The Role of Marine Algae as a Bioindicator in Assessing Environmental Pollution

Abstract

The potential ecological effects of rising levels of heavy metal concentrations in the aquatic environment are of great concern caused by their highly bio-accumulative nature and higher toxicity, which leads to the destroy of several habitats for marine organisms. The purpose of this research are presented analyses, for both the concentration of heavy metals in marine water and algae tissue, in an effort to gain some insight into the level of metal contamination which might exist in the coastal marine environment along the Libya beaches. Assessed by measuring pollution indicating parameters of marine water (TC^O, S ‰, pH, Do), and concentration of heavy metals. This study also determined indices of pollution as a bioaccumulation factor (BAF) and metal pollution index (MPI), from six different sites in two seasons (Spring and summer), 2016. The results indicate the slightly higher level of temperature and pH on the summer season, while salinity and dissolved oxygen were slightly higher level in spring. A Positive correlation was found between dissolved oxygen and salinity (r²= 0.897*) and, a negative correlation was found between other parameters. The results show that there is a statistically significant difference in averages of concentration of (Pb), (Mn) and (Zn) between algae species and stations overall.  The highest concentration of (Pb) was recorded in the Enteromorpha sp., 1.228 μg g^-1. The highest concentration of (Mn) was recorded in the U. lactuca, Corallina sp., and Chaetomorpha sp. The present study recorded higher concentrations of Zinc (Zn) 0.867 μg g^-1, in the Enteromorpha sp., and Laurencia sp. 0.861 μg g^-1. In general, Cadmium recorded low values irrespective of sites and algal species. The region of S6(Libya station) can be identified as a place with higher Pb and Zn contents while the region of S1(Libya harbor), shows higher contents of Mn. As well the region of S2(Libya company), shows higher contents of Cd. The metals concentrations recorded for the different tissues and sites of the present study confirm the occurrence of significant seasonal variability, with maximum concentrations usually observed in summer. The data  demonstrate a positive correlation between all the metals, except the negative correlation between Zn and Mn. The concentration of the metals in seawater in the six sampling sites followed the order of Mn>Zn>Pb>Cd. A somewhat, BAF of the different heavy metals showed a common pattern of peaking at S2(Libya company), with moderate reduction at S6 (Libya station), S3(Libya station), S4(Libya station) and S1(Libya harbor), and a relatively greater reduction at S5(Libya station). The ability to accumulate heavy metals MPI was highest in Laurencia sp., which was substantially higher than those of the accompanying species at all species at all stations. The present study emphasizes of control of pollutants such as sewage and industrial effluent discharges into the marine environment without treatment.