As per the ZDHC Wastewater and Sludge Guidelines requirements, five boron based flame retardants (boric acid, diboron trioxide, disodium octaborate, disodium tetraborate anhydrous, and tetraboron disodium heptaoxide, hydrate) are detected as total elemental boron via ICP (Inductively Coupled Plasma) spectroscopy method. Therefore, if the total elemental boron content is higher than 500 μg/L, then all five boron flame retardants will be marked as non-conformant in the ClearStream Report.

There could be instances where manufacturing facilities that do not use flame retardants detect elemental boron concentrations in their wastewater beyond the threshold limit. In these scenarios, a facility should conduct a proper root cause analysis to find the reason for the boron detection. A thorough examination of all input chemicals (including commodity, sundry, and lab chemicals) and inlet water should be completed. The manufacturing processes should also be studied, including the raw materials used (which may contain contaminants).

Elemental boron is not a restricted substance itself in the ZDHC MRSL V3.1 or ZDHC Wastewater and Sludge Guidelines requirements. But it is advised to know the root cause if the total elemental boron is detected above the limit of 500 μg/L