




Although the field containing the study area was peri- 
odically mowed, hay within the area was not harvested 
(except in 1965) and was allowed to remain as ground 
cover. In May 1966, the study area was divided into 18 
plots, 10 m square; aluminum flashing was buried to a 
depth of 25-30 cm around each plot. The flashing pro- 
truded vertically for 30-35 cm before being bent horizon- 
tally into each plot, which prevented earthworths from 
entering or leaving the plots. 
The 18 plots were divided between two square blocks, 
one coinciding with the half of the area that had been 
mulched and the other with the half that had been 
mulched and rototilled. All treatments were randomized 
within each block in a randomized complete block design 
(Cochran and Cox 1957). The treatments, consisting of 
wettable powder formulations containing either 50% 
DDT, 50% dieldrin, or 25% heptachlor, were applied at 
().56, 2.24, and 8.97 kg active ingredient per hectare 
(ai/ha). 
Plots were mowed and raked before any chemicals were 
applied. Chemicals were mixed with well water and 
applied by an operator carrying a back-pack spray can 
while walking at about 1.2 m/s. The solutions were 
applied under pressure of 2 kg/cm?. The width of the 
spray boom (1.2 m with three equally spaced nozzles) and 
the height at which the spray was delivered (30 cm) per- 
mitted five parallel passes per plot for each 9.5-L can of 
solution. Half of the chemical was applied in one direction 
and the other half applied perpendicular to the first. Each 
plot was then sprinkled with well water to remove spray 
from the vegetation and covered by a mulch of barley 
straw and alfalfa. There was neither precipitation nor 
noticeable wind during chemical application; tem- 
peratures approached 32° C. 
Sampling Procedures 
Soils and earthworms were collected simultaneously at 
time of treatment (same day) and at 0.5, 1, 2, 4, 6, 8, 10, 
12, 16, 20, and 24 months after application. Samples were 
collected at random within each plot during each 
sampling period; however, attempts were made to avoid 
collection from sites previously sampled. Samples 
consisted of about 15 g of earthworms and 50 g of soil. 
The soil, an Elsinboro loam, is well drained with a 
0-2% slope. The top 2.5 cm of soil was sampled with a 
shovel. Roots, stems, rocks, and soil animals were 
removed in the field. Soils were placed in acetone-rinsed, 
wide-mouth quart jars fitted with metal lids and rubber 
seals; samples were then frozen. 
Earthworms were obtained by hand-sorting the soil. 
Species included immature and adult Allolobophora 
chlorotica, A. trapezoides, A. turgida, Eisenia rosea, and 
Lumbricus terrestris. The most abundant species were A, 
trapezoides and A. turgida; least abundant were A. 
chlorotica and E. rosea. All species from one plot were 
pooled into one sample and placed into acetone-rinsed jars 
while in the field. The jars were placed in a refrigerator 
for 24 h to allow the worms time to purge soil from the 
gut. The earthworms were then rinsed lightly with water 
to remove excess soil, laid on paper toweling to dry 
slightly, placed into acetone-rinsed, 0.06-L screwtop jars 
fitted with plastic lids, and frozen. 
Chemical Methodology 
The wettable powder formulations of technical grade 
DDT, dieldrin, and heptachlor were analyzed for their 
active ingredient components. A 1-g sample was weighed 
into a 100-mL beaker with 5 mL of ethyl ether and 95 mL 
of hexane. The solution was allowed to stand for 1 week 
with periodic shakings. Determinations were made with a 
Jarrell-Ash gas chromatograph equipped with a flame 
ionization detector. The glass column (4mm x 2.4 m) 
was packed with 10% DC-200 on Gas Chrom Q (80/100 
mesh). Nitrogen flow was 70-100 mL/min under pressure 
of 5-10 psi; temperatures were column, 210° C; injector, 
210° C; and detector, 250° C. Extraction procedures and 
residue determinations for earthworms and soils were 
identical to those reported earlier (Gish 1970), 
Residue determinations in the clean extracts were 
accomplished with a Barber Colman 5360 gas 
chromatograph equipped with an electron capture (Sr 90) 
detector. The glass column (4 mm by 1.2 m) was packed 
with 5% DC-200 on Chromport XXX (70/90 mesh), 
Nitrogen flow rate was 70-90 mL/min; temperatures 
were column, 200° C; injector, 230° C; and detector, 
240° C. Confirmatory analyses were made by thin-layer 
chromatography on about 10% of the samples; the results 
were very similar to those obtained by gas 
chromatography. For this reason, only gas 
chromatographic determinations are presented. 
Micrograms of lipids in earthworms were determined 
by evaporating a sample of the extract to dryness. Soil 
moisture was determined by transferring 2-10 g of soil to 
a porcelain crucible and placing the crucible into a 100° C 
vacuum oven for 5 h. The cooled sample was weighed for 
moisture determination and then placed into a 550° C 
muffle furnace for 4 h. The cooled sample was reweighed 
to calculate the organic fraction. Soil pH was determined 
by adding 50 g of water to 5 g of soil in a beaker which 
was placed on a magnetic stirrer and read to the nearest 
0.1 unit on a Beckman Zeromatic II pH meter. 
Possible PCB Interference with 
Insecticide Residues 
Soils and earthworms were collected from each block 
just before chemical application. Soils averaged 
0.006 ppm or less of DDE, DDD, or DDT; worms 
averaged 0.004 ppm or less of DDE, DDD, DDT, or diel- 
drin. No other compounds were detected in these 
