Metals in soil are partitioned between the solid and solution phases of soils. In which of these forms are earthworms exposed to the metal concentrations in soil??
earthworms exposed to heavy metals(Cu,Ni,Pb,V,Zn) via the solid phase of soil and via the soil solution both, but in soluble form much higher
I think its in solution form, this is because metals in solution. Metals are more mobile in solution form e.g. the transportation of metals from soils into the freshwater ecosystem, is also dependent on their presence in the solution phase. Complexed metals are less toxic to micro-organisms than free ions
Since earthworms injest the soil and the pore water, exposure should be to both
I think earthworm would be exposed to heavymetals in soil than solution.as heavymetal need not to be completely soluble in solution
Yes!! heavy metals can affect soil organisms when they area above the threshold!! An increasing body of evidence suggests that microorganisms are far more sensitive to heavy metal stress than soil animals or plants growing on the same soils. and also Extreme metal contamination in the vicinity of smelters caused clearly visible effects such as accumulation of deep layers of organic matter on the soil surface through inhibition of the activity of soil microorganisms and soil fauna. There is now a considerable amount of evidence documenting a decrease in the soil microbial biomass as a result of long-term exposure to heavy metal contamination from past applications of sewage sludge as reviewed by
earthworms exposed to heavy metals(Cu,Ni,Pb,V,Zn) are via the solid phase of soil
thank you all for your answers,... I am most grateful for your knwledge and for papers shared.
After we had isolated Tubifex and limnodrilus sp. from sediments of the River Danube, some elements gave better correlations with the concentrations in the pore water, and others with weak-acid mobile fractions. Therefore I think, this depends on the element in question, and there is no general answer. Exposition is both via the surface and ingested material. Digestion inside Worms is not done with acids, but with enzymes only. Elements almost insoluble in the water (Pb, Cr) tend to depend from the solid rather, easily soluble (Zn) rather from the liquid. When organic Detritus is digested, metal Ions bound here, are liberated.
When you analyze the worms, please consider the purpose: there is much more mass in the gut than in the animal itself. For consideration as a link in the food chain, you might analyze the animal as it is. To investigate the transfer to the tissue of the animals, you have to empty the gut (with aeration and without starvation!), which takes 2-3 days.
earthworms exposed to heavy metals(Cu,Ni,Pb,V,Zn) via the solid phase of soil and via the soil solution both, but in soluble form much higher
Please, look the links
http://www.tandfonline.com/doi/pdf/10.3184/095422998782775835
http://www.scielo.br/pdf/sa/v60n4/a29v60n4.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592491/
http://www.scielo.org.mx/pdf/rica/v30n1/v30n1a4.pdf
thank you all for your answers. found a very interesting answer in the handbook of ecotoxicology (P. Calow, 1995:257). "for soft bodied organisms living in close contact with the soil, e.g earthworms and enchytraeids, van Gestel and Mai (1988, 1990) demonstrated that exposure via pore water would be more important. i.e. they uptake soil pollutants from the soil solution.
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