SUMMARY

The geochemistry of selenium and its relation with health

Quách Đức Tín, Nguyễn Thị Xuân, Phạm Thị Nhung Lý,
Nguyễn Thị Thủy, Mai Trọng Nhuận

This paper presents some basic knowledges on selenium (Se) based upon the geological environment point of views and its relation with health in Việt Nam. The concentration of Se in nature depends on 2 factors: geoenvironment and human activities. In the Earth’s evolution process, the concentration of selenium tends to increase in the lithological crust via intrusion by magma or volcanic lavas, most abundantly in sediments. In coal, the popular concentration of Se is over 80 ppm. The concentration of Se in soil often reflects the host rock and geography of the area. The content of Se in soil in Thái Bình, Hải Phòng and Quảng Nam are 2.15, 0.098 and 0.008 ppm respectively. Se is strongly related to the multielements minerals and ores, thus the water resource around these bodies often contains high concentration of Se. Typical areas are Cúc Đường, Núi Pháo and Nà Tùm in North Việt Nam.

Se is an essential elements for living organisms. At sufficient dose, Se plays an useful role for man, but it can cause deseases when Se is absorbed insufficiently or excessively. The white muscle and Keshan deseases are related to the Se deficiency in the geoenvironment. This leads to the fact that, the concentration of Se in cereals in Keshan desease area is low, often less than 0,01 ppm. The goitre is often caused by iodine deficiency. Interestingly, a studies in Hải Phòng, however, is resulted in relatively high concentration of iodine in geoenvironment of soil, stream water, shallow groundwater and rainy water of 3,56 ppm; 4,9 mg/l; 11,4 mg/l and 3,6 mg/l respectively, while the goitre rate is still very high of 58,81%. The alternative explaination for high goitre rate in this area may be the low concentration of Se in the geoenvironment. The Se deficiency in geoenvironment may cause decreasing the immune system or endocrine disrupting and risks of not only goitre, but some other deseases for the local community.

Ngày nhận bài: 22/06/2008

Người biên tập: Võ Công Nghiệp.