Malaysia is rapidly developing towards being an industrial country. Many industries such as heavy and light industries, small and medium industries and backyard industries have been growing in the last ten years. The increase in industrial and agricultural activities has created a new demand in housing, urbanization, transportation and medication as the population increase. All these will contribute to environmental problems especially pollution due to the accumulation of hazardous chemicals such as heavy metals in environment.
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Environmental pollution has become a major issue that requires immediate action as it may effects human health. Pollution can take many forms such as water and air that we breathe. Urbanization in developed and development country, civilization and industrialization make the situation of the environment worsened as such that there is no more safe place to live. From the chemistry dictionary, pollution can be define as an undesirable change in the physical, chemical, or biological characteristics of the natural environment, brought about by man’s activities. It may be harmful to human or non living things. Basically there are two main classes of pollutants which are biodegradable which means it can be rendered harmless by natural processes and need therefore cause no permanent harm if adequately dispersed or treated such as sewage. Another type is nonbiodegradable which cannot be decomposing by microbial activity. For example heavy metals such as lead, DDT and other chlorinated hydrocarbons used as pesticides, which eventually accumulate in the environment and may be concentrated in food chains.
Pollution also can be describes as the introduction of foreign substances into the biosphere. It may affect the soil, rivers, seas, or the atmosphere. The pollutants that are released from the anthropogenic activities such as agricultural industries, open burning, solid waste disposal, sewage treatment plants and transportation produce hazardous and poisonous pollutants such as SO2, NOx, heavy metals and hydrocarbon compounds that effects not only human but also both plants and animals that can cause death. Some of these hazardous pollutants find their way into the human system through the food web. They may undergo biotransformation, metabolism and excreted without the risk of toxicity depending on the chemical characteristics of the compound and the dose in human body. However, some of the pollutants resist chemical and biological transformation and accumulate in the tissues, including the nerves, to cause toxicity. The adverse effects of these pollutants on the nerves system give rise to neurotoxicity. Rana et al.,(2004); Katranitsas et al., (2003) found that there is evidence that increasing exposure to toxic elements in marine and terrestrial organisms is having adverse toxicological consequences. Therefore heavy metals pollution become serious issues that must been concerned.
Unlike other pollutants such as petroleum hydrocarbons and domestic and municipal litter which may visibly build up in the environment, trace metals in the environment may accumulate unnoticed to toxic levels. Generally, human health problems associated with trace metal contamination have been well-highlighted in the literature. In spite of the relatively low level of industrial activity in less developed regions there is nevertheless a high potential of toxic heavy metal pollution. The distribution of metals in the environment is a result of natural processes (volcanoes, erosion, spring water, bacterial activity) and anthropogenic activities (fossil fuel combustion, industrial and agricultural processes) (Florea and Busselberg, 2006).
Heavy metals such as arsenic lead, copper, cadmium, or zinc are released from the earthâ€™s crust into the environment through anthropogenic sources such as non-ferrous metal industry or non-renewable energy consumption. These substances can cause major damage to human health or to ecosystem stability even at low concentrations in soils. To overcome this issue, many countries have taken numerous initiatives especially the developed country. For example, in 2001 the European Union council signed the 1979 Convention on Long-range Transboundary Air Pollution on Heavy Metals (Europa, 2007). Therefore there are many methods to evaluate and assess the presence of these substances. One of them is biological used.
The application of biological forms as the indicators is the best ways to evaluate the environmental condition. According to (Szczepaniak and Biziuk, 2003; Bargagli, 1998), in order to detect, evaluate and minimize the effects, there has been an emphasis in the use of natural bioindicators to monitor atmospheric quality in both urban and rural environments. Examples of bioindicators are lichens, fish, and mosses.
One of the bioindicators that can be used is lichens. Lichens are widely known as an excellent indicator to assess our environment. Lichens play importance roles to forest communities. Lichens represent a rare source of readily digestible food at all times of year and in diverse environments due to their ability to survive in extreme climate condition. More generally, lichens act as pioneer species in barren or disturbed environments; their growth on rock surfaces is one of the primary stages of soil formation in such environments (BrÃ¥kenhielm, 1998; Cooper, 1953 in Dawson, 2008). Lichens are small, non-vascular plants consisting of a fungus and an alga growing together in one tissue. Normally lichens are found on the bark of trees, or the reindeer lichens growing on the ground, but many other species grow on rocks, fences, roofs, tombstones, and other objects. The characteristic of lichen that sensitive to the changes of the surrounding makes them as an excellent bioindicators and biomonitors for air pollution, especially sulfur dioxide pollution, since they derive their water and essential nutrients mainly from the atmosphere rather than from the soil.
