More action needed to protect food chain

PUBLISHED : Friday, 17 February, 2006, 12:00am
UPDATED : Friday, 17 February, 2006, 12:00am

The food scares that have hit Hong Kong in recent times have tended to boost the wholesome image of vegetables. As markets were disrupted by the discovery of a cancer-causing chemical in fish and potentially fatal bacteria in pork, we took comfort from the assumption that at least our vegetable supplies are safe. Alas, even that reassurance is now looking a little shaky.

A Baptist University study has revealed levels of the cancer-causing heavy metal cadmium exceed Hong Kong standards in some of our farm and supermarket vegetables, including the staples choi sum and pak choi. Both the incidence and level of contamination was higher than previously disclosed by government testing.

That is no cause for panic. The worst readings are still below international standards. You would have to consume a large quantity of contaminated vegetables to exceed the safe daily maximum. There seems no reason to question the government's insistence that vegetables sold in Hong Kong are safe for consumption. And the university's organic research centre director, Jonathan Wong Woon-chung, agrees there is no immediate health risk.

That does not mean, however, that there is no cause for concern. Professor Wong says the results reflect increasing pollution on the mainland, which provides 90 per cent of Hong Kong's vegetables. They also show that cadmium levels in mainland vegetables have risen.

Cadmium, which causes infertility, is found on the surface of vegetables. Fine-particle, heavy-metal pollution is finding its way into our food chain. This is reason enough for concern. But recent studies have shown some types of fine-particulate air pollution are more dangerous to our health than previously thought and that the damage can begin in childhood.

Air pollution is a global problem and has long been a big problem in Hong Kong. The Baptist University study reinforces the need to do something about it.

The fight against environmental degradation must begin here, in Hong Kong. But the difficulty is that much of our pollution arises from causes on the mainland beyond our immediate control. Environmental degradation next door is so serious that state leaders have made it a national priority to try to turn it around. Hong Kong must try to tap into this heightened awareness to further develop co-operation with neighbouring Guangdong in tackling the problem.

The joint air-quality monitoring network established late last year is a good start. So are moves by our environment authorities to target pollution from Hong Kong-owned factories in the Pearl River Delta. But it is unclear how effective these will be.

Meanwhile, Professor Wong says rinsing vegetables and soaking them in water for 30 minutes will get rid of 40 per cent of cadmium. Let us hope the problem does not get any worse than that.