Pollution Source Sought

Press, Volume CIX, Issue 31902, 1 February 1969, Page 14

Pollution Source Sought

The possibility that farmyard annd domestic wastes are polluting Lake Forsyth and encouraging its growths of poisonous algae will be investigated for a report to be prepared for the North Canterbury Catchment Board. This decision was reached by the board yesterday after it had been told that Dr E. A. Flint, who identified the algae last week, was concerned at the lack of information as to possible sources of lake pollution. “It would be quite wrong if, after the publication of information about Dr Flint’s work, we did nothing,” said Mr L. W. McCaskill, who on Wednesday visited the lake with Dr Flint. “This is extremely serious, and we have got to take notice of it as a board, because we could be heavily involved. We should ask Dr Flint and the Health Department to keep us fully informed, and our water committee should make a report. “If any people, any far-

mers, get the idea that this is no concern of ours, we could be open to severe criticism.”

Any risk of damage to a body of natural water was the immediate responsibility of the board, whether the risk was a public health risk or not, said the chairman of the board’s water committee (Mr H. E. Connor). He had visited Lake Forsyth, and the board should immediately ask its engineers to look into discharges into the lake, and investigate the possibility of polluted discharges into water going into the lake. There must, he said, be many small cowsheds in the valleys, and close to streams. There was a poultry industry and other possible pollution risks. Algae did not build up unless the nitrogen or phosphate level was high. Mr McCaskill referred to the damage done to North Island lakes by algae, and said he himself had smelt Lake Constance in Switzerland. The algae infestation at

Zurich was like that at Lake Forsyth. “I don’t say it is the same, because Lake Forsyth is brackish,” he said. "The algae could spread to Lake Ellesmere, and then there would be a howl from the fishermen. That’s what the Water and Soil Conservation Act is to stop.” The board agreed to have its engineers prepare a report. When Mr R. M. D. Johnson

asked how the engineers could fit this in with other work, the chief engineer (Mr E. B. Dalmer) replied: “It is for Mr J. A. McDonald (the assistant engineer) to decide, and perhaps get outside help, consultants, if necessary.”

The photograph shows heaped algae decomposing on the shore of Lake Forsyth, with clumps of algae in the water beyond.