Geochemical behavior of 210Pb and 210Po in the nearshore waters off western Taiwan

Dissolved and particulate 210Pb and 210Po were determined at 15 stations along the coastline off western Taiwan in April 2007. The 210Pb activities in dissolved and particulate phases fell within a relatively small range of 2.4–5.2 dpm 100 L−1 and 1.0–3.2 dpm 100 L−1, respectively. The dissolved and particulate 210Po activities also fell within a small range of 0.8–3.4 dpm 100 L−1 and 1.1–2.9 dpm 100 L−1, respectively. The correlation of the distribution coefficients (Kd) of 210Pb and 210Po with particle concentration in turbid waters are not as evident as in the open ocean. The mass balance calculation shows that the residence times of 210Pb and 210Po with respect to particle removal from the nearshore waters ranges from 3 to 15 days and from 14 to 125 days, respectively. The flux of particulate organic carbon was estimated by 210Po proxy and ranged from 4.8 to 33.7 mmol-C m−2 d−1.