South Korea: Carcinogens from rice produced in China and the US: DMMTA with high toxicity
-Imported 490,000 tons last year = South Korea-
Korean imported rice:
500,000 tons of rice produced in China and the United States is imported to South Korea annually.
It was raised that the imported rice from South Korea may contain As component.
Possibility of containing As component:
Preparations for countermeasures such as inspection of harmful substances and setting of standard values are urgently needed.
Nanjing Agricultural University, China,
University of Bayreuth, Germany,
University of Queensland, Australia
The international research team made a presentation through Environmental science and technology.
Paper of presentation:
The results of analysis of the highly toxic components of DMMTA in rice in China and around the world have been released.
Produced in China and the US and Europe:
Rice produced in some parts of China and in the United States, Europe, etc.
Dimethylated monothioarsenate (DMMTA) is said to have been measured high.
DMMTA contamination:
This is the first extensive investigation into DMMTA contamination.
DMMTA is a type of organic arsenic.
DMMTA of organic arsenic:
Unlike the organic arsenic DMA (dimethylated Arsenate), it is extremely toxic.
It is 3-10 times more toxic than inorganic arsenic.
Highest from the US:
Made in the United States, DMMTA concentration is the highest
Research team analysis:
103 rice samples collected in China by the enzyme extraction method,
Collected from markets in 16 countries on 6 continents around the world,
130 rice samples were analyzed.
Analysis in China:
Of the 103 samples in China, 14 samples (13%) exceeded the standard value of 200 ppb for inorganic arsenic.
Analysis in North America:
The average DMMTA concentration from the United States was 29.3 ppb, and the average from China was 12.1 ppb.
It was not uncommon for the maximum value of DMMTA to exceed 20 ppb among Chinese products.
DMMTA concentration ranking:
The average DMMTA concentration of rice produced in North America is the highest with an average of 25.7 ppb.
Europe averages 18.9ppb,
Asia averages 5.01 ppb,
It was explained that the African average was 3.11 ppb.
Joongang Ilbo
https://s.japanese.joins.com/JArticle/288047?sectcode=400&servcode=400
Dynamics of Dimethylated Monothioarsenate (DMMTA) in Paddy Soils and Its Accumulation in Rice Grains
Environmental Science & Technology
Abstract
Arsenic species transformation in paddy soils has important implications for arsenic accumulation in rice grains and its safety to the consumers.
Methylated thioarsenates including highly toxic dimethylated monothioarsenate (DMMTA)
have been detected in paddy soils, but their production and dynamics remain poorly understood.
In the present study,
we first optimized a HPLC-ICP-MS method to quantify methylated thioarsenate species.Using this method together with 10 mM diethylenetriamine pentaacetate (DTPA) to preserve As speciation,
we investigated methylated thioarsenate species in porewaters of seven As-contaminated soils incubated under flooded conditions and of two paddy fields.
DMMTA was the main methylated thioarsenate species in the porewaters in both incubated soils and paddy fields,
with concentrations ranging from 0.2 to 36.2 μg/L and representing ca.
58% of its precursor dimethylarsenate (DMA).
The temporal production and dynamics of DMMTA were linked with the DMA concentrations.
When soils were drained, DMMTA was converted to DMA.
In the two paddy fields,
DMMTA concentrations in rice grains were 0.4–10.1 μg/kg.Addition of sulfur fertilizer and rice straw incorporation increased grain DMMTA by 9–28%.
These results suggest that DMMTA is an important As species in paddy soils and can accumulate in rice grains,
presenting a risk to food safety and human health.