Analytical Techniques for Arsenic and Antimony Speciation Studies in Interstitial Water of River Sediments

Three separation techniques for obtaining interstitial water, i.e., by solvent displacement, modified centrifugation, and gas squeezing, have been investigated. A simple nitrogen gas squeezing technique utilizing an Amicon ultrafiltration cell was found effective to obtain interstitial waters from river sediments. several analytical techniques for measuring arsenic and antimony species in natural waters were also evaluated. A solvent extraction procedure using ammonium pyrrolidinedithiocarbamate (APDC) as an extractant coupled with neutron activation analysis was chosen for arsenic and antimony speciation studies of interstitial waters in this work. The distributions of arsenic and antimony species in natural waters and in interstitial waters of the polluted sediments of the Coeur d'Alene River in northern Idaho were investigated. High concentrations of arsenic and high ratios of As(III)/As(V) were observed in the interstitial waters obtained from the sediments of the South Fork of the river. The As and Sb levels in the interstitial waters of the sediments collected from the Coeur d'Alene River were found to be proportional to the levels of these elements in the surface waters, indicating a correlation of pollutants between waters and sediments. The distribution of As species in deep well waters of the Blackfoot Disease endemic area in southwest Taiwan was also studied. High concentrations of As(III) were found in the well waters which may be related to the Blackfoot Disease