Water Quality Evaluation of the Intertidal Zone of Pars Special Economic Energy Zone in Differ-ent Seasons by Measuring the Concentration of Heavy Metals and Using WQI and TRIX

Pars Special Economic Energy Zone (PSEEZ) in Bushehr province, Iran is a coastal ecosystem that is severely influenced by industrial and municipal activities. The present study was therefore conducted to monitor the health status of the intertidal zone of this ecosystem in different seasons using the Water Quality Index (WQI), Trophic Index (TRIX) and the concentration of heavy metals, including lead, copper, zinc and iron. To assess the desired indicators, 16 stations were selected along the region’s coast, and three samples were taken from each station. The required parameters of each index were then measured using standard methods. Investigating the variations in WQI in different seasons found WQI to be the lowest (WQI=27.89) in winter, suggesting a bad status, followed respectively by summer (WQI=30.63), autumn (WQI=31.42) and spring (WQI=31.77), suggesting a relatively bad situation. The values of TRIX showed that the overall water quality of the intertidal zone is classified as oligotrophic. Moreover, the highest TRIX was associated with winter (TRIX=3.53) and the lowest with autumn (TRIX=1.93). The sequence of the overall mean concentrations of heavy metals in the water samples was also measured as Zn> Fe> Cu> Pb. The obtained findings attribute the high concentration of heavy metals and the low water quality of the coasts in winter to leaching contaminants from industrial, municipal and agricultural activities and the transmission of pollutants by surface currents to the coast of the region.