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Lead-based consumer paints posing health risk

May 30, 2010

KARACHI, May 29 A number of samples of consumer paints analysed at a Karachi University (KU) laboratory have shown a significantly high content of lead, a pervasive chemical well known for its toxicity and severe damaging effects.

The testing was carried out by MSc (Final) students at the KU's department of chemistry under the supervision of Dr Nasiruddin Khan. The samples were analysed to determine the lead content in consumer paints of various colours and brands available in the local market.

International studies have shown that lead-based paints are a major contributor to creating lead-contaminated dust, which represents a major pathway of exposure to children. Other major sources of lead in the environment include petrol, water, food, cosmetics and lead-glazed ceramics. Ironically, lead-based paints are also used in manufacturing toys in many countries, making children vulnerable to slow poisoning.

The health risks posed by products containing lead have led many developed countries to either limit or ban the use of lead in paints in recent years. For instance, the United States has further restricted the use of lead in paints by bringing the permissible limit down to 90 parts per million (total lead in paint) from 600ppm (600mg/kg) last year.

There have also been a number of instances in recent years where consumer products being imported into a country have been recalled due to health and safety fears. One of the major concerns in this respect has been the amount of lead, chromium and cadmium in consumer products, particularly toys.

Lead can cause anaemia, muscle weakness and brain damage, if swallowed in large amounts. Even small quantities are linked to behavioural problems and low IQ scores.

While developed countries have imposed strict bans and limits on lead content, however, developing countries like Pakistan either do not have the proper rules and regulations, or said rules are not enforced.

Consumer paints in Pakistan, for example, are not included in the list of 78 products that require compulsory certification and regular monitoring by the Pakistan Standards Quality Control Authority (PSQCA), the highest body to regulate quality control in the country. The PSQCA, though, provides specifications (last revised in 1997) for 'lead-free paints', if required (300mg/kg).

'One of the most hazardous poisons'

According to the research findings, three samples out of 15, including six samples of distemper, had very high concentrations of lead, ranging from 784.46 mg/kg to 195,139mg/kg. Other samples had lead concentration between 19.63mg/kg and 505.6mg/kg.

A sample of lead-free matte-finish was tested to be free from lead, while another had lead concentration of 37.9 mg/kg. A sample of lime (chuna) had 172.31mg/kg lead.

“Lead has been identified as one of the most hazardous poisons because of its cumulative nature. Lead ingestion in children is most common and most dangerous, during hand-to-mouth activities from dislodged and deteriorated paint.

“The human exposure to multiple sources of lead has led experts to advocate for lead-free products, for instance lead-free petrol and lead-free paints, instead of going for different permissible limits and then instituting measures to enforce them,” said Dr Nasiruddin Khan, the research supervisor.

Common lead compounds, he said, were especially dangerous (lead acetate and lead nitrate) because of their high solubility in water. “Debris containing old lead-containing paint is a hazardous waste and should be disposed of using regulations for environment protection. Contamination of as little as 5ppm makes waste hazardous, according to well-defined rules,” he said.

About the reasons for using lead in paints and other options available, Dr Khan said that lead and its compounds were used in paints to impart good colour, bring durability and to improve drying. Lead-based paints were also believed to be corrosion-resistant.

“The chances of high lead content increases with the fastness of the colour. So, it is advisable that hard colours should not be used in schools and kindergartens. Besides, precautionary measures must be taking while using or removing lead-based paints,” he said.

Regarding the use of lead in residential paints, Esar A. Butt, developing manager, ICI Pakistan Limited, said that there were no regulations on paint contents in Pakistan.

“Lead-based pigments are very cheap whether locally manufactured or imported. Lead-free inorganic pigments (commonly used ones are titanium oxide and zinc oxide) along with organic dyes are very expensive. People manufacturing lead-based paints and those using lead-based spray paints are at grave risk if they are not using any safety gear,” he said.

The smell emanating from a freshly painted place, he added, was because of some solvents and should not be of concern. However, a health risk was involved if someone directly swallowed a lead-based paint.

Commenting on the matter, Dr Zafar Fatmi, head of the Environmental Health Sciences division and Community Medicine Residency Programme Director at the Aga Khan University, said that though lead could also be found in the paint on toys and on products marketed to children, the major source of lead exposure to Pakistani children could be lead-contaminated house dust found in deteriorating old buildings.

Regarding the health effects of lead, he said the effects of lead exposure depended on age and it also depended on whether the exposure was chronic or acute. “Lead found in the dust of a household due to paint leads to chronic exposure and more adverse health effects. It particularly affects children under six months, and its severity depends on whether the exposure is chronic or acute.

“In children, lead exposure can cause hyperactivity, anemia, brain damage, and mental retardation, while adults may suffer increased blood pressure, hearing and vision impairment, and nerve damage.

“An examination of lead levels in paints of the same brands purchased in different countries had also showed that some brands had lead-based paints in one country and paints meeting the US limits in another where regulations were applicable,” he said.

A global health problem

Though different countries have set different permissible limits for lead content in consumer paints, it is now widely acknowledged that countries should promote lead-free practices in manufacturing, as children are affected at very low exposure levels.

While commenting on the US measures to revise the lead standard in consumer paints, Dr Scott Clark, a professor of environmental health at University of Cincinnati and principal investigator of a study on consumer paints, stated in an interview to a website “This revised standard for lead in consumer paint is grossly overdue. The previous limit of 600ppm for lead in new paint was established more than 30 years ago when the blood-lead level of concern was much higher than at present. Modern research has shown that children are affected at very low exposure levels and that there is no safe level of exposure.”

Dr Clark, along with his team carried out global research on residential paints in 12 countries in Asia, Africa and South America. The countries included China, India and Malaysia. The study was published in the Environmental Research journal last year, which was Dr Clark's second study on the subject.

According to the research, there is no significant consumer price difference between leaded and unleaded consumer paints. “Our studies have shown that when comparing the prices of the same size can of paint produced by several companies within India with a wide range of lead concentrations, there is no significant consumer price difference between leaded and unleaded consumer paint,” said Dr Clark.

The study found that approximately 73 per cent of residential paint brands tested from 12 countries representing 46 per cent of the world's population exceeded the US standard of 600ppm for lead in paint. In addition, 69 percent of the brands had at least one sample exceeding 10,000ppm. High lead paints were detected in all countries.

The study emphasises the need for a worldwide ban on the use of lead in paints in order to prevent an increase in exposure and disease from this very preventable environmental source.