As per the ZDHC Wastewater Guidelines V2.1, five boron flame retardants in textiles (boric acid, diboron trioxide, disodium octaborate, disodium tetraborate anhydrous, and tetraboron disodium heptaoxide, hydrate) are determined as total elemental boron via ICP (Inductively Coupled Plasma) spectroscopy method. Therefore, if the total elemental boron content is higher than 100 μg/L, which is the threshold limit of five boron flame retardants, then all five boron flame retardants will be marked as non-conformant to the Wastewater Guidelines in the ClearStream Report.
In the textile industry, boron is not added intentionally except in boron flame retardants and boron zinc salt (another flame retardant). But there could be rare instances where manufacturing facilities that do not use flame retardants detect elemental boron concentrations in their wastewater beyond the threshold limit of the ZDHC Wastewater Guidelines V2.1. In these scenarios, a facility should conduct a proper root cause analysis to find the reason for the boron detection. This takes expertise and investment in testing. A thorough examination of all input chemicals (including commodity, sundry, and lab chemicals) should be completed. The manufacturing processes should also be studied, including the raw materials used (which may contain contaminants). On most occasions, these non-compliances occur due to contamination/impurity of an input chemical(s). For example, by conducting a root cause analysis, a facility found boron was found as an impurity in one of the commodity chemicals (NaHCO3).
Elemental boron is not a restricted substance itself in the ZDHC MRSL V3.1 or ZDHC Wastewater Guidelines V2.1. But it is advised to determine the root cause and develop a suitable corrective action plan and replace that with a boron non-contaminated ZDHC MRSL conformant chemical since boron is not an intentionally added substance as mentioned above.
This matter will be further evaluated by the Wastewater Council and appropriate actions will be taken to avoid any dilemma pertaining to the existing boron flame retardant testing approach in the next wastewater guideline update (V3.0) which will be launched in May 2024.