PESTICIDES 965
of this remark-able phenomenon resulted from the treatment
of Clear Lake, California with DDD at 0.014−0.02 ppm and
the observance of DDD residues in Western grebes and pre-
daceous fish at 1600−2500 ppm. The overall magnification
was about 120,000-fold (Hunt and Bishoff, 1960). Woodwell
et al. (1967) describe a Long Island, New York estuary where
a DDT concentration of 0.00005 ppm became successively
magnified in plankton (0.04 ppm), invertebrates (0.16−0.42
ppm), fish (0.17–2.07 ppm), and predatory birds (3.15–75.5
ppm). The DDT level was concentrated about 10-fold in each
trophic level and appeared in the upper levels of the food
web largely as DDE the most stable metabolite. The overall
magnification was about 120,00 fold. The magnification of
aldrin through a terrestrial ecosystem where Missouri corn-
fields were treated over a 15 yr period with a total of about25 kgha was studied by Korschgen (1970). The soil con-
tained an average residue of 0.06 ppm aldrin, earthworms
averaged 1.49 ppm; seed-eating ground beetles Harpalus
contained 1.1 ppm; the predaceous beetle Poecilus 9.67 ppm;
the seed-eating mice Peromyscus, Mus, and Reithrodontomys
averaged 0.98 ppm; toads, Bufo americanus, feeding
on insects and other invertebrates, 4.60 ppm; and garter
snakes Thamnophis sirtailis which eat salamanders, toads,
earth-worms, and small birds and mammals, accumulated
10.3−14.4 ppm. Most of the aldrin was stored as the more
stable metabolic oxidation product dieldrin and the overall
magnification was about 200-fold.
The aquatic habit favors the concentration of trace resi-
dues in the stable organochlorine compounds in invertebrates
and fish. Dustman and Stickel (1969) cite examples suchTABLE 8
Comparative toxicity of pesticides to various organismsa24-hr LC 50 Topical LD 50 , mg/gOral LD 50 m/kg Rainbow Fairy Musca ApisPesticide Rat Mallard Pheasant Trout Blue gill shrimpb Stoneflyc Water flead dometica melliferaAldrin 36–60 520 16.8 0.0061 0.010 45 0.008(2d) 0.028 2.9 4.5
Atrazine 3080 2000 12.6(2d) 3.6 100
Carbaryl 850 2179 2000 2.0 2.5 0.040 0.030 0.0064 900 2.3
Carbofuran 5 0.40 4.2 0.24(4d) 4.6
Chlordane 335–430 1200 0.022 0.095 0.160 0.170 0.029 6.0
Diazinon 108–76 3.5 4.3 0.380 0.052 0.80 0.06(2d) 0.0009 2.95
DDT 113–118 2240 1296 0.012 0.005(2d) 0.0047 0.041 0.0036 1.9 20.0
Dicamba 2900 673–800 35(ed) 130(2d) 10 100
Dieldrin 46–46 381 79 0.0031 0.015 1.4 0.006 0.240 0.95 2.2
Disulfoton 6.8–2.3 6.5 0.040(2d) 0.110 0.040
Diuron 3400 2000 0.70 3.6 1.4 100
2,4-D acid 375 1000 472 8 1.4–6.8
(ester)8.5 (ester) 0.2 100Endrin 17.8–7.5 5.6 1.8 0.0028 0.0008 0.0064 0.004 0.020 3.15 20.8
Heptachlor 100–162 2000 0.013 0.026 0.150 0.008 0.042 2.25
Lindane 88–91 500–600 0.018(2d) 0.10 0.120 0.012 0.460 0.85 2.0
Malathion 1375–1000 1485 0.130 0.110 0.0038 0.035 0.0018 26.5 1.1
Methoxychlor 6000 2000 0.074 0.083 0.0047 0.030 0.00078 9.0
Parathion, ethyl 13–3.6 1.9–2.1 12.4 2.0 0.047 0.012 0.028 0.0004 0.9 3.5
Parathion, methyl 14–24 10.0 8.2 2.75(3d) 8.0(2d) 1.2 0.84
Phorate 2.3–1.1 0.62 7.1 0.0055(2d) 0.024
Toxaphene 90–80 70.7 40 0.004(2d) 0.0066 0.180 0.018 0.015 11.0 274
Trifluralin 10,000 2000 2000 0.098 0.130 8.8 13 0.240
Zectran 14.1–19 3.0 4.5 8 11.2 0.086 0.032 0.01 65 0.6
a Values from Pimentel (1971), Hayes (1963).
b Gammarus lacustris.
c Pteronarcys californicus.
d Daphnid pulex, 2 day values.C016_004_r03.indd 965C016_004_r03.indd 965 11/18/2005 11:00:07 AM11/18/2005 11:00:07 AM