Why basic slag is not used in Indian acidic soil? Is it due to heavy metal content ? We have analyzed the basic slag and contain the following as, Chromium=600 ppm, lead= 90 ppm, nickel=40 ppm, cadmium = 8 ppm, arsenic = 0.4 ppm. Is it safe to apply in acidic soil for cultivation rice and other pulses ??
Application of basic slag for steel industry slag have potential and has acid neutralizing capacity, so it can be utilized for reduction of soil acidity and is cost effective also.
The material is alkaline and an effective liming material, but with the high levels of contaminants you listed it is unsuitable for use in cropping soils
As mentioned by Dr Paul, the slag is alkaline. It is full of silica and alumina which can be dissolved in high pH conditions producing a good binder in the places we have soft soil improvement. So, it remove the acidity of the soil (effecting the organic matter content percentage of the soil) and that might be the reason makes it unsuitable for cropping soil usage.
http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290899-1561%282006%2918%3A2%28229%29
Dear Dr Hossein Moayedi, Please send me the pdf of the article listed by describing the unsuitability of basic slag in soil. Further I request Dr. Paul Milham to provide me the permissible limit of heavy metal in basic slag, that can be applied to acidic soils.
Dr. Paul Milham, You have rightly pointed out the contaminants in basic slag as per my analysis report and unsuitable for use in soil. please provide me the permissible limit of heavy metal if any in basic slag, that can be applied to acidic soils.
In my opinion, first you should look your local legistation about soil amendments application for decontamination purposes, and also, the legislation or normatives about the use of a industrial waste. Furthermore, the aplication od this slag and its efficiency depends on the type of soil (physical and chemical parameters); pollutants (concentration, ageing, etc); site characterization (contamiantion in surface? in depth?; contaminated area? land uses?....). Also, for an industrial slag application you need tha further lan use of the osin (industrial / recreative areas / agriculture, farming / urban area....) that it is limitant for this remedial actions. Finally, an industrial slag needs to be well characterized in order to know all potential contaminants it has and the contaminants concentration range (max.; min.; average; it the composition constant or depend of the industrial propuction?). In some cases, it is necessary to know their speciation (to evaluate the toxicity), availabity (if crooping or farming could be affected), and other related data before application.
The steel factory waste (basic slag) is plentily available in our locality. The major concern is the heavy metal content in it. Long run application of this slag may pose problem on soil health due to build up of heavy metal. Should we promote it?
Then, among the other factors I mentioned above, the dosage (amount / ha / year) has to be calculated in order to avoid an accumulative effect of contaminants in soils and an implementation of monitoring actions is strictly necesary (contaminant variation and accumulation; changes in soil quality and parameters). Or, it is importan to mix this slag with other potential soil amendments.
I request to expert working on heavy metal, please clarify the questions asked on LD SLAG and should give their views. Thanks to all for their comments till date.The slag is being dumped by steel industry. The question is how to nullify the heavy metal content in it. In long run, it may pose threat to soil - plant -human system.
Dear Dr. Naik,
Heavy metal limits in basic slag for good soil quality have been fixed by the Netherlands and Denmark. I present those values here for your information:
Netherlands: Mercury 0.3 ppm, Lead 85 ppm, Cadmium 0.8 ppm, and Chromium 100 ppm. Denmark: Mercury 0.5 ppm, Lead 40 ppm, Cadmium 0.5 ppm, and Chromium 30 ppm.
I hope you find this information useful for your research.
For more details you may go through: European Commission DG ENV.E3 (2002) Heavy Metals in Waste: Final Report. Web link: ec.europa.eu/environment/waste/studies/ pdf/heavy_metals
Thanks Dr. Kundu Sir for sharing important information on basic slag. Whether any standard of heavy metal content in basic slag under indian condition.
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