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Palladium (Pd), in platinum group elements (PGEs), is widely used as a catalyst in vehicle exhaust catalytic converters (VECs). The cumulative level of Pd in the environment is growing rapidly, and the potential threat to human health is increasing. In this paper, the mangrove wetland in Dongzhai Harbor, Hainan Province, China, was taken as the research area for the collection of water samples. The particulate Pd was determined by microwave digestion and inductively coupled plasma-mass spectrometry (ICP-MS). The particulate Pd showed a decreasing trend from the estuary to offshore. The land origin of Pd in the mangrove wetland was explained. The Pd concentrations in the suspended state were lower in the wet season than in the dry season. Tide had an obvious influence on particulate Pd. The concentrations of particulate Pd at spring tide were higher than those at neap tide. The concentrations of particulate Pd at ebb tide were higher than those at flood tide. The rainfall intensity also had a strong influence on the particulate Pd. The particulate Pd increased after moderate and light rain but decreased after heavy rain. The pH, redox potential(Eh), and Cl - had little effect on particulate Pd in the water environment. This study is helpful for understanding the environmental geochemical characteristics of Pd in mangrove wetlands and provides a theoretical basis for the study of Pd in urban coastal mangrove environment.

Palladium (Pd) is widely used in the production of automotive catalytic converters that serve to reduce toxic emissions from motor vehicles. The aim of this study was to explore the transport of Pd in the urban water environment. The results showed that the amounts of transported Pd in the pollution chain followed the order of rainfall runoff > estuary > receiving water body > wet deposition, indicating that rainfall runoff was the main source of Pd input. The amount of transported Pd might not depend entirely on the short-term Pd inputs from rainfall runoff and wet deposition. In the estuary, the phenomenon that Pd transport was dominated by suspended matter appeared for the first time in the entire pollution chain. Acertain amount of the inputted Pd was absorbed and accumulated in the urban water environment so that the inputted Pd was not completely outputted. [ABSTRACT FROM AUTHOR]

Heavy metals and PGEs are accumulating in the environment, due to industrial activities and car emissions. In this research, we chose the heavy industrial city (Changji, China) as a study area, and used ICP-MS to examine concentrations of some platinum group elements (PGEs) [platinum (Pt), palladium (Pd), and rhodium (Rh)] and heavy metals in total suspended particulate (TSP) in arid urban environment. We also investigated seasonal variation and distribution of size-fractionated atmospheric particulate matter for PGEs and heavy metals in TSP. The results indicated that PGEs and heavy metal concentrations in TSP followed the same seasonal trend: winter > autumn > spring > summer; this may be attributed to seasonal variation in pollution sources in Changji. However, there was a difference between PGEs and heavy metal distributions in size-fractionated atmospheric particulate matter in TSP. The highest concentrations of PGEs were not observed in the smallest size fraction of atmospheric particulate matter, while the concentrations of heavy metals increased as particulate matter size decreased. The emission mechanism of PGEs may lead to this special distribution of size fractionated. [ABSTRACT FROM AUTHOR]

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 concentrations led to a higher dissolved Pd concentration. [ABSTRACT FROM AUTHOR]

Estuaries are environmental systems with great resource potential and environmental benefits. This study investigates the role of particulate palladium (Pd) in the Nandu River Estuary in the enrichment of estuarine geochemical processes during spring-neap tides. Particulate Pd was found to show different characteristics during spring-neap tides, with the hydrodynamic condition being one of the key factors causing the difference. In addition, particulate Pd showed a decreasing trend while moving from the mouth to the upstream. The highest value of particulate Pd was 35.32 ng L−1, which occurred at the intersection of the mainstream and the branch during the neap tide, and the lowest value was 0.86 ng·L−1, which occurred in the far mouth area during the spring tide. The concentrations of particulate Pd during the neap and spring tides were 5.53 (1.01–35.32) ng·L−1 and 2.33 (0.86–5.22) ng·L−1, respectively. With the exception of stations 1, 5, 10, 11, and 15, the concentration of particulate Pd during the neap tide was greater than that during the spring tide. The variation in the particulate Pd was inconsistent between the spring tide and the neap tide, and the fluctuation in each study section during the neap tide was greater than that during the spring tide. In addition, since the emissions from catalytic converter are in the form of nanoparticles, they are difficult to be dissolve in natural water, and therefore, the concentration of particulate Pd was obviously greater in the waters near large bridges and main roads. An analysis of the physical and chemical properties of the water showed that Cl− easily combined with dissolved Pd and was one of the important factors that affected the concentration of particulate Pd. In addition, DO and Eh had little effect on the change in the particulate Pd during the tidal cycle, and pH had a significant positive correlation with particulate Pd. [Display omitted] • The particulate Pd in the estuary area was discussed. • Combining tides with pollutant changes. [ABSTRACT FROM AUTHOR]

The influx of rainfall runoff intensifies phase partition of the pollutant in receiving water bodies, and the phase partition plays an important role in the speciation transformation and spatial partition of pollutants. In this study, the Meishe River on Hainan Island, China, was adopted as the research area, and palladium (Pd) was selected as the target pollutant. The purpose of this study was to explore phase partition of Pd in receiving water bodies and the underlying influential mechanism. The partition coefficients (K d s) of Pd between water and suspended particulate matter in receiving water bodies and rainfall runoff were 0.74 (0.1 × 10−2 - 8.75) and 2.74 (0.5 × 10−2 - 15.70), respectively. These results indicated that Pd dominated the dissolved phase in the receiving water bodies and that Pd dominated the particulate phase in rainfall runoff. Variations in the K d value of Pd in the receiving water bodies were relatively smooth over time during the precipitation events in May and June. There were no significant differences in phase partition of Pd between the receiving water bodies and rainfall runoff. The K d value for Pd in the receiving water bodies showed a fluctuating upward trend over time during the precipitation events in August, and the difference in K d values of Pd between the receiving water bodies and the rainfall runoff were large. Variations in the K d value of Pd among sections of the receiving water bodies could be roughly divided into two categories, namely, U and inverted-U types. After rainfall runoff converged for 20–25 min, the Pd phase transitions were more frequent within 7 m downstream of the outfall. The K d value of Pd in the receiving water bodies was correlated with pH, Eh, and total suspended solid (TSS), and the correlation coefficients were 0.52, −0.57, and 0.84, respectively (p < 0.05). Compared with rainfall runoff, pH, Eh, TSS had less influence on phase partition of Pd in receiving water bodies. This might be attributed to the dilution effect of natural water and the unique dynamic mechanism of rivers. • Pd dominated the dissolved phase in the receiving water bodies. • Phase transfer of Pd was more frequent within 7 m downstream of the outfall. • The K d of Pd in receiving water bodies was closely related to rainfall characteristics. • Rainfall runoff had larger influence on phase partition of Pd in the receiving water bodies. [ABSTRACT FROM AUTHOR]

A scalable procedure for the efficient cross-coupling of (1-bromovinyl) or (1-chlorovinyl)phosphonates with various aryl and hetarylboronic acids is developed. [ABSTRACT FROM AUTHOR]