The New Zealand Ministry of Health recently stated that "As lead is a bioaccumulative toxin, prolonged exposure to a low level of contamination can lead to appreciable concentration in the body over time, sufficient to give rise to adverse health effects" ("The Environmental Case Management of Lead-exposed Persons: Guidelines for Public Health Units (Revised Edition) June 2007, p18). One of the potential sources of lead exposure discussed in the Ministry of Health Guidelines is lead in drinking water from dissolution of lead pipes and solders, and brass fittings in homes.
The World Health Organisation has produced a paper entitled "Lead in Drinking-water", which states that lead is present in tap water to some extent as a result of its dissolution from natural sources but primarily from household plumbing systems in which the pipes, solder, fittings or service connections to homes contain lead (WHO, Geneva, "Lead in Drinking-water: Background document for development of WHO Guidelines for Drinking-water Quality", 2003, p2). The report goes on to state that "lead is a cumulative general poison" (p5) and that there is evidence from human studies that adverse effects may occur at very low lead levels (p10).
Other reasonably recent articles supporting a link between cumulative exposure to low levels of lead in drinking water and adverse health effects (particularly in children) are Dr Maas et al (Environmental Quality Institute, University of North Carolina), "Reducing Lead Exposure from Drinking Water: Recent History and Current Status", Public Health Reports, May-June 2005, Vol. 120, p316 and Dr Maas et al, "Lead-leaching characteristics of submersible residential water pumps", Journal of Environmental Health, Jan-Feb 1998, Vol. 60).
