Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia

Contamination of heavy metals and hydrocarbons in the coastal and estuarine sediment could harm water quality and aquatic organisms, leading to potential long-term health risks to the environment and humans. Thus, this study was carried out to determine the concentration of heavy metals, aliphatic h...

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Main Author: Ebenezer Aquisman, Asare
Format: Thesis
Language:English
Published: 2023
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Online Access:http://ir.unimas.my/id/eprint/42022/1/Asare%27s%20Thesis%20%20UNIMAS.pdf
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id my-unimas-ir.42022
record_format uketd_dc
institution Universiti Malaysia Sarawak
collection UNIMAS Institutional Repository
language English
topic QD Chemistry
spellingShingle QD Chemistry
Ebenezer Aquisman, Asare
Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia
description Contamination of heavy metals and hydrocarbons in the coastal and estuarine sediment could harm water quality and aquatic organisms, leading to potential long-term health risks to the environment and humans. Thus, this study was carried out to determine the concentration of heavy metals, aliphatic hydrocarbons (AHs), and polycyclic aromatic hydrocarbons (PAHs) distribution in surface sediments and to establish baseline concentrations of heavy metals using core sediments from the coastal and four rivers estuary of the Kuching Division of Sarawak, Malaysia. Validated inductively coupled optical emission spectroscopy (ICP-OES) was used to determine heavy metals and their distribution in surface sediments was evaluated for eco-toxicological impacts. Source appointment of the heavy metals within the catchment area was determined using geochemical indices. The ICP-OES technique validated was appropriate and less laborious for determining the 12 metals of interest (i.e., Al, Mn, Ca, Cd, Cu, Fe, Cr, Ni, Co, Zn, and Pb) in the sediments. Heavy metal concentrations were recorded based on dry weight (d.w). The concentrations of heavy metals in core sediments varied in the range: Pb(8.9 – 188.9 mg/kg), Zn(19.4 – 431.8 mg/kg), Cd(0.014 – 0.061 mg/kg), Ni(6.6 – 33.4 mg/kg), Mn(2.4 – 16.8 mg/kg), Cu(9.4 – 133.3 mg/kg), Ba(1.3 – 9.9 mg/kg), As(0.4 – 7.9 mg/kg), Co(0.9 – 5.1 mg/kg), Cr(1.4 – 7.8 mg/kg), Mg(68.8 – 499.3 mg/kg), Ca(11.3 – 64.9 mg/kg), Al(24.7 – 141.7 mg/kg), Na(8.8 – 29.4 mg/kg), and Fe (12011 – 35124.6 mg/kg). The enrichment factor assessment suggested enrichment of Pb, Zn, Cu, As, Co, and Mg occurred at the top layer of the core sediments. Continuous accumulation of Pb and Cu metals over time can be detrimental to living organisms and the ecology. The pollution load index values indicated that the study area is unpolluted. Sediment quality guidelines (SQGs) compared to the detected heavy metals suggested no likely deleterious impact on bottom-dwelling living things. The risk index estimation in each study site showed a low ecological risk impact on the environment. The statistical analysis suggested that the deposition of As, Cd, Pb, Cu, Mn, and Zn in the study sites is due to anthropogenic inputs from the adjacent land-based sources while Fe, Al, Mg, Na, Ni, and Ba are from lithogenic origin. This study further explains the monitoring, sources, and risk assessment of hydrocarbons in surface sediments. Validation of the performance of gas chromatography flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS)showed that these techniques are in an excellent position to quantify aliphatic and polycyclic aromatic hydrocarbons, respectively. Total n-alkanes (C10 – C33) concentrations varied from 96.63 – 367.28 ng/g. The lowest and highest n-alkane content was observed at Santubong estuary (CZ10) and offshore of Batang Rambungan opposite small Satang Island (CZ2), respectively. The contents of PAHs varied from 12.54 – 21.20 ng/g. The highest PAH content was detected in the sediments of coastal site CZ8 (21.20 ng/g), whereas; the lowest content was recorded in the sediments of coastal site CZ3 (12.54 ng/g). The aliphatic diagnostic indices values showed hydrocarbon input from biogenic and petrogenic sources. The isomeric ratios values also indicated that PAHs in sediments are from a mixture of petrogenic and pyrogenic origins. The carcinogenic PAHs risk assessment suggested no risk impacts of carcinogenic PAHs in the study area. The findings of this study can be used to understand the sources and possible risks of hydrocarbons and provide information for safeguarding human health and aquatic bodies in coastal and estuary settings.
format Thesis
qualification_name Doctor of Philosophy (PhD.)
