Improved estimates of environmental copper release rates from antifouling products

Abstract

The US Navy Dome method for measuring copper release rates from antifouling paint in-service on ships' hulls can be considered to be the most reliable indicator of environmental release rates. In this paper, the relationship between the apparent copper release rate and the environmental release rate is established for a number of antifouling coating types using data from a variety of available laboratory, field and calculation methods. Apart from a modified Dome method using panels, all laboratory, field and calculation methods significantly overestimate the environmental release rate of copper from antifouling coatings. The difference is greatest for self-polishing copolymer antifoulings (SPCs) and smallest for certain erodible/ablative antifoulings, where the ASTM/ISO standard and the CEPE calculation method are seen to typically overestimate environmental release rates by factors of about 10 and 4, respectively. Where ASTM/ISO or CEPE copper release rate data are used for environmental risk assessment or regulatory purposes, it is proposed that the release rate values should be divided by a correction factor to enable more reliable generic environmental risk assessments to be made. Using a conservative approach based on a realistic worst case and accounting for experimental uncertainty in the data that are currently available, proposed default correction factors for use with all paint types are 5.4 for the ASTM/ISO method and 2.9 for the CEPE calculation method. Further work is required to expand this data-set and refine the correction factors through correlation of laboratory measured and calculated copper release rates with the direct in situ environmental release rate for different antifouling paints under a range of environmental conditions.

XRF measurements of tin, copper and zinc in antifouling paints coated on leisure boats

“…In addition, tin concentrations in a TBT paint were also determined. The area concentrations were calculated using the CEPE mass-balance calculation method (Finnie, 2006), a method which is also accepted in the EU for estimating the release rate of biocides (reportworkshop-report, 2006). The method calculates the total area concentration of biocides in the dry antifouling paint and estimates the sum of a 14-d cumulative initial release and a steady-state release (mg/cm 2 /d) for the remainder of the specified lifetime by the use of Equations (1) and (2).…”

Spatial, Seasonal, and Temporal Variation of Antifouling Agent Concentration in a Small Marina, Predicted by 3D Unsteady Numerical Model

“…It is a general practice to measure the leaching rate by the rotating cylinder test established by ISO1518-1 23) . However, it is also well known that the leaching rate measured by the ISO/ASTM method is often greater than the one expected for actual ship data 24,25) . If the leaching rate measured by the ISO/ASTM method was accurate under actual ship conditions, antifouling paints would disappear much earlier than the service period for a ship.…”

Leaching Phenomena of Antifouling Agents from Ships’ Hull Paints

“…As for the rotating cylinder tests, it has been found that D DAVID PUBLISHING the release rate is influenced by pH, dissolved ion content and the rotation speed of test cylinder [9]. However, the leaching phenomena of antifouling agents actually occurring in the ocean are considered to be much different from those observed in the laboratory tests [7,11].…”

“…Furthermore, the test method serves only as a guide for characterization of the early stage of the release as well as estimating the steady state leaching rate of antifouling ingredients from coatings. Further, it is stated in ISO (15181-1) that actual release rate of antifouling ingredients from ships' hull paints into the environment will depend on many factors such as ship operating schedules, length of service, berthing, conditions, paint condition, as well as temperature, salinity, pH, pollutants and bacterial effect [7,8].…”