Immobilization of cadmium and lead in contaminated paddy field using inorganic and organic additives

by:Y&M Crafts     2019-08-19
Heavy metal pollution in agricultural soil has posed a threat to the environment and human health.
The purpose of this study was to evaluate the effectiveness of soil supplements in reducing cadmium (Cd)and lead (Pb)
Absorption of rice (Oryza sativa L)
In the contaminated fields
The soil improvements used include lime and Dashan yuan (DASY), DiKang No. 1 (DEK1), biochar, Fe-
Biological charcoal, Yirang, phosphorus application ,(
Green stabilizer)GSA-1, GSA-2, GSA-3, and GSA-
4, applied at a speed of 1% in field experiments.
The results exposed GSA-
4 treatment has the best effect on reducing plant effectiveness and early rice absorption of Cd and Pb in soil.
Linear increase in PH (i. e. 5. 69 to 6. 75)
Recorded in GSA-
4 fix the soil from 3rd months of sowing to growing season. GSA-
4 decrease in the content of soluble cadmium (Cd)from 0. 324 to 0.
Soil and lead of 136 mg kgkg-1 (Pb)from 53. 21 to 24.
The soil of 68 mg kgkg-1 was corrected for 90 days.
Treatment with GSA
4 improvement of rice growth (56%)
Grain production (42%).
The enhanced effect on grain production may be due to GSA-
4 Application of improving photosynthesis (116%)
Rate of evaporation (152%)
Compared to the control.
Cd and Pb absorption in stems decreased significantly (42% and 44%)and in grains (77 and 88%)
Observed in GSA respectively
4 treatment compared to control.
In addition, directly dependent on the applied revision, there is a negative correlation between the Cd/Pb that can be extracted by gd and the pH value of the soil.
In summary, the use of the consolidated Amendment (GSA-4)
Compared to other tested corrected products, it more effectively fixes heavy metals in contaminated rice fields and ensures safe production of rice. Heavy metals (HMs)
Enter the soil environment through different human activitiesg.
Smelting, mining, disposal of harmful substances and fertilization.
Metal contamination of the soil is related to industrial emissions and waste disposal of agricultural land.
The accumulation of heavy metals in the food chain has adverse effects on human health.
Among trace metals, Cd and Pb are the most phytotoxic metals that inhibit plant growth and enter the food chain by absorbing plants from contaminated soil.
S. Environmental Protection Agency lists cadmium and lead as the most dangerous metals (US-EPA).
In most cases, metals are
Biodegradable, seriously affecting plant growth, soil quality and human health.
In order to reduce the metal accumulation in the food chain, cost-effective and environment-friendly technologies are urgently needed.
Reducing metal utilization is the key to repairing HMs contaminated soil.
Different Practicesg.
Physical, biological, chemical and plant remediation techniques have been used to repair metal contaminated sites, but most of them are inefficient in terms of time and cost.
Repair HMs with different kinds of soil (
Organic, inorganic and clay minerals)
There has been a lot of attention in the past decade.
The amendment reduces the metal risk and absorption in the plant and reduces off-site contamination through leaching.
However, organic fertilizers, especially fertilizers and biological charcoal, enhance the fixation of heavy metals by increasing soil pH, CEC and providing adsorption sites to bind metals.
Organic materials form soluble or insoluble complexes with heavy metals, reducing the absorption of metals by plants and ultimately reducing the risk of food chains.
Organic materials such as organic fertilizer, animal waste, and compost can effectively repair contaminated sites by converting exchangeable/soluble parts into organic binding or residual parts that are not very usable for plants.
Organic materials are also a good source of essential nutrients;
Increase soil fertility and the interaction of microorganisms in the soil.
It is reported that the availability of heavy metals has been reduced by the fixation of clay minerals such as seaweed and zeolite.
Clay minerals are rich in nature and have high negative charge layer for adsorption of cation.
Due to the presence of oh-based, the mineral acts as an adsorption agent and effectively reduces the availability of heavy metals by adsorption or complex.
This adsorption process helps to reduce the loss of metal in the soil profile.
The biological effectiveness of heavy metals depends largely on the pH value, which is higher than alkaline conditions under acidic conditions, so the application of lime materials can neutralize acidic soil and enhance the stability of metals in soil.
The alkaline material acts as a pH-regulated medium and increases metal precipitation with the help of oh and carboxyl bases, or provides more adsorption sites by causing deporization on the soil surface.
Different lime-based materialsg.
Calcium carbonate (CaCO), burnt lime (CaO)and dolomite (CaMg(CO))
It has been widely used to stabilize HMs in soil.
Some studies have been reported on individual results of organic, inorganic and clay minerals for the adsorption of heavy metals in soil, but their combined effects on heavy metal fixation in field conditions have not been well recognized.
Therefore, the design goal of this experiment is :(1)
Comparing the effects of different commercial soil fixing products on reducing Cd and Pb absorption in early rice(2)
Understand the response of metals to pH changes at different time intervals; (3)
Determine the best effective amendments for early rice growth and safe production. ion.
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