Trace Metals Trajectory of Wastewater and Their Toxicity to Marine Fish Using Numerical Simulation Model

The adverse ecological conditions caused to the commercial sea breams: Diplodus sargus sargus L., Rhabdosargus sarba F., and Crenidens crenidens F., were observed due to increased wastewater pollution. Using the DESCAR-3.2 software program, trace metals trajectories from drain outfalls were modeled alongside the assessment of static toxicity and bioaccumulation tests in the laboratory. The wastewater discharged from seven drain outfalls (SI-SVII) showed a high trace metals sequence (Zn>Fe>Cu>Pb>Cr>As>Hg) during winter compared to the summer seasons. Toxicity tests revealed high trace metals sensitivity in the sequence of C. crenidens > D. sargus > R. sarba. A bioaccumulation factor (BAF) >1 in these fish exposed for 30 days indicated significant trace metals accumulation from wastewater. Fish indicating BAF <1 suggested that the trace metals in their body parts were due to adsorption processes or through victuals. This novel multidimensional study not only labeled the sampled fish species as bio-indicators and bio-accumulators of wastewater pollution but also validated the specific seasonal orientation and dispersion of wastewater into the marine environment unlike earlier findings in the region.