All forms of mercury are toxic to humans, but methylmercury is especially of concern because our bodies have a less well developed defense mechanism against this toxin. Effects on the nervous system are the most prevalent in humans. In each case, hundreds of people died, and thousands were affected, many with permanent damage. In milder cases of mercury poisoning, adults complain of reductions in motor skills and dulled senses of touch, taste, and sight. These milder effects are generally reversible if exposure to mercury is halted.
Unborn children are at greatest risk from low-level exposure to methylmercury.
Recent research suggests that prenatal effects occur at intake levels 5-10 times lower than that of adults. If these results are confirmed, a substantial fraction of unborn children would be at risk. Mercury Cycling in the Environment Mercury can take a myriad of pathways through the environment. Figure 6 Mercury cycling pathways in aquatic environments are very complex. Ultimately, mercury ends up in the sediments, fish and wildlife, or evades back to the atmosphere by volatilization.