Sediment properties and trace metal pollution assessment in surface sediments of the Laizhou Bay, China

Abstract

Spatial distribution, ecological risk, pollutant source, and transportation of trace metals in surface sediments, as well as the sediment properties, were analyzed in this study to assess the pollution status of trace metal in the Laizhou Bay, China. Results of provenance analyses indicate that surface sediments were primarily from weathering products carried by the surrounding short rivers and partially from loess matters carried by the Yellow River. Variations of trace metal concentrations were mostly controlled by the accumulation of weathering products, organic matters, and the hydrodynamics. Geoaccumulation index suggests that no Cr pollution occurred in the study area, and Cu, Pb, and Zn pollutions appeared only at a few stations. Comparatively, Cd and As pollutions were at noticeably weak to moderate level at many stations. The combination of six trace metals in this study had a 21% probability of being toxic in our study area based on sediment quality guidelines. Enrichment factors (EFs) and statistical analyses indicate that Cu, Pb, and Zn were primarily derived from the natural process of weathering. By contrast, Cd, As, and Cr (especially Cd and As) were provided by the anthropogenic activities to a large extent. Due to the dilution of coarse-grained sediments, there was even no contamination at some of stations that were obviously influenced by humans. Based on the current study of transportation process of fine-grained sediments in combination with the spatial distribution of EFs, it is found that the migration of anthropogenic trace metals was mainly controlled by the tide in the Laizhou Bay. The study suggests that an effective strategies and remedial measures should be designed and undertaken to prevent further anthropogenic Cd and As pollutions in this area in the future.

Distributions, sources and ecological risk assessment of arsenic and mercury in the surface sediments of the southwestern coastal Laizhou Bay, Bohai Sea

“…According to the recently published literature of Xu et al (2015), sediment in the Laizhou Bay was primarily from the material discharged by rivers along its western and southern coasts. So, the background concentrations of As and Hg in soil of Shandong Province (Table 1) were adopted to calculate the I geo values in this research as that of Xu et al (2015) did.…”

“…According to the recently published literature of Xu et al (2015), sediment in the Laizhou Bay was primarily from the material discharged by rivers along its western and southern coasts. So, the background concentrations of As and Hg in soil of Shandong Province (Table 1) were adopted to calculate the I geo values in this research as that of Xu et al (2015) did. The geoaccumulation index consists of seven classes: I geo 6 0 (Class 0, practically uncontaminated); 0 < I geo 6 1 (Class 1, uncontaminated to moderately contaminated); 1 < I geo 6 2 (Class 2, moderately contaminated); 2 < I geo 6 3 (Class 3, moderately to heavily contaminated); 3 < I geo 6 4 (Class 4, heavily contaminated); 4 < I geo 6 5 (Class 5, heavily to extremely contaminated); 5 < I geo (Class 6, extremely contaminated) (Müller, 1969).…”

Sources and geochemical background of potentially toxic metals in surface sediments from the Zhejiang coastal mud area of the East China Sea

“…Trace elements of Cd and Cr were measured by inductively coupled plasma mass spectrometry (ICP-MS) according to Dai et al (2007). Total organic carbon (TOC) was determined with a Carlo-Erba™ elemental analyzer, as per Xu et al (2015).…”

Heavy metals in surface sediments of the intertidal Laizhou Bay, Bohai Sea, China: Distributions, sources and contamination assessment

“…According to the recently published literature of Xu et al (2015), sediment in the Laizhou Bay was primarily from the material discharged by rivers along its western and southern coasts. So, the element background concentrations in soil of Shandong Province were adopted to calculate the EF values in this research as that of Xu et al (2015) did.…”

“…According to the recently published literature of Xu et al (2015), sediment in the Laizhou Bay was primarily from the material discharged by rivers along its western and southern coasts. So, the element background concentrations in soil of Shandong Province were adopted to calculate the EF values in this research as that of Xu et al (2015) did. It is generally accepted that it may be entirely from crustal materials or natural weathering processes if the EF value of a metal in solid geochemical samples such as marine sediments or suspended particulate matter is between 0.5 and 1.5, and a significant portion of it is from other sources rather than natural origins if its EF value is greater than 1.5 (Zhang and Liu, 2002;Feng et al, 2004).…”