School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, Guangdong, China.
School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, Guangdong, China.
Chemosphere. 2019 Mar;219:165-173. doi: 10.1016/j.chemosphere.2018.11.160. Epub 2018 Nov 27.
Urban mangroves are affected by surrounding anthropogenic activities. Heavy metals in urban mangroves lack systematic evaluation, and their relationships with surrounding anthropogenic activities have not been explored with quantified data. In this study, urban mangroves with different urban functional zonings were selected in Shenzhen, South China, including: Shajing mangrove (SJM) and Xixiang mangrove (XXM) featured with industry district, Futian mangrove (FTM) and Baguang mangrove (BGM) featured with central business district and ecological preserve, respectively. The distribution, ecological risk, and pollution sources of heavy metals were determined. Heavy metals' relationships with surrounding functional zonings were also explored. The levels of Cu, Zn, Pb, Ni and Cr in SJM were significantly higher than the other mangrove stands, which may be related to its proximity to point-source discharges of Maozhou River in Pearl River Estuary, China. Potential ecological risk index, pollution load index, mean PEL quotient, mean effect range median quotient, and total toxic unit showed the highest ecological risk in SJM, followed by XXM, FTM, and BGM. With the order of BGM - FTM - XXM - SJM, Zn, Ni, and Cr presented dominantly in the labile fraction, demonstrating increased anthropogenic impacts. Heavy metals in FTM and BGM were mainly from anthropogenic and lithogenic originations, with only anthropogenic origination of heavy metals to be detected in SJM and XXM. Heavy metal pollution was highest in SJM featured with industry district, and metal products industry in surrounding district should attract special attention due to its affinity for heavy metal accumulation in urban mangroves.
城市红树林受到周围人为活动的影响。城市红树林中的重金属缺乏系统评价，其与周围人为活动的关系尚未通过量化数据进行探索。本研究在中国华南深圳选择了具有不同城市功能分区的城市红树林，包括：具有工业区特征的沙井红树林（SJM）和西乡红树林（XXM），以及分别具有中央商务区和生态保护区特征的福田红树林（FTM）和八卦岭红树林（BGM）。确定了重金属的分布、生态风险和污染源。还探讨了重金属与周围功能分区的关系。SJM 中的 Cu、Zn、Pb、Ni 和 Cr 水平明显高于其他红树林，这可能与其靠近珠江口茅洲河的点源排放有关。潜在生态风险指数、污染负荷指数、平均 PEL 商、平均效应范围中值商和总毒性单位表明 SJM 具有最高的生态风险，其次是 XXM、FTM 和 BGM。按照 BGM - FTM - XXM - SJM 的顺序，Zn、Ni 和 Cr 主要存在于不稳定部分，表明人为影响增加。FTM 和 BGM 中的重金属主要来自人为和岩石成因，而仅在 SJM 和 XXM 中检测到重金属的人为起源。工业区特征的 SJM 中重金属污染最高，周边地区的金属制品工业应特别注意，因为它容易在城市红树林中积累重金属。
