Study on the arsenic load of the food chain in an agricultural affected area of the Inner Mongolia, Hetao-Plain, China

Subject of this case study were the consequences of irrigation by As contaminated water
in the Hetao-Plain, part of the Inner Mongolia Autonomous Region in China. Therefore, the
arsenic (As) distribution within the water-soil-plant-system was examined in a
representative farming village in the North-West of the plain in order to assess As within
the food chain. Especially the horizontal and vertical distribution of As in field soil was a
matter of particular interest as well as the abundance of As in crops.
Two fields (a sunflower and a corn field) were sampled in July 2007, each irrigated twice
a month since three years by groundwater, which is characterized by high salinity and
alkaline pH. On both study sites, two soil pits of 1 m3 were excavated and a grid for topsoil
sampling installed. Additionally, water and plants were sampled at both fields and in the
surroundings.
Various analysis were carried out by means of ED-XRF, Micro-SyXRF, XRD, FIAS and HR-ICPMS
to determine the elemental and mineralogical compositions. Total As concentration in
the groundwater used for irrigation of the corn was about 0,15 mg/l and 0,24 mg/l. ... mehrBoth
concentrations clearly exceeded the Chinese drinking water standard of 0,01mg As/l. Vertical
distribution of As in soil indicated a slight enrichment in topsoil and a possible relation to
grain size. In contrast, the spatial distribution in topsoil (11.0 to 22.0 mg As/kg) varies
strongly and seems to be reflecting the surface micro-relieve. Although the concentration
in soil is not that serious, As could have also been detected in plant parts, ranging up to
3,21 mg/kg. The results allude to the necessity of further monitoring of the use of As
contaminated groundwater for irrigation purposes in Inner Mongolia.