Study has good news for dolphins

PUBLISHED : Saturday, 21 May, 2005, 12:00am
UPDATED : Saturday, 21 May, 2005, 12:00am

Levels of toxic chemicals in Chinese white dolphins may be lower than initially feared, but are still cause for concern, researchers have found.

The Hong Kong Dolphin Conservation Society tested six biopsy samples taken from live white dolphins for the first time last year.

The samples contained the pollutant DDT - a banned chemical used in pesticides - and PCBs.

'Definitely, we could tell from this study the dolphin is affected by marine pollution,' said researcher Samuel Hung Ka-yiu.

'We have found the existence of DDT and PCB in their tissues, but the level is less than what we found in dead dolphins in the past.'

Mr Hung said the data obtained from live dolphins was more reliable than that from autopsies on the bodies of stranded dolphins, which may have undergone secondary contamination during decomposition.

The findings of the study will be reported in a conference to be held at City University by white dolphin expert Thomas Jefferson.

Aside from measuring contaminants in dolphins, Mr Hung said the study allowed researchers for the first time to identify the sex of the dolphins they were tracking.

The study was approved by the Agriculture, Fisheries and Conservation Department because it involved an endangered species.

There are around 1,000 Chinese white dolphins in local sea habitats, mainly to the west of the city.