To study the heavy metal presents of a sediment in the water body. is it necessary to determine the OC% and CaCo3% in the particular sediment sample. How can we relate both.
It would be interesting to know the relation between OC % and available heavy metal concentration because OC locks in many heavy metals. Relevance of CaCO3 ( in terms of pH ) may also be interesting to the solubility of heavy metal compounds.
Thank you Dilip kumar Pal sir for your kind reply.
Sir, can you clarify that ,suppose i am reporting the level of heavy metal results in sediments(analyzed using AAS) without studying about CO and Co3 details is justifiable or not.
I agree with Dr. Dilip. The measurement of heavy metals in soil as environmental cursor is OK, but the reason behind reporting variables such as OC, carbonates, Clay minerals type and percentages, heavy minerals contents in soil and their varieties is to know the source, behavior and fate of heavy metals in this soil and also the proper way of remediation.
Best regards
It kind of depends on what you are doing with the data. If you are interested in screening sediments for potential contamination that may be of biological significance, you may not need OC and CaCO3 data (ie if concentrations don't exceed recognised guideline values, the additional data may not be that useful). However, if you find elevated concentrations of metals, then it is useful to have this data for interpretation about potential bioavailability and risk. OC is very important for modifying the potential toxicity of Cu and Hg for example and pH (modified by CaCO3 content) important for modifying the toxicity of most metals/metalloids). Care needed though as not all metals behave the same way. Some metals/metalloids may be more available at high pH (eg arsenic) although most become less so. You might also want to know in which particle size fraction the metals occur. If concentrated in the fine sediment
OC and CaCO3 are very important in the study of heavy metal because the more OC in in soil, the more the presence of HM. it is important to know the available OC in soil in heavy metal study and the possible source as it will help in interpreting the data generated in cause of the study. on the other hand, CaCO3 could be used as buffer in soil deficient in Ca and Mg in the process, some metals might also leached into the soil consequently increasing the heavy metal content.
Thank you Mr.yehia H dawood, Mr.keneeth M towe,Mr.Andrew Butler and Mr.Osakpolor Marvellous Omorogieve for your valuable answers.
Can anyone clarify that , if we found an elevated level of Heavy metal in a particular sediment, how can we say it is from the external source or due to the speciality of the particular soil( or available in the minerals of the soil). In this direction finding the OC% and Caco3% have any advantage.
Muhammed, you may need to collect background data from a similar river/stream nearby that is not affected by (or is upstream of) the polluting activities . The difference in concentrations between the two areas can therefore be linked to polluting activities. Some people prefer to use changes in the concentrations of the
Muhammed. To answer your question, you have to know first if this soil is
residual or transported by studying the soil profile reaching to the bed rock and also you need to know the source of this elevated heavy metal inside the sediments. To do that you can either separate each component in the sediments like sand, clay, carbonates, heavy minerals, organic matters and analyze them separately to know the source of abnormalities and relate individual heavy metal to one or more component of the sediments, OR simply what i do, is to perform a correlation matrix for all variables (percentages of sand, clay, carbonates, heavy minerals, organic matters, and the concentration of each heavy metal) to know the significant correlations and then source of metal.
best regards
1) If you want to compare two different areas for metal accumulation, the carbonate content should be nearly similar. In the context of knowing mas accumulation rates of metals, one has to consider the carbonate content.
2) Measuring OC will be important in areas with high organic matter (black shales, kerogens....). Also metals bind well with OC. If you want to understand the pathways of metal incorporation, it will be necessary to measure OC.
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