Effects of low levels of lead exposure on cognitive function--a review.

The relationship between low levels of lead and cognitive functioning in animals is reviewed. The data suggest that within animals lead can produce a massive disruption of learning ability while not affecting either morbidity or mortality. Concentration of lead appears to insidiously cause damage to learning function where extremely low doses disrupt the hard-to-measure higher levels of cognitive function. It is concluded that the current standards of lead concentration should be reappraised in terms of measures of damage to cognitive learning.