Benthic foraminiferal assemblages and trace metals reveal the environment outside the Pearl River Estuary

We investigated the distribution patterns of the benthic foraminiferal assemblages outside the Pearl River Estuary in relation to trace metals, organic carbon and sedimentary particle fractions. The study area is unpolluted to moderately polluted by Cr, Cu, Pb and Zn and is completely polluted by Ni. The highest levels are found in the western coastal zone. Spatial distributions of the measured elements are strongly related to the behavior of the sedimentary clay fraction. The analyses of species abundance and community diversity as well as subsequent canonical correspondence analysis were used to reveal the relationship between foraminifera data and environmental parameters. Four sampling site groups established by factor analysis were distributed from the coastal area to the inner shelf. Their distribution patterns have a strong correlation with Cu, Pb and Ba. This research shows that benthic foraminifera can be used as bioindicators of trace metal pollutants outside the Pearl River Estuary.