Occurrence, removal and emission of per- and polyfluorinated alkyl substances (PFASs) from chrome plating industry: A case study in Southeast China

Abstract

Per- and polyfluorinated alkyl substances (PFASs) have been used since the 1950s as chrome mist suppressant (CMS) in the electroplating industry. In this study, various samples within an electroplating factory, the related wastewater treatment facilities and surrounding environment at Hangzhou Bay in Southeast China were investigated for the occurrence and removal of PFASs. PFOS and 6:2 Cl-PFAES are predominant compounds in the samples. The PFASs in the bath solution of the workshops had some differences from the final releases, partly because of the historic usage and memory effects. PFOS and 6:2 Cl-PFAES were found in high concentration (5500 and 154.5 μg/L in influent, 795 and 985 μg/L in effluent) in the electroplating Wastewater Treatment Plant (WWTP). The ultrafiltration and reverse osmosis (RO) treatment had a significant removal efficiency (74%–100%). On the other hand the reduction, precipitation and anaerobic/anoxic/oxic (A2/O) treatment had poor removal efficiency for PFASs. The receiving river samples had levels of PFASs between 300 and 1500 ng/L, and the concentrations of PFOS and 6:2 Cl-PFAES decreased with increasing distance to the municipal WWTP outlet due to dilution. The concentrations of PFOA in the river water samples were also high but might originate from other sources. The relevant ecological risk is noteworthy, especially for PFOS and PFOA for which limits have been defined. There is an urgent need to control plating industries in China and worldwide. Currently a GEF project related to Stockholm Convention implementation has reduced and possibly eliminated PFOS use and release in the plating industry in China. In addition, it will be important to evaluate and control the alternatives used.

Keywords

• PFASs
• Chrome plating
• Removal
• PFOS
• F–53B