An Investigation into the Biochemical Effects of Heavy Metal Exposure on Seaweeds

Abstract Optimised methods, developed in this novel study, were utilised throughout the research. In environmental studies of Newfoundland and Ireland, interspecies and spatial variations in the total protein content and polyphenol levels of seaweeds were demonstrated. A positive correlation between total protein and temperature was established. A downstream increase in polyphenol levels of seaweeds was observed and correlated with a downstream increase in seawater salinity. P. lanosa contained the highest levels of all metals. Levels of Pb2+, Cr3+ and Cu2+ in seaweed were highest for sites in Waterford City. The highest proportions of Pb2+, As3+, Cr3+, Cu2+, Ni2+ and Al3+ were intracellular. Baseline levels of total protein, extracted protein and polyphenols of four different seaweed species varied significantly. P. lanosa contained the highest total protein. F. vesiculosus and A. nodosum yielded the highest levels of polyphenols. Significant interspecies variations in total and intracellular metals were observed. Zn2+, As3+ and Mn2+ were dominant for all species. P. lanosa demonstrated the best overall metal bioaccumulation potential. Regression analysis demonstrated correlations between total protein and Pb2+, Ni2+, Cu2+ and Cd2+. Seasonal variations in levels of Cd2+, total protein, extracted protein and polyphenols of P. lanosa were observed. The highest levels of total protein were yielded in May. February demonstrated the highest extracted protein and November the lowest polyphenols. Increases in protein concentration following Cd2+ exposure were observed for P. lanosa sampled in February. Increases in polyphenol levels following Cd2+ exposure were observed in the November samples. Potentiometric titrations and FTIR analysis demonstrated seasonal variations in the binding potential of P. lanosa. Gel filtration chromatography, HPLC analysis and SDS PAGE demonstrated changes to the molecular weights of protein derived from P. lanosa following heavy metal exposure