Sex Changing Hormones Present In Waikato River
3 April 2002
Green co-leader Jeanette Fitzsimons today said research published by Auckland University in 1998 showed that hormone disrupting chemicals being discharged into the Waikato River were changing the sex of fish.
The PhD research found that effluent discharges into the Waikato from the Kinleith Mill contained compounds acting as endocrine (hormone) disruptors. Over four per cent of fish from the site exposed to the highest concentration of effluent were found to contain both male and female sex organs.
The study noted both the masculinisation of female fish and the feminisation of male fish as well as clear evidence of female goldfish failing to release eggs, with massive inflammation of ovarian tissues.
"While the chemicals discharged from the Kinleith mill are not estrogen, but other chemicals which mimic it, it is not true to say 'Water from the Waikato is free of gender-altering chemicals' as has been reported in the media."
Estrogen from the contraceptive pill is just one of a large group of chemicals which disrupt the hormone system and can affect reproductive health. Others include chlorinated pesticides like DDT, tributyl tin used in anti-fouling of boats, and PCBs. They tend to bioaccumulate, so that even very tiny quantities over time can accumulate to a significant dose.
"Reports from the UK that half of all male fish in some rivers had developed female organs is important not because we will have the same concentrations here, but because estrogen from sewage will be adding to the other endocrine disrupting effects from similar chemicals already in the river by the time it reaches Hamilton. A recent UK study has also linked this hormone contamination of drinking water to a drop in male fertility."
Ms Fitzsimons said reports that some female hormones could feminise fish at one part per billion, which could be undetectable, made effects on fish an important early warning for humans. That is why the Greens called last week for ecological monitoring in the Waikato.
"In May water from the Waikato River will be pumped into Auckland's permanent water supply. Given that there is no screening for hormonal contamination of drinking water, and no requirement for hormones to be removed, Aucklanders can have no meaningful assurances that this water is free of these hormones.
"However there is no reason for Aucklanders to drink the Waikato River water at all. The Greens have been saying for years that water in the high quality forested catchments of the Waitakeres and Hunuas can supply all such uses and the Waikato should be used only for a few large industries near the pipeline and for emergency supply to Auckland," she said.