Residues of DDT, Dieldrin, and Heptachlor in Earthworms 
During Two Years Following Application 
by 
Charles D. Gish! 
U.S, Fish and Wildlife Service 
Patuxent Wildlife Research Center 
Laurel, Maryland 20811 
and 
Donald L. Hughes 
Raltech Scientific Services, Inc. 
Madison, Wisconsin, 53707 
Abstract 
Study plots were treated at 0.56, 2.24, or 8.97 kg active ingredient per hectare with either DDT, 
dieldrin, or heptachlor. Earthworms and soils were sampled from each plot when treated and 0.5, 1, 2, 
4, 6, 8, 10, 12, 16, 20, and 24 months thereafter, and analyzed by gas chromatography for residues of 
aldrin, dieldrin, endrin, heptachlor, heptachlor epoxide, a-chlordane, y-chlordane, y-BHC, o,p'-DDT, 
p.p'-DDT, p,p'-DDD, and p,p’-DDE. Individual and total metabolites in soils and earthworms tended 
to increase linearly with increasing levels of application. In soils, no significant losses of dieldrin, 
p.p'-DDT, DDD + DDT, DDE + DDD, DDE + DDD + DDT, y-chlordane, or total heptachlors or 
chlordanes occurred during the 2 years following application. Heptachlor epoxide and p,p'-DDE 
increased significantly during the 2 years, but heptachlor decreased. In earthworms, maximum residues 
usually occurred 2—4 months after application and then declined. During the decline, residue levels were 
cyclic: levels were elevated from late spring to early fall and depressed from late fall to early spring. 
High levels usually occurred in May and lows in January, coinciding with seasonal high and low activity 
periods of earthworms. Decomposition of soil organic matter and retention of moisture by earthworms 
were influenced by levels of application or by chemicals. 
Residues of DDT have been reported to accumulate in 
tissues of earthworms (Barker 1958) and to alter earth- 
worm behavior in removing leaf debris (Baker 1946). 
Interacting effects of chemical residues in soil, earth- 
worms, and birds have been reported in several studies 
(Stringer and Pickard 1964; Boykins 1966; Collett and 
Harrison 1968: Davis 1968; Wheatley and Hardman 1968; 
Davis and French 1969; Hunt and Sacho 1969; Johnson 
1969; Bailey et al. 1970; Dimond et al. 1970; Gish 1970; 
Korschgen 1970, 1971). However, few reports have con- 
tained information on factors affecting the residue relation 
between soils and earthworms. Because earthworms 
appear to be generally resistant to organochlorine insecti- 
cides (Davey 1963; Edwards 1965), and are eaten by 
\Present address: Office of Biological Services, U.S. Fish and 
Wildlife Service, Washington, D.C. 20240. 
many vertebrate species, an understanding of the relation 
between residues in earthworms and residues in soils is of 
value in assessing the dietary effects on vertebrates eating 
earthworms containing residues. 
Study plots were established during 1966 to elucidate 
some of the factors affecting this residue relation. This 
report covers data collected between May 1966 and May 
1968. 
Materials and Methods 
A study area 30.5 x 61m was established at the 
Patuxent Wildlife Research Center in December 1963. 
Rotted barley was mulched over the entire area at about 
6,700 kg/ha, and half the area (30.5 x 30.5 m) was later 
rototilled to a depth of 20-25 cm. 

