Lead pollution connected to crime
High levels of blood lead were found in teenage offenders and children with behavioural problems by Dr Neil Ward, an environmental chemist at Surrey University.
"Our work is at a very early stage, but we believe there is a correlation between lead and behaviour," he said.
Dr Ward, whose work involved about 100 children and teenagers, has called for more funding for research. He stressed that behaviour was very complex and was not just linked to chemical factors.
Previous research has shown that lead can reduce intelligence. Other specialists in poisons were fascinated by Dr Ward's findings and joined him in calling for more research to open up what could be a new area of concern about lead pollution.
Lead has built up in the environment and despite the introduction of unleaded petrol, pollution levels are still a cause for concern, according to Dr Ward and other researchers.
Lead can remain in the environment for decades and particles of the metal in roadside dust can be brought into nearby homes. These particles can also get into the food chain where crops are grown next to main roads.
Houses in some areas are supplied with water through lead pipes and lead paint can flake off in older homes, with the risk of it being chewed by toddlers.
Dr Ward carried out three studies and used a number of control groups. The children involved were aged eight to 11 and there were two groups of teenagers aged 16 to 19.
Details are to due be published later this year in the Journal of Nutritional and Environmental Medicine.
The journal's editor, Dr Damien Downing, said the research would give policy makers "something to think about" if it were proved.
Professor John Henry, a consultant for 15 years with the National Poisons Unit, said the results were fascinating, but he stressed the link could be a coincidence. Lead levels might be higher in difficult children because they were more likely to be prone to hyperactivity one consequence of which would be to chew paintwork, which in turn could contain lead.
The Lead Development Association, which represents the lead industry, said exposure to the metal was falling.