Leaching Rate of Polychlorinated Biphenyls (PCBs) from Marine Paint Chips

Allen D. Uhler,Deborah A. Edwards,Guilherme R. Lotufo,Jeffery H. Hardenstine

doi:10.1007/s00244-021-00868-6

Abstract

Polychlorinated biphenyls (PCBs) were added to certain marine vessel bottom paints as a plasticizer to improve the adhesion and durability of the paint. The most common PCB formulation used to amend such paints was Aroclor 1254. Fugitive Aroclor-containing paint chips generated from vessel maintenance and repair operations represent a potential source of PCB contamination to sediments. Limited published studies indicate that Aroclor-containing paint is largely inert and exhibits low PCB leaching into water; however, the rate and degree of leaching of PCBs from paint chips have not been directly studied. This laboratory-based study evaluated the rate and extent of leaching of PCBs from paint chips into freshwater. The results of this investigation demonstrate that the rate of PCB dissolution from paint chips decreased rapidly and exponentially over time. Based on this study, it is estimated that the rate of leaching of PCBs from paint chips would cease after approximately 3 years of exposure to water. When all leachable PCBs were exhausted, it is estimated that less than 1% of the mass of PCBs in the paint chips was amenable to dissolution. The results of this experiment suggest that Aroclor-containing paint chips found in sediments are likely short-term sources of dissolved-phase PCB to pore or surface waters and that the majority of the PCBs in paint chips remain in the paint matrix and unavailable for partitioning into water.Graphic

Highlights

Polychlorinated biphenyls (PCBs) are a class of synthetic chlorinated organic compounds that, due to their chemical and physical stability, were used in a variety of commercial and industrial applications around the world beginning in 1929 and, in the USA, ending in 1977 (EPA 2013)
Each Aroclor product contained a subset of PCB congeners and was formulated to contain a specific relative amount of chlorine by weight, resulting in products with different physical characteristics that were found useful for a range of different commercial and/or industrial applications (Johnson et al 2006)
A numerical best-fit to the leaching rate data indicated that PCBs would cease leaching from the paint chips after 1,150 days

Summary

Introduction

PCBs are a class of synthetic chlorinated organic compounds that, due to their chemical and physical stability, were used in a variety of commercial and industrial applications around the world beginning in 1929 and, in the USA, ending in 1977 (EPA 2013). Each Aroclor product contained a subset of PCB congeners and was formulated to contain a specific relative amount of chlorine by weight, resulting in products with different physical characteristics that were found useful for a range of different commercial and/or industrial applications (Johnson et al 2006). Construction materials containing Aroclors were widely used in industrial and institutional settings (Scott and Snyder 2015; Jartun et al 2009), and in construction and maintenance of military and civilian vessels. Many vessel maintenance facilities have been sites of ship refurbishing and application of paints and coating materials on decks, cabins, and hulls of vessels to provide protection against erosion, corrosion, and biofouling. Release of spent paint residues from ship repair yards and direct release from the hull during port calls were responsible for introduction of various contaminants, including PCBs, to sediments outside of ship repair yards and around quay structures in Norway (Johnsen and Engoy 2000)

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Conclusion