Scholar eyes up southern pesticide

17:00, May 18 2014

A pesticide banned in the United States but discovered in southern waterways will be the focus of a study into contaminated fish in the Clutha River.

Chlorpyrifos is used to fight pests such as grass grubs on sheep and beef farms in New Zealand but has been banned for use in homes and gardens in the US, Europe and South Africa.

An Otago University study discovered the pesticide in the sediment of 15 South Island streams, including three in Eastern Southland, Owaka and Canterbury.

Chlorpyrifos is toxic to freshwater fish, aquatic invertebrates, and estuarine and marine organisms. Overall, only one of the samples exceeded the US Environmental Protection Authority quality recommendations.

Chemical engineering student Rachel Scholes, from Olympia, Washington, will arrive in Otago next year to study the Clutha River. She is one of eight Fulbright US Graduate Award recipients announced this month.

Her focus is on the chlorpyrifos that was found in 87 per cent of samples from South Island streams. Scholes hoped her pesticide research at Otago University would improve freshwater resources worldwide.


During an internship with the National Oceanic and Atmospheric Administration in the US, she helped develop methods to detect trace endocrine-disrupters in juvenile chinook salmon.

Endocrine-disrupters were chemicals that interfered with hormones and could cause cancerous tumours, birth defects and other developmental disorders, Scholes said.

Her interest in environmental chemistry and sustainability was part of the reason she chose New Zealand for her research.

"I think that something that stands out in New Zealand compared with the US is a different way of thinking about environmental sustainability."

Chemical engineers in New Zealand were predominantly interested in tackling environmental issues while in the US their research was wider and concentrated on less environmentally friendly topics, such as petroleum, she said.

Fulbright awards are given to promising US graduate students to undertake postgraduate study or research at New Zealand institutions. Scholes' research will start in February.

The Southland Times