Whether N.Z. needs a new smelter or not — is it safe for man, land or beast?

Press, 27 November 1980, Page 21

Whether N.Z. needs a new smelter or not — is it safe for man, land or beast?

By

GARRY ARTHUR

Is it safe for Timaru to have an aluminium smeller right in its backyard? Or for Dunedin to have one at the very entrance to its harbour? That aspect of the great smelter debate is one which has been overshadowed by the economic and social implications of offering cheap power to a foreign-dominated consortium, wherever it chooses to build its smelter — whether at Washdyke or Aramoana.

Aluminium smelters emit gaseous fluorides, and fluoride is one of the most important global air pollutants in terms of the damage it causes to plants. Fluoride has also caused more damage to livestock than any other air pollutant. It accumulates in the bones and teeth, and excessive amounts lead to fluorosis, which can be acute or chronic.

Alusuisse, the principal partner in the second; smelter consortium, has already been in trouble in its home country over fluoride poisoning from its smelters in Das Wallis. In the 19605, fluoride pollution resulting in fluorosis led to Alusuisse paying

out complete or partial pensions to 39 people. It also paid compensation for animals, bees, fruit, grapes, and pine trees. New Swiss Government guidelines require the smelters to reduce fluoride emissions to 1.5 kilograms per tohne of aluminium produced by the end of 1981 (although Alusuisse’s older smelter was given until 1993).

Cattle are considered to have a tolerance to fluoride of 40 milligrams per kilogram of feed. This is the upper limit set for forage in the vicinity of the Bluff smelter at Tiwai Point, and the same level is likely to be fixed for the next smelter, wherever it is sited.

However, recent research by leading American veterinary scientists at Cornell University raises serious doubts whether the 40 milligrams upper limit is really safe. They reported severe fluorosis in cattle eating forage containing fluoride at levels as low as 13 to 25 milligrams per kilogram. (See tomorrow’s story’.) Mr D. R. Pullen, regional air pollution control officer for the Department

of, Health in Christchurch, says that if evidence is produced which makes the 40 milligrams level appear unsafe, the department will have to consider seriously lowering the permitted level. Mr Pullen is chairman of the inter-departmental committee which monitors environmental effects around the Bluff aluminium smelter.

Washdyke is a very different site from Tiwai Point. The Seadown dis-

trict is good farming land, and the surrounding area is used for town milk supply dairy farming as well as for cropping. It is considered to have considerable potential for horticulture, and already produces crops of peas and beans for the Watties cannery at Washdyke.' Cattle and sheep are known to contract chronic fluorosis when exposed to moderate fluoride levels over long periods. Cattle suffering from chronic fluorosis first get dental mottling, then their teeth

become rough and brittle, their bones become chalky, irregular and coarse, and their joint tendons calcify. "The final stages of fluorosis are quite severe and debilitating,” says the New South Wales Pollution Control Commission in a recent study' of the pollution implications of proposed new aluminium smelters in the Hunter Vahey. “The animal loses weight, is unable to feed, and becomes stiff and

lame. Death may ensue.” The effect of fluoride on plants has been observed,, the commission says, at hydrogen fluoride concentrations in air as low’ as 0.2 micrograms per cubic metre; effects at still low'er concentrations are likely. Fluoride causes visible leaf changes ■ and has been shown to cause chromosomal changes. The Bluff smelter operates under a "no damage”clause, and the environment around Tiwai Point is monitored continuously by. both the Health Department and the smelter

company., Mr Pullen says that no adverse effects have been detected in the pasture, native vegetation, the air, water, native birds or farm stock. Stock are monitored on two farms about 3km and 10km respectively downwind from the smelter, both of which are owned by the smelter company. Ministry of Agriculture and Fisheries scientists at Invermay Research Station oversee he monitoring of stock. The only thing 'a:y have found was a couple of incidents of bad teeth in sheep, but these were discovered to have, dietary causes.

Gaseous fluoride emissions from the Tiwai Point smelter are required to be no more than 1 microgram per cubic metre of air on a monthly average. The daily average must not exceed 3 micrograms. These limits permit six or seven times as much fluoride to be emitted as will be allowed for a second smelter.

Mr Pullen says that the actual amount measured at Tiwai Point is so small that it approaches the lower limits of detection. Up to August this year

the average was only 3 per cent of the monthly standard, and 5 per cent of the daily standard. On the nearer of the two experimental farms, the level of fluoride in forage has beet measured at 60 per cent of the permitted amount. On privately owned “grazing monitor farms” further away, fluoride has been found to be 25 to 37 per cent of the permitted maximum of 40 milligrams per kilogram.

“We also monitor urine levels in cattle and sheep, and we do tailbone biopsies,” Mr Pullen says. "No hazard has been found. Sheep have lambed for two years running and there has been no effect on the lambs. In fact, I think they have been graded Prime 1."

The Health Department is already doing random sampling of fluoride levels in vegetation in the Washdvke area because of the Ravensdown fertiliser works. Superphosphate contains 2 to 2.5 per cent fluoride. There is a fertiliser works near Tiwai Point too, but it is about 10 miles away from the smelter. The Washdyke fertiliser works are only

about a mile from the proposed smelter site.

“Weather details at Washdyke are well established,” Mr Pullen says.

“because it is right alongside the airport. Much less is known about the weather at Aramoana.” Information about both possible sites has been fed into the Health Department’s computer for pollution dispersion calculations to decide the height of the chimney stack. If Washdyke becomes the smelter site, a tall chim-

ney stack will be needed — high enough to disperse fluorides above the inversion layers which are a fairly common meteorological phenomenon in ne site area.

The Clean Air Act, 1972, requires the consortium to apply to the Health Department for a licence to operate the smelter. Standards of operation will be set on the licence, and Mr Pullen says that if these are set at unrealistic levels, the

consortium could appeal against them. To give maximum environmental protection, the Health Department wi? probably set an emission standard for the new smelter of about 1 kilogram per tonne of metal produced. With the latest technology. Mr Pullen says, it appears that fluoride emission can be limited to less than 1 kilogram per tonne. Even better results could be achieved by wetscrubbing of the roof

emissions, but this could create water pollution problems. How far the Health Department deviates from the 1 kilogram per tonne limit will depend on the site characteristics. “If fhe site is particularly critical we might have to go down to 0.75.” Mr Pullen says. "On the other hand a more lenient level of 1.25 could be set. The actual standards for operating the smelter will be set when the site evaluation is completed.”