What are some examples of environmental contamination affecting humans?

I use only one reference for this assay (LaGrega et al., 1994).

Mercury salts, which were used to form felt in the Dutch hat industry, caused neurulogic disorder renowned as being "mad as a hatter." Organic forms of mercury (e.g. methyl mercury) have proven to be more pernicious, having caused hundreds of cases of paralysis and sensory loss at Minamata Bay area in Japan. Inorganic mercury discharged from a chemical plant became methylated in sediments and then bioaccumulated in shellfish. Due to the fact that shellfish are the principal protein source of the local people, this situation was an epidemic waiting to happen. In the late 1960s, this poisoning (itai itai disease) heightened global awareness of industrial pollution.

Two cases of accidental contamination of rice cooking oil in Japan and Taiwan in the late 1960s and mid-1970s exposed thousands of Asians to hşgh concentrations of PCBs (poly chlorinated biphenlys). Miscarriages and birth defects increased within the exposed populations. Although later it would be shown that these prenatal health problems resulted not from PCBs themselves but from polychlorinated dibenzofurans (PCDFs) that formed when heating the contaminated rice cooking oil, the riveting environmental journalism made the World population vividly aware of the adverse human effects of "PCB" exposure.

Nearly the same time in the United States, the contamination of Michigan cattle feed by polybrominated biphenyls (PBBs) not only caused widespread human exposures via milk and other dairy products, but also followed more complex pathways to reach humans.

Afflicted cattle were rendered and then used to prepare chicken feed; thousands of human consumers were exposed to PBBs through eggs and egg products. One incident involved 24 thousand crates of PBB-contaminated shorthcakes which were confiscated in Alabama. PBBs were found in some Michigan mothers' breast milk.

Love Canal is the symbol of environmental contamination by hazardous wate. Not useful as a canal, this canal was sealed off at the ends and used in the 1940s and 1950s by Hooker Chemical Company and others as a hazardous waste disposal site. Later, this site was sold to the Niagara Falls, New York, School Districts. The School District built an elementary school on the site despite the fact that a warning was made against any excavation and underground construction.

Later the developed area caused sickness in children and some residents. You can get details: https://www.geneseo.edu/history/love_canal_history

Reference:

LaGrega, M. D., Buckingham, P. L., and Evans, J. C. (1994). Hazardous Waste Management. McGraw Hill, Inc. New York, NY. USA.