Dissolved palladium in heavy traffic location runoff: dynamic variation and influencing factors

ABSTRACT

Palladium (Pd) is widely used in vehicle exhaust catalysts (VECs) and rapidly increasing in urban environments worldwide. This research collected runoff samples in a typical heavy traffic location and analysed the concentrations of dissolved palladium by inductively coupled plasma-mass spectrometry (ICP-MS). For most precipitation events, the maximum Pd concentration level occurred at the beginning of the runoff period and then decreased in subsequent runoff. The results showed that the Pd concentration in runoff was lower in the wet season when compared with the dry season. The wet season had fewer clear days to accumulate pollutants on the impervious surface and had a higher precipitation intensity to dilute dissolved Pd in runoff. Our experimental results also proved that the migration and transformation of palladium in urban environments are affected by runoff water quality parameters. Lower pH, higher Eh and higher $\mathrm{C}{\mathrm{l}}^{-}$ concentrations led to a higher dissolved Pd concentration.

KEYWORDS:

• Runoff pollution
• dissolved palladium
• precipitation properties
• water quality parameters

Acknowledgements

We thank Changdong Zou, Xing Yang Linsheng He, Siying Wang, Lin Wang Xi Yang, Fang Heng and Hongqi Zhou for the assistance. In addition, Bo Fu especially wishes to thank Zeyang Zhao, whose love has gave him powerful spiritual support over the past five years.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Hainan Natural Science Foundation (418MS049), the National Natural Science Foundation of China (41867060, 41461090) and the Hainan Natural Science Foundation Innovation Team (2017CXTD006).