Michigan Department of Natural Resources
Institute for Fisheries Research Report No. 1756, 1969
The Dynamics of DDT in the Lentic Environment
Jerry Lee Hamelink
Abstract.-The fate of DDT in the water of lentic ecosystems was studied in a productive farm pond and in three artificial pools. The effect of fish and food organisms on the degradation and distribution of DDT was assessed in pools by placing both trophic levels in one pools, just food organisms in another pool and fish without food organisms in a third pool.
Methods for collection, preparation, cleanup and analysis of samples from lentic ecosystems for DDT residues were developed. Gas chromatographic methods for residue analysis were evaluated and refined.
DDT applied to the experimental units was lost from the units, apparently by codistillation with evaporating water. DDT in the water was rapidly taken up the flora, fauna and sediments. DDT deposited on the bottom was degraded to DDD. Both DDD and DDT were recycled back into the water from the bottom.
Invertebrates and fish degraded DDT and DDE. Biological transfers to DDT facilitated its degradation to DDE. Increasing the biological productivity of the lentic ecosystem appeared to promote DDT degradation to DDE.
The concentration of DDT-R (DDT, DDD and DDE) persisting in the flora and fauna was mediated by the concentration of DDT-R in the water. DDT-R was concentrated from the water about 1 X 103 times by algae, 1 X 104 times by invertebrates and 1 X 105 times by lean fish.
A mechanism to account for the process of biological magnification of chlorinated hydrocarbons in lentic ecosystems was proposed. The mechanism is based on the principle that the compounds are exchanged between water and fats. Exchange in fish passes through two stages, from water to blood and from blood to fats, hence a high degree of magnification is possible in fish. The mechanism accounts for the reported observations that pesticides are excreted by fish, that the body load of pesticides increases as fat content of fish increases, that pesticide magnification by fish is inverse to water solubility of the compounds, and that pesticides persist longer in oligotrophic ecosystems than eutrophic lentic ecosystems.