Imagine turning a barren, toxic wasteland into a thriving green space. It might sound like the plot of a science fiction movie, but in the real world of polluted soils, this transformation is not just possible but essential. Shockingly, over 20% of the world’s arable lands are now diminished due to pollution. Yet, hope lies in the science of management and remediation of polluted soils.

From innovative techniques like ‘phytoremediation’ using plants as pollution sponges, to earthworms detoxifying soil patches, the fight to reclaim our planet’s health is both fascinating and urgent. So, in this chapter, we will dive into the intriguing world of soil remediation and discover how we’re fixing the ground beneath our feet, one plot at a time.

What is Soil Pollution Risk Assessment?

Soil pollution risk assessment is a cumbersome process. It requires frequent monitoring of various soil parameters at designated sample locations while constructing a sampling net for a particular region of interest.

Following that, the findings of the chemical analysis are compared to the threshold values established as permissible levels by national or international regulations. So, when it comes to solving a specific problem involving the remediation of polluted soils or making decisions in that regard, decisions that are based solely on single sets of results rather than classification and modeling of the monitoring output for the region of interest are frequently based on comparison to single sets of results.

Risk Assessment Approaches 

It is feasible to uncover hidden links within monitoring data sets, both between sampling locations and between characteristics defining the sample sites, by using multivariate statistical techniques to address the issues of soil quality.

Some methods of Risk assessment approaches:

• Sampling and chemical analysis
• Intelligent data analysis method
• Cluster analysis
• Principal component analysis

Read More: Details about Assessment Techniques

Main Techniques for Remediation of Polluted Soils

Research on remediation of polluted soils is becoming increasingly popular in a variety of fields, including ecology, agriculture, biogeochemistry, soil science, and environmental science. Many risk assessment techniques have been used, namely total concentration-based and bioavailability-based techniques. The preliminary evaluation results have applied physical, chemical, and biological approaches for soil remediation.

Soil can be remedied using procedures for site decontamination following testing to identify the kind and quantity of pollutants present. This can be done in situ or by excavating the soil (ex-situ) and transporting it somewhere for treatment.

Techniques for remediating polluted soils are:

• Bioremediation: In biological treatment or bioremediation, pollutants in the soil are broken down by microorganisms.
• Chemical Oxidation: Contaminated soils are changed into safe soils by chemical oxidation.
• Soil Stabilization: Immobilizing agents are added to the soil during soil stabilization to lessen the leachability of pollutants.
• Soil Washing: Water is used physically to separate or eliminate pollutants, such as when washing dirt.

Changes In Agronomic Practices to Minimise Food-Chain Contamination and Impacts on Ecosystem Services 

The “cheaper food” ideology has molded our food system over the past few decades. The goal of economic and political systems has been to produce more food for less money. Increased food production is required to meet demand since increased agricultural output destroys soils and ecosystems, reducing the land’s productivity. These challenges are made worse by the rising worldwide consumption of foods with high resource demands and inexpensive calories.

The usage of inputs like fertilizer, pesticides, energy, land, and water, as well as non-sustainable methods like monocropping and intensive tilling, are key components of today’s food production. As a result, there are fewer different types of landscapes and ecosystems, which threatens or eliminates the opportunities for birds, animals, insects, and microbiological creatures to reproduce, feed, and/or nest, as well as driving out many native plant species.

Fertilizers 

Consider perennial pasture and crops, cover crops in rotation with annual crops, and excellent grazing management for animal producers as three fundamental methods to limit the usage of synthetic fertilizer. These methods increase soil carbon, which is essential for promoting soil fertility and health.

The biological activity of the soil can then be improved by lowering fertilizers high in nitrogen and phosphorus, which obstruct the transfer of carbon from microorganisms to plants. A decrease of 20% for the first year, followed by reductions of 30% for the second and third years, and then tiny additions of nitrogen, probably between 5 and 10 pounds per acre each year, to jump-start soil life in the spring.

Pesticides 

Pesticide usage can be decreased by using agricultural methods like crop rotation and resistant crop cultivars. It’s also suggested to monitor fields for levels of activity that can be controlled rather than spraying on a regular timetable. These are some of the fundamental methods of integrated pest management (IPM), a way of thinking that aims to use fewer pesticides. In addition to using insecticides, IPM also uses biological and cultural methods to manage agricultural pests. The goal is to lessen agricultural damage while still preserving the ecosystem, including bees and other helpful insects. There are IPM standards for every agronomic and horticultural crop. The most recent suggestions for your specific crop should be known to you.

Metals 

It is important to lower the dangers involved with metals in soil. To make the land resource available for agricultural production, improve food security, and lessen land tenure issues brought on by changes in land use patterns, heavy metal-contaminated soils must be remedied. The best demonstrated available technologies (BDATs) for cleaning up locations with heavy metal contamination are typically mentioned. Field implementations of these technologies have only been documented in industrialized nations, despite their affordability and environmental friendliness.

Metalloids 

As we know, for Plant development and agricultural yield, metalloid elements like silicon and boron are essential. Toxic metalloids, like arsenic, are, nevertheless, becoming more prevalent in the environment as a result of inputs from both natural and human sources. If these dangerous metalloids get into the food chain, they can pose major health concerns to both people and animals. Low concentrations are crucial for their toxicity. The environmental issue is mostly brought on by human activities that raise the concentrations of heavy metals and metalloids, particularly in the refinement and mining of ores, the use of pesticides, the fertilizer industry, and solid wastes.

Radionuclides

Radioactive substances that are emitted during nuclear crises and accidents may contaminate food. The effect on food will depend on the radionuclide kinds that are emitted and the quantity of radioactivity that is deposited on or in the food. The two radionuclides that provide the greatest health risks out of all those that were emitted are radioiodine and radiocaesium. Foods like rice and corn that have edible portions covered in husks or leaves are currently considered to be generally safe. But over the course of a few weeks, the radioactive particles are consumed by animals or land in the ground where plants’ roots can absorb them.

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