Abstract
The writers measured methemoglobin formation with solvent extracts from the sediments of the Tama and the Ayase Rivers, two rivers run through urban areas, and several urban and rural rivers.
Hemoglobin was converted to methemoglobin with the n-hexane extract obtained from the sediments of the upstream of the Tama River and rural rivers, but not with those from the downstream and urban river sediments. The formation of methemoglobin was remarkable with the extracts of ethyl acetate and methanol from polluted river sediments. Doses of solvent extracts for 20% methemoglobin formation in the researched rivers were as follows : below 0.1 mg/ml in hexane extract, 0.1-1.0 mg/ml in ethyl acetate extract and below 0.5 mg/ml in methanol extract.
