PARENT SESSION
3F Long-range transport of pesticides and other pollutants
9:00 AM to 7:00 PM, Monday, 07 May 2001

(M/EH099) Distribution of POPs in soils collected along a wide altitudinal and latitudinal gradient in Chile.

Borghini, Francesca¹, Grimalt, Joan², Sanchez-Hernandez, JuanCarlos³, Barra, Ricardo⁴, Focardi, Silvano¹, ^{1 2 3 4}

ABSTRACT- A study on persistent organic pollutants (POPs), such as DDT, DDE, HCB, HCHs and several PCBs isomers, in soils was conducted to test the global distillation and fractionation hypothesis in the southern hemisphere. Samples were collected from remote sites along a wide latitudinal (from 18°S to 45°S) and altitudinal (from 10 to 4500m above sea level, a.s.l.) gradient in Chile. Soil extracts were analysed by capillary GC-ECD. Previous studies on chlorinated hydrocarbons have shown that physicochemical properties and environmental temperature are the most important factors in determining the distribution patterns of these compounds in remote areas. Organochlorine (OC) pesticides and PCBs were detected in all samples at the same concentration range to or even lower than those reported for other remote sites. Significant (p<0.01, r > 0.66, Pearson′s test) positive correlations were found between pp′-DDE, -HCH, HCB and PCBs concentrations and altitude whereas pp′-DDE, HCB and PCBs levels were inversely related to latitude. Current preliminary results give evidence for supporting global distillation and fractionation hypothesis of POPs. Concentrations of those more volatile chemicals (HCB, lindane and tri- and tretachlorinated byphenils) were much higher in high altitude (>3000 m a.s.l.) sampling points than lower altitude.

Key words: POPs, soil, Chile