饮用水源中的微囊藻毒素与大肠癌发病的关系

目的：研究不同类型饮用水源中的微囊藻毒素与大肠癌发病的关系。方法 在浙江省海宁市的８个乡镇,对近２０年的共４０８例大肠癌患进行一生中饮水情况的调查,并分别采集井水、自来水、池塘水及河浜水的水样,用间接竞争酶联免疫方法测定微囊藻毒素的含量。结果：饮用池塘水及河浜水的大肠癌发病率均明显高于饮用水和自来水的发病率,经与饮用井水相比,饮用自来水,河浜水及池塘水的相对危险度分别为１．８８、７．９４和７．７

Drinking water types, microcystins and colorectal cancer

Objective To assess the relationship between microcystins (a blue-green algal toxin) in drinking water and colorectal cancer. Methods Eight townships were randomly selected as study sites in Haining city of Zhejiang province, China. Four hundred and eight colon and rectum carcinoma cases diagnosed from 1977 to 1996 were identified from cancer registry in the study sites. A retrospective survey on types of drinking water of all 408 cases was conducted. Population data and drinking water sources data were provided by local household registration and local health institution, respectively. Water samples from different sources (well, tap-water, river and pond) were collected and microcystins concentrations were measured by an indirect competitive ELISA method. Results The incidence rates of colorectal cancer were significantly higher among people drinking river or pond water than those who drank well water or tap-water in both males and females. And comparing with other sources to well water, the relative risks (RR) were much higher for people using river water (794) and pond water(770). The positive detection rates (>50 pg/ml) of microcystin in well, tap-water, river and pond water were 000%, 000%, 3623% and 1714% respectively. The highest concentrations of microcystins were 1 08343 pg/ml (river) and 1 93794 pg/ml (pond) in the positive samples. Microcystins concentrations in river and pond were significantly higher than the concentrations in well and tap water ( P<001). The Spearman rank correlation analysis showed that in the study sites, the microcystins concentrations of river and pond water were positively correlated with the incidence of colorectal cancer (r=0881, P<001). Conclusion Drinking surface water (river or pond) is one of the risk factors for colorectal cancer. Microcystins may be associated with incidence of colorectal cancer. It is suggested that further study should be carried out to clarify the relationship between colorectal cancer and microcystin in drinking water.