Seasonal distributions of Ti-containing NPs in the main tributaries of the Tamsuei River Basin in northern Taiwan

Abstract

ABSTRACT This study aimed to characterize seasonal variations in Ti-containing nanoparticles in the Tamsuei River Basin, situated in northern Taiwan, using sp-ICPMS. The highest particulate mass concentrations were present in the Dahan River, 0.80 − 1.64 ng/mL and 5.65 − 9.94 ng/mL in the dry and wet seasons, respectively, whereas the lowest concentrations were observed in the Xindian River, 0.05 − 0.31 ng/mL and 0.34 − 1.92 ng/mL in the dry and wet seasons, respectively. The highest particulate number concentrations were found in the Keelung River, 170 × 103 − 231 × 103 part./mL in the dry season and 1,372 × 103 − 4,110 × 103 part./mL in the wet season, while the lowest ones presented in the Xindian River. Notably, both particulate mass and number concentrations were significantly elevated during the wet season compared with the dry season, exhibiting a general increase from upstream to downstream. Moreover, a higher proportion of Ti in particulate form was observed in all samples during the wet season. The most frequent sizes for particles present in the samples of the Dahan River were larger during the dry season, 60 − 72 nm, in contrast to the wet season, 38 − 52 nm. These findings suggest that local geology and land use patterns may contribute to variations in Ti-containing nanoparticle concentration distributions among different rivers, particularly during the wet season.