EESA10 - Assignment #1.pdf

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Environmental Science
Jovan Stefanovic

R i s kB e n e f i t A s s e s s m e n t B o a r dA s b e s t o s i s a m i n e r a l w i t h m a n y u n i q u e p r o p e r t i e sw h i c h a i d s i n i t s m a n y a p p l i c a t i o n sA s b e s t o s i s a b l eto withstand high temperatures chemical attack wear and as a poor conductor acts as a very good insulator against heat and electricity Pintos Parent Case RousseauSiemiatycki 2009 Asbestos has a wide variety of applications but until the 1980s it was mainly used in office buildings public buildings and schools as insulator against fire and sound CHMC nd Although asbestos has many practical applications I disapprove of its widespread use Studies have shown that inhalation of asbestos fibers can cause health complications such as asbestosis which describes severe scarring of lung tissue that impairs lung function CMHC nd and mesothelioma a form of cancer which affects the membranes lining internal organs Pintos et al 2009 Fiberglass can be used as a safe substitute for asbestos insulation because it saves energy money and keeps a moderately temperate home across various temperatures Dodson HammarPoye 2008D D T w a s w i d e l y u s e d a s a p o t e n t i n s e c t i c i d e f o r a g r i c u l t u r a l a n d h e a l t h p u r p o s e s f r o m t h e 1 9 4 0 s t o 1 9 7 0 s until health concerns led to its prohibited use in most parts of the world Eskenazi ChevrierRosas 2009 DDT proved to be a cheap and effective means of vector control against mosquitoes and lice helping to prevent malaria and typhus respectivelyI disapprove of the widespread use of DDT due to its toxic effects its environmental persistence and concentration in the food supply Due to its chemical stability DDT tends to accumulate within the crops that are sprayed and people that consumed the crops became negatively affected by the chemical as is suggested by current research in the field A growing body of evidence presents that exposure to DDT may be associated with adverse health outcomes such as breast cancer diabetes decreased semen quality spontaneous abortion and impaired neurodevelopment in children Eskenazi et al 2009 Although DDT was very effective in controlling the vector population many species of insects are developing resistance to DDT decreasing its effectiveness as an insectide C F Curtis and J D Lines 2000 More research is required to find alternative methods of vector control as a substitute for DDT use in countries that are at high risk for malarial infectionsChlorine is used as a disinfectant to purify drinking water by eliminating harmful microorganisms Chlorination of drinking water is more beneficial than the use of alternative treatments because of the lower health risks and its ability to degrade pesticides very effectively Magara Aizawa Matumoto and Souna 1994 Studies have shown that organic matter in the water and the amount of chlorine used to purify the water can create harmful byproducts Cancer Research Society 2010 However by keeping the organic matter and the chlorine at a minimum level while ensuring the safe quality of the tap water can help avoid harmful byproducts I approve the widespread use of chlorine in tap water because it does not exceptionally affect the human health and is a superior disinfectant compared to other disinfecting agentsaT o r o n t os o n l y w a t e r s o u r c e i s L a k e O n t a r i ow h i c h s u p p l i e s d r i n k i n g w a t e r t o a l l r e s i d e n t i a l a n dcommercial areas City of Toronto ndb According to the City of Torontos website these are the steps taken to ensure clean and safe drinking water is provided to residents of Toronto First water intake pipes collect raw water from Lake Ontario which then goes through a screening process The screening process removes large objects and debris Chlorine and aluminum are then added to kill any microorganisms and clump together any remaining small particles Flocs are formed from the mechanical mixture of the two chemicals Water then travels to the basin where safe levels of chlorine are added to kill any remaining microorganisms After this stage sulphur dioxide is added at the storage stage to remove any excess chlorine Fluoride is also added to prevent any cavities from forming After adding chlorine sulphur dioxide and fluoride the water is sent through a filtration process where bits of floc algae silt chemicals and impurities are removed In a settling tank heavy flocs drop out of the water to the bottom and the cleaner water is left at the surface Before being distributed ammonia is added to water to stabilize any remaining chlorine and to keep the water safe during the trip from the plant to outside Finally the water is tested to ensure quality and
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