Lead in Drinking Water
The level of public concern related to lead in drinking water is high, due to the reports of community exposures reported in the media in recent years. While the various governmental organizations in Canada and the US have lead-management strategies in place, the situation is complex.
Why is lead present in drinking water?
Lead is present in the environment from both natural and human-related sources. Lead can be found in drinking water due to leaching from older service lines, solders and fittings that were used in the past. The Canadian National Plumbing Code has restricted the use of lead in service lines since 1975, and leaded solder in plumbing and related repairs since 1986 within drinking water infrastructure. Even with these restrictions, many homes, schools, institutions and businesses continue to be served by aging water infrastructure. Leaching occurs particularly in situations when more corrosive water enters water systems in older homes and neighbourhoods. The leaching depends on the characteristics of the lead-containing materials, the water (temperature, pH), and whether or not municipalities are employing the use of anti-corrosive agents.
How can lead affect my health?
Children under the age of 5-years, including infants and the developing fetus, are the most sensitive to the effects of lead exposure. This is due to their smaller body weights, enhanced hand-to-mouth behaviours, and their still-developing nervous systems. The effects of lead exposure in children are irreversible, and may include effects on behaviour, learning, brain development, intelligence and physical growth.
Long-term lead exposure in adults has been associated with increased blood pressure (hypertension), kidney problems, learning difficulties and behavioural changes.
The best measure of short-term lead exposure is through the measurement of lead from a blood sample. At a population level, an average blood lead level less than 1 to 2 µg/dL is generally accepted as being associated with a negligible degree of risk, based on the weight of scientific evidence.
What is the Canadian guideline for lead in water?
The science regarding lead and its effects is continually evolving. As a result, regulatory agencies are evaluating the science and updating their approaches for lead risk management.
In March 2019, Health Canada lowered the drinking water guideline for lead from 10 µg/L to 5 µg/L. The new guideline is based on a 1 point decline in intellectual quotient (IQ) at a population level in young children.
While the provinces and territories have their own drinking water guidelines for lead, these are typically based on the Health Canada drinking water value. With the recent change in the Federal guideline, future changes in the guidelines for the provincial/territorial values are imminent.
The current National Primary Water Drinking Water standard in the United States is 15 µg/L (as of April 2020).
If lead is in our environment, what is the government doing about it?
Blood lead levels have been declining in Canada and the United States since the 1970s, following the ban on leaded fuel additives, the gradual reduction in the use of leaded paints, and improved environmental regulation.
In addition to lowering the drinking water guideline, other lead-reduction strategies being considered by the Government of Canada (described in the 2013 Risk Management for Lead document) include reducing tolerance levels for lead in food and natural health products, and consumer products. This publication also noted that the soil quality guidelines and household dust screening concentrations for lead are both under review by Health Canada. Lead is included in the biomonitoring study completed every two-years as part of the Canadian Health Measures Survey.
Lead concentrations in drinking water infrastructure continue to be monitored. In drinking water, the primary strategies to reduce lead include corrosion reduction and the removal of lead-containing water infrastructure. The most commonly used corrosion inhibitors for lead include orthophosphate and zinc orthophosphate. Various treatment technologies can also be used to remove lead at treatment facilities, but this approach is secondary to the reduction of corrosion and replacement of lead-containing water system components. Municipalities can also flush pipes with high-pressure water to remove scale and biofilms from within the pipes which can affect the release of lead particles in the water.
The replacement of lead-containing water infrastructure that exists in older neighbourhoods and areas with aging infrastructure takes time and is expensive. Further, homes and buildings that are privately owned may also contain lead-containing materials within water lines that can contribute to the lead content at the tap. To help off-set this, several municipalities have developed various strategies for reducing lead exposure.
Alberta Environment and Parks recently announced a two-phased framework for waterworks systems in Alberta. The first phase (2020-2024) includes planning, assessment and implementation of lead management strategies. This phase also includes requirements for records management, lead risk-mapping, sample collection, communications and training. The second phase (to be implemented after 2025) includes monitoring and mitigation.
The public health agencies for the various Canadian provinces and territories work closely with regional and municipal water treatment organizations and Health Canada in evaluating the potential health risks associated with lead in drinking water and developing strategies for reducing lead levels.
The United States Environmental Protection Agency (US EPA) has developed a program named the “3Ts for Reducing Lead in Drinking Water Toolkit”, where a guide to resources is provided with an emphasis on schools and child-care facilities (US EPA 2020). The “3Ts” stand for “Training, Testing and Taking Action”. Different States also have their own lead management policies.
How can I reduce the risk of lead health effects from drinking water?
If you are concerned about lead in your drinking water, you can:
- Contact your public health department or Medical Officer of Health
- Either get your water tested (many municipalities offer water bottles for testing, and a reasonable charge for lead in water analysis), or, let water run from the tap (for 1 to 5 minutes) if it has been sitting in pipes for more than a few hours, before using it for drinking or cooking
- Use only cold water for drinking, cooking and making baby formula. Boiling water does not remove lead
- Consider using certified residential treatment devices and filters
- Remove or replace sources of lead in your lead service lines
How can Intrinsik help?
Intrinsik scientists have extensive experience evaluating the potential health impacts associated with lead in the environment, including drinking water. We have managed the design and completion of community-wide risk assessments and biomonitoring programs related to lead exposures. Intrinsik can aid in the development of environmental programs to monitor and assess lead exposure, evaluate potential lead health impacts, and identify areas for risk mitigation.
Where can I get additional information?
British Columbia Health Link BC
Manitoba Sustainable Development
Ontario Ministry of Health
United States Environmental Protection Agency (US EPA)
United States Agency for Toxic Substances and Disease Registry (ATSDR)