ONLY three per cent of the total industrial units treat their wastes while the rest discharge untreated effluent into rivers, lakes and sea. Dumping of untreated wastes has contaminated the surface and ground water resources and threatened the aquatic life. About 47 per cent of the population is still without access to safe drinking water, and nearly 84 per cent of rural population is without sanitation facilities. Water borne diseases account for 20 to 30 per cent of infant deaths.

The number of textile, leather, sports, surgical and food processing mills and factories have grown in numbers. And these factories are emitting more and more toxic effluents into the air and water.

The polluted water crisis has not only eclipsed its agriculture and economy but also ruined the ecology, health, life-style and social fabric.. When toxic substances enter lakes, streams, rivers, oceans, and other water bodies, they get dissolved or lie suspended in water or get deposited on the bed. This results in the pollution of water whereby the quality of water deteriorates, affecting aquatic ecosystems. Pollutants can also seep down and affect the groundwater deposits. The effects of water pollution are devastating both to human beings and animals, fish, and birds.

Polluted water is not suitable for drinking, agriculture, and industry. It diminishes the aesthetic quality of lakes and rivers. Contaminated water is a threat to aquatic life and reduces its reproductive ability. Eventually, it is hazardous for human health.

Groundwater quality has also suffered from increasing use of pesticides and fertilisers. Pollutants from these wastes create lot of problems for the aquatic life, crops, animals and human beings.

The use of land for agriculture and the practices followed in cultivation greatly affect the quality of groundwater. Intensive cultivation of crops causes chemicals from fertilisers (e.g. nitrate) and pesticides to seep into groundwater, a process commonly known as leaching. Routine applications of fertilisers and pesticides for agriculture and indiscriminate disposal of industrial and domestic wastes are increasingly being recognised as significant sources of water pollution. The high nitrate content in groundwater is mainly from irrigation run-off from agricultural fields where chemical fertilisers have been used indiscriminately.

Waste water from manufacturing or chemical processes in industries contributes to water pollution. Industrial waste water usually contains specific and readily identifiable chemical compounds. But water pollution is concentrated within a few sub-sectors, mainly in the form of toxic wastes and organic pollutants. Out of this a large portion can be traced to the processing of industrial chemicals and to the food products industry.

In fact, a number of large and medium-sized industries in the region do not have adequate effluent treatment facilities. Most of these defaulting industries are sugar mills, distilleries, leather processing industries, and thermal power stations. Most major industries have treatment facilities for industrial effluents. But this is not the case with small-scale industries, which cannot afford enormous investments in pollution control equipment as their profit margin is very low. In this scenario, the following steps should be taken promptly..

• Establishment and operation of cost-effective water quality monitoring systems for agricultural uses.

• Prevention of adverse effects of agricultural activities on water quality for other social and economic activities and on wetlands through optimal use of on-farm inputs and the minimisation of the use of external inputs in agricultural activities.

• Establishment of biological, physical and chemical water quality criteria for agricultural water users and for marine and riverine ecosystems.

• Prevention of soil runoff and sedimentation.

• Proper disposal of sewage from human settlements and of manure produced by intensive livestock breeding. Minimisation of adverse effects from agricultural chemicals by use of integrated pest management.

• Education of communities about the pollution impacts of the use of fertilisers and chemicals on water quality and food safety.

For the last few decades, research activities all over the world are focusing on some green technologies to tackle polluted environment problem and particularly the industrial wastes. Plants can help clean up many kinds of pollution, including metals, pesticides, explosives, and oil. The plants also help prevent wind, rain, and groundwater from carrying pollution away from sites. Green plant can absorb organic as well as inorganic contaminants from polluted water as well as soil and subsequently break them internally or discharge them into the air along with the transpiring water. The use of green plants does not have the destructive impact on soil fertility and structure that some more vigorous conventional technologies may have, such as acid extraction and soil washing. Instead, the presence of plants is likely to improve the overall condition of the soil, regardless of the degree of contaminant reduction.

Green plants can work best at sites with low to medium amounts of pollution. Plants remove harmful chemicals from the ground when their roots take in water and nutrients from polluted soil, streams, and groundwater. Plants can clean up chemicals as deep as their roots can grow. Tree roots grow deeper than smaller plants, so they are used to reach pollution deeper in the ground.

Once inside the plant, chemicals can be stored in roots, stems, or leaves or changed into less harmful chemicals within the plant or changed into gases that are released into the air as the plant transpires.

Green plants will be of worth even if chemicals are not taken into the plant by roots. For example, chemicals can stick to plant roots or they can be changed into less harmful chemicals by bugs or microbes that live near plant roots. The plants are allowed to grow and take in chemicals. Afterward, they are harvested and destroyed, or recycled if metals stored in the plants can be reused. Usually, trees are left to grow and are not harvested. Growing plants can help keep harmful chemicals from moving from a polluted site to other areas. The plants limit the amount of chemicals that can be carried away by the wind or by rain that soaks into the soil or flows off the site.

All developed nations prefer green technologies to handle contaminated environment because it takes advantage of natural plant processes. It requires less equipment and labour than other methods since plants do most of the work. Trees and plants can make a site more attractive as well. The site can be cleaned up without removing polluted soil or pumping polluted groundwater. This allows workers to avoid contact with harmful chemicals.

The idea of using green plants to recover precious metal from contaminated soil and water (phyto-mining) makes the concept more aesthetically appealing. Phyto-miners (peoples who perform phyto-mining) grow a crop of a metal hyper-accumulating plant species, harvest the biomass and burn it to produce a bio-ore. Further the plants used for this purpose will be rich source of various organic as well as inorganic compounds which can be used for thermal energy production after harvest. So there is dire need to develop means to use green plants to handle the contaminated environment in a valuable way.