[Opinion] The Truth About Fluoride Contamination

The site for the new Seoul Metropolitan Office of Education building is reportedly contaminated with fluorine. It appears that 60,000 tons of soil need to be purified from the 30,000㎡ site. This is a task requiring over a year and a cost of 5.7 billion KRW. This situation arose after the Ministry of Environment designated fluorine as a ‘pollutant’ under the Soil Environment Conservation Act in 2002. Fluorine contamination in soil is emerging as a new obstacle in large-scale redevelopment and reconstruction projects.

The chemical rationale behind the Ministry of Environment’s active management of fluorine soil contamination is unclear. There have been no cases of serious damage caused by fluorine contamination in soil. Moreover, fluorine, which has very high electronegativity and chemical bonding strength, stabilizes immediately once released into the environment. This is especially true in soil, which contains various impurities mixed together.

Of course, the situation changes if highly toxic fluorine compounds such as hydrogen fluoride (HF), used in industrial settings, leak directly into the atmosphere. The 2012 Gumi hydrogen fluoride leak accident is a representative example. Semiconductor factories also monitor indoor air contamination by hydrogen fluoride carefully. The concentration of fluorine in indoor air is managed so as not to exceed 2.0 ppm. Even in such industrial environments, serious soil contamination by fluorine has never been confirmed. Furthermore, industrial sites using fluorine are not common.

Most fluorine detected in soil originates from natural minerals such as fluorite (hyeongseok, 螢石) and fluorapatite, whose main component is calcium fluoride. Fluorite and fluorapatite, types of igneous rock formed as magma cools, are widely distributed throughout South Korea. Consequently, it is common for soil in South Korea to contain fluorine levels exceeding 250 ppm. (Therefore, the Ministry of Environment’s permissible limit of 400 ppm is excessively strict.)

The possibility that soil containing fluorine derived from natural minerals causes direct harm to humans or ecosystems is low. Fluorine in soil does not pose a risk of contaminating indoor or outdoor air like gaseous radon or volatile organic compounds (VOCs) such as benzene and toluene. There is no clear reason to abandon land use simply because fluorine is detected in soil. The same applies to ‘heavy metals’ classified as pollutants under the Soil Environment Conservation Act, such as cadmium, copper, arsenic, mercury, lead, hexavalent chromium, zinc, and nickel.

However, groundwater contamination by naturally derived fluorine should be monitored carefully. Long-term, repeated consumption of fluorine-contaminated water can cause dental fluorosis, characterized by white spots on teeth, or skeletal deformities. The permissible fluorine limit in drinking water is 2.0 ppm. Water quality testing for fluorine is essential when using groundwater as drinking water.

Contamination caused by fluorine used in industrial settings is extremely limited. Hydrogen fluoride (HF), widely used in semiconductor processes, disperses immediately if leaked into the air. PTFE (Teflon), used as a coating for building exteriors and kitchenware, is chemically stable and does not pose a risk of soil contamination. CFCs (chlorofluorocarbons), which destroyed the ozone layer in the stratosphere, were banned from production and use by the 1989 Montreal Protocol. Although some pesticides contain fluorine, they do not cause soil contamination at concerning levels.

Blind rejection of naturally derived fluorine is foolish. Especially in the case of naturally derived fluorine, there is no special purification technology available. Digging up perfectly good soil and dumping it elsewhere does not make the soil environment cleaner.

Lee Deok-hwan, Professor Emeritus at Sogang University (Chemistry and Science Communication)

This content was produced with the assistance of AI translation services.