Sediment quality assessment in an industrialized Greek coastal marine area (western Saronikos Gulf)

[摘要] Eight sediment cores from the coastal marine area of the westernSaronikos Gulf have been analysed for grain size and geochemistry. Theconcentrations of eight metals (Al, Fe, Mn, Cu, Cr, Ni, Pb and Zn) were measured alongwith total organic carbon (TOC) and carbonate content. Thecores are fairly homogeneous in terms of carbonates and the downcorevariability of TOC percentage (% TOC) and are characterized by high surficial values thatdecrease with depth. Metal concentrations from both geological (Al, Mn, Cr,Ni) and anthropogenic origin (Cu, Pb, Zn) are higher in the muddy fraction than in thesand fraction of sediments. The spatial distribution of Al, Fe, Mn, Cu, Pband Zn in surface sediments presents increasing concentrations from thenortheast to the southwest part of the study area and from the shallow to thedeeper parts in contrast to Cr and Ni, which are increased in the northernnearshore stations. Based on the vertical distributions, the metal to Alratios of Cu, Pb and Zn show a constant decrease over depth along mostcores, indicating the anthropogenic effects to surface sediments, while Fe / Al is constant. Spearman's correlation analysis performed among the fine-grain metal contents demonstrated a strong positive correlation ( r >0.5 , p <0.05 ) between Al, Fe, Mn, Cu, Pb and Zn. Thecalculated enrichment factors indicate minimal to moderate pollution. Theconcentrations of Cr at most surface sediments are higher than the “effects range low” (ERL) value(81 mg kg −1 ) but below the “effects range median” (ERM) value (370 mg kg −1 ) , and theconcentrations of Ni are always higher than the ERM value (51.6 mg kg −1 ) . In contrast, the concentrations of Cu, Pb and Zn at most surfacesediments are below ERL values. The mean effects range medium quotients(mERMq) of surface sediments, based on the overall metal concentrations,indicated that the surface sediments of most cores are moderately toxic.The levels of Cr, Ni, Mn and Zn at most stations are decreased in 2017, butthe concentrations of Pb and Cu are increased in 2017, compared to aprevious study of 2007. The concentrations of Cu, Pb and Zn in the surfacesediments of the western Saronikos Gulf are lower than levels reported for the innerSaronikos Gulf, Elefsis Bay and other polluted hotspot areas in Greece,owing to a lower degree of urban and industrial development.

[学科分类] 大气科学