A lot of studies towards lichens had been done related to pollution especially air pollution in most Europen countries and North America Asia. During the period 1973-1988, approximately 1500 papers were published on the effects of air pollution on lichens Richardson (1988) cited in Ahmadjian (1993), and many general reviews of lichens and air pollution have been compiled (Ahmadjian, 1993). The legislation about air quality that they made has been passes through out the countries especially in developing countries where air pollution is bad. In Malaysia, several studies has been conducted (Mokhtar et al., 2006) to determine the heavy metals pollution level using lichen at difference places. From the research, they found out that the sensitivity of lichens towards heavy metals vary from each species. Most of species of lichen have a wide geographical distribution, which allows for a study of pollution covering wide areas and its high capacity to accumulate metals (Burton, 1986). Hutchinson et al., (1996) stated that lichens do not have seasonal variations and therefore accumulation of pollutants can occur all year-round. Lichens and mosses usually have considerable longevity, which led to their use as long-term integrators of atmospheric deposition (Sloof, 1993). The benefits of using lichens as quantitative biological monitors of air metal deposition compare to conventional air sampling techniques rise from that lichens are present in most terrestrial habitats, are perennial, inexpensive and easy reproduced (Baffi et al., 2002).
Nowadays the level of heavy metals in the environment increasing day by day as the world becomes much more developed. This is because the uncontrolled released of heavy metals leads to the pollution due to the excessive anthropogenic activities. The continuous loading of heavy metals into inland and coastal water make the situation worsens. Anthropogenic activities such as mining, smelting and agriculture have locally increased the levels of heavy metals such as cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), arsenic (As) and nickel (Ni) in soil up to dangerous levels for plants, animals and human beings. Although with the forest around us, the status of heavy metals level quite crucial as the result of human daily activities, dense population area near the forest and also an increasing of the transportation. These activities give adverse effect to the life being as they enter into the environment. Other than that the regulations provided by Malaysian government which is the Environmental Quality Act 1974 by Department of Environment, still not fully been forced due to the involvement other parties such as local authority to take action when the level of pollutants exceed the standard given especially in coastal area. This is due to the different department have different responsibilities. Nevertheless these parties can be work together to create a better life. Meanwhile due to the lack of studies towards the lichens in our country, the data obtained can help the local authority in decision making process thus maintained the quality. Besides that, it would help to make an assessment about the environmental condition and perhaps to improve environmental quality status.
This study was carried out in order to achieve as the followings:
To quantify the heavy metals present in lichens.
To evaluate the level of heavy metals in lichens.
To establish the correlation of heavy metals pollutants in lichens with the surrounding environment.
Significant of study
By knowing that different species has different sensitivity towards heavy metals, it allow bettering understanding about the sensitivity of lichens towards heavy metals at surrounding environment. The presence or absences of species in areas can give better understanding about the sensitivity of lichens towards the pollutants. The data obtained also can be used to assess the toxicology effects not only to the lichens but also on human. Heavy metals can very toxic if the level of the pollutants higher than the limited given. The data also can create the distribution patterns of lichens at that place. The pollution level and status place also can be determined. This study provides a reference record for conducting further biomonitoring studies.
The determination of heavy metals in lichens as bioindicators is a thesis based on previous research in different sampling location. Overall, this thesis consists of five chapters which are to assist in understanding and ease to organize through writing process. The chapters in this thesis have been organizing as follows:
Chapter 2 generally discuss about the used on lichens as bioindicators. In this chapter, it also has detailed explanation on the morphology of lichens that play important role in accumulate heavy metals. It also include the history on the scientific research on lichens, the significant role on absorb the heavy metals and the effects of air pollution and metal pollution towards lichens.
Chapter 3 is more focusing on research methodology. In this part, it is divided into three parts which are the description on area of study, sampling collection and lastly laboratory analysis which is the procedure to determine heavy metals using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS).
Chapter 4 is focusing on the results obtained and discussion. In this chapter, it discuss about the data obtained after analyze by ICP-MS. It also include the statistical tools to analyze the precision of the data obtain in order to have a good data. It also states the results and the data interpretation between the samples.
Chapter 5 is the last chapter which is the conclusion. In this part, it concludes for the whole chapter in the thesis. It related on the objective of the study including the recommendation to improve the research on lichens.
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