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QMRA Exercises

QMRA Exercises. QMRA for Beach Exposure. Given) An effluent from a municipal wastewater plant, which has a secondary treatment system, is released into a near beach in a Lake and it is assumed that the initial dilution the is 1/100.

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QMRA Exercises

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  1. QMRA Exercises

  2. QMRA for Beach Exposure Given) • An effluent from a municipal wastewater plant, which has a secondary treatment system, is released into a near beach in a Lake and it is assumed that the initial dilution the is 1/100. • A person at a beach may ingest 0.1 L of the beach water during swimming • Assume parameters based on available data in the following table.

  3. QMRA for Beach Exposure

  4. QMRA for Beach Exposure Find) • Choose pathogens from a list of viruses, bacteria, and protozoan in the table and calculate point estimate risks for a swimmer at the beach. • Does the treatment system remove enough pathogens to protect swimmers’ health? EPA acceptable risk for recreational fresh water is 0.008 (marine is 0.019). How much removal at the treatment plant would be recommended? • A sewage spill has occurred resulting in releasing untreated wastewater introduced in to the beach. How long a beach should close?

  5. QMRA for Anthrax Exposure Given) • Suspicious white powders were delivered to an office. All employee were evacuated in a short time but several employees in a small room were hospitalized. • Assuming that the inhalation rates for adult males, adult females, and children are 0.0106, 0.0078, and 0.0060 m3/min, respectively. • The white powder was identified as Bacillus anthracis. The fatal risk for inhalation of B. anthracis base on animal tests (guinea pigs, rabbits, and rhesus monkey) was estimate by Risk (fatal) = 1-(1+(dose/62817)*(2^(1/0.974)-1))^-0.974

  6. QMRA for Anthrax Exposure Find) • If the concentration is the same, who would be at most risk, adult males, females, or children? • What concentrations could have been at the safe level for 15 min exposure? Assuming that an air exchange and particle settling and re-suspending were negligible. Assuming that the acceptable risk is 10-4. • The room has been decontaminated. Does the room have to be completely spore free? If not, how many numbers of spores should not be available for further exposures in the room?

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