Heavy metal pollution promotes antibiotic resistance potential in the aquatic environment.

Water pollution is one of the main challenges and water crises, which has caused the existing water resources to be unusable due to contamination. To understand the determinants of the distribution and abundance of antibiotic resistance genes (ARGs), we examined the distribution of 22 ARGs in relation to habitat type, heavy metal pollution and antibiotics concentration across six lakes and wetlands of Iran. The concentration of 13 heavy metals was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) by Thermo Electron Corporation, and five antibiotics by online enrichment and triple-quadrupole LC-MS/MS were investigated. We further performed a global meta-analysis to evaluate the distribution of ARGs across global lakes compared with our studied lakes. While habitat type effect was negligible, we found a strong correlation between waste discharge into the lakes and the abundance of ARGs. The ARGs abundance showed stronger correlation with the concentration of heavy metals, such as Vanadium, than with that of antibiotics. Our meta-analysis also confirmed that overuse of antibiotics and discharge of heavy metals in the studied lakes. These data point to an increase in the distribution of ARGs among bacteria and their increasing resistance to various antibiotics, implying the susceptibility of aquatic environment to industrial pollution.