Paul Kwan Sing Lam

The environmental characteristics of usage of coal gangue in bricking-making: a case study at Huainan, China.

The behaviors of natural radionuclides and toxic elements during coal gangue brick making processes are described. A simulation experiment of coal gangue brick firing was carried out to evaluate the enrichments of natural radionuclides and volatilizations of elements. Simultaneous sampling of coal gangue and corresponding combustion product (slag) was performed. The radioactivities of the radionuclide were determined by high-purity germanium gamma ray spectrometer, and the concentrations of toxic elements were analyzed by ICP-MS. Results have shown that the level of natural radionuclides may not cause immediate or acute environmental impacts because the Raeq values and Hex (in the brick) are 345 Bq kg(-1) and 0.89, lower than the limit values of 370 Bq kg(-1) and 1, respectively. However, the Raeq and Hex values are near the limit values, their chronic-environmental and health impacts should be considered noteworthy. The elements found in the emission could be categorized into two types: non-volatilized elements (Co, Cr, Mn and V) and volatilized elements (As, Cd, Cu, Ni, Se, Sn and Zn). Understanding the behaviors of natural radionuclides and toxic elements during brick making processes is helpful for the assessment of their potential impacts to human health and the environment.

Temporal Trends and Pattern Changes of Short- and Medium-Chain Chlorinated Paraffins in Marine Mammals from the South China Sea over the Past Decade

Temporal trends of short- (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were examined in blubber samples of 50 finless porpoises (Neophocaena phocaenoides) and 25 Indo-Pacific humpback dolphins (Sousa chinensis) collected from the South China Sea between 2004 and 2014. Elevated levels of SCCPs and MCCPs were detected in all blubber samples of both cetacean species. Concentrations of SCCPs ranged from 280 to 3900 ng·g(-1) dry weight (dw) in porpoises and from 430 to 9100 ng·g(-1) dw in dolphins, while concentrations of MCCPs ranged from 320 to 8600 ng·g(-1) dw in porpoises and from 530 to 23 000 ng·g(-1) dw in dolphins. Significantly higher concentrations were present in dolphins than porpoises due to their exposure levels in their living habitats. Strongly linear correlations existed between SCCPs and MCCPs, but there were no significant concentration differences between the genders of the two cetacean species in the same sampling year. Significantly temporal increasing trends of ∑SCCPs and ∑MCCPs have been observed in both porpoise and dolphin samples over the past decade, which reflect the influence of histories of production and usage on the bioaccumulation of CPs in marine mammals in China. An apparent temporal shift trend from SCCPs to MCCPs was also observed in CP accumulation profiles. Complex environmental fractionation from localized sources in the study region via atmospheric transport, oceanic/offshore water transport, and trophic transfer have resulted in different CP accumulation levels and homologue patterns in the two cetacean species. This is the first report of systematic temporal trends of SCCPs and MCCPs in marine mammals.

Boiling significantly promotes photodegradation of perfluorooctane sulfonate

The application of photochemical processes for perfluorooctane sulfonate (PFOS) degradation has been limited by a low treatment efficiency. This study reports a significant acceleration of PFOS photodegradation under boiling condition compared with the non-boiling control. The PFOS decomposition rate increased with the increasing boiling intensity, but declined at a higher hydronium level or under oxygenation. These results suggest that the boiling state of solution resulted in higher effective concentrations of reactants at the gas-liquid interface and enhanced the interfacial mass transfer, thereby accelerating the PFOS decomposition. This study broadens our knowledge of PFOS photodegradation process and may have implications for development of efficient photodegradation technologies.