SOME PRELIMINARY STUDIES ON RESIDUAL OF DIOXIN (2,3,7,8-TCDD) USED IN VIETNAM WAR AT VIETNAM-LAOS BORDER (KONTUM-QUANGNAM PROVINCES AND LONGTERM EFFECTS OF DIOXIN INTO NATURAL ECOSYSTEMS AND BIODIVERSITY IN THIS AREA
Up to now, more than 40 years ago after the end of the sprayed operation, soil in the Vietnam-Laos border (Kontum-Quangnam provinces), particularly in the Charly range and adjaction area are polluted by dioxin. Analytic results of dioxin residual in samples of soil, stream sediment collected in late June and early July 2008 show that concentrations of 2,3,7,8 TCDD ranged from 106.57 to 845.48 ppt (ng/kg drying soil). These concentrations of 2,3,7,8-TCDD are lower than the permissible level for non-agricultural soil of the US Environmental Protection Agency (USEPA) being 1,000 ppt, but higher than the permissible level for agricultural soil (27 ppt). Concentrations of 2,3,7,8-TCDD in soil are higher than stream sediment. In 2008, preliminary research results show that hebicides used in the war have caused long term impacts into natural ecosystems and biodiversity of this area. The natural vegetation in Charly range before spraying is primary forest, with abundant and storied forest but can not rehabilitated, and now only grasses, bushes occurred. A such degraded forest vegetation, species composition and quantity of small size mammal belonging to Chidoptera and Rodentia orders in the Charly range are lower than unsprayed other area with the same landscape (Chu Mom Ray range). Biodiverse index (Shannon index-H) of various animal groups in this area is also lower than unsprayed area: Average value H of fishes of streams in the Charly valley 0.9340, lower than H value of fishes in streams of unsprayed areas (1.1561-1.2738); H value of insects in the Charly range fluctuated 1.7544-4.3803, lower than unsprayed areas (2.8791-4.6697).
Le Xuan Canh Ho Thanh Hai Ta Huy Thinh Do Huu Thu Nguyen Quyet Tien
INSTITUTE OF ECOLOGY AND BIO-RESOURCES 18 Hoang Quoc Viet Road,Cau Giay,Hanoi,Vietnam INSTITUTE OF ECOLOGY AND BIO-RESOURCES Ho Thanh Hai 18 Hoang Quoc Viet Road,Cau Giay,Hanoi,Vietnam INSTITUTE OF CHEMISTRY 18 Hoang Quoc Viet Road,Cau Giay,Hanoi,Vietnam
国际会议
北京
英文
1-6
2009-08-24（万方平台首次上网日期，不代表论文的发表时间）