"Heavy metal" is defined as any metallic element that has a relatively high density on the atomic scale and which negatively affect's people's health. Oeko-Tex and GOTS both limit these heavy metals:
Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. Interestingly, small amounts of these elements are common in our environment and diet and are actually necessary for good health. Lead can even be found in natural fibers, such as cotton, flax and hemp, which can absorb it from the soil.
It's when our bodies have to deal with large amounts of these heavy metals that we get into trouble. Heavy metal poisoning could result, for instance, from drinking-water contamination (e.g. lead pipes), high ambient air concentrations near emission sources, intake via the food chain or through skin absorption – and in the case of crawling children, from inhaling carpet particles or other abraded textiles in dust. For some heavy metals, toxic levels can be just above the background concentrations naturally found in nature. Therefore, it is important for us to inform ourselves about the heavy metals and to take protective measures against excessive exposure.
Heavy metals are used in the textile industry in many ways, often as components of dyestuffs, so if your fabrics are dyed, there may well be heavy metals to thank for the coloration. The health risks associated with some of these heavy metals include:
- Lead: Lead is a neurotoxin. It affects the human brain and cognitive development, as well as the reproductive system. Some of the kinds of neurological damage caused by lead are not reversible. Specifically, it affects reading and reasoning abilities in children, and is also linked to hearing loss, speech delay, balance difficulties and violent tendencies.1 According to Ruth Ann Norton, executive director of the Coalition to End Childhood Lead Poisoning, "There are kids who are disruptive, then there are 'lead' kids – very disruptive, very low levels of concentration."2 The daily intake of lead is not as important a determinant of ultimate harm as is the duration of exposure and the total lead ingested over time. Children are uniquely susceptible to lead exposure over time, and neural damage occurring during the period from 1 to 3 years of age is not likely to be reversible. It's also important to be aware that lead available from tested products would not be the only source of exposure in a child's environment. Although substantial and very successful efforts have been made in the past twenty years to reduce environmental lead, children are still exposed to lead in many products, including toys and fabrics. The textile industry used lead acetate in dyestuffs, lead molybdate in pigments and lead nitrate as a mordant and oxidizer in dyeing.
- Chromium: Chromium VI (Hexavalent Chromium) is recognized as a human carcinogen by the U.S. Environmental Protection Agency; and is linked to lung, respiratory system, and sinus cancers. It is used to tan leather, and in textiles as a catalyst in the dyeing process and as a dye for wool.
- Copper: The fact that copper is essential to life is well known, but it's also a toxic metal, and that toxicity, except for the genetic overload diseases (Wilson's disease and hemochromatosis) is not so well known. Humans can become copper-toxic or copper-deficient, often because of "copper imbalance" which can include arthritis, fatigue, insomnia, migraine headaches, depression, panic attacks, and attention deficit disorder. Copper is listed as an EPA Priority pollutant, and an EPA Hazardous air pollutant.4 It is also ranked a Type II Moderate Hazard by the World Health Organization Acute Hazard Rankings. There is NO DATA on its carcinogenity, whether it is a developmental or reproductive toxin or endocrine disruptor or whether it contaminates groundwater. Copper impregnated fabrics are legally sold in the USA, because the EPA has not issued any regulations regarding use.
- Mercury: Mercury – methylmercury - is a persistent and bioaccumulative toxin. It is used in textile processing as a component of dyestuffs and a catalyst of the dyeing process. "Persistent" toxins are those that, once absorbed by a living system, are not expelled as normal waste, so they build up in the system, or "bioaccumulate." Mercury is easily absorbed through the skin or from the inhalation of dust which contains residues. Mercury is a neurotoxin, and the primary health effect is of impaired neurological development. It also alters genetic data. Methylmercury exposure in the womb, which can result from a mother's consumption of fish and shellfish that contain methylmercury, can adversely affect a baby's growing brain and nervous system.5 Impacts on cognitive thinking, memory, attention, language, and fine motor and visual spatial skills have been seen in children exposed to methylmercury in the womb.6
1" 'Safe' levels of lead still harm IQ", Associated Press, 2001
2"Study: Lead more harmful to kids than first thought", USA Today; 4.30.2001; http://usatoday30.usatoday.com/news/health/2001-04-30-lead-paint.htm
3Hartwig, A, "Cadmium and Cancer", Met Ions Life Sci 2013; 11:491-507 http://www.ncbi.nlm.nih.gov/pubmed/23430782
5United States Environmental Protection Agency: http://www.epa.gov/mercury/effects.htm