Elsevier

Chemosphere

Volume 287, Part 1, January 2022, 132069
Chemosphere

Seasonal variation and mobility of trace metals in the beach sediments of NW Borneo

https://doi.org/10.1016/j.chemosphere.2021.132069Get rights and content

Highlights

  • Most of the Cu and Zn is in the exchangeable fraction that is readily bioavailable.

  • Cu and Zn contamination is a threat to the corals and aquatic organisms.

  • Pb and Cd are also dominant in the nonresidual fractions.

  • Littoral currents affect the grain size and the trace elements content of the sediments.

Abstract

Miri city has a dynamic coastal environment, mainly influenced by intensive sedimentation from the Baram River and excessive trace metal loading by the Miri River, which are significant environmental concerns. As the mobility, bioavailability, and toxicity of the trace metals in the sediments are largely controlled by their particulate speciation, the modified BCR sequential extraction protocol was applied to determine the particulate speciation of trace metals in the coastal sediments of Miri, to unravel the seasonal geochemical processes responsible for known observations, and to identify possible sources of these trace metals. The granulometric analysis results showed that littoral currents aided by the monsoonal winds have influenced the grain size distribution of the sediments, enabling us to divide the study area into north-east and south-west segments where the geochemical composition are distinct. The Cu (>84%) and Zn (82%) concentrations are predominantly associated with the exchangeable fraction, which is readily bioavailable. Pb and Cd are dominant in non-residual fractions and other metals viz., Fe, Mn, Co, Ni, and Cr are dominant in the residual fraction. Using Pearson's correlation and factor analysis, the major mechanisms controlling the chemistry of the sediments are identified as association of Cu and Zn with fine fraction sediments, sulphide oxidation in the SW segment of the study area, atmospheric fallout of Pb and Cd in the river basins, precipitation of dissolved Fe and Mn supplied from the rivers and remobilization of Mn from the coastal sediments. Based on various pollution indices, it is inferred that the coastal sediments of NW Borneo are contaminated with Cu and Zn, and are largely bioavailable, which can be a threat to the local aquatic organisms, coral reefs, and coastal mangroves.

Introduction

Globally the contamination of a coastal ecosystem by trace and heavy metals is a serious environmental problem. Trace metals such as chromium, cobalt, copper, iron, magnesium, and zinc are generally occurring at very small levels in the environment. Living organisms need very lesser quantities of some trace metals, but high levels of the same metals can be toxic. Trace metals originate from both natural (erosion and mineral weathering) and anthropogenic sources (industrial and mining activities) and are transferred into the coastal environment via river runoff, discharge of municipal and industrial effluents through small streams and atmospheric fallout (Hyun et al., 2007; Li et al., 2013; Liu et al., 2018; Nagarajan et al., 2019). Under reasonable environmental conditions, where freshwater is well-oxygenated, the concentration of trace metals is high in the sediments compared to the water column. The partitioning of trace metals between the water column and sediments results from the adsorption and complexation by clay minerals and organic matter in the sediments. Trace metal concentration in the sediments often reflects their lithological source (Govindasamy and Azariah, 1999; Gopinath et al., 2010; Prabakaran et al., 2020) but sometimes anthropogenic contamination (Barath Kumar et al., 2017; Lu and Kang, 2018; Sajimol et al., 2021). The physicochemical changes occurring in the overlying water column and within sediments remobilize the trace metals (Förstner, 1985; Chakraborty et al., 2015; Tiquio et al., 2017; Xie et al., 2019). After remobilization, various physicochemical and biological processes recycle the trace metals (Xu et al., 2017), which undergo bioaccumulation and biomagnification through a complex food web structure that initiates adverse health effects to aquatic organisms and humans (Gleyzes et al., 2002; Barath Kumar et al., 2017; Liang et al., 2018; Anandkumar et al., 2020).

The bioaccumulation and biomagnification depend on the physicochemical availability (mobility) dictated by the carrier phase with which the trace metals are associated in the sediments and the prevailing environmental conditions (Tessier et al., 1979; Salomons and Förstner, 1980; Rauret et al., 1988; Szefer et al., 1995; Chakraborty et al., 2014, 2019, 2019; Tiquio et al., 2017). The labile form of the trace metals primarily exists in five different phases viz., exchangeable, bound to carbonates, adsorbed onto iron and manganese oxides, complexed with natural organic matter, and as sulphides (Gibbs, 1973). The mobility and bioavailability of the trace metals differ across these carrier phases. Thus, measuring the total metal concentrations is inadequate to explore the contamination status of the sediments (Cottenie et al., 1980; Gleyzes et al., 2002). Therefore, earlier researchers have employed different sequential extraction procedures (Tessier et al., 1979; Ure et al., 1993; Morillo et al., 2004; Nemati et al., 2011; Chakraborty et al., 2014, 2021; Wali et al., 2015; Schintu et al., 2016; Lu and Kang, 2018; Prabakaran et al., 2019; Dong et al., 2019; Zhao et al., 2021) of which the Tessier et al. (1979) protocol is widely adopted.

