Environmental risk assessment(ERA)methodologies for consumer product chemicals are well-established in most developed regions including the United States,Canada,and the European ***,such methodologies are not yet full...
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Environmental risk assessment(ERA)methodologies for consumer product chemicals are well-established in most developed regions including the United States,Canada,and the European ***,such methodologies are not yet fully developed for emerging economies,such as ***,the Chinese government embarked on a journey to develop new chemical legislation that includes science-based risk assessment and appropriate risk *** objective of this presentation is to share an environmental risk assessment framework involving an exposure methodology using conditions specific to China(i.e.,physical setting,infrastructure,and consumers'habits and practice).Incorporated in this framework are China's current regulatory screening and prioritization schemes as part of a tiered risk assessment *** ERA framework for consumer product chemicals starts with Tier Zero,which utilizes the existing Chinese regulatory qualitative method,whereas Tiers One and Two use deterministic and probabilistic methods that account for per capita residential water usage,wastewater treatment capability,as well as wastewater/in-stream dilution *** to major differences in wastewater treatment infrastructure and water usage between urban versus rural regions in China,two scenarios were identified for quantitatively assessing environmental exposure:(1)Urban with wastewater treatment,and;(2)Rural without wastewater treatment(i.e.,direct-discharge of wastewater).By applying this methodology and specific exposure parameters for Urban and Rural scenarios,a case study was conducted for assessing a key fragrance chemical,the polycyclic musk HHCB(1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[gamma]-2-benzopyran).HHCB is widely used as a fragrance in a variety of consumer products in China,and occurrences of this compound have been frequently reported in sewage influents,effluents,sludge,surface water and sediments across several major metropolitan regions within ***
Ozone(O3)has been assumed to be the most phytotoxic air pollutant due to significant damage to the *** some researchers suggest that hydrogen peroxide(H202)and organic peroxides such as methyl hydroperoxide(MHP)maybe ...
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Ozone(O3)has been assumed to be the most phytotoxic air pollutant due to significant damage to the *** some researchers suggest that hydrogen peroxide(H202)and organic peroxides such as methyl hydroperoxide(MHP)maybe a new reason caused damage of ***"peroxides theory"is also supported by the results that high concentrations of hydrogen peroxide and organic hydroproxides were observed in the declined forest,and compared with exposure to 100 ppb O3,exposure to 2-3 ppb peroxides+50 ppb O3 induced more reduction in biomass of Japanese *** investigate the effects of ambient-level gas-phase peroxides concurrent with O3 on foliar injury and photosynthesis in forest plants,we exposed Japanese white birch and beech to clean air,50 ppb O3,100 ppb O3,and 2-3 ppb peroxides 150 ppb O3 in outdoor *** with exposure to 100 ppb O3,exposure to 2-3 ppb peroxides+50ppb O3 induced greater damage in foliar injury and net photosynthetic rates both in white birch(Fig.1,Table I)and *** pattern of foliar injury induced by 2-3 ppb peroxides+50 ppb O3 is differed from those occurring with O3 exposure *** with exposure to 100 ppb O3,significant decrease in net photosynthetic rates were found both in white birch and beech exposure to 2-3 ppb peroxides+50 ppb *** reasons induced the decrease in net photosynthetic rates in white birch exposure to 2-3 ppb peroxides+50 ppb O3 are different from that in *** results indicate for the first time that sub-ppb peroxides t 50 ppb O3 can cause more severe damage to forest plants than 100 ppb O3,and that not only O3,but also peroxides,could be contributing to the forest plant damage observed in Japan's remote mountains areas.
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