Humic acids as a scavenger of manganese(II) and zinc(II) in soil environment using a radiotracer technique

The uptake of manganese(II) and zinc(II) by humic acids (HA) was investigated using a radiotracer technique in order to elucidate their ability of scavenging heavy metals released into the soil environment. Metal uptake by HA was affected by aqueous pH, in which the amounts of Mn(II) and Zn(II) associated with HA showed a similar pattern against pH. These facts indicate that interactions of Mn(II) and Zn(II) with HA would be ionic in character, and affected by properties of the carboxyl groups in HA. (author)