toxicological profile for malathion - Agency for Toxic Substances and ...

MALATHION 165
3. HEALTH EFFECTS
There are no adequate data to evaluate whether pharmacokinetics of malathion in children are different
from adults. There is no information to evaluate whether metabolism of malathion is different in children
than in adults since the specific P-450 enzymes involved in the metabolism are not known. Only one
report was found regarding levels of malathion (or metabolites) in human milk (Roggi et al. 1991). There
is evidence in animals that it (or its metabolites) can be transferred via breast milk to the offspring
(Chhabra et al. 1993) and that it can cross the placenta (Machin and McBride 1989b; Mathews and Devi
1994). Further information on the dynamics of malathion and metabolites during pregnancy and lactation
would be useful.
Biomarkers of exposure need to be further studied in order to better estimate human exposure at all age
levels following acute or chronic exposure to malathion. There are no data on the interaction of
malathion with other chemicals in children. Studies in animals have suggested that malnutrition, as may
occur among some sectors of the general population, may exacerbate the toxicity of malathion (Bulusu
and Chakravarty 1984; Prabhakaran and Devi 1993). Further studies on children from undernourished
populations should be conducted to explore this issue. The information available indicates that methods
to reduce peak absorption of malathion and to interfere with the mechanism of action used for
intoxication in adults are applicable to children.
Child health data needs relating to exposure are discussed in 6.8.1 Identification of Data Needs:
Exposures of Children.
3.12.3 Ongoing Studies
The following ongoing studies concerning health effects associated with malathion have been identified
in the Federal Research in Progress (FEDRIP 2002) database.
Dr. R.L. Carr at the Mississippi State University has proposed to determine the effects on behavior and
neurochemical function in animals exposed to chronic low levels of malathion and other insecticides.
Laboratory rats will be exposed at birth and continue until weaning, a critical time of central nervous
system development. The research is sponsored by the U.S. Department of Agriculture.
Dr. H.P. Misra at the Virginia Polytechnic Institute plans to investigate the mechanism of potential
genotoxicity of malathion and pesticide mixtures in immune cells in vitro. Specific studies include
(1) induction of apoptotic cell death by pesticides, (2) the role of p38 MAP kinase and NF-kappa B in