|BIO.REM - Integrating multiple toxicological BIOmarkers in a phytoREMemediation assay of Pb and Cd contaminated sites|
Programme - PTDC/AAC-AMB/112804/2009
Execution dates - 2011-03-01 - 2014-02-28 (36 Months)
Funding Entity - FCT
Funding for CESAM - 140000 €
Total Funding - 172000 €
Proponent Institution - Universidade de Aveiro
EU included Cd and Pb in the 33 priority substances (2455/2001/EC,2001). Some Estarreja regions showed 30% and 76% of the soils analysed with, respectively, Cd and Pb levels above Maximum Admissible Levels (http://www.ccdrc.pt/regiao/bac.....uga/).Also children from this region were diagnosed with high blood-Pb levels (http://repositorio.up.pt/abert.....216/9696). Risk assessment and remediation strategies of these sites claim adequate biomarkers. Most recommended tests are focused on non-specific responses of seedling emergence or plant growth (eg.ISO17126:2005; ISO11269-2:2005). In particular Cd and Pb specifically affect physiological aspects as plant nutrition and oxidative stress leading to senescence. Understanding the overall processes of Cd or Pb induced senescence, describing the cascade enzymatic protection strategies against the metals, is crucial to develop relevant plant biomarkers for environmental risk assessment (ERA). The first aim of BIO.REM is to test a large battery of parameters and select the most sensitive as biomarkers for: A) Cd/Pb entrance/accumulation; B) cytotoxicity (oxidative stress and viability) and C) genotoxicity and gene expression. For this we’ll use sensitive vs. accumulator genotypes (Lactuca sativa and Thlaspi sp.). The second aim is to evaluate these plants in phytorremediation of contaminated soils and its impact in soil/rizhosphere, and assess the proposed biomarkers efficacy in situ. BIOMARKERS FOR CD/PB ACCUMULATION AND INTERFENCE WITH NUTRIENTS: Cd and Pb differ in the profiles of accumulation and interference with nutrients (eg. Zn, Ca or Fe) (Deckert 2008; Sengar et al 2008), being Pb more complex to phytoextract (Chaney et al 2007). Lettuce and Thlaspi sp. individuals are exposed to Cd or Pb and analysed for classical parameters (eg. growth). Metal allocations are assessed by cell fractionation and XRay-TEM/SEM microanalyses. Nutrient, Cd and Pb zonal partitioning are quantified by ICP-AES. Membrane H+ATPase activity, phytochelatine (PCs) accumulation and PCS activity are characterized for all conditions. BIOMARKERS FOR CD/PB EFFECTS ON CYTOTOXICITY: Phytochelatins (PCs) are synthesised from GSH, associated to the Ascorbate-GSH cycle. This cycle, as well as the SOD family, peroxidases (APX) and catalases (CAT) control excess of ROS (Herbette et al 2006). ...