Coupling sedimentary records of anthropogenic metal(loid)s in urban waterscape parks with the "Coal to Gas" transition.

ABSTRACT

Energy consumption structure has been adjusted worldwide as a measure to reduce CO2 emission and mitigate air pollution. The "Coal to Gas" transition in mainland China has successfully controlled air pollution in recent decades, but its impacts on the environment beyond air quality improvement remain unknown. With 210Pb dating, this study chronicled profiles of eight anthropogenic metal(loid)s in sediment core from 14 waterscape parks across the Ring Road Network of Beijing, China. Six sediment cores were dated showing a timing coupling of metal(loid) loadings with annual coal consumption during the increasing period before 2000. Two downwind sediment cores in downtown Beijing presented such couplings in both increasing and descending periods for coal consumption before and after 2000, respectively, close to the tipping point observed in 2002 for primary energy consumption efficiency. Evidence from stable Pb isotope composition and exceedances of Cu loadings against sediment quality guidelines of China and the USA suggest that vehicular sources have been dominating metal(loid) loadings in sedimentation in these waterscape parks after the "Coal to Gas" transition. These findings would be helpful in identifying environmental impact patterns resulting from shifts in energy consumption structure and dominance of emission sources thereafter.