Assessment of hazardous substances in the snail, Nerita lineata gmelin, and sediments from selected mangrove areas of Peninsular Malaysia
Rapid growth of the land and marine based industries has generated various contaminations to the coastal areas of Malaysia. Thus, continuous assessments and monitoring of pollutants especially trace metals and polycyclic aromatic hydrocarbons (PAHs) are crucial. The aim of this study is to det...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2015
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/65407/1/FS%202015%2038IR.pdf |
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| Summary: | Rapid growth of the land and marine based industries has generated various
contaminations to the coastal areas of Malaysia. Thus, continuous assessments and
monitoring of pollutants especially trace metals and polycyclic aromatic hydrocarbons
(PAHs) are crucial. The aim of this study is to determine the baseline data, ecological
risk and health risk assessments of trace metals and PAHs in mangrove snails, Nerita
lineata and surface sediments of at least 9 sampling sites in Peninsular Malaysia
between 2010 − 2012. Metal analysis was done by using the Atomic Absorption
Spectrophotometer (AAS) and Inductively Coupled Plasma-mass Spectrometer
(ICPMS). Analysis of PAHs was carried out by using gas chromatography-mass
spectrophotometry (GC-MS) while Inter-Simple Sequence Repeat (ISSR) markers were
applied for genetic polymorphism study in the snails. All 18 metals in the snails ranged
from BDL (below detection limit) – 3235 µg/g dw, with higher accumulation of
essential metals in the soft tissues and non-essential metals in the shells and opercula.
For sediments, all 18 metals ranged from 0.003 – 48916 µg/g dw. The ∑16 PAHs
concentrations (ng/g dw) ranged from 871 – 3066 and 273 – 18030 for soft tissues and
sediments, respectively. To determine the ecological risks of habitat on surface
sediments, the sediment quality guidelines (SQGs), geochemical indices, potential
ecological risk index (PERI) and mean ERM quotient (m-ERM-q) were used. Based on
the SQGs, all the metals investigated were unlikely to cause any adverse ecological
effects. The ecological risk indices revealed that the pollution and ecological risks of all
metals and PAHs were minimal, except for PAHs in JPKetam being ‘moderately to
highly polluted’. Potential health risks were assessed from calculations of estimated
daily intakes (EDI), target hazard quotients (THQ) and total THQ (TTHQ) of the
snails’ soft tissues for trace metals, while excess cancer risks (ECR) were applied for
PAHs assessments. Non-carcinogenic risks estimation (THQ and TTHQ) for trace
metals showed that average snails consumers were exposed to low potential health risk
whereas the high consumers were at high risks (TTHQ>1). The carcinogenic risks
approach (ECR) showed that the snail consumption from most sites were in a range of
moderate to high carcinogenic risks exposure (1×10-6
< ECR< 1×10-4
) to PAHs,
implying moderation (<17.86 g/day) in snail consumption. The ISSR markers were
found to have positive relationships from comparison of patterns of genetic clustering
and trace metal levels of the snail muscle tissues but not PAHs. This implied that the polymorphic loci could be used as potential biomarkers for metals pollution. Generally this study suggested that all metals and PAHs from the sampling sites were not likely to cause hazardous effects to the environment. Consumption of the snails should be of moderation especially to high consumers of the snails as the data showed possible health risks for both trace metals and PAHs. This study has produced important data of the hazardous pollutants in the snails and sediments which can be used for environmental management in future. |
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