Establishing historical 90Sr activity in seawater of the China seas from 1963 to 2018.

Historical 90Sr activity in seawater was established in the China seas from 1963 to 2018. Based on the exponential decrease in 90Sr activity in seawater, the effective half-life (EHL) of 90Sr was quantified to be 11.5 ± 1.6 a, 16.5 ± 2.4 a, 27.2 ± 6.2 a, and 26.7 ± 4.3 a in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea, respectively. We found contrasting patterns in the EHL of 90Sr and 137Cs in the marginal seas and open oceans that were closely related to the subtly different pathways of 90Sr and 137Cs in marine environment. Additionally, we demonstrated that Fukushima-derived 90Sr (<0.01 Bq/m3) would be difficult to identify in the China seas. Our study not only provided the key parameter of the EHL in marine models for predicting the 90Sr activity in the China seas in the post-Fukushima era but also enhanced our understanding of 90Sr behavior and its fate in marine environments.