4. Conclusions
This work revealed that although the concentrations of metals in
Ebro Riverwaterwere generally lowor even undetectable, in sediments
could reach values of concern, especially for Hg, As, Cr, Zn, Ni and Cu.
This proved the necessity of taking into account more seriously levels
of trace elements in sediments. The BCR method allowed studying
how metals are associated with the solid fraction of the sediment,
as well as allowed the prediction of the bioavailable fraction and the
distinction between geological and anthropic pollution. Bioaccumulation
results indicated that undetectable concentrations of metals in
water are not guarantee that these will not be accumulated in fish in
high concentrations, as it has been observed and predicted by means
of BCR for Hg, Cd and Cr. Regarding to biological indices, diatoms has
been the most sensitive community to metal pollution, followed by
macroinvertebates and macrophytes due to metal pollution. However,
as it has been stated in this work, the complexity of aquatic systems
and the high quantity of variables that could influence in the pollutants
toxicity sometimesmakes difficult to found answers for all observations
and it has been demonstrated that further research to develop biological
indiceswithmore specificity and sensitivity towardsmetal pollution are
still needed.
4. ConclusionsThis work revealed that although the concentrations of metals inEbro Riverwaterwere generally lowor even undetectable, in sedimentscould reach values of concern, especially for Hg, As, Cr, Zn, Ni and Cu.This proved the necessity of taking into account more seriously levelsof trace elements in sediments. The BCR method allowed studyinghow metals are associated with the solid fraction of the sediment,as well as allowed the prediction of the bioavailable fraction and thedistinction between geological and anthropic pollution. Bioaccumulationresults indicated that undetectable concentrations of metals inwater are not guarantee that these will not be accumulated in fish inhigh concentrations, as it has been observed and predicted by meansof BCR for Hg, Cd and Cr. Regarding to biological indices, diatoms hasbeen the most sensitive community to metal pollution, followed bymacroinvertebates and macrophytes due to metal pollution. However,as it has been stated in this work, the complexity of aquatic systemsand the high quantity of variables that could influence in the pollutantstoxicity sometimesmakes difficult to found answers for all observationsand it has been demonstrated that further research to develop biologicalindiceswithmore specificity and sensitivity towardsmetal pollution arestill needed.
การแปล กรุณารอสักครู่..
