Rise and fall of lead (Pb) pollution in East Asia:  lessons learnt from a 60-yr long modern coral

Despite the global phase-out of leaded gasoline, lead (Pb) pollution remains a persistent and serious issue, particularly in developing nations. To portray the temporal dynamics of Pb emissions and their responses to evolving policy interventions in Asia, we reconstructed a 60-year record of Pb concentration (Pb/Ca) and isotopic composition (i.e., 206Pb/207Pb and 208Pb/206Pb) in a coral from Dongsha Atoll, the South China Sea. Our study reveals a fourfold increase in coral Pb/Ca levels from 1953 to mid-2000s, followed by a ~ 60% decline in the subsequent decade. In the early era from 1953 to 1960, Pb isotopic compositions in the Dongsha coral align closely with the values in natural marine sediments. When anthropogenic Pb sources became to prevail, we observe an increase in Pb/Ca values and altered isotopic compositions, attributable mostly to automotive Pb emissions but also with significant contribution from industrial Pb emissions especially after 1990s. With Pb isotopic analysis on the coral, we identify that, after 1990s, the Chinese Pb was the primary endmember that impacts the regional Pb. The influence of Chinese Pb is also registered in other East and Southeast Asian coral records, probably also in those from the Indian Ocean. The increasing trend of Pb in these records underscores the necessity to reduce Pb emissions in the post-leaded gasoline era, particularly in developing countries in the region. On the other hand, the decline in Pb/Ca in our record after the mid-2000s provides encouraging evidence of the positive impact of environmental policies in safeguarding the environment and public health.