Lead pollution is a serious problem seen all over the world, and shows high accumulation to the environment and organisms. This toxicity  negatively affects soil microbial ecosystems which have various functions on material cycles. In this study, we focused on denitrification as a measure of microbial activity and evaluated how lead pollution affects the microbial community.
To examine these objectives, through 4 weeks of soil incubation study with Pb(CH3COO)2 and application of KNO3 or KNO2, denitrification activity was evaluated every week by measuring the amount of NO3-N, NO2-N and N2O-N, and quantifying denitrification genes such as nirS, norB and nosZ.
In result, the delay of denitrification by lead pollution has occurred,  especially it was remarkable in the reduction of nitrate to nitrite and metabolism of nitrite. In addition, the qPCR results showed that in soils with low carbon source availability, the denitrification activity was lower than soils with added-carbon, while the amount of denitrification genes was relatively higher. The carbon source availability may have contributed to the enzyme synthesis from DNA or enzyme activity.

These results indicated that lead pollution and the carbon source availability may have substantial effects separately on the denitrification in soil.