Traces of lead, mercury and other heavy and dangerous metals for health were found in many products tested by a Congressional investigation of dietary herbal supplements, a report in the New York Times said on Wednesday. Furthermore, the report said that numerous illegal health claims were made by these supplement manufacturers.

In addition to the heavy metal contaminants found in the supplements – which did not exceed established limits – investigators discovered a troubling and possibly unacceptable levels of pesticide residue in 16 of 40 supplements, the newspaper reported.

The claims made on some supplement bottles said it could ‘treat Alzheimer’s disease’, which has no effective treatment as yet, and another said that it can prevent both diabetes and cancer when it contained ginseng.

The president of the Council for Responsible Nutrition, Steve Mister, who also represent the dietary supplement industry, said the results found in herbal supplements weren’t surprising as the heavy metal traces were usually found in soil and plants.

“I don’t think this should be of concern to consumers,” he said.

The reports discovered will be shown to the Senate on Wednesday, almost two weeks before the discussion begins on a major food safety bill that will likely place more controls on food manufacturers.

At least nine misleading health claims were noted in the report, which was prepared by the Government Accountability Office (GAO), the newspaper said. Any products that promised to treat or relieve disease must go through strict reviews because they are considered drugs by the U.S. Food and Drug Administration (FDA).

Dr. Tod Cooperman who is the president of ConsumerLab.com and will be one of the witnesses scheduled to testify for Wednesday’s hearing said that supplements with too little of the indicated ingredients and those contaminated with heavy metals were major problems. In testing more than 2,000 dietary supplements from some 300 manufacturers, his lab has found that one in four has quality problems, the Times said.

The New York Times report said that the food safety bill could require that supplement manufacturers register annually with the FDA and permit the agency to recall potentially dangerous supplements.

The Times estimated in its reports that half of adult Americans take vitamin supplements regularly, and about a quarter take herbal supplements at least occasionally, making the annual sales approximately $25 billion a year.