The importance of mangrove was widely reported. However, the potential risks of pollutants (e.g., Hg) accumulated in the mangroves are often ignored. Thus, the present study aimed to explore the distribution and risk of mercury (Hg) in the sediments of mangroves along South China Coast. Results showed that concentrations of total Hg ranged from 0.0815 to 0.6377 mg/kg, with an arithmetic mean value of 0.2503 mg/kg. The contamination index (P_i) showed mild pollution toxicity risks in NS, slight toxicity risks in DZG, QZ, SY, ND, GQ, TLG, and free pollutions in BMW, SJ, ZJK and BLHK. NS, DZG and SY scored the highest values of I_geo among the eleven mangrove regions studied, indicating moderate to heavy pollution inputs in these regions. As for the distribution of Hg in the sediments along tidal gradient, concentrations of Hg in the sediments sharply increased from seaward mudflat to landward mangrove, corresponding with the increases of TOC. In summary, the present data indicated that mangrove ecosystem is efficient in Hg reservoir. However, the potential ecological risks of Hg, especially in some mangrove regions easily affected by human activities, should be noted.

红树林的重要性已被广泛报道。然而，红树林中累积的污染物（例如汞）的潜在风险通常被忽略。因此，本研究旨在探讨华南沿岸红树林沉积物中汞（Hg）的分布和风险。结果表明，总汞浓度范围为0.0815至0.6377 mg / kg，算术平均值为0.2503 mg / kg。污染指数（P _i）在NS中表现为轻度污染毒性风险，在DZG，QZ，SY，ND，GQ，TLG中表现为轻度毒性风险，在BMW，SJ，ZJK和BLHK中表现为自由污染。NS，DZG和SY得分的最高值，我_的地理在所研究的11个红树林地区中，表明这些地区的污染输入为中度到重度。至于Hg在潮汐梯度上的分布，Hg的浓度从沿海滩涂向陆地红树林急剧增加，与TOC的增加相对应。总而言之，目前的数据表明，红树林生态系统在汞储层中是有效的。但是，应注意汞的潜在生态风险，特别是在一些容易受到人类活动影响的红树林地区。