Persistent lipophilic contaminants and other chemical residues in the southern hemisphere
Des W. Connell, Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong on leave from the Faculty of Environmental Sciences, Griffith University, Nathan, Qld 4111, Australia.
Gregory J.Miller, Munro R.Mortimer, Glen R. Shaw and Shelly M. Anderson
Envirotest, Mt. Gravatt Research Park, Nathan Qld 4111, Australia
(To be published in Critical Review of Environmental Science and Technology, 1998.
Data on the levels of persistent lipophilic contaminants and other chemicals has been reviewed and the dominant persistent lipophilic contaminants in the Southern Hemisphere found to be the chlorohydrocarbons commonly described as the DDTs, HCH’s and the PCBs. The distribution patterns suggest that long range transport, probably by global distillation, occurred with these substances. Endosulfan residues appear significant in areas of usage but the data is limited.
The data is in accord with a reduction in usage of chlorohydrocarbons in developed countries but an increase in usage in many tropical countries. A systematic comparison of data on the Northern and Southern Hemispheres indicates that the Northern Hemisphere is generally more contaminated than the Southern Hemisphere.
It also suggests that the process of equilibration between the two hemispheres is relatively slow. In addition with the HCB’s there is an equatorial to polar gradation in concentration probably as a result of global distillation. With the HCH’s relatively high concentrations exist in the tropics probably due to their heavy usage in these regions. With the HCB’s, DDTs and PCBs the concentrations appear to be more localised in relation to the sources since these substances are less volatile than the compounds mentioned previously.
KEY WORDS: persistent lipophilic contaminants, chlorohydrocarbons, endosulfan, global distillation, global contamination, pesticides, southern hemisphere.