Evaluation of extraction techniques for the determination of heavy metals in river sediments.

Abstract

In order to distinguish whether heavy metal contents originate from a rock matrix or pollution, six different extraction techniques for copper, lead and cadmium were studied in Nagara River sediments in Gifu Prefecture, Japan. The extraction agents were hydrochloric-nitric acid mixture (1+1), 3N hydrochloric acid solution, 0.5N hydrochloric acid solution, 6M formic acid solution, 1N hydroxylamine hydrochloride plus 25% acetic acid solution and 0.05N ethylenediaminetetraacetic acid solution.The comparison of the six extraction techniques was conducted on the basis of the heavy metal contents originating from pollution, which was estimated by subtracting background values from total contents. For copper, 3N hydrochloric acid is preferable, but in sediments with poor ignition loss, 0.5N hydrochloric acid and 6M formic acid are recommended. 1N hydroxylamine hydrochloride plus 25% acetic acid is suitable for lead and cadmium.