Nickel is another dangerous element in heavy metals. The solutions of nickel and its compounds are toxic and pose a danger to human health. It is a very low element in the environment and its main application is stainless steel materials. Plants are known to collect nickel. Nickel intake is high in those who eat a lot of vegetables. Smokers also have a high rate of nickel. Detergents also contain some nickel. Some amount of nickel is actually required for the human body, but its high rate is dangerous for human health. In general, people can receive nickel through inhaled air, drinking water and consumed foods as well as textiles that come into contact with the skin. Nickel can be used in dyes and chemicals used in textile sector.

The Communiqué on Market Surveillance and Inspection of Hazardous Chemical Substances of Certain Consumer Products issued by the Ministry of Customs and Trade includes restrictions on substances and restrictions criteria. Accordingly, jewelery items such as rivet buttons, fasteners, rivets, zippers and metal stamps used in garments cannot be placed on the market under the following conditions:

• If the nickel release rate in jewelry articles is higher than 0.2 micrograms / cm² / week
• If the nickel release rate is higher than 0.5 microgram / cm² / week in direct and long-term contact with skin

In the laboratories accredited in accordance with TS EN ISO / IEC 17025 standard from domestic or foreign accreditation organizations, measurements and analyzes are performed to determine the amount of nickel in textile products within the scope of chemical and ecological studies. The standards adopted in these studies are as follows:

• TS EN 12472 + A1 Metallic coatings - Determination of nickel separation method in coated materials abrasion and corrosion simulation tests
• TS EN 1811 Reference test method for the release of nickel from products that may come into direct and prolonged skin contact