Lead can enter drinking water through lead-containing pipes, solder, and faucets. It is a toxic heavy metal that can cause neurological, cardiovascular, and renal problems even at low doses. A 1975-1976 UK survey found that many households had lead concentrations above the current WHO guideline of 0.01 mg/L. A case study in Washington DC from 2001-2004 found that changing the disinfectant used increased the corrosiveness of the water system, causing lead to leach from pipes into the water supply and resulting in elevated blood lead levels in thousands of children. Methods to manage lead in drinking water include educating consumers, adjusting water treatment to reduce corrosivity, replacing lead service lines, and removing

1. Drinking Water QualityLead Andrew Haddock Mathew NkemIkediashi 1

3. Occurrence in drinking-water.

4. Toxic/Adverse effects.

5. Rationale for water quality standard.

6. Case study.

7. Methods of management.2

9. It has been used in paints and pigments, in batteries, alloys, solder, pipes, ammunition, glazes, it was also used as an antiknock compound in petrol, however this has been phased out (WHO, 2003).

10. Lead has been known to be toxic for centuries, in the last 35 years experiments have revealed that it has health implications even at low doses.

11. As a result of the ban on the sale of leaded petrol in the UK in the year 2000 the levels of particulate lead in the environment have been reduced.

12. Levels in drinking water remain predominantly unchanged and can now provide the largest controllable source of lead intake. (Gray, 2008). 3

13. How does lead get into drinking water? Lead can enter water by leaching from Lead-containing pipes Brass faucets and Solder The problem arises where water is plumbosolvent. The rate of leaching increases dramatically below pH 8.0. Other factors include the water temperature, the contact time between the water and the source of lead and the amount of lead piping Vibrations in pipes, scouring by high water velocities, thermal expansion effects, age and nature of pipe, the presence of particulate lead deposits and electrochemical reactions caused by mixing pipes. 4

14. Occurrence in UK Drinking Water 5 Table 1. Lead concentrations in households in the UK during a survey in 1975-1976 by the Department of Environment. Reproduced from Gray, (2008).

16. Neurological problems: significant impact on child development.

17. Hypertension and cardiovascular problems.

18. Interferes with enzymes involved in haeme synthesis resulting in anaemia.

19. Disturbed calcium metabolism, bone/tooth formation.

20. Reduced Cytochrome P450 levels, reduction in drug metabolizing enzymes.

21. Reproductive abnormalities: depressed sperm counts.

22. Renal damage and abnormalities. (WHO, 2003, WHO, 2008, Lanphear et al., 2000) 6

24. Neurological problems in young primates at levels of 10.9 -33µg/dl which persisted into adulthood (Rice, 1987).

25. Studies of rats, mice and hamsters have shown that lead is carcinogenic in these species, causing predominantly renal tumours (Silbergeld et al., 2000)

27. Rationale for water quality standard-European Community. The EC responded with the revised drinking water directive, lowering the maximum level to 0.01mg/l. Costly work would need to be undertaken by member states to achieve this goal. A fifteen year transition period was granted requiring member states to reach an interim value of 0.025mg/l by 25th December 2003. The European interim standard will be tightened to 0.01mg/l in 2013 for all member states. (Gray, 2008) 9

29. Elevated blood lead levels were highly correlated with elevated water lead levels.

30. There were differences in the risk of elevated blood lead levels between neighbourhoods, areas with the highest number of lead pipes being high risk.

31. (Edwards et al., 2008)10

32. 11 Case study: Washington USA

34. Reducing the plumbosolvency of water at treatment plants before discharge.

35. Avoid the use of substances in drinking water that make water more plumbosolvent (eg. Washington case study).

36. Line lead pipes, particularly service pipes.

37. Replace lead pipes entirely – best option but expensive.(Gray, 2008) 12

38. References 13 Chen, A. M., Dietrich, K. N., Ware, J. H., Radcliffe, J. and Rogan, W. J. (2005) 'IQ and blood lead from 2 to 7 years of age: Are the effects in older children the residual of high blood lead concentrations in 2-year-olds?', Environmental Health Perspectives, 113(5), 597-601. Chu, P. H., Lin, J. L. and Tan, D. T. (2005) 'The blood lead level in chronic hypertension patients', Journal of Hypertension, 23, S391-S392. Dye, B. A., Hirsch, R. and Brody, D. J. (2002) 'The relationship between blood lead levels and periodontal bone loss in the United States, 1988-1994', Environmental Health Perspectives, 110(10), 997-1002. Edwards, M., Triantafyllidou, S. and Best, D. (2009) 'Elevated Blood Lead in Young Children Due to Lead-Contaminated Drinking Water: Washington, DC, 2001-2004', Environmental Science & Technology, 43(5), 1618-1623. Fulton, M., Raab, G., Thomson, G., Laxen, D., Hunter, R. and Hepburn, W. (1987) 'Influence of blood lead on the ability and attainment of children in Edinburgh Scotland', Lancet, 10(8544), 1221-1226. Gray, N. F. (2008) Drinking Water Quality, Problems and Solutions., Second Edition ed., United States of America, New York.:Cambridge University Press.

39. References Lanphear, B. P., Dietrich, K., Auinger, P. and Cox, C. (2000) 'Cognitive deficits associated with blood lead concentrations < 10 mu g/dL in US children and adolescents', Public Health Reports, 115(6), 521-529. Rice, D. C. (1987) 'Primate Research - Relevance to human learning and development', Developmental Pharmacology and Therapeutics, 10(5), 314-327. Ronis, M. J. J., Badger, T. M., Shema, S. J., Roberson, P. K. and Shaikh, F. (1996) 'Reproductive toxicity and growth effects in rats exposed to lead at different periods during development', Toxicology and Applied Pharmacology, 136(2), 361-371. Silbergeld, E. K., Waalkes, M. and Rice, J. M. (2000) 'Lead as a carcinogen: Experimental evidence and mechanisms of action', American Journal of Industrial Medicine, 38(3), 316-323. WHO (2003) 'Lead in Drinking-Water. Background document for preparation of WHO Guidelines for Drinking-water quality.' (Online) http://www.who.int/water_sanitation_health/dwq/chemicals/lead.pdf (Available 10/03/11) WHO(2008) ‘Guide to drinking water quality’(Online) http://www.who.int/water_sanitation_health/dwq/gdwq3rev/en/ (Available 10/03/11) 14