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

MALATHION 196
6. POTENTIAL FOR HUMAN EXPOSURE
was detected in 11 of the soil samples from the six sites (a total of 822 samples were collected from the
18 total sites in the study), at a mean concentration of 125 µg/kg (ppb) and at a concentration range of
31–690 µg/kg; the common range of detections was 22–100 µg/kg.
No monitoring data were found in the available literature for malathion detections in sediment.
6.4.4 Other Environmental Media
Monitoring studies have been conducted to determine the presence of malathion residues in/on food and
feeds. Malathion residues were present, at 0.05–>2.0 ppm, in 249 of the 19,851 samples of food and
animal feeds tested by the FDA in fiscal years 1982–1986; the selection of test samples was not random,
but was geared toward choosing samples most likely to contain pesticide residues based on various
factors (Luke et al. 1988). The malathion degradate malaoxon was detected in only two of the samples.
In an FDA monitoring study of organohalogen and organophosphorus pesticide residues in 545 domestic
surveillance samples of mixed feed rations conducted during fiscal years 1989–1994, malathion was the
most commonly detected pesticide, occurring in 425 of the samples (in trace amounts in 53 of those
samples) and accounting for approximately 53% of all pesticide residues detected (Lovell et al. 1996).
Malathion was detected in the samples at a concentration range of 0.006–4 ppm, with a median
concentration of 0.098 ppm. In a study conducted in 1977 to determine malathion residues on and in
oranges following low-volume (100 gal/ac) and dilute applications (1,500 gal/ac) to orange trees in
California, malathion residues on and in unwashed whole fruits were below the then current residue
tolerance levels of 8 ppm (Carman et al. 1981). In the edible portion (pulp) of the fruits, malathion
residues were 0.01–0.03 ppm 7 days after treatment and