Cr (VI), a chromium ion, is dangerous because it has a negative effect on living things and must be kept under constant control. In particular, the wastewater containing Cr (VI) needs to be reduced to zero before being released to the receiving environment.

A significant number of industrial establishments cause liquid wastes and water pollution and thus pollution of soil and vegetation. This situation destroys the nature irreversibly. For example, one of these industries is the metal sector. In this sector, chrome plating processes with electrochemical methods are frequently applied. Chromium compounds (Cr + 6) used in these processes are toxic and carcinogenic. Cr + 6 continues to be widely used, as there is yet no other application to replace this technology. A large amount of wastewater is generated in these processes. Acidic chromium plating wastewater has low organic matter content and biological oxygen demand and high chemical oxygen demand.

Another important sector in terms of industrial pollution is the leather sector. During the processing of raw leather, many processes are carried out and a wide variety of chemicals are used, both of which are separated from the skin and the chemicals used in these processes make it difficult to treat wastewater. As such, contaminants containing sulfur, chromium (VI) and residues of organic matter are released to the nature without purification.

Chromium (Cr + 6) determination in water and wastewater is carried out in authorized laboratories within the scope of chemical tests. These studies comply with the standards published by national and international organizations and test methods accepted worldwide. These standards are based on a few standards:

• DIN 53314 Skin tests - Determination of CR (VI) content in the skin
• ISO 17075 Skin tests - Chemical tests - Determination of chromium (VI) content
• TS EN ISO 17075 Leather - Chemical tests - Determination of chromium 6