Aquatic plants solution to arsenic contamination

Aquatic plants solution to arsenic contamination

A HortResearch scientist thinks that aquatic plants may provide an answer to a global problem of arsenic-contaminated drinking water.

While searching for plants that have the potential to remove arsenic from contaminated soil, scientist Dr Brett Robinson from Palmerston North discovered that most aquatic plants accumulated this element to concentrations of up to 3000 parts per million of arsenic. The plants were taken from geothermal regions around Taupo and Rotorua as well as the Waikato River.

Dr Robinson said, "This was an extraordinary find, and quite disturbing as people eat watercress. The water itself was found to have less than 0.1 parts per million. Fortunately, watercress from uncontaminated streams that have no geothermal inflows is safe to eat."

Arsenic is naturally occurring in some rocks and geothermal water dissolves considerable amounts. The researchers collected aquatic plants such as parrot's feather, hornwort, watercress, willow weed and other oxygen weeds.

"We would like to find out how these aquatic plants accumulate arsenic, and whether they could be used to remove arsenic from drinking water. This may be a low-cost means of improving public health in countries like Bangladesh and West Bengal in India, where there are high levels of arsenic in the water that can result in widespread poisoning," said Dr Robinson.

Arsenic is a poisonous element that is persistent in the environment. In New Zealand, arsenic is a significant problem at an estimated 10,000 former sheep dip sites as well as in geothermal water, and even in sawdust and wood shavings from treated timber.

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For further information contact Brett Robinson, HortResearch Palmerston North Tel: +64-6-356 8080, Fax: +64-6-354 6731 Email: brobinson@hortresearch.co.nz

Paula McCool Writer Public Relations & Communications HortResearch Palmerston North tel 06 356 8080 extn 7785