However, the lack of standardized procedures favored the development of the BCR method (Ure et al., 1993). The present work utilized the modified BCR procedure of Rauret et al. (1999). The revised protocol involves the use of an increased concentration of hydroxylammonium chloride and a lower pH. This allows for a more efficient dissolution of the soil/sediment matrix in the reducible fraction, in particular, metals bound to the iron oxyhydroxide phase (Mossop and Davidson, 2003). Many researchers (Morillo et al., 2004; Cuong and Obbard, 2006; Nemati et al., 2011; Alshemmari et al., 2012; Chakraborty et al., 2015; Schintu et al., 2016; Akhbarizadeh et al., 2017) have successfully applied this modified BCR sequential extraction protocol to investigate bioavailability, mobility and toxicity of trace metals in the coastal sediments.

The Miri coast of the Sarawak consists of scenic geological structures, such as rock cliffs, arches, caves, stacks, beach rocks, a recreational waterfront area, and coral reefs (Miri-Sibuti Coral Reef National Park; MSCRNP), which makes them regularly visited hotspot areas for local and foreign travelers. Apart from the coastal ecosystems, three rivers (Baram River: the 2nd longest River in Sarawak and Miri, and Sibuti Rivers are minor rivers) that originate inland of Sarawak and confluence in the South China Sea and deliver a vast amount of sediments to the South China Sea. Compared to these three rivers, the Baram River contributes a much higher sediment flux to the Miri coast. Research on the alluvial sediments on the Miri coastal belts, which delineate the source and nature of these sediments is limited (Nagarajan et al., 2013; Ismail, 1993; Sim et al., 2017; Prabakaran et al., 2019).

An earlier study by Nagarajan et al. (2013) in the tourist beach sediments of Miri revealed possible anthropogenic influence based on the acid leachable trace metals in the sediments and not reported the total trace metals in the beach sediment. Later, Nagarajan et al. (2019) reported the total trace metals including Rare Earth Elements (REEs) and mainly emphasized the source rock characterization, weathering intensity and the geological processes controlling the geochemical signature of the sediments. A high rate of erosion in the catchment area of the Baram River led to enhanced sediment transport to the Miri coast, which resulted in the formation of the sand bar opposite the Baram River mouth (Nagarajan et al., 2015a, 2019). Such a sand bar modulates the alongshore transport and distribution of the sediments delivered by the Baram River to the South China Sea. The enhanced upstream erosion due to changing land use and land cover modulate sediment delivery, and dictate accretion and erosional features of the Miri coast (Anandkumar et al., 2019a), and impact the nearshore Miri-Sibuti Coral Reef National Park (Browne et al., 2019). Studies on trace metal accumulation in biological tissues were also reported from the Miri Estuary of Sarawak (Billah et al., 2016) and the Miri coastal area (Anandkumar et al., 2017, 2018, 2019) which observed a higher concentration of Cu and Zn in different tissue organs of consumable aquatic organisms such as fish, crab, and prawn, etc. Even though there have been some studies on the trace and heavy metals in the sediments of coastal areas of Borneo, a combined study that addresses the nature of the source, the seasonal, environmental, and biological impact of the trace metals, seasonal variations and mobility of the trace metals in the sediments of adjacent coastal belts are limited. In addition, geochemical fingerprinting studies to address the impact on the coral reef ecosystem in the MSCRNP by the local rivers, as well as the adjacent coastal belts, are also limited to evaluate the future threats to the reef due to high suspended sediment input with a significant amount of pollutants (e.g. Browne et al., 2019). Thus, the present study mainly focuses on the sequential extraction of trace metals of various beach sediments of the Miri coast to assess their bioavailability, toxicity, the association of metals in the different sediment fractions, to identify possible sources of the contaminants, and the pollution status based on the sediment quality guidelines (SQGs).

