RESUMO
Cigarette butts, often discarded as litter, are considered a common form of waste, containing a variety of pollutants within this hazardous residue. This study, which was designed to assess the environmental release of certain metals from cigarette butts, investigates a variety of scenarios under varying climatic conditions. Thus, in order to assess the level of metal contamination, samples of cigarette butts were collected in urban areas from seven popular brands in China, smoked artificially, and examined through graphite furnace atomic absorption (GF-AAS). The findings indicated mean concentrations of 1.77 for Cr, 2.88 for Ni, 12.93 for Cu, 24.25 for Zn, and 1.77 µg/g for Pb in the case of newly smoked butts. The emission of each of the metals increases to 8-10% when cigarette butts remain in the environment for an extended period of time. Furthermore, rainfall can accelerate metal leaching, reaching values of 18-20% compared to the controlled scenario. The worst-case scenario releases 2129.31 kg/year of metals into the environment, while the best-case scenario sees a lower release of 844.97 kg/year. The data reflect variations in metal emissions across different scenarios. There was also a strong correlation between cigarette butts in public spaces and cities. This research highlights the need to educate smokers and increase urban maintenance efficiency to reduce this litter and the metals it leaches into the environment.
RESUMO
Surface roughness is an important factor to consider when evaluating the loads of surface runoff caused by road-deposited sediment (RDS) wash-off and creating management solutions for this occurrence in metropolitan areas. Nevertheless, the implications of surface roughness on RDS development and escape remain unclear due to a paucity of experimental evidence distinguishing the significance of surface roughness. This research aimed to differentiate the impact of surface roughness on RDS accumulation and wash-off by employing paired asphalt, rainfall simulation designs, and concrete road surfaces. Our findings indicated that normal asphalt surfaces are typically rougher than typical concrete surfaces because they frequently contain deeper depressions. Compared to concrete surfaces, asphalt surfaces typically retain more RDS, a higher proportion of coarse aggregates, more RDS wash-off loads, and a lower proportion of wash-off. Surface roughness has varying impacts on the RDS motilities of particulates of varying sizes during rainy runoff; nevertheless, the settleable particles (40-150 µm) were more noticeably impacted by it. The first flush effect also seemed to be more pronounced on surfaces with lower roughness. Hence, surface roughness has a significant impact on how RDS builds on and is washed off of various road aspects.
