1. Chemical Contaminants for Soil, Air and Aquatic Ecosystem

Chemicals from fossil fuel use, domestic and industrial waste products, mining and agriculture contaminate air, water and soil. Contaminant chemicals may have considerable implications for human health and safety, welfare and the value of nature. Air contaminants include carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), nitrogen oxides (NO_x), hydrofluorocarbons (HFC_s), perfluorocarbons (PFC_s) and sulphur hexafluoride (SF₆). These gases brings climate change by increasing the temperature of the earth’s atmosphere and oceans. Climate change is responsible for unpredictable changes in precipitation, rising sea level and extreme climate events. Air contamination can be controlled by passing a law against harmful chemicals production, introducing special devices that reduce green houses gases, and making use of alternative sources of energy. Major water contaminants include sewages, petroleum products (like polychlorinated biphenyls), nitrates, insecticides, sediments and excess organic matters. Harmful chemicals may reach water bodies from outlet of pipes in industries; leakage of pipe line or storage tanks, mining operations, improper application of fertilizers and pesticides in agricultural fields and some leakage from ships. Water contaminants inflict vital body organs, nervous systems, and cause different types of cancers and cardiovascular effects. Soil contamination is caused by dispersion of toxic compounds, acidification, salinization and sodification, enhanced soil erosion, chemical fertilizers, pesticides, fungicides, and the accumulation of heavy metals and other inorganic contaminants. Like air and water contaminants, soil contaminants, if they enter into our body, are also causative agents of many diseases. There are many tangible mechanisms to control soil contaminants such as landfills, incineration or burning, composting and recycling.