qBac725R)、牛源(BacB2-590F/Bac708Rm)、猪源(Bac41F/Bac163R)及禽类(qC160F-HU/qBac265R-HU)特异性拟杆菌引物的源强特征进行了探索,并进一步对西江流域广东段进行微生物污染来源定量解析,结果表明:针对不同目标宿主,不同特异性拟杆菌引物的源强特征为人源(qHB)>猪源(qPB)>牛源(qRB)>禽类(qCB),DNA模板浓度对引物的源强特征影响较小.选取的目标研究区域水体普遍受到人、猪、牛及禽类粪便污染.干流中qHB、qCB及qPB自上游至下游缓慢升高.各支流中qHB、qCB及qPB的平均浓度较干流均上升了1个数量级,qRB在不同河段变化较小.说明下游河段的生活污水、猪源及禽类粪便污染较为严重,牛源污染的影响较小.统计分析显示在污染水平较高的各支流中,人源特异性拟杆菌引物与传统指示菌具有一定的相关性(P<0.05),说明生活污水是传统指示菌浓度较高的主要原因,且为持续排放源.

Understanding the characteristic of source strength of the microbial gene marker is the key for quantitative analyzing the microbial contamination from different sources.In this study,the source strength of human-(qHS601F/qBac725R),porcine-(Bac41F/Bac163R),cattle-(BacB2-590F/Bac708Rm)and poultry-specific(qC160F-HU/qBac265R-HU)bacteroides primers were explored by qPCR method,and then quantitative analysis of the source and level of microbial pollution in Xijiang river in Guangdong province.The results showed that the source strength of different specific bacteroides primers was human(qHB)>porcine(qPB)>cattle(qRB)>poultry(qCB).The concentration of DNA had little effect on source strength of each primers.The selected target area was generally contaminated by human,pig,cattle and poultry feces.The concentration of human,porcine and poultry-specific primers were increased slowly from upstream to downstream in the main stream.In the tributary,the mean concentration of human-,porcine-and poultry-specific primers were increased 1-order magnitude compared to the main stream.qRB had little change in different section of the river.This suggests that the pollution of domestic sewage,porcine source and poultry excrement in the downstream was more serious.The influence of cattle source pollution was not significant.Statistic analysis showed that human-specific premier had a significant correlation with traditional fecal indicator bacteria in the tributary which had high level of fecal pollution(FIB)(P<0.05).It reflected that human source was the major reason for the high concentration of FIB,and human feces was the persistent pollution source.