Managing risks of noncancer health effects at hazardous waste sites: A case study using the Reference Concentration (RfC) of trichloroethylene (TCE)

Health risk assessment of endocrine disruptor bisphenol A leaching from plastic bottles of milk and soft drinks

Bisphenol A (BPA) is of major concern to public health due to its toxic potential and xenoestrogenic endocrine-disrupting effect. One of the major sources of BPA comes from the plastic bottles used to pack milk and soft drinks. The purpose of the present study was to assess and compare the risk associated with BPA transfer from plastic bottles to milk and soft drinks being stored in summer and winter conditions. A sensitive and reliable method of solid phase extraction cartridge packed with multi-walled carbon nanotubes (MWCNTs) was employed. In milk samples (supplied in plastic bottles) of winter season, BPA levels were 0.17-0.32 mg/ kg. In milk samples of summer season, BPA levels were 0.77-1.59 mg/ kg. In soft drink samples of winter, BPA levels were between 0.14 and 0.3 mg/kg. While in 4-month-aged summer soft drink samples, BPA levels were 0.7-1.02 mg/kg of food. The daily exposure dose (DED) of BPA in milk samples of winter season was 1.42-2.67 μg/kg which was below the standard tolerable daily intake (TDI) of 50 μg of BPA/kg of body weight as per USEPA. The DED of BPA in milk samples of summer season was 5.58-10 μg/kg of body weight which was also less than TDI. For soft drink samples, BPA from winter samples was ranged from 1.17 to 1.67 μg/kg of body weight while for summer 4-month-aged samples was 2.5-7.08 μg/kg of body weight. Both types of samples were still less than TDI of BPA.

Hazardous infectious waste collection and government aid distribution during COVID-19: A robust mathematical leader-follower model approach

The outbreak of COVID-19 has posed significant challenges to governments across the world. The increase in hazardous infectious waste (HIW) caused by the pandemic is associated with the risk of transmitting the virus. In this study, hazardous waste includes infectious waste generated both by individuals and by hospitals during the COVID-19 pandemic. To control the outbreak by maintaining social distance and home quarantine protocols, daily necessities and health supplies must be provided to the people affected. Governments play an essential role in the management of the crisis, creating an elaborate plan for collecting HIW and providing necessities and health supplies. This paper proposes a leader-follower approach for hazardous infectious waste collection and government aid distribution to control COVID-19. At the top level of the model, government policies are designed to support people by distributing daily necessities and health supplies, and to support contractors by waste collection. The lower level of the model is related to the operational decisions of contractors with limited capacities. Due to the potential risk of virus transmission via contaminated waste, the proposed model considers the complications imposed on contractors at the lower level. Applying a stochastic programming approach, four possible scenarios are examined, dependent of the severity of the outbreak. As a solution approach, the Benders decomposition method is combined with Karush-Kuhn-Tucker conditions. The results show that government support, in addition to much better management of citizen demand, can control the spread of the virus by implementing quarantine decisions.