More than 20 percent of the whitening and freckle-reducing cosmetic products consumers can easily find on the market contain excessive heavy metals, a survey by 11 non-governmental organizations showed on Tuesday.

The national standard for mercury content in cosmetics is below 1 part per million. But mercury content found in 23 percent of the sample products exceeded standards by 18 to 44,000 times.

Volunteers from the 11 NGOs randomly chose 477 whitening and freckle-reducing products in 10 cities across China and tested the heavy metal in them, using X-ray fluorescence.

Selected samples varied in price and sales channels, from stores online and offline. But many of the problematic products were bought in wholesale markets.

"I was surprised by the results," said Joseph DiGangi, senior scientific adviser from International POPs Elimination Network, one of the major organizers.

"And we found that whether the cosmetic products have excessive heavy metal is not relevant to prices."

Many of the samples with excessive heavy metal found in the survey use words like herbal medicine and Chinese drugs on the package, yet about 20 of the 112 problematic products contain at least three types of heavy metal - mercury, lead and arsenic.

"None of the problematic products have cited the content of heavy metal in their trade description, which is also against the law," said Wang Qiuxia, a researcher from Beijing-based Daerwen Environmental Institute, another major player in the survey.

The cosmetics market has been one of the industries witnessing rapid development in recent years, and the whitening products have been key to winning Chinese consumers, who consider a lighter and paler complexion most beautiful.

Wang Yue, 23, a senior student from Beijing Foreign Studies University, said she was shocked that the overuse of heavy metal in whitening cosmetics might cause damage to skin and even kidneys.

"I have never thought of the damage that might come with the whitening effect," she said. "It's irresponsible of the companies not to label the heavy metal ingredients on the package."

Wang said she was considering reducing the frequency of applying the whitening cosmetics and purchasing some expensive products for better quality.

"Mega brands might be safer than the cheap ones, at least," she said.

According to the World Health Organization, the mercury in cosmetics might lead to kidney damage, depression, anxiety, mental disorders, a deteriorating immune system and other disorders.

Hao Fengtong, director of the department of vocational illness and toxicology at Beijing Chaoyang Hospital, said mercury poisoning does not always take months or years.

"I've received several patients with mercury poisoning who had only used whitening and freckle-reducing cosmetic products for about a month," he said.

"One reason is the high level of mercury in the products. Another is that many customers today are using whitening products one after another, from day cream to night cream and essence."

However, according to experts, the cosmetics can only achieve a lighter skin temporarily. The condition of skin is also related to the living environment and metabolism. It's important that the public doesn't go crazy over cosmetics.

Hao recommended that customers accept their natural skin color and not use whitening and freckle-reducing cosmetics.

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