Toxicology Assessment of Organophosphate Fire Retarded Products - Research Proposal Example

TOXICOLOGY ASSESSMENT OF ORGANOPHOSPHATE FIRE RETARDED PRODUCTS Name: Course: Instructor: Institution: Date of Submission: Toxicology Assessment of Organophosphate Fire Retarded Products 1.0 Aims and Objectives The objective of this project will be to evaluate the most commonly used flame retardants based on phosphorus element. The flame retardants are Triphenyl phosphate, Tributylphosphate, Tris (2-butoxyethyl) phosphate, Tritolyl Phosphate and Tris (2-choroethyl) phosphate). 2.0 Literature Review Triphenyl phosphate a. Common applications In 1984, Triphenyl phosphate was used in Japan in resins for manufacturing automobile and electrical parts and as a non-flammable plasticizer in cellulose acetate for photographic films. It is also used as a plasticizer in lacquers and varnishes, a non-combustible substitute for camphor in celluloid and for impregnating roofing paper and as component of hydraulic fluids and lubricant oils (Sundkvist, Olofsson & Haglund, 2012, p. 943). b. Chemical and physical properties It is white in physical appearance, its Phosphorus content, is 9.5% by weight. The specific gravity is 60°C / 60 °C is 1.268 the melting Point is 49°C and its acidity as phosphoric acid is 0.003%. It is solid at room temperature and has a melting point of about 48 -50 °C. Its boiling point is 245 °C (at 14.6hPa). It also has a density of 1.2055 g/cm³ at 50 °C. It is heavier than water with a vapor pressure of 25 °C with 0.000835 Pa. (Vidair 2004, P. 300). c. Intrinsic toxic effects on human health and the environment According the van der Veen, & de Boer, (2012, p. 1137) tryphenyl phosphate causes contact dermatitis and it can act as an inhibition to human blood monocyte carboxylesterase which has adverse effects on the immunologic body defense system. There are different reports with different results from different authors about tryphenyl phosphate. Some authors say that the compound is neurotoxic but others have found that it has a low neurotoxicity or causes delayed neurotoxicity. d. Exposure assessments, persistence and bioaccumulation According to the World Health Organization (1991) concentrations in water within the environment are low and there are no possibilities for toxic effects on aquatic organisms. Triphenyl phosphate is rapidly removed from the bodies of fish after exposure. Bioaccumulation is not seen as a hazard (Kasper, Daae, Thorud, Ellingsen, Lundanes, & Molander, 2010, p. 2259). Because it is used in lubricants and in hydraulic fluids, there is a possibility for it being released into water, air or land in the process of manufacture or use. It however does not persist in the environment and it has a very low bioaccumulation potential. The potential of exposure to the environment and people is only medium (Wright & Hartmann, 2010, p. 1755). Tributyl phosphate a. Common applications TBP is used as a component of aircraft hydraulic fluid and also as a solvent for extracting and purifying rare earth metals from the ores. It is also used as a solvent in ink, adhesives, gums, synthetic resins, fungicide and herbicide. It also serves as an anti-forming agent in detergents, paints, adhesives and emulsions (van der Veen, & de Boer, 2012, p. 1125). In is used in mercerizing liquids to improve the wetting properties and as a medium for heat exchange. It serves as a plasticizer and extractant. b. Chemical Description and Physical Properties It is colorless to pale yellow, odorless liquid with a molecular weight of 266 and a boiling point of 560°F. Its vapor pressure is extremely low and the melting point is -112°F. It is a non-hazardous liquid (Follmann & Wober, 2006, p. 127). c. Intrinsic toxic effects on human health and the environment It shows a slight inhibitory effect on human plasma cholinesterase. It has harmful effects when inhaled and can enter the body through the skin as well. It irritates the eyes, throat, nose and the skin. When inhaled it irritates the lungs and result in shortness of breath and coughing. Higher exposure may be the cause of fluid accumulating in the lungs which may also cause shortness of breath. High exposure may result into drowsiness, tremors, headache, coma and convulsion. d. Exposure assessments, persistence and bioaccumulation When TBP enters the air, only a small quantity of it will persist in the air. If it enters water it exhibits moderate sorption to solid in the water based on the approximate Koc value of about 3 and the experimental log Kow of about 4. If it is released into water, it remains mainly in the water or it may form sediments. It has slight mobility when in soil. Therefore, in soil, it is likely to remain there (Green 1996, p. 353). Tris(2-butoxyethyl) phosphate a. Common applications Tris(2-butoxyethyl) phosphate is used as a flame retardant and a viscosity regulator in different types of polymers such as polyacrylates, polyurethanes and polyester resins. It is also used as a plasticizer (Wright & Hartmann, 2010, p. 1756) b. Chemical and physical