Bioaccumulation, biochemical responses and health risk assessment of heavy metals in seaweeds from Alexandria Coast: pollution case

The present study discussed the escalating, threatening pollution issue at two spots along Alexandria Coast, Egypt. It mainly aimed to compare the biological responses of some seaweeds in relatively clean and heavily polluted areas. Atomic inductively coupled plasma atomic emission spectrometry was utilized to quantify heavy metals in seaweeds subsequent to acid digestion. Antioxidant capacity, phenol, pigments and biochemical contents were evaluated calorimetrically by spectrophotometer. Physicochemical data showed deteriorating conditions at El-Mex due to heavy metals contamination, compared to Abu Talaat. In response, seaweeds, especially green algae, showed an efficient capacity to bioaccumulate heavy metals at higher magnitudes. Metals bioaccumulation decreased as follows: Ni > Zn > Fe > Co > Mn > Pb > Cu > Cd, at Abu Talaat, and Fe > Co > Pb > Mn > Zn > Ni > Cu > Cd at El-Mex. Biochemical contents and antioxidant activity of six different species collected from study areas were determined to evaluate the impact of the different habitats. At El-Mex, pigments (chlorophyll contents and carotenoids), proteins and carbohydrates exhibited a responsive increase related to the huge loads of nutrients in this area. Antioxidants as phenols, as well as total antioxidant capacity and DPPH scavenging activity, were highly associated with seaweeds subjected to pollution stress at El-Mex as a self-defense mechanism. Assessing the potential risk of seaweeds consumption proved hazardous non-carcinogenic and carcinogenic potentials on human health, owing to heavy metals pollution, especially with Cd, Ni and Pb. To follow-up significant differences among tested parameters in seaweed classes, species and the two research regions, one-way and two-way ANOVA tests were applied.