Section snippets

Study area

Miri is the birthplace of the Malaysian oil industries and it is located in the northern part of Sarawak in Borneo Island. The beaches in this region are exposed to several types of natural and anthropogenic influences (Nagarajan et al., 2013, 2019, 2019; Billah et al., 2016; Anandkumar et al., 2017, 2018, 2018; Prabakaran et al., 2019). The Baram, Miri, and Sibuti rivers deliver freshwater and sediments to the coastal area of the South China Sea. The sediment input from the Baram River is much

Sample collection and analysis

A total of 57 beach sand samples were collected during monsoon (MON; December 2013; n = 26) and post-monsoon seasons (POM; June 2014; n = 31) during low tides. Using a clean plastic scoop, sediment samples were collected from 0 to 10 cm depth, transferred to the polyethylene bags, labelled, transported to the laboratory and stored under refrigeration at 4 °C. Before sample processing, all the samples were thawed to attain ambient temperature. After removal of organic debris, the sediments were

Sediment texture

The Miri beach sediments were mainly composed of fine sand and silt; the coarse fraction was lesser than 1%. Based on grain size analysis the study area is divided into two segments – the northeastern (NE) and the southwestern (SW) segments. The fine sand dominates in the NE segment while silt is predominant in the SW segment. The Kualabaram River mouth/Estuary (KBE), Fish Landing Center (FLC), Lutong Beach (LB), Piasau Boat Club Beach (PBC) and, Miri River estuary (MRE) fall under the NE

Conclusion

The modified BCR sequential extraction method was adopted for the first time in the study area to analyze the potential mobility of trace metals and their seasonal variations in the sediment samples collected from the different beaches of the Miri coast. The sediments are predominantly composed of fine sand (SW segment) and are followed by silt (NE segment). The association of trace metals in the exchangeable fraction (the most mobile and bioavailable) can be ranked as

Credit author statement

A.Anandkumar: Conceptualization (equal), methodology, investigation (lead), writing-original draft (lead). R. Nagarajan – Funding acquisition, conceptualization (equal), supervision, validation (lead), data curation, formal analysis (equal), writing-review and editing (lead). Eswaramoorthi Sellappa Gounder – Formal analysis (equal), validation (supporting), writing-review and editing (supporting). K. Prabakaran – Investigation (supporting), writing-original draft (supporting), visualization.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

The first author wishes to express his gratefulness to Curtin Sarawak Research Institute Academic Grant (CSRI 1011: Ramasamy Nagarajan) during his doctoral program at Curtin University Malaysia. The valuable help by Dr. Vijith Hamza in this study is highly acknowledged. We are grateful to Mr. David Patenaude for his valuable comments and linguistic corrections. The authors extend their sincere thanks to the Editor and two anonymous reviewers for their valuable comments that improved the quality

References (127)

  • P. Chakraborty et al.

    Mercury speciation in coastal sediments from the central east coast of India by modified BCR method

    Mar. Pollut. Bull.

    (2014)
  • P. Chakraborty et al.

    Geochemical partitioning of Cu and Ni in mangrove sediments: relationships with their bioavailability

    Mar. Pollut. Bull.

    (2015)
  • S. Chakraborty et al.

    Evidence for increasing anthropogenic Pb concentrations in Indian shelf sediments during the last century

    Sci. Total Environ.

    (2021)
  • P. Ciffroy et al.

    Kinetic partitioning of Co, Mn, Cs, Fe, Ag, Zn and Cd in fresh waters (Loire) mixed with brackish waters (Loire Estuary): experimental and modelling approaches

    Mar. Pollut. Bull.

    (2003)
  • M.H. Cotté-Krief et al.

    Trace metal (Cd, Cu, Ni and Pb) cycling in the upper water column near the shelf edge of the European continental margin (Celtic Sea)

    Mar. Chem.

    (2002)
  • A. Cottenie et al.

    Fractionation and determination of trace elements in plants, soils and sediments

  • D.T. Cuong et al.

    Metal speciation in coastal marine sediments from Singapore using a modified BCR-sequential extraction procedure

    Appl. Geochem.

    (2006)
  • S. Dash et al.

    Heavy metal pollution and potential ecological risk assessment for surficial sediments of Deepor Beel, India

    Ecol. Indicat.

    (2021)
  • J.A. Davis

    Complexation of trace metals by adsorbed natural organic matter

    Geochem. Cosmochim. Acta

    (1984)
  • G.S. Douglas et al.

    Organic copper and chromium complexes in the interstitial waters of narragansett bay sediments

    Mar. Chem.

    (1986)
  • J.M. Edmond et al.

    Chemical dynamics of the changjiang estuary

    Continent. Shelf Res.

    (1985)
  • J.F. Gaillard et al.

    Interstitial water chemistry of villefranche bay sediments: trace metal diagenesis

    Mar. Chem.

    (1986)
  • J.M. Garnier et al.

    Implications of short and long term (30 days) sorption on the desorption kinetic of trace metals (Cd, Zn, Co, Mn, Fe, Ag, Cs) associated with river suspended matter

    Sci. Total Environ.

    (2006)
  • C. Gleyzes et al.

    Fractionation studies of trace elements in contaminated soils and sediments: a review of sequential extraction procedures

    TrAC Trends Anal. Chem. (Reference Ed.)

