Distributions and sources of heavy metals in seawater of the Northern Beibu Gulf

摘要

Seawater heavy metals' (Cr, Cu, As, Pb) distributions and sources were analyzed based on results of two voyages in April and August 2011 of the Northern Beibu Gulf. Average contents of Cr and As in spring and summer were less than the grade-one seawater quality standard of China, but over limit-ratios of Cu and Pb were 3% and 19% respectively relative to the grade-one standard. Contents of heavy metals which affected by runoff, drainage, atmospheric deposition, biological action and hydrodynamics were high in offshore while low in far-shore and high in central while low all around. The correlation analysis shows that Cu and Cr were strongly correlated in spring and summer, so as to Cu, Cr, Pb to nitrate ion in summer. Principle component and background value analysis show that As was related to rivers' input and background value of the studied area, while Cu, Pb and Cr were related to the sewage disposal of point source of industry.