The phase-out of leaded petrol has been a measure widely used to reduce atmospheric lead pollution. Since the 1980s, China began to promote unleaded petrol. In order to assess the effectiveness of the measure an isotope fingerprint technique was applied for aerosol samples in the city of Tianjin. After dilute acid leaching, the lead concentration and isotope abundance ratios were determined for 123 samples collected in Tianjin during eight years (1994-2001). The 206Pb/207Pb ratio was lower in summer, when coal combustion emission was low and vehicle exhaust became more important, indicating that the 206Pb/207Pb ratio of leaded petrol in Tianjin is lower than that of aerosol samples. The 206Pb/207Pb ratio gradually increased from 1994 to 2001, a trend that suggests that the contribution from vehicle exhaust was diminishing. Overall, the measurements matched well with national statistical data of leaded and unleaded petrol production. After the nationwide switch to unleaded gasoline, comprehensive control measures are urgently needed to reduce air lead pollution in China, as aerosol lead reduced slightly but remains at a relatively high level.
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"), and the ratios in Chinese aerosols further increased after the phase out of leaded gasoline around 2000 (Chen et al., 2005; Wang et al., 2006; Cheng and Hu, 2010). However, if the Pb isotope offset was caused by differences in aeolian anthropogenic Pb inputs only, the largest offset between the two basins should appear at the surface and in the upper water column above $1500 m, where Pb concentrations are increased due to anthropogenic Pb inputs (Fig. 8). "
[Show abstract][Hide abstract] ABSTRACT: Pb and Pb isotope ratios in the modern ocean have been altered significantly by anthropogenic Pb inputs over the past century. Most studies of anthropogenic Pb in the ocean have focused on the North Atlantic and North Pacific Oceans, and the impact of anthropogenic Pb inputs to the Indian Ocean and processes controlling the distribution of Pb in the Indian Ocean are poorly known. This study presents the Pb and Pb isotopic composition (206 Pb/ 207 Pb, 208 Pb/ 207 Pb) of 11 deep stations from the Indian Ocean Japanese GEOTRACES cruise (KH-09-5), from the Bay of Bengal and Arabian Sea to the Southern Ocean (62°S). The Pb isotope ratios of the Indian Ocean range 1.140–1.190 for 206 Pb/ 207 Pb and 2.417–2.468 for 208 Pb/ 207 Pb, with lower ratios appearing in the shallow waters of the northern Indian Ocean and higher ratios appearing in the deep layers of the Southern Ocean. This result agrees with a previous study on Pb concentrations (Echegoyen et al., 2014) showing that the Indian Ocean, particularly its northern part, is largely perturbed by anthropogenic Pb inputs. 206 Pb/ 207 Pb and 208 Pb/ 207 Pb of the Indian sector Southern Ocean are still lower than natural Pb, showing this region was also affected by anthropogenic Pb. Anomalously low or high 206 Pb/ 207 Pb and 208 Pb/ 207 Pb were observed in the thermocline and shallow waters of the southern Indian Ocean and the Arabian Sea, which are ascribed to water mass distribution (e.g., Subantarctic Mode Water) and evolving Pb isotope ratios of this region as dominant anthropogenic Pb sources change. 206 Pb/ 207 Pb and 208 Pb/ 207 Pb in the Bay of Bengal are higher than those in the Arabian Sea, which might be the result of the anthropogenic Pb inputs from different provenance or seawater exchanging Pb isotopes with natural particles derived from rivers and/or sediments at the basin boundaries.
"Studies of airborne particulate matter from Asian cities demonstrated that atmospheric Pb levels in urban China were considerably influenced by coal combustion and industrial emission , despite the usage of leaded gasoline (Mukai et al., 1993, 2001). Since the banning of leaded gasoline in China in the year of 2000 (Wang et al., 2006), many studies have been conducted to investigate the main sources of atmospheric Pb in Chinese megacities such as Shanghai (Zheng et al., 2004; Chen et al., 2005; Li et al., 2009), Tianjin (Wang et al., 2006.), as well as the Pearl River Delta region (Wong et al., 2003; Lee et al., 2005; Zhu et al., 2001) including Guangzhou (Duzgoren-Aydin, 2007) and Hong Kong (Duzgoren-Aydin et al., 2004; Lee et al., 2006). In the past decade, due to the policy of the China Western Development that is to boost the economy in the less developed regions, some studies focused on environmental problems such as Pb pollution in urban and remote regions in the western China such as Chengdu (Gao et al., 2004.), "
[Show abstract][Hide abstract] ABSTRACT: Total suspended particles (TSP) and their source-related samples from Guiyang, Southwest China, were collected and analyzed for their lead (Pb) concentrations and Pb isotopic compositions, to identify the sources of atmosphere lead in urban Guiyang. Coals from Guizhou Province had significantly high radiogenic Pb, different to those from North China. Local vehicle exhaust had similar Pb isotope ratios to those of other areas in China. Pb isotopic compositions of atmospheric aerosols, rainwaters, plant samples, and acid-soluble fraction of street dusts were similar to each other. The results clearly suggest that the Pb–Zn ore-related industrial emission, and/or vehicle exhaust, rather than the local coal combustion, are the main sources of atmospheric Pb in Guiyang. Furthermore, binary mixing model indicates that the contribution of coal combustion to the local atmospheric Pb decreased from about 40% in 1988 to about 10% in 2013.
"The comparison between 206Pb/207Pb and 208Pb/207Pb ratios in sediments and other environmental samples showed that the 206Pb/207Pb ratios in surface sediments collected from Bohai Bay were obviously higher than those from the emission of vehicle exhaust and Pb ores mining, indicating that these two anthropogenic inputs were not important factors for Pb pollution in sediments (Figure 3). Wang et al. also have confirmed that lead concentrations of atmospheric aerosols in Tianjin were decreased significantly after the leaded gasoline ban . In fact, the 206Pb/207Pb and 208Pb/207Pb ratios in sediments were significantly similar to those in natural sources, unburned coal, and aerosol samples in the city of Tianjin. "
[Show abstract][Hide abstract] ABSTRACT: To investigate the characteristics and potential sources of heavy metals pollution, surface sediments collected from Bohai Bay, North China, were analyzed for the selected metals (Cd, Cr, Cu, Ni, Pb, and Zn). The Geoaccumulation Index was used to assess the level of heavy metal pollution. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. The results showed that the average concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were 0.15, 79.73, 28.70, 36.56, 25.63, and 72.83 mg/kg, respectively. The mean concentrations of the studied metals were slightly higher than the background values. However, the heavy metals concentrations in surface sediments in Bohai Bay were below the other important bays or estuaries in China. The assessment by Geoaccumulation Index indicated that Cr, Zn, and Cd were classified as "the unpolluted" level, while Ni, Cu, and Pb were ranked as "unpolluted to moderately polluted" level. The order of pollution level of heavy metals was: Pb > Ni > Cu > Cr > Zn > Cd. The Pb isotopic ratios in surface sediments varied from 1.159 to 1.185 for (206)Pb/(207)Pb and from 2.456 to 2.482 for (208)Pb/(207)Pb. Compared with Pb isotopic radios in other sources, Pb contaminations in the surface sediments of Bohai Bay may be controlled by the mix process of coal combustion, aerosol particles deposition, and natural sources.