Identifying Human Fecal Contamination In Water By Microbial Source Tracking

Non-point source pollution has become an important environmental pollution affecting water quality.To solve this problem, scientists proposed MST (Microbial Source Tracking). Traditional methods only can show the extent of water fecal contamination by counting the number of indicator bacteria, but can not identify the true source. MST can achieve the purpose of identifying the true source of fecal pollution through the analysis of host-specific microbes or specific fingerprints.The purpose of this study is identifying human fecal contamination in water Enterococci, Bacteroides and polyomavirus were selected as indica to microrgani-sms Esp gene of enterococci,16SrRNA gene of Bacteroides and polyomavirus genes were selected as indicator genes. ESP protein expressed by enterococci esp gene was selected as indicator protein. The purpose of this study can be achieved through the detection of indicator genes and identification of indicator protein.This study established a method for detecting indicator genes, and applying it to typical water sources of five river. The following sample points have a great possibility of being contaminated by human fecal:QH, GYG and CH in the Liaohe River; BGS, LYG and HN in the Huaihe River. The following sample points is more likely contaminated by human fecal:GSLZ and NMGBT in Yellow River; all sample points in the Yangtze River.The study also established a identification method for indicator protein-ESP by LC-MS/MS protein. The growth of Enterococcus faecalis CGMCC1.2135changes with temperature and culture condition. There is specific sequence. in esp gene. The highest expression period is stable period. ESP protein can be specifically detected by LC-MS/MS as a protein marker.Its preliminary application is in the following two sample points:Gansu Lanzhou and Inner Mongolia Baotou in Yellow River which were esp gene positive. The two sample points was negative in ESP protein identification maybe for the reason of very low protein ESP abundance.We could assess the source of pollution with great possibility supported by analyzing results of this study. Relevant results and data can provide technical support and solutions for local bureau.