I have calculated MPI and BAF for the same fish for Cu, Ni, Fe, Co, Mn and Zn. The result obtained by MPI follows the trend liver>kidney>gills>integument>muscle. While from the BAF was liver>gills>kidney>muscle>integument. According to me, both give metal load. MPI gives total metal concentrations and BAF gives them with respect to water. How can I justify this?
I can refer you to the following critical review in Reviews in Environmental Science and Bio/Technology
May 2013
"From geochemical background determination to pollution assessment of heavy metals in sediments and soils"
Written by
* Tran Thi Thu Dung,
* Valérie Cappuyns,
* Rudy Swennen,
* Nguyen Ky Phung
Please contact me for a copy
I've always been told that the BAF for certain metals is not really a good measurement because there they are regulated (Cu, Zn, Fe, Mn,...). Is the BAF not more for PAH's?
I´m not exactly sure if that would be a correct way to analyse your data, unless you do the MPI for one metal at a time. Could you let me know how you calculated each one (equation)?
Usually when any pollutant is taken in to the body, it gets absorbed in the gut and comes ultimately to liver where detoxification takes place and therefore when you calculate MPI, you get liver>kidney>gills>integument>muscle whereas bioaccumulation gets a pattern as liver>gills>kidney>muscle>integument on the basis of their accumulation pattern.
I think BAF is useless to determine metal contamination in fish, except for Hg.
Please find the article below for reference, you will understand the reasons.
McGeer et al, 2003. Inverse relationship between bioconcentration factor and exposure concentration for metals: implications for hazard assessment of metals in the aquatic environment. Environ Toxicol Chem. 22(5):1017-37. Good luck
Hi, following the storyline of our colleagues, I think it would be important to determine (and to decide) whether you are studying metals are mainly found in the water or could be incorporated with diet or sediment inhabited these vertebrates. This would help to select the most appropriate index for their tests. In addition, a principal component analysis (incorporating all variables) in your ecological system would be useful.
I'm agree with my colleague and I think it’s better to choose one index and it's better to addition a PCA for your analysis data. Fish have different physiologic comportment in each month, so many factors influenced bioaccumulation.
Dear Valerie please provide me the copies. I have calculated MPI for each organ that is MPI=(concentration of Metal1xMetal2x................Metal n) to the whole power 1/n. I just calculated to know the metal load in each organ in order to conclude which organ is highly influenced. Is my approach correct. What is PRINCIPAL COMPONENT ANALYSIS (PCA) and how is it determined.
n is the number of metals. yes all these metals are present in water. I am not at all concerned with food and sediments.
BCF is concerned only accumulation from water and is valid under laboratory conditions and BAF from both water and dietary sources and is valid under natural conditions. In field study that is in natural environment which is better to use when i am concerned only accumulation from water.
HelloI Mehjabeen, the multivariate statistics is used to describe and analyze observations multidimensional obtained to collect information on several variables for ach of units or cases under study. The PCA is one of these possible statistical analysis. For example, in this example the varibales are the metal concentrations and the tissues and organs are classification criterium.
As already suggested a multivariate statistic like PCA or discriminant analysis can help sort out the differential preference for each organ to each metal.
Second, understanding from theory the propensity of each organ towards each metal will aid in explaining your observed trends.
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