**5. Conclusions**

In both aquatic and terrestrial environments, heavy metals and metalloids are common pollutants. The hazard of an environmental chemical is determined by its persistence in the environment, as well as its toxicity and bioaccumulative potential. Toxic environmental pollutants that are persistent and bioaccumulative are more hazardous. persistence, bioaccumulation, and toxicity (PBT) are the three characteristics of heavy metals that make them hazardous. Some of the most environmentally hazardous heavy metals and metalloids are Cr, Ni, Cu, Zn, Cd, Pb, Hg, and As. These components' trophic transmission in aquatic and terrestrial food chains/webs has significant implications for animal and human health. The concentrations of potentially hazardous heavy metals and metalloids in various environmental segments as well as in the resident biota must be measured and monitored. Environmental chemistry and ecotoxicology of hazardous heavy metals and metalloids reveal that measures should be done to decrease their impact on human health and the environment. Some suggestions are as follows:


*Marine Pollution - Recent Developments*
