Build a database of tea risk substances to address green trade barriers

China is the world's largest tea growing country and the second largest exporter, in 2021, China's tea exports and exports have reached a record high
.

The EU and some tea importing countries have continuously set limit standards for new risk substances in tea based on green trade barriers, which has hindered the development of
China's tea industry.

Sources and control measures for heavy metals

At present, the heavy metals in tea include manganese, lead, arsenic, chromium, cadmium, nickel, mercury, antimony, thallium, etc.

Heavy metal pollution in tea may come from tea garden soil, water bodies, atmosphere, fertilizers, etc.

The current effective heavy metal control measures for tea gardens mainly include: scientific site selection and construction of gardens, testing the air, irrigation water and soil of the base before the establishment of the park, and selecting a base with low heavy metal content to build a tea garden; Standardize agronomic measures, ensure the quality and safety of fertilizers, pesticides and other agricultural inputs, rationally apply fertilizers, pesticides, etc.

Choose clean energy to control anthraquinones

9,10-Anthraquinone (abbreviated anthraquinone (AQ), is an oxygenated derivative of polycyclic aromatic hydrocarbons used in natural dyes, papermaking, DNA probe markers and other fields, with potential carcinogenic risks
.

From 2016 to 2020, the European Commission notified a total of 17 cases of tea exports in China due to the problem of AQ exceeding the standard, which caused concern
about the problem of AQ pollution in China's tea.

Although the residual level of AQ in the field environment and processing process will be significantly reduced, the low residual amount of AQ in fresh leaves can still cause the AQ content in dry tea to exceed the standard
.

Since AQ is used as an additive in the papermaking process to increase yield, tea leaves are often in contact with paper, coated paper and other papers, which may lead to an increase
in its AQ content.

Environmental remediation controls perchlorate

Perchlorate is an inorganic salt and a thyroid toxin
.

China's tea production areas are widely distributed, the environment is different, and the regional differences in the perchlorate content in tea need to be paid attention to
.

Given the high detection rate of perchlorate in tea, similar to heavy metals, it is speculated that it is more likely to be introduced in the cultivation of tea plants, such as fertilizer, water and soil
.

Perchlorate is recognized as a widespread environmental pollutant in the global water and soil, more than 90% of the perchlorate in the soil exists in the form of water soluble, and its anion exchange capacity is only 1%-2% of other ions, which is difficult to adsorb on soil particles; It is preserved
mainly by dissolving in soil pore water or deposits in the soil.

At present, the control measures of perchlorate pollution mainly focus on environmental remediation, and the use of chemical remediation, bioremediation and other means to reduce perchlorate pollution in water and soil, the remediation means are similar
to heavy metals.

(Sun Hezhi, Zhou Li, Yu Jiawei, Chen Zongmao)

China Food News (2022/09/22/07)

(Editor-in-charge: Yuan Guofeng)