Adsorption and pH Values Determine the Distribution of Cadmium in Terrestrial and Marine Soils in the Nansha Area, Pearl River Delta

Abstract

Cadmium is a toxic element with a half-life of several decades, which can accumulate in the human body by entering the food chain and seriously harm health. The cadmium adsorption and desorption processes in the soil directly affect the migration, transformation, bioavailability, and ecotoxicity of this element in soil-plant systems. Coastal zones are located in the transitional zone between land and sea, and large amounts of terrigenous material input have important environmental effects on this ecosystem. The pH, hydrodynamic conditions, soil organic matter (SOM), and other factors defining the sea-land interaction within the sedimentary environment are significantly different from those defining land facies. In order to study the key factors affecting cadmium adsorption in soils at the sea-land interface in the Nansha area of the Pearl River Delta, a test was conducted on a column of undisturbed soil. The results showed that the adsorption constant KF and the Cd2+ adsorption capacity of marine soils were higher than those of terrestrial soils. However, the saturation adsorption of cadmium in terrestrial sediments was higher than in marine sediments. Soil pH was an important factor affecting cadmium adsorption capacity in both terrestrial and ma-rine sediments. Neutral and alkaline topsoil conditions inhibited the vertical migration of cadmium, while the acidic environment favored it. The higher the clay and SOM were, the stronger the Cd2+ adsorption capacity of the soil was. These findings suggest that the distribution of cadmium in marine and continental sedimentary soils is not only related to adsorption, but also to the physical and chemical processes occurring in different sedimentary environments.

Determining indicator plant species of Pinus brutia Ten. Site index classes using interspecific correlation analysis in Antalya (Turkey)

“…Aspect was divided into 4 groups as north (0°-45° and 315°-360°), west (45°-135°), south (135°-225°) and east (225°-325°). Finally, the soil depth variable was represented by 4 classes as 0-20cm, 20-50cm, 50-90cm, and 90cm above (Wang et al, 2022;Wu et al, 2022). One Way Anova method was performed to determine whether there is a difference between the site index values corresponding to the variable classes prepared in the stated order (Table 3).…”

Adsorption Characteristics of Modified Bamboo Charcoal on Cu(II) and Cd(II) in Water

“…Prolonged exposure to heavy metal ions can cause serious harm to the human body, such as affecting the activity of enzymes, the nervous system, and some organs with detoxification functions. For example, in the 1950s and 1960s, when Japanese production mines exceeded the Cd(II) standard in nearby waters, some residents reported suffering from "bone pain", a painful dent in the body caused by osteochondrosis [8]. The problem of how to treat heavy metals in river sediments and water bodies has become a pressing one [9].…”

A Review of the Distribution Coefficient (<i>K<sub>d</sub></i>) of Some Selected Heavy Metals over the Last Decade (2012-2021)

“…Studies have implemented several laboratory approaches to determining K d values of heavy metals. The factors influencing K d values include sorption systems (either mono-metal system-MS or competitive system-CS), element properties (e.g., element type and characteristics), physical and chemical properties of soil (e.g., soil texture, mineralogical composition, and cation exchange capacity, and soil pH), and experimental conditions (e.g., reaction time and temperature) (Braz et al, 2013;Gu et al, 2014;Guo et al, 2013;Kumar et al, 2019;Loganathan et al, 2012;Wang et al, 2022;Zheng et al, 2016). The diversity of influencing factors eventually results in a wide range of K d values for heavy metals in soils, which can make it difficult to deduce some standard K d values or magnitudes to be used as reliable indicators for assessing the remediation process of toxic metals in soils.…”