Change of the cadmium, lead and uranium content in the soil pore water depending on the temperature in conditions of low soil moisture

Abstract

Effect of the soil temperature on concentration and total reserve of cadmium, lead and uranium in the interstitial (pore) water of (0–20)-cm samples of sod-podzolic soil with moisture content of 60 % of the water capacity (WC) after their keeping at the definite temperature (in the range of 14–40 °С) was established. It was found that character and extent to which temperature effects on concentration and total reserve of every heavy metal (Cd, Pb, U) in the soil pore solution depended on the chemical nature of heavy metal and peculiarities of soil. In the temperature range of 14–40 °С and moisture content in the soil samples 60 % of the WC, portions of the cadmium, lead and uranium in the soil pore solution decreased in the following way: aCd (0.2–0.4 %) > aPb (0.06–0.07 %) > aU (0.03–0.04 %). The concentrations and total reserves of cadmium, lead and uranium in the soil pore solution increased with lowering the temperature and it was especially true in regard to cadmium. The 5 °С temperature decrease in the range of 14–40 °С caused the content of cadmium in the soil pore solution to increase an average of 25 %, lead – 5.2 and U – 4.6 %. The iron content in the soil solution also increased with decreasing temperature, which indicated a decrease in the sorption capacity of iron hydroxides present in the soil, which probably played a prominent role in fixing cadmium, lead and uranium in the soil studied.