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Chapter 9
Possible Application of Bio-Analytical Assays in the Biological Impact Assessment of Persistent Organic Pollutants (POPs) in Mangrove Sediments in South East Asia with Particular Reference to Malaysia Poorani Krishnan,1,2 Narayanan Kannan,*,3,4 Ahmad Zaharin Aris,1 Palanisamy Arulselvan,2 and Sharida Fakurazi4 1Faculty
of Environmental Studies, Department of Environmental Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 2Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia 3AIMST University, Semeling, 08100 Bedong, Kedah Darul Aman, Malaysia 4Taylor’s University, No. 1, Jalan SS15/8, 47500 Subang Jaya, Selangor, Malaysia 4Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia *E-mail:
[email protected]. Current Address: Institute for Graduate Studies, Taylor’s University (Lakeside Campus), No. 1, Jalan Taylor’s, 47500, Subang Jaya, Selangor Darul Ehsan, Malaysia.
South Asia in general and Malaysia in particular face severe marine pollution due to industrialization and modernization. Although an analytical approach using chemical measurements is common in pollution monitoring, biological impact assessments using in vitro bioassays remain largely unexplored. Hence only a limited understanding has been achieved on the ecological impacts of pollutants in Asia, especially in Malaysia. The mangrove ecosystem is attributed with high economic and ecological values and, at the same time, is highly sensitive. Severe marine pollution along the coastal areas has affected the mangrove ecosystem. Hence it is imperative to identify and
© 2016 American Chemical Society Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries II ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
characterize the level and impact of pollution on the mangrove ecosystem both biologically and chemically. A battery of in vitro cell bioassays are listed and discussed in this review which would help the Malaysian researchers in assessing the chemical impact of pollution in the mangrove ecosystem.
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Introduction Bioassays are biological test systems that consist of whole organisms or parts of organisms (e.g., tissues, cells, proteins), which show a measurable and potentially biologically relevant response when exposed to natural or xenobiotic compounds, or complex mixtures present in environmental samples. Xenobiotics are anthropogenic agrochemicals and industrial products that enter the environment via atmospheric and riverine inputs. Persistent organic pollutants are a class of such chemicals. Once released into the marine environment, for example, organic pollutants are readily absorbed to suspended particles due to their lipophilic nature, and subsequently settled down in bottom sediments causing toxic impact to benthic biota and trophic organisms through food web transfer. The advantage using effect-based bioassay measurements is that they determine the integrated toxic potency of the complex mixture of microcontaminants in marine sediments. In addition, bioassays will reveal the additive effects of a mixture, even when the individual constituents of the mixture are present at concentrations too low to cause an effect or to be detected by chemical analysis.
Mangrove Ecosystem Mangroves are an ecological assemblage of trees, shrubs, palms and ferns that are adapted to grow above mean sea level in the inter-tidal regions of coastal and estuarine environments (1). Mangrove is one of 10 forest types found in Malaysia. In Peninsular Malaysia alone, 70% of these mangroves are officially recognized permanent reserve forests (2). Mangroves in Malaysia (Figure 1) bring both economic benefits alongside valuable ecosystem services (3). For example, they are highly productive and provide economic benefits from fish and shrimp catching, timber harvesting and non-timber products as well as recreation revenues (4). In particular, the mangrove ecosystem holds a crucial role in maintaining edible mud crab (Scylla serrata), gastropods (Cerithidea spp.) and cockles (Anadara granosa). According to Shukor et al. (5) the mangrove fishing industry alone contributes RM 650 million annually to the Malaysian national economy. Besides, mangroves act as the spawning and nursery ground for birds, fish, crustaceans, shell fish, reptiles and mammals, a renewable source of wood; and they offer protection against coastal erosion (6). It also supports the estuarine and near shore fisheries by providing detritus and nutrients. Unfortunately, mangrove sediments trap and accumulate anthropogenic pollutants. The mangrove ecosystem worldwide faces severe threat due to urban development, aquaculture, mining, pollution, overexploitation of timber and seafood. The increasing growth of human population in coastal areas results 204 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries II ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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in increased waste generation in the mangroves. This elevating pollution from urbanization and development severely affect mangrove ecosystem at rates faster than their regeneration capacity (7). This elevating pollution level causes concern on the potential toxicity to mangrove nurseries and associated biota. It is indeed crucial to identify and monitor the pollutants that affect the mangrove ecosystem in order to ensure its preservation and sustainability.
Figure 1. Distribution of mangrove forests in Peninsular Malaysia (Adopted from SCS/80/WP/94b). The east and west coasts of Peninsular Malaysia are strategically surrounded by South China Sea and Straits of Malacca respectively. The Straits of Malacca is the shortest shipping route for transportation of oil tankers from the Middle East to Asian countries such as Japan and China. This in turn makes it the busiest waterway in Southeast Asia. As a result, the west coast of peninsular Malaysia has become highly susceptible to marine pollution. Additionally, Malaysian industrialization and urbanization occur along the west coast of Malaysia leading to heavy loads of anthropogenic pollutants (8, 9). Studies demonstrate that the sediments of the mangrove ecosystem facing the Straits of Malacca and Sumatra are burdened with anthropogenic PAH inputs as a result of human activities such as biomass burning, vehicle emissions and boating activities (10). Malaysia has the second largest mangrove forests in Southeast Asia with a land area of 641,886 ha. 17% of the mangrove forest in Malaysia is to be found in Peninsular Malaysia (5) and the west coast contributes 96% of the total mangrove area found in Peninsular Malaysia (11). This indicates that a large percentage of this sensitive ecosystem is presently endangered by marine pollution. 205 Loganathan et al.; Persistent Organic Chemicals in the Environment: Status and Trends in the Pacific Basin Countries II ... ACS Symposium Series; American Chemical Society: Washington, DC, 2016.
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Persistent Organic Pollutants (POPs) in Marine Sediments in Malaysia In order to monitor the increasing marine pollution in Malaysia, chemical analysis is sought. Various instrumental techniques such as GC-FID, GC-ECD GC-MS, and HPLC have been applied to detect pollutants. In Malaysia, polycyclic aromatic hydrocarbons (PAHs) are found to be the major pollutant so far monitored in marine sediments. These ubiquitous pollutants are hydrophobic, lipophilic and generally resistant to biological and chemical degradation, and are available to filter feeders and sessile organisms. The PAHs (2–3 rings) in Malaysian sediments originate from petrogenic sources through major and minor oil spills (12, 13). Retnam et al. (9) identified both pyrogenic and petrogenic sources in coastal sediments. A study conducted on the surface sediments of the Malacca and Prai Rivers shows that the PAHs concentrations in the samples ranged from 716–1210 ng/g, and 1102–7938 ng/g respectively (14). Another comprehensive study conducted on the sediments of mangrove estuary from the western part of Peninsular Malaysia shows that the total PAH concentrations in the sediments ranged from 20 to 112 ng/g on a dry-weight basis. The levels of these compounds found in Malaysia are at moderate to high levels from a global perspective and capable of causing adverse toxic effects to the ecosystems.
Table 1. Mean concentration of PCBs in sediments collected from Asian countries (ng/g dry weight) Country
Sampling Location
PCBs
Reference
Vietnam
Mekong River Delta
0.49
(63)
Red River delta
4.32
(64)
Ho Chi Minh
46.4
(65)
Ho Chi Minh city canals
81
(66)
Hanoi (sewer)
104
(67)
Thi Nai Lagoon
2.4
(68)
Indonesia
Jakarta
-
(69)
Philippines
Manila Bay
