EN
A method of trivalent and sexivalent chromium speciation in well waters in the city of Poznań was developed. The determinations were performed using atomic spectrophotometric absorption with a graphite cuvette, which involved multiple injection and the CDS (initial tube cooling). The total chromium was determined directly in the collected and acidified samples, while the sexivalent chromium in the extract from a water sample. The extraction was performed using ammonium tetramethylendithiocarbamate (APDC) and methy-isobuthylketone (MIBK) in the presence of a buffer. The trivalent chromium was calculated from the difference between the Cr and Cr(VI). Chromium concentration in underground waters falls between 0.0-5.0 μg/1, with the detection limit for the direct determination method for chromium - 0.01 μg/1. The amount of Cr(VI) ranges from 0.00-1.20 μg/l, with the detection limit for the determination method in extract - 0.01 μg/l.