[Heavy metal exposure and reproductive toxicity: Advances in studies].

Heavy metals are among the major pollutants affecting the environment, with a higher density of metal element than that of water and an extensive presence in the natural environment. Trace elements such as zinc, copper, nickel and chromium mediate important physiological functions and metabolic regulation at normal levels, and insufficient intake of them will lead to related diseases. Heavy metals such as cadmium, lead and mercury do not participate in the normal metabolism of the human body and will cause damage to the body even at an extremely low dose. Heavy metal pollution mainly comes from industrial wastewater, fossil fuel combustion, wastewater, smelting, mining, vehicle exhaust, hazardous waste dumping, and fertilizer abuse. Unable to be biodegraded, heavy metals have a long biological half-life in nature, which in turn leads to bio-accumulation and -amplification. Eating contaminated vegetables is one way of being exposed to heavy metals. Heavy metals produce adverse effects not only on the human reproductive system, but also on the fetus by penetrating the placental barrier, and on the hypothalamic-pituitary-gonadal axis as well, consequently affecting sexual maturation and reproductive function. With the sharp increase of heavy metals in the environment, researches on their reproductive toxicity and antagonistic drugs have an important clinical significance.