properties, It has a vapor density of 13.7 (vs air), vapor pressure of 0.03 mmHg (150 °C), assay 94%, refractive index at n 20/D 1.438(lit.), bp at 215-228 °C/4 mmHg(lit.) and density 1.006 g/mL at 25 °C (lit.) (van der Veen & de Boer, 2012, p. 1130). c. Intrinsic toxic effects on human health and the environment It irritates the skin and the eyes and can cause swelling and inflammation. It can irritate local tissue resulting in rhinorrhea, bronchospasm, irritation of oral mucous membranes, cough, acute lung injury shortness of breath and rarely upper airway swelling (Wright & Hartmann, 2010, p. 1756). When produced and used in as a plasticizer in rubber gaskets and commercial floor care products it may be released into the environment via different waste streams. It causes adverse biological effect on people including reproductive and hemolytic effects such as low fertility, reduced sperm density and motility and a longer estrous cycle length (Follmann & Wober, 2006, p. 127). e. Exposure assessments, persistence and bioaccumulation When tri (2-butoxyethyl) phosphate (TBEP) is produced and used as a plasticizer in rubber gaskets and commercial floor care products it can be released into the environment through different waste streams (Green, 1996, p. 353). When released into the air it remains as particulates. When released into soil it exhibits slight mobility based on a Koc of 2600. There is no volatization from moist soils based on an approximate Henry's Law constant of 1.2X10-11 atm-cu m/mole. When it enters the water it sticks on sediments and suspended solids. It is however not readily biodegradable (Vidair, 2004, p. 297). Tritolyl Phosphate a. Applications It serves as a platicizer especially in nitrocellulose, polyvinyl chloride, varnishes and acrylate lacquers. In rubber and plastic it is a flame retardant. It also serves as a gasoline additive being a lead scavenger for tetraethyl lead (Wright & Hartmann, 2010, p. 1754). It is also a medium of heat exchange and a hydraulic fluid. It is also important in waterproofing materials, and as a solvent for polymers, nitrocellulose and for extractions. It is also used as a pressure additive in hydraulic fluids and lubricants and as an anti-wear (Gordon, O'Dell & Watkin, 1994, p. 93). b. Chemical and physical properties It is either a colorless, brown or light yellow liquid. It has a vapor pressure of 0.03 mmHg (25 °C), assay at 90%, auto-ignition temperature of 770 °F, refractive index of n20/D 1.555(lit.), b p of 265 °C/10 mmHg(lit.) and density of 1.143 g/mL at 25 °C (lit.) (Vidair, 2004, p. 290). c. Intrinsic toxic effects on human health and the environment Ingesting the substance can be fatal or seriously damage a person’s health. It does not irritate the eyes but it causes transient discomfort when it enters the eye. On the skin it causes serious, irreversible damage to body organs. It triggers a skin reaction called non-allergic contact dermatitis (Follmann & Wober, 2006, p. 127). When it enters the blood stream it can cause systemic injury and harmful effects. It does not irritate the respiratory tract. However, prolonged inhalation can cause respiratory discomfort and distress at times. d. Exposure assessments, persistence and bioaccumulation When exposed to flames and heat, it poses a slight fire hazard. When heated it can cause decomposition or expansion and this can cause containers to rapture violently. It can emit toxic fumes on combustion with carbon monoxide fumes. It may also emit acrid smoke. Mists can be explosive especially if they have combustible materials (Saleem, Williams, Wilkins, Shakoori & Mantle, 1998, p. 73). Tris(2-chloroethyl) phosphate) a. Common applications of the organo-phosphorus fire retardants It is used as noncombustible substitute for camphor in celluloid, roofing paper impregnation, as a plasticizer in lacquers & varnishes, rendering nitrocellulose and acetylecellulose and fire proofing (Gordon, O'Dell & Watkin, 1994, p. 90). b. Chemical and physical properties Tris (2-chloroethyl) phosphate is an additive FR and when subjected to fire, the phosphorus becomes active only in the solid state. It also has a gas phase action mechanism. Its boiling point is 351 °C and it remains stable at 150°C when exposed for a short time. However, at 220°C, it undergoes rapid decomposition to form hydrogen chloride, carbon monoxide, dichloroethane and 2-chloroethane. As the pressure and temperature increase, the hydrolytic stability of the compound goes drown. This is the same case when the pH is extreme. TCEP is highly soluble in water with a solubility of 7.1g/l., a log kow value of 1.44. TCEP is harmful to the environment and is very bio-accumulative. It has a BCF of 1.37 (van der Veen & de Boer, (2012, p. 1138). c. Intrinsic toxic effects on human health and the environment, It has been shown through several studies to have toxic effects such as adverse liver, brain, kidney, and brain effects. It produces tumors in different organs and it has been believed to be carcinogenic. It inhibits the expression of the proteins