Trace amounts of industrial chemicals have been found in the blood of children in a study carried out by the environmental pressure group WWF (World Wildlife Fund).
Some of the children in the study had higher levels of certain chemicals in their blood than adults, prompting WWF to warn of the potential hazards to future generations.
Justin Woolford, a health campaigner at WWF, said children as young as nine had been contaminated with man-made chemicals and that some of the newer substances were at higher concentrations in the children than in their parents and grandparents.
"These results are extremely worrying because of the unknown long-term health effects of the majority of industrial chemicals people are exposed to," Mr Woolford said. "The contamination of three generations of families, including children as young as nine, with hazardous man-made chemicals clearly illustrates that industry and government have failed to control these chemicals."
WWF analysed the blood of 33 people from seven families to look for 105 industrial chemicals such as brominated flame-retardants used in television sets and perfluorinated chemicals used in non-stick frying pans.
But although analysis detected 80 of these chemicals, they were present in extremely low levels - measured in parts per billion - well below the thresholds where they are likely to cause immediate harm, according to Professor John Henry, a leading toxicologist at Imperial College, London.
He said: "The bottom line is that evidence of presence is not evidence of harm. It's good that we know these things and that someone is alerting us to them, but it's no good doing so in an alarmist fashion."
An earlier survey of 155 people carried out by the WWF concluded that many people are contaminated by a cocktail of man-made chemicals which WWF said could be hazardous to long-term health.
The latest study investigated whether there were any chemical differences between the three generations within a family. It found that children seemed to be at higher risk of accumulating certain newer substances.
The WWF report concluded: "The continuing contamination of the youngest members of families with hazardous man-made chemicals clearly illustrates that industry and government have failed to regulate hazardous chemicals."
The WWF wants stronger rules governing the manufacture and safety of the thousands of chemicals used by industry.