If we recall, in ZDHC WWG v2.1, the reporting limits for the five boron-based flame retardants (FRs) and zinc borate were set at 100 ppb. This led to a significant number of failures and potential false positives for these parameters. The topic was subsequently discussed at the Wastewater Council, where one member from the Wastewater Council presented a study indicating that incoming water at certain locations already contained boron at 200–300 ppb. Based on this insight, we analysed historical data, which supported the decision to set the reporting limit for the five boron-based FRs to 500 ppb in the updated version. Accordingly, in ZDHC WWG v2.2, the reporting limit for the five boron-based FRs has been set at 500 ppb, while the reporting limit for zinc borate remained at 100 ppb. Recognising this inconsistency, the Wastewater Council has addressed the issue in the new version of the ZDHC Wastewater and Sludge Guideline (WSG v2) by increasing the reporting limit for zinc borate to 500 ppb, thereby aligning it with the boron-based FRs. The logic applied for determining conformance or non-conformance for Zinc-borate under ZDHC WWG v2.2 is as follows: If zinc > 100 µg/L and boron < 100 µg/L: Conformant If zinc < 100 µg/L and boron > 100 µg/L: Conformant If both zinc and boron > 100 µg/L: Non-conformant The same logic will continue to be applied when ZDHC WSG v2 is implemented from 1 November 2026 onwards; only 100 ppb will be replaced by 500 ppb. However, based on your query, it is not clear what specific change you are proposing. Could you please clarify whether you are suggesting the following? A revision to the reporting limits for the five boron-based FRs? A revision to the reporting limit for zinc borate? A change to the zinc limits for direct discharge? Or proposing to test zinc for the facilities that are an indirect type of discharge?