Vol.:(0123456789) 1 3 Paddy and Water Environment https://doi.org/10.1007/s10333-020-00804-9 ARTICLE Adsorption kinetic and cadmium fractions in two calcareous soils afected by zinc and diferent moisture regimes Farzad Rassaei 1  · Mehran Hoodaji 1  · Seyed Ali Abtahi 2 Received: 16 October 2019 / Revised: 30 March 2020 / Accepted: 7 April 2020 © The International Society of Paddy and Water Environment Engineering 2020 Abstract This study has been conducted to ascertain the impact of zinc (Zn) on cadmium (Cd) fractions in two types of calcareous soils of the Fars Province in Iran at the waterlogged and feld capacity conditions; also we investigated the adsorption of Cd in soils throughout diferent shaking times. We examined the efect of Zn on Cd fractions due to their similar characteristics. Treatments were three levels of Cd (0, 30 and 60 mg kg −1 of soil as CdSO 4 ·8H 2 O), three levels of Zn (0, 5 and 10 mg kg −1 of soil as ZnSO 4 ·7 H 2 O) three-level incubation times (2, 4 and 8 weeks), two types of soils (clay and sandy clay loam) and two moisture regimes (waterlogged and feld capacity). The randomized completed block design (RCBD) was used for this experi- ment. After 2, 4 and 8 weeks of treatments, the sequential extraction technique was used to determine the Cd concentration in (WsEx), (Fe–MnOx), (Car), (OM) and (Res) fractions. In the waterlogged condition, adding Zn as zinc sulphate reduced the concentration of Cd in Fe–MnOx, Car and OM fractions but had no signifcant efect on the WsEx and Res fractions. Changes in the chemical fractions of Cd under the infuence of zinc sulphate in both soils followed a similar trend. In the feld capacity condition, adding Zn as zinc sulphate reduced the concentration of Cd in WsEx, Car and OM fractions and increased the concentration of Cd in the Fe–MnOx and Res fractions in the clay soil. In the sandy clay loam soil, adding Zn decreased the Cd concentration in Car and OM fractions and increased the Fe–MnOx fraction while has no signifcant efect on WsEx and Res fractions. It can be concluded that the changing in the Cd concentration in its chemical fractions caused by Zn addition might be from the competitive transport and adsorption interactions between these two ions. The presence of Zn reduces the concentration of Cd in those fractions that are easily released into the soil solution from where they can be absorbed by plants. The results showed that the best-ftted model which can describe the Cd adsorption was the power func- tion model. It seems that clay and organic mineral are the dominant parts which control the Cd adsorption in soils. The rate of Cd adsorption in almost all shaking times was high which shows that Cd has more ability to occupy the adsorption sites. Keywords Adsorption · Cadmium · Chemical fractions · Field capacity · Sequential technique · Waterlogged condition · Zinc Introduction Heavy metal pollution risks in soils are a wide environ- mental problem and makes us worried about the food chain safety and human health (Duan et al. 2016; Li et al. 2016; Wu and Sun 2016). Among the heavy metals, Cd is consid- ered as a more toxic element (Wu et al. 2016). Cd is a non- essential element which can take up by plants and enter our food chain (Adriano 1986). Changes in soil-moisture condition have a signifcant impact on soil-redox potential (Eh) and heavy metals solu- bility (Kashem and Singh 2001). High-reduced condition in soil reduces Cd solubility because of the development of Cd sulphide (Rassaei et al. 2019; Zheng et al. 2013; De * Farzad Rassaei Farzad.rassaei20@gmail.com Mehran Hoodaji m_hoodaji@khuisf.ac.ir Seyed Ali Abtahi seyedaliabtahi@yahoo.com 1 Department of Soil Science, Isfahan (Khorasgan) branch, Islamic Azad University, Isfahan, Iran 2 Department of Soil Science, Shiraz University, Shiraz, Iran