By IISD's SDG Knowledge Hub, July 24, 2020

The World Health Organization (WHO) and the Global Environment Facility (GEF) have published an overview of analytical methods for measuring lead in paint both in the laboratory and in situ where lead paint has been used.

The Brief guide to analytical methods for measuring lead in paint seeks to inform public health officials, scientific institutions and policymakers who are not laboratory specialists but who may need to develop plans for measuring lead concentrations in new paint and for studies on lead paint availability on the market.

Lead paint is an important source of exposure to lead, particularly for children and workers. It is preventable as paints with similar colors and properties can be manufactured without using lead additives. However, even with restrictions on use of lead in paint, a legacy of lead paint in buildings and structures might continue to be a source of exposure for many years.

The document details: well-established analytical methods for measuring lead content of paint that vary in terms of cost and complexity; strengths and limitations of these methods; and considerations when deciding whether to use a laboratory-based method or portable technology, and whether to establish a laboratory service for measuring lead or to use services from another laboratory.

The document identifies two reasons for measuring the lead content in paint, namely: assessing new paints to check for compliance with regulatory or legal restrictions, or to help determine whether lead paints are being sold; or to find out whether existing paint on surfaces in homes, or on furniture, playground equipment, or toys, contains lead to assess the need for risk management measures.
 
Specific methods to measure lead in paint include laboratory methods, benchtop or portable X-ray fluorescence (XRF) devices, and test kits. While chemical test kits are available, the brief explains they cannot measure the lead content of paint with the same accuracy as laboratory and XRF measurements.

Methodology choice, according to the document, depends on, inter alia: reason for analysis (compliance, risk assessment or screening); number of samples to be tested; substrate to be tested (new paint, existing painted surface, surface size and shape); cost limitations; need for precise measurement; quantification limit required; and availability of trained personnel and analytical equipment.

The brief recommends using a laboratory certified by a recognized body and accredited to carry the required tests. It also suggests considering, when choosing a laboratory: experience in testing paints; analytical methods used and limit of detection; capacity to handle the number of samples required; analyses costs, including shipping; and turnaround time.

The document explains that establishing a laboratory service requires significant investment of resources. It also underscores the need to prevent external contamination, and ensure quality assurance and control in laboratory practices. It identifies standards, certification and accreditation as important measures for ensuring and demonstrating laboratory quality.