74ISSN 1007-9327CN 14-1018 /RWorld J GastroenteroSeptember 2000 Volume 6 Supplement 3Survey on the pollution of drinking water in Cixian area with the highestincidence rate of esophageal cancerXiuLanZhang'. Su0 Yuan Liang', Xue Dong Li', Shao Sheng Lf，Cui Yun Qiao2 and Hai Guang LPSubject headings esophageal neoplasms /etiology; esophageal neoplasms/prevention and control; incidencerates; drinking; nitrogen; water pollutionZhang XL; LiangSY. LXD. Li ss, Qiao CYWoraxaoalionsyt 200t 9ig. LiHG Suvey on the plulion of dinkng water n Cxian are with the hghet ncdece rale of eopogag cncerAIM To understand the pollution status of drinking water in Cixian area and to find out a way to solute it.METHODSContents of nitrate nitrogen, nitrite nitrogen and ammonia nitrogen were mcasured andcompared with controls and national standards.RESULTS. Levels of nitratc nitrogen, nitrite nitrogen and ammonia nitrogen were higher than the nationalpermissive levels by 20 . 60%，50 . 50% and 33.30% respectively. Also the levels in Cixian are significantlyhigher than those of a controls areas of Chicheng - a county with very low incidcnce rate of esophagealcancer.CONCLUSION Three nitrogen levels in drinking water中國煤化工。-ount of N-containingfertilizer used in these areas and the mortality rates of esopMYHCNMHGEdited by You DY'Hebei Cancer Institute Shijazhuang 050011, -Cixian Cancer Institute, Hebei Province, ChinaCorrespondence to:Dr. Xiu lan Zhang. Hebei Cancer Insitute Shijiazhuang 05011. ttebei Provincc, (ChinaTel. 0086-311-6033511，F(xiàn)ax. 0086-31 1-6077634Rcceived 1999.06-23 Acepted 2000-05-18