Latest research queries ‘safe’ fluoride levels

Press, 28 November 1980, Page 13

Latest research queries ‘safe’ fluoride levels

The Health Department is required to set maximum permitted emission levels for fluorides from the second aluminium smelter, and these are likely to follow the guide lines set by the United States Environmental Protection Agency. But recent research raises serious doubts about the safety of existing “safe" fluoride levels. GARRY ARTHUR reports in the third and final article in a series which began yesterday.

Just how serious fluoride poisoning can be was described in ?. report by two Cornell University veterinary scientists, Lennart Krook and George Maylin (a New Zealander), in the “Cornell Veterinarian” last year. They investigated the plight of Mohawk Indian farmers on Cornwall Island in the Gulf of St Lawrence where, since 1959, cattle had started going lame with swollen distal leg bones. The lameness became so severe that the cattle had to lie down to graze and crawl from one place to another to reach forage. Older animals had trouble drinking and chewing, and mortality was high in both calves and calving cows. The island’s bees disappeared, crop yields fell, the partridge population declined drastically, and pine forests became diseased. Cornwall Island residents suspected the Reynolds aluminium plant upwind from the island on the south bank of the St Lawrence. In 1973, Reynolds installed $l7. S million worth of pollution control equipment and eventually reduced the plant’s fluoride emissions from more than 300 lb an hour to about 75 lb an hour. Conditions on Cornwall Island improved but the problems continued. Cattle were still dying, and the Mohawks asked Lennart Krook, a veterinary scientist of international reputation, to look into it. After- diagnostic and pathology tests of the island cattle, Krook reached the conclusion that because of extensive and serious chronic fluoride poisoning, no cattle born on Cornwall Island would live more than five years. Stunted growth was the

most obvious external sign, the two scientists said in their findings, and there was conclusve evidence that this was the result of chronic fluorosis. Krook and Maylin also found bone lesions, bone necrosis (death), great mottling of teeth, and delayed eruption of permanent teeth. As a result of their findings, the two scientists believe .that the level of 40 parts per million of fluoride in forage, recommended as safe in a 1974 National Academy of Sciences report, is anything but safe. “Science News” reported in July that a followup study by Krook and his colleagues in April this year reported severe fluorosis in New York cattle exposed to fluoride levels in forage ranging from only 13 to 25 parts per million. Scientists from the University of Illinois studied the vegetation on Cornwall Island and concluded that the smelter was the cause of the very high levels of fluoride found and the damage measured. They also studied- the islanders themselves and found “significant numbers of people with abnormalities of the muscular, skeletal, nervous, and hematologic (blood) systems.” They said island physicians noted high rates of anaemia, irritability, rashes, diabetes, high blood pressure, and thyriod disease. Schoolteachers told them that the island children were irritable and hyperactive, and appeared to be suffering from a considerable amount of „ chronic fatigue. "Additionally, some had complained of aching in the legs, particularly the muscles. And in one case, the son of one of the

teachers had so much pain in his feet that he frequently had difficulty sleeping.” Carnow and Conibear, the Illinois researchers, found that “unquestionably heavy exposure to fluorides” had “affected all of the life forms studied.” They recommended an immediate reduction in fluoride emissions from the smelter and the start of a detailed epidemiological study of the islanders. Such a study was initiated in June this year, four months after the Mohawks filed a $l5O million lawsuit against Reynolds and Alcoa, who also have an aluminium plant in the vicinity.

The United States Environmental Protection Agency’s New Source Performance Standards, which went into effect from June 30 this year, allow smelter emissions of 0.05 kg to I.3kg of fluoride per tonne of aluminium produced, depending on the process regulated. “Science News” says that should the study of Cornwall Island residents find notable correlations between fluoride exposure and adverse health effects, major changes in the way the E.P.A. looks at fluoride could result. Health effects on humans are at present not included, in the absence of scientific evidence that adverse health effects could occur; after chronic exposure. The article says that pollutants adversely affecting plants, livestock, or other property, are classified as “welfare” pollutants and are controlled on the basis of ba- ‘ lancing the cost of anticipated economic losses against the cost of reducing emissions. If they were classified as “hazardous” pollutants, different standards would apply.