The health reference value of rare earth elements has no trace in the world. However, Chinese scholars have studied the allowable daily intake (adi) of rare earth elements and proposed the strictest adi value of 0.07 mg/kg (the three reported values ​​are 0.24, 0.102, and 0.07, respectively). Taking the average per capita weight of about 63kg in the health department, the adi was 4.41mg/d.
Chen Zongxi, an academician of the Chinese Academy of Engineering, believes that the amount of rare earths ingested into the human body through drinking tea is safe to the human body based on the safety risk assessment results. He gave such a set of data: According to the world's largest tea consumption 13g per day, the amount of rare earth in tea is calculated according to the highest value of 13.95mg/kg, the leaching rate of tea in tea is calculated as the highest value of the experiment 62%. Then, the amount of rare earth (ie, exposure) consumed by the human body through tea consumption is calculated as 2.55% of the adi value. If the rare earth intake is calculated as the average value of 3.57 mg/kg, then the average amount of rare earth ingested by each person is only 0.65% of the adi value.
According to the rules of the United Nations Food and Agriculture Commission Codex Alimentarius Commission (cac) Procedural Manual on Contaminant Limitation, if the contribution rate of any pollutant is less than 5% of adi, it is not necessary to establish limit standards. Chen Zongxi pointed out that the rare earth safety assessment results show that the maximum does not exceed 2.55%, so it can be set indefinite scope, "the (rare earth element limit) standard withdrawal will not affect the health of consumers."
Yang Xiufang also believes that the current limit value of rare earth tea is too strict and lacks scientificity and operability. This limit standard does not play a fundamental role in accurately guiding the market and guiding consumption.
However, Yang Xiufang believes that considering the differences in rare-earth content in tea garden soils and the differences in the rare-earth content of tea, it is still advisable to formulate limit requirements for rare earths in tea, “so that measures can be taken from the source for the actual situation of different regions and teas. Controlling the high levels of rare earths in individual teas will not only promote the healthy development of the tea industry but also ensure the health and safety of consumers."
"I propose to reassess the rare earth elements in tea. According to the new method of measurement, based on the perspective of consumer health, we must consider the daily intake of tea, the solubility of rare earth in tea and the proportion of tea in people's diet. It is necessary to appropriately relax the current limited standards based on the risk exposure of dietary rare earths in China and the risk assessment of tea rare earth, said Yang Xiufang.
She said: "At present, China's residents in the diet of rare earth risk exposure assessment work has been started in May this year, our team has also joined the tea rare earth risk assessment work, and the National Food Safety Risk Assessment Center and other units of experts actively promote tea rare earth risk The assessment work provides a fuller basis for the scientific and rational formulation of tea rare earth limit standards."
Zhai Jianyun also believes that the current standard limits for the allowable content of rare earths in tea still use the past data. At that time, there was no comprehensive study, and there was no sufficient scientific basis to urgently require a thorough reevaluation. In addition to considering the form of rare earth in tea, the solubility in tea, the daily allowance (adi value) of rare earth in tea (soup), and the background value of rare earth elements in the natural environment during the formulation of standards. And distribution.
Chen Zongxi, an academician of the Chinese Academy of Engineering, believes that the amount of rare earths ingested into the human body through drinking tea is safe to the human body based on the safety risk assessment results. He gave such a set of data: According to the world's largest tea consumption 13g per day, the amount of rare earth in tea is calculated according to the highest value of 13.95mg/kg, the leaching rate of tea in tea is calculated as the highest value of the experiment 62%. Then, the amount of rare earth (ie, exposure) consumed by the human body through tea consumption is calculated as 2.55% of the adi value. If the rare earth intake is calculated as the average value of 3.57 mg/kg, then the average amount of rare earth ingested by each person is only 0.65% of the adi value.
According to the rules of the United Nations Food and Agriculture Commission Codex Alimentarius Commission (cac) Procedural Manual on Contaminant Limitation, if the contribution rate of any pollutant is less than 5% of adi, it is not necessary to establish limit standards. Chen Zongxi pointed out that the rare earth safety assessment results show that the maximum does not exceed 2.55%, so it can be set indefinite scope, "the (rare earth element limit) standard withdrawal will not affect the health of consumers."
Yang Xiufang also believes that the current limit value of rare earth tea is too strict and lacks scientificity and operability. This limit standard does not play a fundamental role in accurately guiding the market and guiding consumption.
However, Yang Xiufang believes that considering the differences in rare-earth content in tea garden soils and the differences in the rare-earth content of tea, it is still advisable to formulate limit requirements for rare earths in tea, “so that measures can be taken from the source for the actual situation of different regions and teas. Controlling the high levels of rare earths in individual teas will not only promote the healthy development of the tea industry but also ensure the health and safety of consumers."
"I propose to reassess the rare earth elements in tea. According to the new method of measurement, based on the perspective of consumer health, we must consider the daily intake of tea, the solubility of rare earth in tea and the proportion of tea in people's diet. It is necessary to appropriately relax the current limited standards based on the risk exposure of dietary rare earths in China and the risk assessment of tea rare earth, said Yang Xiufang.
She said: "At present, China's residents in the diet of rare earth risk exposure assessment work has been started in May this year, our team has also joined the tea rare earth risk assessment work, and the National Food Safety Risk Assessment Center and other units of experts actively promote tea rare earth risk The assessment work provides a fuller basis for the scientific and rational formulation of tea rare earth limit standards."
Zhai Jianyun also believes that the current standard limits for the allowable content of rare earths in tea still use the past data. At that time, there was no comprehensive study, and there was no sufficient scientific basis to urgently require a thorough reevaluation. In addition to considering the form of rare earth in tea, the solubility in tea, the daily allowance (adi value) of rare earth in tea (soup), and the background value of rare earth elements in the natural environment during the formulation of standards. And distribution.
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