[Regulation Effects of Humus Active Components on Soil Cadmium Availability and Critical Threshold for Rice Safety].

Organic materials containing humic acids (HAs) play important roles in regulating the bioavailability of cadmium (Cd) in soils and thus its accumulation in crops. The effects of the two active components of HAs, humic acid (HA) and fulvic acid (FA), in organic materials and their different ratios (HA/FA) on Cd uptake and accumulation in rice were investigated using a field plot experiment, and their relationships with the Cd fractions and availability in paddy soil as influenced by the use of these organic materials were analyzed in combination with the fractionation method of chemical continuous extraction. The results showed that the effects of HAs on Cd availability in soil and Cd accumulation in rice grains were controlled by the ratios of the active components in the organic materials.

[Screening and Evaluation of Methods for Determining Available Lead (Pb) and Cadmium (Cd) in Farmland Soil].

The accumulation of heavy metals in crops is largely dependent on the availability of heavy metals in soils. Due to the differences of soil types and pollution characteristics, there is no widely recognized method for the determination of the bio-available heavy metals in soils such as Pb and Cd. In order to screen and establish suitable methods, the extractable abilities of five extractants (CaCl, NHOAc, HCl, EDTA, and DTPA) and Gradient Diffusion Film Technology (DGT) on four typical farmland soils with very different properties in Chongqing (acid purple soil, neutral purple soil, calcareous yellow soil and calcareous purple soil) were systematically compared.

[Adsorption Effect and Mechanism of Aqueous Arsenic on FeMnNi-LDHs].

Removing As(Ⅲ)from water steadily and efficiently is still a challenging global issue. In this study, novel FeMnNi-LDHs were prepared by a co-precipitation method using Fe, Mn, and Ni as lamellar cations, and the structure were characterized by XRD, TEM, FT-IR, and XPS techniques, and the adsorption performance and mechanism of As(Ⅲ)was explored. The results showed that FeMnNi-LDHs have typical characteristic peaks of layered double hydroxides, with sharp peaks and high crystallinity.

[Safe Utilization of Paddy Soils Lightly Polluted with Cadmium in Western Chongqing].

The western Chongqing region is the main grain-producing area in Chongqing. This region's soils are characterized by light-to-moderate cadmium (Cd) pollution. Two types of typical paddy soils in this area (acidic and calcareous purple soils) were selected for the development of safe rice production techniques using in situ field remediation experiments.

[Effects of the Active Components of Humic Acids and Their Proportions on the Dynamics of Lead Transformation and Availability in Purple Alluvial Soil].

Humic acids (HAs) play important roles in mediating the occurring forms and activity of Lead (Pb) in soils. Simulating experiments together with chemical sequential extraction were carried out to understand the dynamics of lead transformation and availability in purple alluvial soil as influenced by humic acid (HA) and fulvic acid (FA) and their ratios (HA/FA). The main results obtained are as following:1 The distributions of Pb forms bound by Fe-Mn oxides and organic matter increased, while the proportions of exchangeable Pb and residual Pb fraction decreased after the establishment of transformation equilibrium in 60 d.

Adsorption of phenolic compounds from aqueous solutions by aminated hypercrosslinked polymers.

Two novel polymers (NJ-1 and NJ-2) were synthesized by chemically modified a hypercrosslinked polymer NJ-0 with dimethylamine and trimethylamine, respectively. The comparison of the adsorption properties of the three polymers toward phenol, resorcin and phloroglucin was made. The study focused on the static equilibrium adsorption behaviors and the adsorption thermodynamics.