Lead in Drinking Water for small supply systems
The problem of lead in drinking water is most-publicized for the larger water supply systems of Cities and Towns, particularly the older districts, where lead piping was often used to connect houses to a municipal water supply system and for internal plumbing, unto the early 1980s (generally). The problem is more closely associated with the longer established industrialized and urbanized countries.
The same risk to individuals is present in smaller towns, villages and more wide-spread rural areas. Individual houses or small groups of houses with their own independent water supply can also have a problem if lead pipes are in use. Because small systems have less funding for monitoring or necessary corrective action, in many instances problems can be more severe, and have a bearing on the economic balance of corrective actions and the way in which problems are assessed.
For more detailed technical information, the reader can refer to the Best Practice Guide on the Control of Lead in Drinking Water (www.iwapublishing.com) and related training scheme (www.meteau.org)
Whilst these are particularly relevant to larger water supply systems, many of the issues and principles are also relevant to small community water supply systems.
Public health concerns
the effects of lead are well documented and identify a wide range of possible clinical conditions (Troesken, 2006; Hayes and Skubala, 2009), often making medical diagnosis difficult. Published literature draws attention to adverse health effects from prolonged exposure to high amounts of lead from occupational and environmental exposure, including: interference with haemoglobin biosynthesis; interference with calcium and vitamin D metabolism; gastrointestinal irritation; dullness; restlessness; irritability; poor attention span; headaches; muscle tremor; abdominal cramps; kidney damage; hallucination; loss of memory; encephalopathy; hearing impairment, gonad dysfunction, and violent behavior. Lead can accumulate in bone and fatty tissue, with subsequent release, particularly during the latter stages of pregnancy. Most attention has been directed towards the retardation of child development, especially reductions in IQ.
Numerous case studies have correlated exposure to lead with the concentration of lead in blood, and blood lead concentrations to clinical effects. Such quantification is difficult due to the wide range of exposures and human tolerances that complicate such studies, but general effects can be clearly demonstrated. Less well established is the potential for prenatal mortalities, bearing in mind that lead compounds were used historically (Troesken, 2006) to induce abortion, at lead dosages equivalent to high concentrations (350 μg/l) of lead in drinking water that can occur in highly plumb solvent water supply areas (Hayes and Kabala, 2009).
Historically, lead exposure was linked to food, paint, petrol and drinking water. Lead in paint and petrol were removed in the early 1980s. At this time, leaded solder for jointing copper pipes and jointing food cans was also banned. In consequence, any remaining problems are likely to be due to drinking water, primarily in the presence of lead pipes, although concerns continue to be voiced in North America about the potential for exposure from soil and dust. The main source of lead in drinking water is due to the continued use of lead pipes, although lead leaching from brass fittings and galvanic corrosion of leaded solder can be problematic in some circumstances (IWA, 2010).
The basis of the current World Health Organization (WHO) Guideline Value of 10 μg/l for lead in drinking water (WHO, 2004), as an average concentration, is that lead accumulation should be avoided and that blood lead concentrations should be kept well below the level of 10 μg/dl that is generally regarded as the threshold for concern. The WHO has established the Guideline Value on the basis of a provisional tolerable weekly intake of 25 μg/kg body weights, using the weight of an infant of 5 kg, a consumption of drinking water of 0.75 liters/day and an exposure contribution of 50% from drinking water.
Small Community Water Supply
The World Health Organization has progressively tightened its guideline value for lead from a maximum allowable concentration of 0.1 mg/l to the current 0.01 mg/l. The WHO Guidelines recognize that lead is exceptional, and that most lead in drinking-water arises from plumbing and the remedy consists principally of removing plumbing and fittings containing lead. As this requires much time and money, it is recognized that not all watermill meet the guidelines immediately. Meanwhile, all other practical measures to reduce total exposure to lead, including corrosion control should be implemented. Treatment to reduce plumbosolvency usually involves pH adjustment and, additionally, dosing with ortho-phosphate may be necessary.
Small community water supply systems are very numerous throughout the world and problems caused by lead pipes may be exacerbated by the lack of reliable treatment. Particular problems can be associated with low alkalinity sources that are prone to acidic pH conditions. A guide has recently been produced to provide a simplified approach for assessing problems from lead pipes and to provide guidance on corrective options. It is hoped that this Guide will enable those responsible for water supplies to small communities to make important progress in reducing the potential health risks from lead in drinking water.
Guide for Small Community Water Suppliers and Local Health Officials on Lead in Drinking Water
The issues in this article are addressed in the Guide for Small Community Water Suppliers and Local Health Officials on Lead in Drinking Water edited by Dr Colin Hayes of Swansea University, UK.
CLICK TO DOWNLOAD the Guide for Small Community Water Suppliers and Local Health Officials on Lead in Drinking Water
The Guide for Small Community Water Suppliers and Local Health Officials is one of a series produced by the International Water Association’s (IWA) Specialist Group on Metals and Related Substances in Drinking Water. It is an abbreviated compilation of the wide range of scientific, engineering, health and operational issues concerned with the control of lead in drinking water in small water supply systems.
The IWA Specialist Group is supported by members from 26 European countries, Canada and the United States. It is an active research network and has regularly convened international conferences and seminars. It has close working links with the World Health Organization, the European Commission’s Joint Research Centre, Health Canada and the US Environmental Protection Agency. The IWA Specialist Group developed out of COST
Action 637 (www.cost.esf.org), a European research network.
The Guide is supported by a two-day technical training course and a more comprehensive Best Practice Guide on the Control of Lead in Drinking Water (IWA, 2010). Information about training, the Best Practice Guide and the research network in general is available
from www.meteau.org.
This Guide for Small Community Water Suppliers and Local Health Officials explains why lead in drinking water may still be a threat to public health in small communities. It is aimed at Local Health Officials and the operators of drinking water supply systems that serve small communities. Its objectives are to raise awareness, to provide a basis for assessing the extent of problems, and to identify control options.
References
Current Publications
Colin Hayes, Guide for Small Community Water Suppliers and Local Health Officials on Lead in Drinking Water, IWA Publishing, CLICK TO DOWNLOAD
Colin Hayes, Best Practice Guide on the Control of Lead in Drinking Water, IWA Publishing 2010, ISBN: 9781843393696
Forthcoming
Dr Brian Croll, Best Practice Guide on Sampling and Monitoring of Metals in Drinking Water, IWA Publishing, 2011
Prof. Mustafa Ersoz and Lisa Barrott, Best Practice Guide on Metals Removal by Treatment, IWA Publishing, 2011
Dr Matyas Borsanyi, Best Practice Guide on the Control of Arsenic in Drinking Water, IWA Publishing, 2011
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