Most natural waterways include microorganisms, which are extensively dispersed across the natural world. Their diversity and abundance can serve as indicators of whether a body of water is suitable for fish, wildlife, or leisure and recreational uses. Hundreds of antimicrobial medicines have been produced for use in humans and animals since the discovery of penicillin in the late 1920s, significantly lowering the morbidity and mortality linked to a variety of infectious illnesses. Approximately half of the over one million tons of antibiotics that have been discharged into the biosphere in the past fifty years are thought to have entered through veterinary and agricultural systems the ongoing exposure of microbial populations to substances chosen for resistance strains, such as antibiotics, chemical compounds, heavy metals, and other agents. Bacteria that have adapted to the presence of heavy metals and evolved effective metal resistance mechanisms live in ecosystems that have been contaminated by dangerous quantities of heavy metals. Based on the degree of pollution, the frequency of plasmids differed from site to site, according to ecological research on the incidence of plasmids in natural populations of freshwater, marine, estuarine, and terrestrial bacteria.