Sediment accumulation and mercury (Hg) flux in Avicennia marina forest of Deep Bay, China

To investigate the rate of sediment accumulation and mercury (Hg) flux in Avicennia marina forest of Deep Bay, China, sediment cores were analyzed. The results showed that Hg concentrations were much higher at all depths compared to the background level. A high correlation between Hg and total organic carbon (TOC) indicated their similar anthropogenic origin. Sedimentation rate was estimated to be 1.38 cm a−1 by 210Pb geochronology. The increase in the mass sediment accumulation rates was rapid (range: 0.5–0.94 g cm−2 a−1), and the Hg fluxes ranged between 76 and 116 ng cm−2 a−1 during the last three decades. The reduction in both Hg concentrations and flux during the last decade may be due to the adoption of contamination control policies. Our results support the notion that the Hg fluxes determined from the sediment cores reveal the effects of anthropogenic influences from the areas around Deep Bay.