The aim of this study is to elucidate the characteristics of marine environmental geochemistry from Ha Tinh - Quang Nam (60-100m water depth) based on analysis of geochemical parameters of seawater and surface sediments. Surface sediments that are high in absorbed capacity of toxic substances mainly accumulated in northern study area. | Vietnam Journal of Earth Sciences, 38(2), 217-230, DOI: Vietnam Academy of Science and Technology (VAST) Vietnam Journal of Earth Sciences Characteristics of marine environmental geochemistry from Ha Tinh to Quang Nam (60-100 m water depth) Luong Le Huy*¹, Mai Trong Nhuan², Tran Dang Quy², Hoang Van Tuan¹, Quach Manh Dat3, Nguyen Duc Hoai4, Nguyen Tai Tue² ¹Sea and Island Research Center - VNU University of Science ²Faculty of Geology - VNU University of Science 3 Vietnam National University Hanoi 4 VNU University of Science Received 8 May 2016. Accepted 28 June 2016 ABSTRACT The aim of this study is to elucidate the characteristics of marine environmental geochemistry from Ha Tinh Quang Nam (60-100m water depth) based on analysis of geochemical parameters of seawater and surface sediments. Surface sediments that are high in absorbed capacity of toxic substances mainly accumulated in northern study area. Seawater dominantly characterized by weak alkaline-weak oxidation and contained biodegradable organic materials. Almost anion and chemical element concentrations in seawater tended to decrease with depth, with an exception for SO42-, Br-, I- concentrations that had an opposite trend, increasing with depth and B, Hg concentrations displayed a complex variation. Sedimentary environments were highly predominant by weak alkaline-strong oxidizing features and carbonate-rich materials. Concentrations of anions and chemical elements tended to be higher in central area in comparison to northern and southern regions, and positively correlated with fine sediment compositions. Organochlorine pesticides (OCPs) concentration decreased with sediment depth, whilst polychlorinated biphenyls (PCBs) concentration had no clear trend. The organic material, heavy metal, OCPs and PCBs concentrations in seawater and sediments were all lower than environmental standards. The present results have provided important baseline
