Heavy metal pollution has become one of the most serious environmental problems at present.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/study-methods-used-treat-wastewater-heavy-metals
[2] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/heavy-metals
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-pollution-control
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environment
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/wastewater-treatment