Distribution and bioavailability of mobile arsenic in sediments from a mining catchment area

In the paper is studied the dynamic partition of As among solids and liquid phases in Baiaga
River from Certej catchment area, as result of historical pollution caused by mining activities. In order to
evaluate the mobility of arsenic from sediments via surface water, were collected and analyzed both
sediments and surface water samples from ten points along Baiaga River. As chemical extraction
procedure was chosed a method applied on a certified reference material (WQB-1, provided by National
Laboratory for Environmental Testing - National Water Research Institute, Ontario, Canada) for
comparing the As mobility from sediments and CRM WQB-1. The extraction procedure consist in cold
acid treatment using 5% HCl, sediment / extraction solution ratio 1:20, followed by Inductively Coupled
Plasma – Mass Spectrometry (ICP-MS) for determination of As content. Total and mobile As values were
situated in the range 46 to 775 mg/kg dry matter, exceeding the MAV for sediment quality, which is 29
mg/kg in Romanian Legislation. The results indicated a relatively high percentage of mobile As reported
to the total content (32.1% to 65.5%), percentage correlated with As values founded in surface water
samples. The study revealed a significant pollution level in the aquatic system as results of arsenic
mobility.