Spatial and temporal dynamics of heavy metal pollution and source identification in sediment cores from the short-term flooding riparian wetlands in a Chinese delta

Abstract

Sediment samples were collected to a depth of 60 cm along a 350-m sampling belt in a short-term-flooding riparian wetland in the Yellow River Delta of China in three sampling seasons. Contents of heavy metals were determined to investigate their spatial and temporal distributions, sources and ecotoxities. Our results showed that As contents in the top 20 cm sediments increased before decreasing along the sampling belt in summer, whereas they kept stable before increasing in fall and spring. Cd contents increased along the sampling belt in three sampling seasons, whereas Ni and Cr generally exhibited a decreasing tendency. Comparatively, Cu, Pb and Zn consistently increased at the first 50 m distance and then decreased before increasing from the distance of 150 m in summer and fall and increased to the maximum at the distance of 250 m and then showed a decrease in spring. Two "hotspots" of heavy metal accumulation in sediment cores along the belt were observed at the distance from 50 to 100 m in summer and at the distance from 200 to 300 m in spring. Most of sediment samples contained higher heavy metals in excess of threshold effect levels except for Zn and Pb in three sampling seasons and the values of toxic units in more than 30% of sediment samples exceeded 4 in summer. As, Ni and Cr had relatively higher contribution to the values of toxic units compared with other heavy metals in three sampling seasons. Multivariance analysis showed that As and Cd might originate from the same source and Cu, Zn, Cr, Pb and Ni might derive from another similar source. Cd was significantly correlated with salinity (p < 0.01) and pH (p < 0.05). Meanwhile, these heavy metals were also significantly correlated with other properties such as S, Al, TP, SOM and Silt + Clay.

Spatial Distribution and Contamination Assessment of Heavy Metals in Surface Sediments of the Caofeidian Adjacent Sea after the Land Reclamation, Bohai Bay

“…The coastal zone is one of the most frequent areas disturbed by human activities through plant and port construction, land reclamation, and tourism [1,[17][18][19]. Human activities, on the one hand, will increase the loadings of heavy metals in the aquatic system through direct industrial discharge, city sewage, domestic runoff, and so forth [20][21][22]; 2 Journal of Chemistry on the other hand, they can change pristine sedimentary environment which may contribute to the release of heavy metals from sediments.…”

Activated Carbon Mixed with Marine Sediment is Suitable as Bioanode Material for Spartina anglica Sediment/Plant Microbial Fuel Cell: Plant Growth, Electricity Generation, and Spatial Microbial Community Diversity

“…A study has shown that at least 33% of global wetlands had been lost as of 2009 due to human activities [1]. This loss was comparable to a previous study reporting that between 1970 and 2008, natural wetland declined globally by about 30% [4].Sediment pollution by human activities is a major problem for wetland ecosystems [5]. By nature, wetland sediments are able to remedy themselves from pollutants, such as petroleum hydrocarbon pollutants, due to the presence of diverse microbial communities [6].…”

“…Sediment pollution by human activities is a major problem for wetland ecosystems [5]. By nature, wetland sediments are able to remedy themselves from pollutants, such as petroleum hydrocarbon pollutants, due to the presence of diverse microbial communities [6].…”

Chronology of anthropogenic impacts reconstructed from sediment records of trace metals and Pb isotopes in Todos os Santos Bay (NE Brazil)

“…A large partmajor portion of the fluxes of the natural and anthropogenic materials introduced into coastal systems tend to accumulate in sediments, producing unequivocal geochemical signatures within sedimentary bodies, thus registering changes in time (Bruland et al, 1974). These anthropogenic geochemical signatures include elevated levels of contaminants such as metals (Bai et al, 2016;Begy et al, 2016;Garcia-Orellana et al, 2011), polycyclic aromatic hydrocarbons (PAHs) (Martins et al, 2015;Peng et al, 2008), pesticides (Alonso-Hernández et al, 2015;Kaiser et al, 2016), polychlorinated biphenyls (PCBs) (Combi et al, 2016;Ruiz-Fernández et al, 2012), in addition to changes in Pb isotopic composition (Nriagu and Pacyna, 1988;Waters et al, 2016;Yu et al, 2016;Zhang et al, 2016).…”