regulating the cell cycle, the synthesis of DNA and cell numbers. According to van der Veen & de Boer, (2012, p. 1138) tris (2-choroethyl) phosphate) has adverse biological effects on humans. These include productive and hemolytic effects including reduced fertility, lower sperm density, reduced sperm motility and a longer estrous cycle length. d. Exposure assessments, persistence and bioaccumulation It is an additive that is not chemically bonded to final products because this can cause an easy release to the environment. It has been detected in indoor air, drinking water, biota, and sediment and house dust before. Laboratory experiments Regnery and Püttmann (2010) cited in Wright & Hartmann, (2010, p. 1756) indicated that it is rapidly degraded by sunlight. It is hard to eliminate from the environment because it persists. Therefore it has been detected in drinking water and in sewage treatment plants. 4. Experiment Design The experiment will be completed in a total of three months. The first two months will be used for laboratory work while the remaining one month will be used for preparing the report. The researcher will make use of pyrolysis Gas Chromatography–Mass Spectrometry (pyGCMS) together with the FTIR interface Brill Cell. The researcher will analyze the resultant mass spectrometry ion fragmentation and FTIR spectra. He will then investigate the pyrolysates such as phosphorus polyclic and cyclic aromatic hydrocarbons as well as other volatile organic compounds. The investigation will be done at different temperatures. The experiment will be done in the provided order of activities. The researcher will run the bland before each compound after which he will run the compounds with varied temperature ranges. From the results obtained from the chromatograms, he will present and compare the blanks and repeatability of the chromatograms for each one of the temperature ranges. He will then give a description of the identities of the compounds characterized through the use of library searches. The next step will be to list the pyrolysates obtained from each sample for each of the temperatures. The list will be among others compounds such as cyclic, phosphorus, PAH. The researcher will then compare and contrast all the thermal degradation products from the various temperature ranges. Finally, he will conduct an evaluation of the toxicology of the pyrolysates. 5. Application for Ethical Approval The researcher will be required to make an application to relevant authorities before undertaking the project. The application will involve a letter requesting permission to be allowed to use the laboratories for the experiment which will be the data collection part of the study. An ethics application will be made to a REC (regional extension center). The REC will carry out a review of the research protocol as well as other documents relevant to the project so ensure that the rights, dignity, well being and safety of the subjects in the research will be protected. The researcher will get the opinion of a recognized REC, authorization from the licensing authority which is the Medicines and Healthcare Products Regulatory Agency Bibliography Follmann, W., & J. Wober. 2006. Investigation of cytotoxic, genotoxic, mutagenic, and estrogenic effects of the flame retardants tris-(2-chloroethyl)-phosphate (TCEP) and tris- (2-chloropropyl)-phosphate (TCPP) in vitro. Toxicol. Lett. 161:124-134. Gordon, P.L & O'Dell, C. & Watkin, J.G 1994. “Synthesis and energetic content of red oil,” Journal of Hazardous Materials, vol. 39, no. 1, pp. 87–105, 1994. Green J. 1996. A Review of Phosphorus- Containing Flame Retardants. Journal of Fire Sciences 1996; 14; 353. Kasper S., Daae, H.L., Thorud, S., Ellingsen, D.G., Lundanes, E. & Molander, P. 2010. Exposure to airborne organophosphates originating from hydraulic and turbine oils among aviation technicians and loaders, J. Environ. Monit., 12, 2259. Patil, L.K & Gaikar, V.G, Kumar, S., Kamachi M.K. & Natarajan, R. 2012. Thermal Decomposition of Nitrated Tri-n-Butyl Phosphate in a Flow Reactor. Institute of Chemical Technology, Mumbai, India. Saleem MA, Williams FM, Wilkins RM, Shakoori AR, Mantle D. 1998. Effect of Tri-O-cresyl phosphate (TOCP) on proteolytic enzyme activities in mouse liver in vivo. J Environ Pathol Toxicol Oncol. 1998; 17(1):69-73. Sundkvist, A.M., Olofsson, U., & Haglund, P. 2012. Organophosphorus flame retardants and plasticizers in marine and fresh water biota and in human milk, J. Environ. Monit., 2010, 12, 943. van der Veen, I., & de Boer, J. 2012. Phosphorus flame retardants: Properties, production, environmental occurrence, toxicity and analysis. Chemosphere 88 (2012) 1119–1153. Vidair C.A. 2004. Age dependence of organophosphate and carbamate neurotoxicity in the postnatal rat: extrapolation to the human. Toxicology and Applied Pharmacology 196 (2004) 287– 302. Wright & Hartmann, P. 2010. “Review of physical and chemical properties of tributyl phosphate/diluent/nitric acid systems,” Separation Science and Technology, vol. 45, no. 12, pp. 1753–1762. Read More