Unfortunately our oceans are suffering from many types of pollutants that are prominent in our environment. One of the main distributors of pollution is sewage. Sewage and other polluting substances flow into the world's rivers and drainage pipes until all of the substances dump out into the ocean. In addition to sewage, other chemicals finds its way to the oceans, which leads to the reduction of oxygen being released into the atmosphere. With this in place, the waters become murky and filled with substances that can harm marine life.
Several efforts have been made over recent years to maintain a safe and clean environment. However, environmental pollution is getting worst and poses a major threat to the Earth. Environmental pollution is “the contamination of the physical and biological components of the Earth to such an extent that normal environmental processes are adversely affected” (Kemp, 1998, p. 129). There are five known pollution which is in the form of air, water, land, noise and light (refer to Figure 1 in Appendix 1). The first type of pollution is air pollution.
Water pollution is one of the main problems of today’s society. Inorganic and organic contaminants release from various industries represents a serious threat to environment due to their accumulation throughout the food chain. Human as final consumer is more sensitive to such pollutants, since biomagnifications of contaminants occurs at each successive trophic level. Conventionally used methods became expensive and require aggressive conditions that may lead to generate secondary pollutants. Therefore, worldwide there is a continuous interest in development of new, effective and inexpensive techniques for the removal of pollutants.
Natural aquatic bodies are being polluted due to untreated effluents released from agricultural, industrial and sewage waste waters. These pollutants are harmfully affecting the aquatic life, including fish (Gagnaire et al., 2004). Among aquatic pollutants, there exist organic and inorganic compounds such as combustible substances, petroleum products, phenol, textile dyes and heavy metals. Among inorganic contaminants, heavy metals are the prominent ones (Jadhavet al., 2010). Fish are more susceptible to the harmful impacts of pollutants and serve as an excellent tool for understanding the health status of aquatic ecosystem (Donohue et al., 2006).
This does not reveal the impact of chemical pollution on the aquatic environment because of potential synergistic/antagonistic effects of complex mixtures of chemical pollutants. It represents a major challenge in current eco-toxicological research by identifying a suitable biomarker of toxicity. (Cheung et al., 2007). Many parameters have been investigated to assess disturbances of various physiological functions linked to chemical exposure (Van der Oost et al., 2003). The role of antioxidant systems is to protect the cells from this oxidative stress through , measuring the components of the antioxidant defense system to determine the exposure of organism to pollutant (Bilbao et al., 2010).
Source of anthropogenic metal contamination include industrial effluents, fuel production, mining, smelting processes, military operation, utilization of agricultural chemicals, small-scale industries (including battery production, metal products, metal smelting and cable coating industries), brick kilns and coal combustion (Zhen-Guo et al., 2002). One of the prominent sources contributing to increased load of soil contamination is disposal of municipal wastage. This wastage is either dumped on roadsides or used as landfills, while sewage is used for irrigation. These wastages, although useful as sources of nutrients, are also source of carcinogens and toxic metals. Other source can include unsafe or excess application of pesticides, fungicides and fertilisers (Zhen-Guo et al., 2002).
Environmental pollution is a wide-reaching problem and it is likely to influence the health of human populations in a great way. The affects of environmental pollution in the perspective of air pollution, water and land/ soil waste pollution on human by diseases and problems, animals and trees/ plants. These kinds of pollutions are not only seriously affecting the human by diseases and problems but also the animals and trees/ plants.  One could claim that air pollution started when humans began burning fuels. In other words, all man-made (anthropogenic) emissions into the air can be called air pollution, because they alter the chemical composition of the natural atmosphere.
Water pollution caused by heavy metals is a global problem. The discharge of toxic metals into the ecosystem may severely affect the biotic as well as abiotic components of the environment. These metals are generally derived from different industrial activities such as mining, metal finishing, battery manufacturing, electroplating, etc. and are responsible for contaminating the receiving water bodies even when present in trace amounts. This is due to their carcinogenic and toxic properties (ATSDR, 2013).
Water plays a great role in our body system. Different contaminants are released to the wastewater with the rapid industrialization of human society, including heavy metal ions, which are serious harmful to human health. Among all water contaminations, heavy metal ions such as Pb2+, Cd2+, Zn2+, Ni2+ and Hg2+ have high toxic properties, can cause severe health problems in animals and human beings . In addition, industries have grown in large numbers throughout the world such as mining activities, refining, battery manufacture, paint production, chemical industries, dye industries and pharmaceutical industries etc. Among these, industries are creating a wide spread of pollution to the environment, especially the increased levels of heavy metals such as cadmium, lead, cobalt and mercury in to the soil and aquatic system; these heavy metals have highly hazardous and toxic nature which can affect the human health and living things.
2.1. Soil contamination Occurrence of man-made actions is the main reason for soil pollution. The waste products which are coming from anthropologic are made of chemicals that are not originating from the environment which will finally lead to soil pollution. Manufacturing activities is one of the reasons for soil pollution, chemicals used in farming and incorrect removal of waste. Straight and unintended interaction with polluted soil leads to health risks.