    (2002)
  • L. Hakanson

    An ecological risk index for aquatic pollution control. A sedimentological approach

    Water Res.

    (1980)
  • A.M. Hansen et al.

    Time-dependent adsorption in near coastal marine sediments: a two-step model

    Adv. Water Resour.

    (1998)
  • V. Hatje et al.

    Kinetics of trace element uptake and release by particles in estuarine waters: effects of ph, salinity, and particle loading

    Environ. Int.

    (2003)
  • C. Heidel et al.

    The isotopic composition of sulfate from anaerobic and low oxygen pyrite oxidation experiments with ferric iron—new insights into oxidation mechanisms

    Chem. Geol.

    (2011)
  • J.D. Hem

    Reactions of metal ions at surfaces of hydrous iron oxide

    Geochem. Cosmochim. Acta

    (1977)
  • S. Hyun et al.

    Anthropogenic contributions to heavy metal distributions in the surface sediments of masan bay, korea

    Mar. Pollut. Bull.

    (2007)
  • C.A. Impellitteri et al.

    Correlation of the partitioning of dissolved organic matter fractions with the desorption of Cd, Cu, Ni, Pb and Zn from 18 Dutch soils

    Environ. Int.

    (2002)
  • M.A. Islam et al.

    Contamination and ecological risk assessment of trace elements in sediments of the rivers of Sundarban mangrove forest, Bangladesh

    Mar. Pollut. Bull.

    (2017)
  • A. Ismail

    Heavy metal concentrations in sediments off bintulu, Malaysia

    Mar. Pollut. Bull.

    (1993)
  • A.E. Lewis

    Review of metal sulphide precipitation

    Hydrometallurgy

    (2010)
  • G. Li et al.

    Heavy metals distribution and contamination in surface sediments of the coastal shandong peninsula (yellow sea)

    Mar. Pollut. Bull.

    (2013)
  • X. Liang et al.

    Source identification and risk assessment based on fractionation of heavy metals in surface sediments of Jiaozhou Bay, China

    Mar. Pollut. Bull.

    (2018)
  • Q. Liu et al.

    Assessment of metal contamination in estuarine surface sediments from Dongying City, China: use of a modified ecological risk index

    Mar. Pollut. Bull.

    (2018)
  • D.H. Loring et al.

    Manual for the geochemical analyses of marine sediments and suspended particulate matter

    Earth Sci. Rev.

    (1992)
  • G.E. Millward et al.

    Modelling metal desorption kinetics in estuaries

    Sci. Total Environ.

    (2003)
  • J. Morillo et al.

    Heavy metal distribution in marine sediments from the southwest coast of Spain

    Chemosphere

    (2004)
  • K.F. Mossop et al.

    Comparison of original and modified BCR sequential extraction procedures for the fractionation of copper, iron, lead, manganese and zinc in soils and sediments

    Anal. Chim. Acta

    (2003)
  • R. Nagarajan et al.

    Metal concentrations in sediments from tourist beaches of Miri city, Sarawak, Malaysia (Borneo island)

    Mar. Pollut. Bull.

    (2013)
  • R. Nagarajan et al.

    Geochemistry of neogene sedimentary rocks from Borneo basin, east Malaysia: paleo-weathering, provenance and tectonic setting

    Chem. Erde

    (2014)
  • R. Nagarajan et al.

    Decadal evolution of a spit in the baram River mouth in eastern Malaysia

    Continent. Shelf Res.

    (2015)
  • R. Nagarajan et al.

    Petrological and geochemical constraints on provenance, paleo-weathering and tectonic setting of clastic sediments from the Neogene Lambir and Sibuti Formations, NW Borneo (Chapter 7)

  • R. Nagarajan et al.

    Geochemical characterization of beach sediments of the NW Borneo, SE Asia: implications on provenance, weathering intensity and assessment of coastal environmental status

  • C. Naylor et al.

    Simultaneous release of sulfide with Fe, Mn, Ni and Zn in marine harbour sediment measured using a combined metal/sulfide DGT probe

    Sci. Total Environ.

    (2004)
  • K. Nemati et al.

    Speciation of heavy metals by modified BCR sequential extraction procedure in different depths of sediments from sungai buloh, selangor, Malaysia

    J. Hazard Mater.

    (2011)
  • A.M. Orani et al.

    First assessment on trace elements in sediment cores from Namibian coast and pollution sources evaluation

    Sci. Total Environ.

    (2019)
  • H. Pekey et al.

    Ecological risk assessment using trace elements from surface sediments of Izmit Bay (Northeastern Marmara Sea) Turkey

    Mar. Pollut. Bull.

    (2004)
  • Cited by (19)

    View all citing articles on Scopus
    View full text