Munira A. Dughish1, Saif A. Alhakimi2, Abdo A. Othman3
1Department of Biochemistry, Faculty of Medicine and Health Sciences, 2Faculty of Science, 3Faculty of Art, Sana’a University, Yemen.
Exposure to heavy metals continues, and is even increasing in some parts of the World, in particular, in less developed countries . Both children and adult are susceptible to health effect from lead and cadmium [2, 3].
Studies have found that heavy metals such as mercury, cadmium, lead, aluminum, and tin affect chemical synaptic transmission in the brain and the peripheral and central nervous system. The toxic metals have been
documented to be reproductive and developmental toxins, causing birth defects and damaging fetal development, as well as neurological effects  , developmental delays, learning disabilities,
depression, and behavioral abnormalities in many otherwise normal-appearing children. These toxic metals have been found to have synergistic negative effects on childhood development and cognitive ability. Also high exposure of lead and cadmium can cause mental retardation, disability and learning difficulties [3-6].
Lead is neurotoxin and harmful to the developing nervous systems of fetuses and young children. Extremely high blood lead levels (>70μg/dl) can cause severe neurological problems (e.g., seizure, coma, and death). Lead can cause damage to kidneys and blood system . It has been found that lead can cause mental retardation, attention problems, distractibility, restlessness, and hearing impairment [8, 9]. The Center for Disease Control has found that exposure to lead is