Environmental Hazard analysis - Dioxins
Introduction
Dioxin compounds are a group of hazardous chemicals, which are discharged into the environment as a by-product of human processes like chlorine bleaching of paper, combustion, forest fires, and manufacturing processes . The most widely known compound among the dioxin family of compounds is 2, 3, 7, 8-tetrachloro-p-dibenzo-dioxin (2, 3, 7, 8 TCCD), which is regarded as the most toxic.
Classification
Dioxin-bearing wastes are classified into the EPA defined F-type list which contains the non-specific wastes, emanating from different sectors of the industry . These wastes include those generated during the production or manufacturing of tri- or tetrachlorophenol, pentachlorophenol or intermediate byproducts released during their production, discarded formulations consisting of the above compounds, residues produced during the thermal incineration of soil contaminated with above hazardous chemicals .
Legislation
The EPA has imposed several regulatory measures in accordance with the guidelines and provisions of the Clean Air Act (CAA), Toxic Substance Control Act (TSCA), and the Clean Water Effluent guidelines, limiting the emission of dioxins from various sources.
Hazard related risk to the environment and humans
Dioxins are extremely toxic compounds that can cause serious adverse effects on the humans, animals and wildlife. Exposure to these compounds may cause cancer, inhibit the endocrine system and lead to developmental defects. Experimental evidence from many animal and human studies has caused the EPA to classify 2, 3, 7, 8-TCCD and other dioxin compounds such as chlorinated dibenzo-p-dioxins (CDDs) and polychlorinated biphenyls (PCBs) as potential human carcinogens . Several dioxin compounds mimic the hormones of the endocrine system and disrupt their critical functions in the immune and nervous systems that contribute to the normal functioning of the reproductive and developmental systems .
The detrimental effects of dioxins such as pesticides like dichlorodiphenyl- trichloroethane (DDT) and PCBs on the environment and wildlife include reduced fertility rates in shell fishes, birds and mammals, decreases hatching levels in the reptiles, fish and birds. The immune and behavioral functioning in animals and overall survival efficiency is significantly altered with an exposure to dioxins .
Hazard Safety Requirements and Corrective Actions
The United Nation’s Environmental program has recognized dioxin as a persistently threatening pollutant and formed a global treaty to reduce and ban its use. According to the 1998 policy guidelines developed by the Agency for Toxic Substances and Disease Registry (ATSDR), the recommended cleanup levels at Resource conservation and Recovery Act (RCRA) corrective action sites are set up at 1 parts per billion (ppb) of dioxin in residential soils and 5 to 20 ppb in industrial soils .
In the last few years, the EPA, various industries and state governments have worked in concert to significantly decrease the dioxin release into the environment. The EPA released its final document related to Dioxin on February 17, 2012, which provides an up-to-date information on the hazard analysis and dose-response data on the 2, 3, 7, 8 TCCD . Another interesting fact related to dioxin is the exploratory investigation designed by the EPA to examine the potential dioxin exposure to artists that make pottery related items contaminated with the dioxins . The combined efforts of various regulatory agencies and EPA in particular have resulted in up to 90 % reduction in the dioxin concentrations in the environment.
References
EPA. (1998, April 13). Retrieved from United States Environmental Protection Agency: http://www.epa.gov/superfund/policy/remedy/pdfs/92-00426-s.pdf
EPA. (2008, March). Hazardous Waste Listings. Retrieved from EPA.gov: http://www.epa.gov/epawaste/hazard/wastetypes/pdfs/listing-ref.pdf
EPA. (2012, Februrary 12). Integrated Risk Information System . Retrieved from United States Environmental Protection Agency: http://www.epa.gov/iris/supdocs/1024index.html
EPA, 1. (1997, February). Special report on environmental endocrine disruption: An effects assessment and analysis.Prepared for the risk assesment forum U.S Environmental Protection Agency, Washington D.C. US Environmental Protection Agency.EPA/630/R-96/012. Feb. 1996, 111.
EPA, 2. (2000). Information Sheet 1: Dioxin: Summary of the Dioxin Reassessment Science. U.S. Environmental Protection Agency. Office of Research and Development, June.12.2pp.
EPA, 2. (2008, November 25). An Exploratory Study: Assessment of Modeled Dioxin Exposure in Ceramic Art Studios (2008 Final). U.S. Environmental Protection Agency, Washington, DC,EPA/600/R-06/044F, 2008. Retrieved from http://cfpub.epa.gov/ncea/CFM/recordisplay.cfm?deid=199244
