Coloured plastic plates and cups for children may look like a practical and safe choice, thanks to their resistance to drops, knocks and breakage. But the health risks linked to their components have revived concern about their use, after reports suggested that a chemical used in their manufacture could cause cancer and problems with the kidneys and reproductive system.
اضافة اعلان
According to the American newspaper New York Post, the substance is called melamine, an industrial chemical rich in nitrogen. It is used to make some types of hard plastic when combined with formaldehyde under high temperature and pressure, producing a lightweight, durable plastic that is hard to scratch, crack or break.
Melamine is widely used in making children's tableware, because it can be easily moulded into a range of colours, designs and shapes, and because it is more durable than many other materials. It is also used in making cups, plates, bowls and eating utensils, food packaging and industrial coatings.
Health concerns have grown over the possibility that melamine could migrate from plastic tableware into food and drink, prompting a number of countries, including Canada and the member states of the European Union, to reassess its use in tableware.
The link between the substance and cancer
The International Agency for Research on Cancer classifies melamine as "possibly carcinogenic to humans", based partly on animal studies. These found tumours in the urinary bladder of male rats exposed to high doses of the substance over long periods.
However, the agency has stressed that the available research has not established a direct link between exposure to melamine and cancer in humans. The US Environmental Protection Agency has also said that current scientific evidence is not sufficient to determine whether the substance causes cancer in people.
Other risks
The potential risks are not limited to cancer. Consumption of melamine at high levels has been linked to serious kidney problems, including kidney failure.
Some studies also suggest that chronic exposure to low doses may increase the likelihood of kidney stones in children and adults.
One of the most notable incidents that revealed the danger of this substance was the 2008 contamination of infant formula in China, when melamine was deliberately added to it. The incident affected more than 294,000 children, many of whom developed kidney stones, and six children died as a result of the crisis.
Some studies have also raised questions about melamine's ability to affect the body's hormonal system, and the possible consequences for brain function and reproductive health. However, these effects still need further research to determine their nature and how serious they are.
The permitted limit
Despite these concerns, the US Food and Drug Administration still allows melamine to be used in some food-contact products. It notes that tests on tableware made from the substance showed small amounts migrating into food and drink, but well below the levels the agency considers toxic.
The agency has set the acceptable daily intake of melamine at around 0.063 milligrams per kilogram of body weight per day.
The FDA has warned against putting plastic plates and dishes in microwave ovens unless they are explicitly labelled as microwave-safe, because high temperatures can increase the migration of melamine into food.
Tests have also shown that acidic foods and drinks, such as orange juice and foods containing tomatoes, can cause larger amounts of the substance to migrate than less acidic foods.
Alternative materials and warning signs
In light of these concerns, families who want to avoid exposure to melamine can choose tableware made from alternative materials, such as ceramic, glass and stainless steel.
Signs that may indicate melamine poisoning include irritation, blood in the urine, reduced or absent urine output, symptoms of kidney infection, and high blood pressure.
The FDA recommends seeking medical care if these symptoms appear after suspected exposure to the substance, particularly as some of its complications relate to kidney function and need medical treatment.
