T/CSPSTC 34-2019 in English

Scope

This standard mainly stipulates the main types of conditioning agents, technical parameters of soil conditioning agents, application standards, application methods, and field water management requirements for the immobilization technology of heavy metal cadmium in farmland. The immobilization technology of heavy metal cadmium in farmland refers to using physical or chemical methods to fix toxic heavy metals such as cadmium in farmland, or converting them into chemically inert forms to prevent their migration and diffusion in the environment, thereby reducing the toxicity of heavy metal cadmium. The purpose of establishing this standard is to address issues existing in the comprehensive prevention and control of heavy metal pollution in farmland, particularly those caused by a lack of scientific operational norms for technical measures leading to unstable regulation effects of soil conditioning agents, as well as increased costs for human and material resources. This standard can effectively reduce the adverse effects of poor repair results due to environmental and human factors on soil conditioning agents, providing theoretical support for comprehensive prevention and control of heavy metal cadmium pollution in farmland.

The complexity, uncertainty, and information acquisition limitations inherent in measures and operational norms for the immobilization technology of heavy metal cadmium in farmland make establishing operating standards for different types of soil conditioning agents a significant bottleneck in researching and applying implementation standards for this technology. To address these issues, this standard's framework mainly considers the following aspects:

(1) Dividing the main types of soil conditioning agents and determining their technical parameters is the foundation for establishing implementation standards for the immobilization technology of heavy metal cadmium in farmland: By dividing the main conditioning agents used in the immobilization technology of heavy metal cadmium in farmland and determining their technical parameters, we can reflect the current main types of soil conditioning agents used to address heavy metal cadmium pollution, understand their primary physical properties, mechanisms of fixation, and similar technical parameters. This also helps identify differences among different types of soil conditioning agents regarding their primary physical characteristics, mechanisms of fixation, and technical parameters, laying a foundation for formulating application standards and defining the application methods of soil conditioning agents.

(2) Formulating application standards for soil conditioning agents and clearly defining their application methods can play a significant role in addressing issues related to implementation standards for the immobilization technology of heavy metal cadmium in farmland: Application standards for soil conditioning agents are determined based on comprehensive considerations such as the pH level of rice field soils, their regulation range, cadmium content in soil and rice, types and characteristics of soil conditioning agents. The application methods of these agents are summarized from large-scale field trials after considering effects and ease of use, providing scientific basis for operating different soil conditioning agents on farmlands with heavy metal cadmium pollution, reducing the likelihood of unstable repair results.

(3) Limiting requirements for field water management can provide effective assurance in establishing implementation standards for the immobilization technology of heavy metal cadmium in farmland: Water is a key factor influencing the repair effect of soil conditioning agents on heavy metal cadmium pollution in farmlands. Therefore, following the GB5084-2005 standard requirements, selecting irrigation water sources with cadmium content ≤0.01mg/L for polluted rice fields to ensure safe irrigation water quality and strictly controlling field water during different stages of rice growth is crucial.

Therefore, this group standard, from data collection before formulation, experimental design, tracking, data processing to establishing related standards, has regulated the implementation standards for the immobilization technology of heavy metal cadmium in farmland (including main types of soil conditioning agents, technical parameters, application standards, usage methods, and field water management requirements), providing significant scientific support for the immobilization of heavy metal cadmium in farmland.