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• Sum levels of the four isomers were 0.02-0.2 ng/g dw in sediments from New 
Zealand (Simpson et al., 1996). Heptachlor was non-detectable. Mekong sediments 
from Vietnam contained 0.02-0.34 ng/g dw of /ran.s-nonachlor, < 0.02-0.14 ng/g dw 
of /ran.s'-chlordane and 0.02 to 0.36 ng/g dw of c/.s-chlordanc (Hung et al., 2004).