Details

Autor(en) / Beteiligte

• Caldas, E.D. (University of Brazilia, Brasilia, DF, Brazil.)
• Coelho, R
• Souza, L.C.K.R
• Silva, S.C

Titel

Organochlorine pesticides in water, sediment, and fish of Paranoa Lake of Brasilia, Brazil

Ist Teil von

• Bulletin of environmental contamination and toxicology, 1999-02, Vol.62 (2), p.199-206

Ort / Verlag

New York, NY: Springer-Verlag

Erscheinungsjahr

1999

Quelle

MEDLINE

Beschreibungen/Notizen

• Samples were taken from 10 points from 5 areas of the lake, divided according to its limnologic characteristics. Water and sediment were sampled in the dry season (July) of 1995 and the wet season (February) of 1996. Fish samples were taken between August-October 1995 and March-May 1996. Standard samples of pesticides and PCB gave limits of detection for the chlorinated compounds of 0.2-1.2 pg. Recoveries for sediments and fish averaged 86.7 and 92.8 per cent, respectively. Results showed the absence of PCB, endosulfan, endrin and aldrin in all samples above detection limits. Only HCH were detected in water, with considerably higher levels in sediment and fish. Fish samples had higher levels of heptachlor, DDT, epoxide and dieldrin than sediment samples. DDT was present in 98 per cent of fish samples up to levels of 77.7 ug per kg. In fish samples where both alpha-MHH and lindane (gamma-HCH) were detected, the first isomer represented 75.9 per cent of the total HCH. The most stable DDT isomer (pip-DDE) accounted for 32.4-95.5 per cent of the total DDT complex. No correlation was found between levels of residues in fish, sediment or water and sampling point or area in the lake. Total DDT levels varied significantly among fish species with the bottom feeder saguiru and the predatory bagre and tucunare having significantly higher residue levels than the herbivorous redbreast tilapia. The variation was attributed to different feeding and living habits. The potential risk that dietary pesticides posed to consumers was investigated and is described. Four sets of data for local diet, residue in food, the maximal permitted residue level (MRL) and acceptable daily intake (ADI) were evaluated. In this study the levels of DDT, lindane, dieldrin and heptachlor epoxide found in fish were below the MRL established by Brazilian legislation. Chemicals contributing to the highest percentage of ADI, dieldrin and heptachlor epoxide were only detected in 1.6 and1.0 per cent of the samples, respectively.