Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary

Abstract

analysis identified the heavy metal accumulation layers of sediment profiles and showed the various sources of metals in the estuary. AbstractThe concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The 206 Pb/ 207 Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from non-point sources in the estuary. #

Heavy metal and Pb isotopic compositions of aquatic organisms in the Pearl River Estuary, South China

“…Hence, great concern has arisen in recent years over environmental pollution in this coastal region. Elevated concentrations of Cu, Pb, and Zn in the sediments of the PRE have been found (Chen and Zhou, 1992;Zheng, 1992;Li et al, 2000aLi et al, , 2000bLi et al, and 2001Liu et al, 2003). Trace metal contamination of the PRE may have a significant impact on aquatic organisms, disturbing the area's delicate ecological balance and potentially contaminating the marine food chain.…”

“…Stable Pb isotopic studies have been commonly applied to assess the sources of Pb in various ecosystems, including sediments (Farmer et al, 1996;Ritson et al, 1999;Liu et al, 2003), soils (Sugden et al, 1993;Semlali et al, 2001;Wong et al, 2002), suspended matters (Hinrichs et al, 2002), and atmospheric depositions Rosman, 2000 andWong et al, 2003). However, only a few studies have focused on stable Pb isotopes in biological samples to trace the anthropogenic origins of Pb (Kurkjian and Flegal, 2003).…”

“…Studies have recently been conducted on the stable Pb isotopic compositions of various ecosystems in the PRD region, such as agricultural soils (Wong et al, 2002), air depositions (Wong et al, 2003), and sediments (Liu et al 2003;Ip et al, 2004). These environmental media have distinctive ranges of stable Pb isotopic ratios.…”

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

“…4 Vertical profiles of trace elements and Mn in the sediments from the Pearl River and estuary the estuarine environment was seawater; the marine source of Na also showed a strong relationship with Mg and K (Spencer 2002). Previous studies in the Pearl River Estuary had also showed that the distribution of Mg and Ca may reflect the combined effects of parent material influences and sedimentation processes in the interaction with marine water (Li et al 2000;Liu et al 2003). Na had a strong positive correlation with Mg and a negative correlation with K in this study (Table 6).…”

“…The PRE has been a hot spot for research in recent decades (Li et al 2000;Liu et al 2003;Ip et al 2007;Zhou et al 2009;Yu et al 2010Yu et al , 2012. Because of the heavy metal toxicity to aquatic and benthonic organisms and the subsequent effects on humans, the geochemical behavior and pollution assessment of heavy metals account for a large fraction of these studies.…”