Metal and inorganic ion accumulation in biofilms exposed to flowing and stagnant water

Abstract The aim of the present study was to estimate the concentrations of metal ions in biofilms within flowing and stagnant stainless steel systems since this could affect the suitability of stainless steel for use in potable water. There may be occasions when domestic plumbing systems are not used for long periods of time, leading to stagnation of the water, particularly if the supply system has been designed poorly. Stagnation can occur in dead-legs when water is left in the system for extended periods following pressure testing before going into service. It has been established that metal ions are leached from stainless steel in very low amounts. The highest detectable levels of metal ions leached from stainless steel into stagnant water and/or the biofilm were of iron, then molybdenum, nickel, and finally chromium. It seems unlikely that the concentrations of metal ions detected within both biofilms and flowing/stagnant water would adversely affect the suitability of stainless steel pipework for potable water supplies.