EESA10 Assignment 2

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Environmental Science
Jovan Stefanovic

EES A10 H3 "HUMAN HEALTH AND THE ENVIRONMENT" Assignment #2 1A) Screening level risk assessment for a 70 kg male who has worked as an auto mechanic for 8 hours per day for 25 years. The chemical of concern is benzene that has been proven carcinogen and is a constituent of gasoline and automobile exhaust gases. The Estimated Daily Intake (EDI) is calculated below for two routes of exposure, through air, as in inhalation and breathing and through absorption, from the grease on hands. AIR: Where: IR: Inhalation intake rate C: Concentration of benzene in air B: Bioavailability factor EF: Occupational exposure frequency ED: Exposure duration BW: Body weight AT: Averaging time for a carcinogen ( )( ) SKIN: Where: C: Chemical concentration P: Permeability constant SA: Skin surface area (for hands only) B: Bioavailability factor EF: Occupational exposure frequency ED: Exposure duration BW: Body weight AT: Averaging time for a carcinogen ( )( ) The medium the receptor receive his greatest exposure is from inhalation. This could be because a person breathes at a much faster rate than the rate of absorption by skin. Secondly, once the chemical is been inhaled into the lungs, it can quickly be transferred to the bloodstream, passed along and deposited at different organs in the body, while for the absorption through skin, the main target is the hands. It is unlikely for the person to have grease on their hands all the time. Hence, benzene is presented in the air at all times, so the workers may be exposed to it even if he is just relaxing, eating, etc. 1B) The calculations for Relative Margin of Safety (RMOS) are show below: Where: EDI totalTotal Estimated Daily Intake from all routes of exposure (EDI skin EDI )air RsD: Risk Specific Dose - Equation for the RsD: Where: R: Acceptable risk Sf: Slope factor for benzene The RMOS is very large. Since it is greater than 1, we can assume that the decision point is not okay. 2) At this present time, it’s been said that the presences of foreign DNA sequences in food do not have any risk on the human health (Jonathan, 2011). The GM crops have been consumed by hundreds of millions of people across the world for more than 15 years, and so far, there are no ill effects reports or legal cases related to human health (Suzie, et al., 2008). Among the potential risk to human health that has been mentioned are: toxicity, allergenicity, the components thought to have negative effect on nutrition and the instability of the inserted gene (Jonathan, 2011). For example: there was a study on transgenes conducted in which 12 healthy volunteers and 7 ileostomists were given a meal of GM soya which contained the 5′enolpyruviyl shikimate-3′phosphate synthase (EPSPS) transgene glyphosate resistance (Singh et al., 2006). The results showed that in the healthy individuals, DNA from the transgenic plant material was degraded completely after passage through the colon (Singh et al., 2006). In case of six ileostomists, a PCR product spanning the entire gene was detected; in the 7th case, it was estimated that nearly 4 % of the transgenic DNA in the test meal wa
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