EFFECTS OF HEAVY METALS ON SPECIES OF COPEPODA IN HAN AND VU GIA - THU BON DOWNRIVER

Abstract

Currently, heavy metal pollution has become a serious issue in aquatic environments, directly affecting human health and ecosystems. This study was conducted to provide information on the composition of Copepod species; assess the current levels of heavy metal in water and sediment samples; and analyze the impact of heavy metal concentrations on the occurrence and density of Copepod species living in the estuarine areas of Vu Gia - Thu Bon and Han rivers. The research involved field sampling and analysis of heavy metal concentrations (Pb, Cr, Cd, Cu) in surface water and sediment samples collected from 16 locations in the Han river estuary (Da Nang City) and the Vu Gia - Thu Bon river (Quang Nam Province). Zooplankton samples were also collected, classified, and counted to determine species density. The correlation between the density and occurrence of Copepod species was established using a multivariate correlation analysis model (CCA). The results indicated that common Copepod species recorded in both estuaries include Acartia clausi, Mongolodiaptomus mekongensis, Halicyclops lanceolatus, Oithona nana, Paracyclopina nana, and Mesochra bodini. Through multivariate correlation analysis (CCA) of the density and occurrence of Copepod species with heavy metal concentrations in the study area, it is evident that heavy metal significantly influences some Copepod species in the study area. Specifically, species such as S. bulbosa, O. talipes, L. enchinatus, and H. lanceolatus showed a positive correlation with increasing concentrations of Cu, Pb, and Cr in water, as well as Pb and Cu in sediment. Conversely, species such as A. tsuensis, O. nana, T. triangularis, P. trihamatus, and L. sibirica exhibited a negative correlation with rising heavy metal concentrations in the environment.