As our esteemed colleagues have already put some useful remarks about the effect of heavy metals on different soil properties. I feel , yes , both physical , chemical , and even the biological properties of soil will be adversely affected. The heavy metals like Pb, Cd, Cr etc., they by the virtue of their variable valencies exhibit multifarious impact on soil properties , depending upon the period for which soil I is exposed to such contaminants in form of heavy metals. These heavy metals depending upon the concentration in the soil gradually deplete the productivity potential of the soil , unless some phyto-remediation is implemented to clean up the contaminants. Even , some of the accumulator microbes also act as scavenger of heavy metals. Of all , soil microbial load ( Biological properties) will be reduced to minimum. Having said all , Dr Hamaaad, if this site is a chronic source of contaminant , you may get some microbes which are capable of surviving under such high osmotic stress . And , if you undertake some screening , you may get some resistant microbes capable of accumulating some preferential heavy metals. Studies on these lines are still very scanty.
Perhaps, no effect on physical properties can be expected but chemical properties will definitely be affected. Some of the heavy metals may form complex compounds of phosphorus, Zinc and Cu etc making them unavailable for plant uptake.
Nice to see u Sir, how are you Thank you for your answer. Sir, I think organic matter and heavy metal interaction may effect physical properties of soils,
Thank you Hamad, actually all reactions are relative and depend upon quantities, I will say rather on ion concentration. The role of organic matter is very complex, it can release ions, it can bind ions, it can be helpful and it can be harmful in certain cases. Under normal conditions, a balance of ions does exist. When Na ions dominate the clay complex, soil physical conditions are disturbed while Ca, Mg, Al are useful in this regard. Lead can be retained by organic matter as chloropyromorphite and Sb as Sb2O3. The metals may be converted into metalloids by organic matter. Any how, no major role of heavy metals and organic matter complexes in improving or degrading physical properties of normal soils has been reported, as far as I know. May be I am mistaken and some researcher may bring some data to this effect.
Yes. . Some metals as copper change the physical parameters. Others are inhibitors of normal soil flora. In much cases they contaminate ground water by infiltration. It depends on the cationic interchange capacity of the soil,.
As our esteemed colleagues have already put some useful remarks about the effect of heavy metals on different soil properties. I feel , yes , both physical , chemical , and even the biological properties of soil will be adversely affected. The heavy metals like Pb, Cd, Cr etc., they by the virtue of their variable valencies exhibit multifarious impact on soil properties , depending upon the period for which soil I is exposed to such contaminants in form of heavy metals. These heavy metals depending upon the concentration in the soil gradually deplete the productivity potential of the soil , unless some phyto-remediation is implemented to clean up the contaminants. Even , some of the accumulator microbes also act as scavenger of heavy metals. Of all , soil microbial load ( Biological properties) will be reduced to minimum. Having said all , Dr Hamaaad, if this site is a chronic source of contaminant , you may get some microbes which are capable of surviving under such high osmotic stress . And , if you undertake some screening , you may get some resistant microbes capable of accumulating some preferential heavy metals. Studies on these lines are still very scanty.
some metals like Pb ,Cd, etc effects the physical properties of soil,, because the metals have ability to move in different direction, specially by wind , please read the attached file
Article Copper accumulation and changes in soil physical–chemical pr...
Dr. Anoop Kumar has given some good suggestions, especially phytoremediation. Hussain has refereed a paper. I think these all will help Dr. Hamad.
The concern of Dr. Hamad Raza is fairly discussed in above answers of scientists. The heavy metals induce multiple effect of soil properties and soil health. Heavy metal impact on microbial activity and population due to toxic effect which will also be impacting upon the physical properties of soil. Interaction with nutrients in soil will induce negative effect on nutrient avaiability and efficiency , ultimatly on growth and productivity. Growth reduction as a result of changes in physiological and biochemical processes in plants growing on heavy metal polluted soils has been recorded as expressed in various studies. Secondly bioremediation of heavy metal polluted soil is also possible by some strains of micro-organism..
Yes, heavy metal concentraion in soil affected directly chemical and indirectly physical properties of soil or affected more chemical properties than physical.
plz. read review paper " Heavy metals in soils and their environmental significance by KG Tiller published in Advance in Soil Science, Vol 9 (1989)
Why dont we consider the effect of heavy metals on changes in physical properties via changes in organic carbon content , thereby, affecting the aggregate stability cascading its effect further on water transmission properties as a function of hydraulic conductivity , and then microbial diversity , finally affecting the transformation and availability of nutrients. Hence , heavy metals affect the soil both quantitatively as well as qualitatively.
I agree with the scientists who previously answered especially with the answer “changes in physical properties via changes in organic carbon content", because heavy metals affect the entire process of decomposition of soil organic matter, they will eventually cause initially a chemical change and subsequently a physical change.
Yes, organic matter just like blood and changes in its status open a door for series of subsequent changes, may be direct or indirect.
Of course, heavy metal concentrations affect soil physical and chemical properties but geochemical phase of metal is important.
While doing so , let us also keep a watch , can we get some hyper heavy metal accumulating microbes from such sites, so that such microbes can be isolated and characterized , and later used in those contaminated areas where heavy metal accumulation is real problem as a part of phyto-remediation strategy.
Depends on level of HM concentration. In high concentration the chemical properties are mainly affected such primarily pH, CEC, buffer capacity, organic matter quantity and quality, nutrients cicle but also physical properties could be affected by HM (colloidal distruction, lost of structural stability, porosity) and air-water regime.
HM contamination increase the EC as will pH (Above 8) according to our research work, secondly i am agree with Anoop Kumar Srivastava that microbes isolated from the contaminated areas have the natural ability to tolerates the HM, and will be able to use for remediation of HM contaminated soil.
Article Biosorption of heavy metals by Pseudomonas species isolated ...
Congratularions to the answer of Paulette. Also mechanical properties are affectd if the concentration is high. Reconversion is not easy. In some cases ( as with Cu) you may use the capacity of cation interchange with cations of the same Ox. number.
DR. Hamaad actually the toxicity of metals appears on biology through specific ion effects much much before these HM could affect physical, chemical and mechanical properties of soils. Secondly geological sources of these metals mainly control their labile conc in soils. As well as there are very rapid transformation of metals into different fractions with minor changes in redox potential of soils. Further I understand that there is remote possibility of presence of metals in soluble fraction too high which could effect the physical and chemical soil properties significantly. As such biological toxicity of HM remains point of concern.
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