qualification_level Doctorate
author Ebenezer Aquisman, Asare
author_facet Ebenezer Aquisman, Asare
author_sort Ebenezer Aquisman, Asare
title Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia
title_short Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia
title_full Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia
title_fullStr Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia
title_full_unstemmed Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia
title_sort geochemical and ecological risk assessment of heavy metals and hydrocarbons in sediments of the coastal and four rivers estuary of kuching division of sarawak, malaysia
granting_institution Universiti Malaysia Sarawak
granting_department Department of Chemistry
publishDate 2023
url http://ir.unimas.my/id/eprint/42022/1/Asare%27s%20Thesis%20%20UNIMAS.pdf
_version_ 1783728533469659136
spelling my-unimas-ir.420222023-06-22T19:26:50Z Geochemical and Ecological Risk Assessment of Heavy Metals and Hydrocarbons in Sediments of the Coastal and Four Rivers Estuary of Kuching Division of Sarawak, Malaysia 2023-06-21 Ebenezer Aquisman, Asare QD Chemistry Contamination of heavy metals and hydrocarbons in the coastal and estuarine sediment could harm water quality and aquatic organisms, leading to potential long-term health risks to the environment and humans. Thus, this study was carried out to determine the concentration of heavy metals, aliphatic hydrocarbons (AHs), and polycyclic aromatic hydrocarbons (PAHs) distribution in surface sediments and to establish baseline concentrations of heavy metals using core sediments from the coastal and four rivers estuary of the Kuching Division of Sarawak, Malaysia. Validated inductively coupled optical emission spectroscopy (ICP-OES) was used to determine heavy metals and their distribution in surface sediments was evaluated for eco-toxicological impacts. Source appointment of the heavy metals within the catchment area was determined using geochemical indices. The ICP-OES technique validated was appropriate and less laborious for determining the 12 metals of interest (i.e., Al, Mn, Ca, Cd, Cu, Fe, Cr, Ni, Co, Zn, and Pb) in the sediments. Heavy metal concentrations were recorded based on dry weight (d.w). The concentrations of heavy metals in core sediments varied in the range: Pb(8.9 – 188.9 mg/kg), Zn(19.4 – 431.8 mg/kg), Cd(0.014 – 0.061 mg/kg), Ni(6.6 – 33.4 mg/kg), Mn(2.4 – 16.8 mg/kg), Cu(9.4 – 133.3 mg/kg), Ba(1.3 – 9.9 mg/kg), As(0.4 – 7.9 mg/kg), Co(0.9 – 5.1 mg/kg), Cr(1.4 – 7.8 mg/kg), Mg(68.8 – 499.3 mg/kg), Ca(11.3 – 64.9 mg/kg), Al(24.7 – 141.7 mg/kg), Na(8.8 – 29.4 mg/kg), and Fe (12011 – 35124.6 mg/kg). The enrichment factor assessment suggested enrichment of Pb, Zn, Cu, As, Co, and Mg occurred at the top layer of the core sediments. Continuous accumulation of Pb and Cu metals over time can be detrimental to living organisms and the ecology. The pollution load index values indicated that the study area is unpolluted. Sediment quality guidelines (SQGs) compared to the detected heavy metals suggested no likely deleterious impact on bottom-dwelling living things. The risk index estimation in each study site showed a low ecological risk impact on the environment. The statistical analysis suggested that the deposition of As, Cd, Pb, Cu, Mn, and Zn in the study sites is due to anthropogenic inputs from the adjacent land-based sources while Fe, Al, Mg, Na, Ni, and Ba are from lithogenic origin. This study further explains the monitoring, sources, and risk assessment of hydrocarbons in surface sediments. Validation of the performance of gas chromatography flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS)showed that these techniques are in an excellent position to quantify aliphatic and polycyclic aromatic hydrocarbons, respectively. Total n-alkanes (C10 – C33) concentrations varied from 96.63 – 367.28 ng/g. The lowest and highest n-alkane content was observed at Santubong estuary (CZ10) and offshore of Batang Rambungan opposite small Satang Island (CZ2), respectively. The contents of PAHs varied from 12.54 – 21.20 ng/g. The highest PAH content was detected in the sediments of coastal site CZ8 (21.20 ng/g), whereas; the lowest content was recorded in the sediments of coastal site CZ3 (12.54 ng/g). The aliphatic diagnostic indices values showed hydrocarbon input from biogenic and petrogenic sources. The isomeric ratios values also indicated that PAHs in sediments are from a mixture of petrogenic and pyrogenic origins. The carcinogenic PAHs risk assessment suggested no risk impacts of carcinogenic PAHs in the study area. The findings of this study can be used to understand the sources and possible risks of hydrocarbons and provide information for safeguarding human health and aquatic bodies in coastal and estuary settings. Universiti Malaysia Sarawak 2023-06 Thesis http://ir.unimas.my/id/eprint/42022/ http://ir.unimas.my/id/eprint/42022/1/Asare%27s%20Thesis%20%20UNIMAS.pdf text en public phd doctoral Universiti Malaysia Sarawak Department of Chemistry