Spatial controls on riverbed sediment chemistry in three anthropogenically modified tropical mountainous watersheds
Spatial controls on riverbed sediment chemistry in three anthropogenically modified tropical mountainous watersheds
复制标题
DOI：
10.1007/s13762-021-03155-y
复制
发表时间：
2021-02
影响因子：
3.1
通讯作者：
J. Papotto;L. Rodrigues;E. M. Siebert;E. Wagner;S. Goldsmith
中科院分区：
文献类型：
--
作者：
J. Papotto;L. Rodrigues;E. M. Siebert;E. Wagner;S. Goldsmith
热带山区河流向全球海洋输送了不成比例的沉淀物。虽然这些系统也将与沉积物有关的污染物(即金属)输送到海岸，但金属污染物在这些系统内的潜在积累在很大程度上尚未得到探索。这项研究分析了从波多黎各的里约热内卢、里约科和里奥瓜马尼采集的细小河床沉积物(<； 0.63m)中的痕量金属浓度。2019年6月(玛利亚飓风过后21个月)共从这些流域采集了17个样本。采用酸消解和电感耦合等离子体质谱对样品中的铝、钡、镉、铜、铬、铁、锰、镍、锑、锡、铀、锌等金属元素进行定量测定。Cd、Pb、Sb与锡(Ravg>； 0.60，p<； 0.05)以及Ba、Cr与Ni(Ravg>； 0.81，p<； 0.05)之间存在较强的正相关关系。土地覆盖与金属元素浓度的比较表明，铜、锑、锡、锌与发达地呈正相关，铬、镍、铀与农地呈正相关。7%至50%的样品的浓缩系数值表明每种金属的污染程度(EF、 和GT； 2)为中等到严重水平。此外，几种金属浓度超过了基于共识的阈值效应和可能效应值。总而言之，这些数据证实，金属确实在热带山区集水区积累，并可以在影响淡水生态系统的浓度下找到。这些金属浓度升高，再加上周期性的冲刷事件，经常受到飓风的支持，表明这对珊瑚礁等近岸生态系统构成了威胁。
Tropical mountainous rivers transport a disproportionate amount of sediment to the global ocean. While these systems also deliver sediment-related pollutants (i.e., metals) to the coast, the potential accumulation of metal contaminants within these systems has been largely unexplored. This study analyzed the trace metal concentrations of fine riverbed sediment (< 0.63 µm) collected from Rio Loco, Rio Yauco and Rio Guamaní in Puerto Rico. A total of 17 samples were collected in June 2019 (~ 21 months following Hurricane Maria) from these watersheds. Metal concentrations (Al, Ba, Cd, Cu, Cr, Fe, Mn, Ni, Sb, Sn, U and Zn) were quantified with acid digestion and inductively coupled plasma mass spectrometry. Strong positive correlations were found between Cd, Pb, Sb and Sn (ravg> 0.60,p< 0.05) as well as between Ba, Cr and Ni (ravg> 0.81,p< 0.05). A comparison of land cover with metal concentrations revealed positive statistical relationships between Cu, Sb, Sn and Zn with developed land and Cr, Ni and U with agricultural land. Between 7 and 50% of the samples exhibited enrichment factor values indicative of moderate to significant levels of contamination (EF > 2) for each metal. Additionally, several metal concentrations exceeded the consensus-based threshold effect and probable effect values. Altogether, these data confirm that metals do accumulate in tropical mountainous watersheds and can be found at concentrations that impact freshwater ecosystems. These elevated metal concentrations coupled with periodic flushing events, regularly supported by hurricanes, suggest a threat to nearshore ecosystems such as coral reefs.