1992: Coffs Harbour Spray Drift: Pesticides detected: Heptachlor, Chlordane, Dieldrin, Chlorpyrifos, Diazinon, Ethoprophos

The Body Burden of Organochlorine Pesticides

Written By Dorothy M. Bowes October 9, 2003

Coffs Harbour Experience

Coffs Harbour is a Central New South Wales coastal town with surrounding areas engaged in rural pursuits.  The major crop in the area is bananas.  Coffs Harbour is situated in a basin, surrounded by the sea on the east, the Dividing Range to the west and has ridges to the north and south, which are covered with banana plantations.  The unusual topography allows pesticide drift to pool in the airshed and intermingle with other airborne pollutants.  This effect is compounded on days when an atmospheric inversion layer caps the basin preventing pollution from escaping into the upper atmosphere and resulting in increased smog over the area. Depending on wind direction, the plume can be blown out to sea by day, blown back inland at night and take several days to clear the airshed.

Late in 1984 a cluster of cleft and lip palate appeared in local children and this triggered concern in the community about environmental exposures that may have caused such defects.  Because of the unique topography and proximity to banana plantations, much emphasis was placed on exposure to agricultural chemicals as a possible cause of the cleft and lip palate. (Beard, J et al.  1995).

In 1992, the North Coast Public Health Unit carried out a study of ambient air levels of pesticides in the Coffs Harbour area.  Air was monitored for pesticides at four sites and sampling was continuous for five consecutive months across the peak spraying period.  Six pesticides were detected during the monitoring period.  Three of these were the organochlorine pesticides heptachlor, chlordane, and dieldrin, the other three were the organophosphates ethyl-chlorpyrifos, diazinon and ethoprophos. (Beard, J et al.  1995).

None of the organochlorines detected were registered for agricultural use at the time of the study.  However, heptachlor was permitted for use as a domestic termiticide and dieldrin was previously used in the banana industry.  As these are both long acting environmental contaminants, this was thought to explain their detection as low-level contaminants.  The North Coast Public Health Unit thought that community exposures to pesticides in ambient air might relate to domestic usage, even in semirural settings with adjoining agricultural areas.  However, this was not reflected in the results from two monitoring stations located within residential areas. These stations registered five of the six pesticides monitored and while these monitoring stations were not in the immediate vicinity of any new building/domestic developments they were close to banana plantations located on the edge of the residential area.(Beard, J et al.  1995).

Previous land use was thought to be a contributing factor to organochlorine contamination in Coffs Harbour as residential areas have been built on land that was previously used for cattle farming.  There are known contaminated sites in the area.