A treatment method for farmland polluted by heavy metals

Abstract

A treatment method for a heavy metal contaminated farmland comprises the steps that the types and contents of heavy metals in soil are detected; a DTPA extraction method is adopted to determine the contents of heavy metals, capable of being absorbed by plants, in the soil are determined; the contents of nutrient substances in the soil are detected, wherein the contents of the nutrient substances comprise the content of soil organic matter, the content of total nitrogen, the content of available phosphorus, the content of quickly acting potassium, the cation exchange capacity, the unit weight and the like; chemical leaching is conducted; the contents of the heavy metals, capable of being absorbed by plants, in the soil are determined; the contents of the nutrient substances in the soil are detected, if the contents of the nutrient substances in the soil are low, corresponding nutrient substances are supplemented into the soil, so that the contents of the nutrient substances in the soil reach the third soil fertility grade or above; crops are planted in the leached soil, after the crops are harvested, the contents of the heavy metals in edible portions of the crops are detected, and when the contents of the heavy metals in the edible portions of the crops meet the national food safety standard in the Maximum levels of Contaminants in Foods, it is judged that soil treatment is completed. According to the treatment method for the heavy metal contaminated farmland, bio-available components, harmful to the crops, of the heavy metals in the farmland can be effectively removed through chemical leaching, and crop plantation can meet the requirement for safety production.

Description

technical field [0001] The invention relates to a treatment method for farmland polluted by heavy metals, and belongs to the technical field of treatment methods for polluted farmland. Background technique [0002] The treatment of heavy metal pollution in farmland is currently researched on the following types: electrodynamic restoration technology, heat treatment restoration technology, passivation technology, plant extraction restoration technology, engineering measures, chemical leaching restoration technology, etc. [0003] (1) Electric restoration technology has high restoration efficiency and convenient post-treatment, and does not need to add substances harmful to the environment into the soil, and will not cause secondary pollution. However, there are still some problems that need to be improved: for example, the voltage causes the soil to heat up, which leads to changes in efficiency, the selectivity of this technology for pollutants is not high, the change of soil...

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Problems solved by technology

The passivation agents widely used in engineering are generally industrial by-products, so the cost of passivation technology is low, but the passivation technology does not completely remove heavy metals from the soil, so long-term monitoring is required to prevent reactivation of heavy metals

[0006] (4) Phytoextraction remediation technology has little secondary pollution to farmland soil, but the restoration period is long, and large-scale planting will seriously affect the economic benefits of local farmers, which restricts the extensive application of phytoextraction remediation technology in heavy metal-contaminated farmland

However, this method consumes a lot of manpower, financial resources and material resources, the cost is high, and the heavy metals cannot be removed fundamentally, and there are problems such as land occupation, leakage and secondary pollution, so it is not an ideal method for controlling soil heavy metal pollution. method

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