Water standards that would allow nitrogen levels toxic enough to affect young whitebait and trout are being proposed by the Government, Fish and Game Otago environmental officer Peter Wilson says.
The National Objectives Framework being proposed as part of the National Policy Statement on Freshwater Management aimed to determine the values of rivers by a community process, assign A to D band categories, then set nationally consistent limits for in-stream nutrients.
Mr Wilson told the Otago Fish and Game Council this week the proposals were detrimental to fish and game interests and would lead to a degradation of New Zealand waterways' water quality.
Nitrogen levels were set so high only 1% of New Zealand rivers and lakes would fail the new guidelines and algal blooms would affect many of them, he said.
''That shows how far out of wack these numbers are.''
The nitrogen levels were also set at levels approaching toxicity for trout species, apparently on the basis native species were more tolerant of nitrogen, but young whitebait would not survive at those levels, he said.
''This issue is beyond this council; we need a nationwide response.''
Fish and Game chief executive Niall Watson said because of the Otago Regional Council's water quality plan change 6A, the changes, if implemented, would not to apply to the region.
''If we didn't have 6A in the pipeline there'd be trouble.''
Mr Wilson said comparing the council's 6A nitrogen levels with the Government's proposed levels showed extreme differences. For example, a river which fell into band ''C'' would only be allowed a nitrogen level of about 0.4mg per litre under 6A, compared to the proposed about 6.9mg per litre.
Trout began to be affected by nitrates at about 3mg per litre to 4mg per litre, while 7mg per litre was close to ''sewer levels'', Mr Wilson said.
''There is a risk they could assign lowland rivers the status of a working river.''
Band ''A'' rivers would be allowed 0.1mg per litre, which would cover all of Otago rivers.
Councillor Adrian McIntyre said there was no way people would let water quality get that bad.
Councillor John Barlow said it was a real worry given the Government was keen to double agricultural production.
Submissions to the Ministry for the Environment close on February 4.
