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2309395 
Technical Report 
Atmospheric levels of pesticides in the Mississippi Delta 
Arthur, RD; Cain, JD; Barrentine, BF 
1976 
PESTAB/76/1375 
Environ 
2 
129-134; 1976 
PESTAB. A study was designed to qualitate and quantitate the atmospheric level of pesticides and their metabolites in one location in the Mid-Delta area of the Mississippi Delta. Weekly air samples were taken using a MISCO model 88 air pesticide sampler with ethylene glycol as the trapping agent during the years 1972, 1973, and 1974. A total of 156 samples were collected. Only p,p'-DDT and o,p'-DDT were found in all samples. The organophosphates, except for methyl parathion, were generally found between June and October, which corresponds to the pesticide spray season. DEF, used as a cotton defoliant, was only found in September and October. The highest levels of pesticides occurred during the summer months. DDT, methyl parathion, and toxaphene were found more often and at higher levels. These represented about 95% of all the pesticides sold in the Mississippi area prior to the ban on DDT. After this ban, methyl parathion and toxaphene made up about 88% of all the insecticides sold in that state. This study has demonstrated a distinct drop in the concentration of DDT in the atmosphere since the ban on its use. However, even though a decrease in total DDT levels was found, levels as high as 50 ng/m3 were recorded in 1973 and 38 ng/m3 in 1974. The DDT detected apparently came from the soil. DDT levels were observed to increase around the times when farm work in the fields increased. A great increase in the methyl parathion levels was noted in 1973 vs. 1972, the year after the ban on DDT. However, methyl parathion usage was down 38% from 1972. Methyl parathion was less than 1 ng/m3 from November through May and then increased until it peaked in August or September. Toxaphene levels decreased from 1972 to 1973, probably due to a 55% decrease in toxaphene usage over this time. Although a 290% increase in endrin sales occurred after the use of DDT was stopped, the total amount of endrin sold was still only equal to about 2.8% of the toxaphene sales. The average 1973 air level of endrin was lower than that for 1972 in spite of a 290% increase in sales. In 1974, when the total sales of endrin were about the same as for 1973, there was a 2.5 fold increase in air levels.