Cai S W, Zhou S Y, Wang J Q, Li S Y, Zhu X L, Wang J J, Xue J R
Institute of Environmental Health and Engineering, Chinese Academy of Preventive Medicine, Beijing.
Biomed Environ Sci. 1988 Oct;1(3):332-8.
The municipal sewage and raw sludge removed from a sewage treatment plant were the main sources of pollution by pathogenic bacteria and helminthic eggs in land utilization. The level of pollution in the sewage-irrigated areas was as high as that in the areas using fresh night soil. The survival time of Salmonella and Ascaris ova in soil irrigated with sewage was relatively long. The soil had a definite natural capacity for purifying pathogenic bacteria. Because of the different ways of watering, the number of Salmonella detected on vegetables irrigated with sewage was higher than that on vegetables manured with night soil, whereas the reverse held for the number of Ascaris ova. The differences in latent Salmonella infection and the geometric mean titer of serum agglutination for typhoid between the vegetable growers living in the sewage-irrigated area and those living in fresh night soil areas were not remarkable. The prevalence of soil-transmitted ascaridiasis among vegetable growers in sewage-irrigated areas was slightly lower than that among growers in fecal-contaminated areas. When the number of fecal coliforms in sewage was no greater than 10(4)/liter and no less than 85% of Ascaris ova could be removed by sewage treatment, the number of Salmonella and Ascaris ova detected decreased noticeably.
城市污水处理厂排出的城市污水和原生污泥是土地利用中病原菌和蠕虫卵的主要污染源。污水灌溉区的污染程度与使用新鲜人粪尿的地区相当。沙门氏菌和蛔虫卵在污水灌溉土壤中的存活时间相对较长。土壤对病原菌有一定的自然净化能力。由于浇水方式不同，污水灌溉蔬菜上检测到的沙门氏菌数量高于粪肥蔬菜，但蛔虫卵数量情况则相反。生活在污水灌溉区的蔬菜种植者与生活在新鲜人粪尿地区的蔬菜种植者相比，潜在沙门氏菌感染及伤寒血清凝集几何平均滴度的差异不显著。污水灌溉区蔬菜种植者土源性蛔虫病的患病率略低于粪便污染区种植者。当污水中粪大肠菌群数不超过10⁴/L且污水处理对蛔虫卵的去除率不低于85%时，检测到的沙门氏菌和蛔虫卵数量明显减少。
