A multi-metal risk assessment strategy for natural freshwater ecosystems based on the additive inhibitory free metal ion concentration index.
Scientifically sound risk assessment strategies and derivations of environmental quality standards for metals present in freshwater environments are currently hampered by insufficient chronic toxicity data collected from natural ecosystems, as well as inadequate information on metal speciation. Thus, the aim of the present study was to evaluate the impact of freshwater containing multiple metals (Cd, Cr, Cu, Ni, Pb and Zn) on the chronic toxicity (72h) to the alga Pseudokirchneriella subcapitata and compare the observed toxicity results to the total and free metal concentration of the samples. Based on the information obtained herein, an additive inhibitory free multi-metal ion concentration index, calculated as the sum of the equivalent toxicities to the free metal ion concentration of each sample, was developed. The proposed index was well correlated to the observed chronic toxicity results, indicating that the concentration addition, when expressed as the free-ion activity, can be considered a reliable indicator for the evaluation of ecological risk assessments for natural waters containing multiple metals.
REQUIMTE/LAQV, Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465, Porto, Portugal.
Cristina M
CM
Alves
REQUIMTE/LAQV, Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465, Porto, Portugal.
Carlos M H
CMH
Ferreira
Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072 Porto, Portugal; CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
Eduardo V
EV
Soares
REQUIMTE/LAQV, Chemical Engineering Department, Faculty of Engineering, University of Porto, 4200-465, Porto, Portugal. Electronic address: hsoares@fe.up.pt.
Helena M V M
HMVM
Soares
D000460:Chlorophyta / Q000187:drug effects*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water; D008670:Metals / Q000633:toxicity; D019216:Metals, Heavy / Q000032:analysis*; D018570:Risk Assessment; D014874:Water Pollutants, Chemical / Q000032:analysis*
D008670:Metals; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
Additive inhibitory metal concentration index (AIMCi); Alga; Chronic toxicity assay; Metal bioavailability; Metal speciation