Persistent organochlorine pesticide residues in water, sediments and water Hyacinth Eichornia crassipes from the floodplain of high Paraná river, Porto Rico region, Brazil

Residues of organochlorine pesticides have been monitored in water, in the water hyacinth Eichhomia crassipes and in the sediments of three subsystems of the high Paraná river, during the period of August 1992 to August 1994. The Baia river-Guaraná lake subsystem presented the greatest content and frequency of contamination by organochlorines. Also, sediments in this subsystem have shown higher levels of contamination than water and water hyacinth. The pesticides detected in higher concentration in these subsystems were HCH, aldrin, heptachlor, ensosulfan, p.pï-DDE and p.p'-DDT