Socio-sanitary factors of anencephaly at the eastern coast of Lake Maracaibo (Venezuela) and metal pollution

This work presents some socio-sanitary factors from families with clinical history of stillborn fetuses with anencephaly, reported at "Pedro Garcia Clara" hospital from Ciudad Ojeda (eastern coast of lake Maracaibo, State of Zulia, Venezuela), from January 1992 to July 1994. The relationship between mercury, lead and vanadium, and anencephaly was also studied. During this period, 11,931 births were reported with 26 cases of anencephaly for a mean anencephaly rate of 2.9 cases per 1,000 total births. However, during January-July of 1994, the incidence was increased to 5.0 cases per 1,000 total births. The monthly income of the families studied was less than Bs 30,000 (ca. $177) and only 10% of all mothers finished high school. Hut was the predominant dwelling-house, always ubicated nearby industrial activities. Half of the male population worked for the petroleum industry. Fish consumption from lake Maracaibo was routinely done (30%); mercury pollution in this lake is present due to the chlor/alkali plant of the petrochemical complex El Tablazo. Mercury and lead concentrations found in kidney and liver of the anencephalic fetuses were significantly higher (p < 0.001). Vanadium was detected in brain tissue, being higher in controls (p < 0.05). In conclusion, the low socio-sanitary status of pregnant women from the eastern coast of lake Maracaibo made them more vulnerable to toxic metals present in the polluted environment. Further research is required to fully assess the etiological role played by mercury and vanadium in the development of anencephaly.