Eric Pokeung Tsang

Immobilization and phytotoxicity of chromium in contaminated soil remediated by CMC-stabilized nZVI.

The toxic effect of Cr(VI)-contaminated soil remediated by sodium carboxymethyl cellulose stabilized nanoscale zero-valent iron (CMC-stabilized nZVI) was assessed through in vitro toxicity and phytotoxicity tests. In vitro tests showed that 0.09 g L(-1) of Fe(0) nanoparticles (soil-to-solution ratio was 1 g:5 mL) significantly reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiological based extraction test (PBET) bioaccessibility of Cr by 82% and 58%, respectively. Sequential extraction procedures (SEP) revealed that exchangeable (EX) Cr was completely converted to Fe-Mn oxides (OX) and organic matter (OM). Accordingly, phytotoxicity tests indicated that after 72-h remediation, Cr uptakes by edible rape and Chinese cabbage were suppressed by 61% and 36%, respectively. Moreover, no significant increase in Cr uptake was observed for either species after a 1-month static period for the amended soil. Regarding Fe absorption, germination and seedling growth, both plant species were significantly affected by CMC-nZVI-exposed soils. However, similar phytotoxicity tests conducted after 1 month showed an improvement in cultivation for both plants. Overall, this study demonstrated that CMC-nZVI could significantly enhance Cr immobilization, which reduced its leachability, bioavailability and bioaccumulation by plants. From a detoxification perspective, such remediation is technologically feasible and shows great potential in field applications.

Excellently reactive Ni/Fe bimetallic catalyst supported by biochar for the remediation of decabromodiphenyl contaminated soil: Reactivity, mechanism, pathways and reducing secondary risks

Ni/Fe bimetallic nanoparticles were synthesized using biochar as a support (BC@Ni/Fe) and their effectiveness in removing BDE209 from soil was investigated. BET, SEM, TEM, XPS and FTIR were used to characterize the catalyst, and the efficiencies of biochar, Ni/Fe nanoparticles and BC@Ni/Fe for removing BDE209 from soil were compared. The results showed that Ni/Fe bimetallic nanoparticles highly dispersed in the biochar, reducing its agglomeration. Thus, the reaction activity of BC@Ni/Fe was increased. The removal efficiency of BDE209 by BC@Ni/Fe was 30.2% and 69% higher than that by neat Ni/Fe and biochar, respectively. Meanwhile, an enhanced degradation efficiency of PBDEs in soil was realized by monitoring the formation of Br- ions with time in the system. In addition, the degradation products identified by GC-MS showed that the reductive degradation of BDE209 proceeded through stepwise or multistage debromination, for which the degradation pathways and removal mechanisms were speculated. Furthermore, BC@Ni/Fe reduced the bioavailability of metals in soil and adsorbed the degradation products of BDE209, representing an improvement over neat Ni/Fe nanoparticles for the remediation of PBDEs-contaminated soil.

Comparisons of the reactivity, reusability and stability of four different zero-valent iron-based nanoparticles

Our previous reports showed that nano zero-valent iron (nZVI), steel pickle liquor for the synthesis of nZVI (S-nZVI), nZVI immobilised in mesoporous silica microspheres (SiO2@FeOOH@Fe) and nano Ni/Fe bimetallic particles (Ni/Fe) have been proved to show good property for elimination of polybrominated diphenyl ethers (PBDEs). However, it is necessary to compare their reactivity, reusability and stability when applied to in situ remediation. In this study, the performances of different iron-based nanoparticles were compared through reusability, sedimentation and iron dissolution experiments. The SiO2@FeOOH@Fe and Ni/Fe nanoparticles were shown to have higher reusability and stability, as they could be reused more than seven times, and that the SiO2@FeOOH@Fe can effectively avoid leaching iron ions into the solution and causing secondary pollution in the reaction. This study may serve as a reference for PBDE remediation in the future.

Understanding residents’ environmental knowledge in a metropolitan city of Hong Kong, China

This study aimed to understand the environmental knowledge (EK) of the residents of Hong Kong. A territory-wide survey was administered to investigate the subjective and objective EK of the respondents as well as their means of receiving information about the environment. The results indicated that Hong Kong’s residents have a comparatively low level of EK, with a mean environmental knowledge score of 3.35 out of 8. The youngster (15–24 years old), students, and employed individuals reported more extensive EK than the older and unemployed respondents, thus suggesting that the younger generation and employed individuals have increased opportunities to receive EK through various channels. A weak positive correlation was identified between subjective and objective EK, thus implying that the residents of Hong Kong could not accurately evaluate their own level of EK. The results indicate that traditional media plays a significant role in disseminating EK. Digital media, such as websites and digital social networks, were also determined to be influencing factors in disseminating environmental messages to the younger generation.

Effect of humic acid and metal ions on the debromination of BDE209 by nZVM prepared from steel pickling waste liquor

As a promising in situ remediation technology, nanoscale zero-valent iron (nZVI) can remove polybrominated diphenyl ethers such as decabromodiphenyl ether (BDE209) effectively, However its use is limited by its high production cost. Using steel pickling waste liquor as a raw material to prepare nanoscale zero-valent metal (nZVM) can overcome this deficiency. It has been shown that humic acid and metal ions have the greatest influence on remediation. The results showed that nZVM and nZVI both can effectively remove BDE209 with little difference in their removal efficiencies, and humic acid inhibited the removal efficiency, whereas metal ions promoted it. The promoting effects followed the order Ni2+>Cu2+>Co2+ and the cumulative effect of the two factors was a combination of the promoting and inhibitory individual effects. The major difference between nZVM and nZVI lies in their crystal form, as nZVI was found to be amorphous while that of nZVM was crystal. However, it was found that both nZVM and nZVI removed BDE209 with similar removal efficiencies. The effects and cumulative effects of humic acid and metal ions on nZVM and nZVI were very similar in terms of the efficiency of the BDE209 removal.

ESD Projects, Initiatives and Research in Hong Kong and Mainland China

Education for sustainable Development (ESD) in Hong Kong schools is administered by the Environmental Campaign Committee (ECC) through its core education programs, mainly the Hong Kong Green School Awards (HKGSA) and Student Environmental Protection Ambassador Scheme (SEPAS). This is supported partly by the SAR Government Education and Development Bureau (EDB) which seeks the permeation of ESD through the formal curriculum but is seriously hindered by the curriculum structure. Research recently conducted by the authors reveals that there are still questions to be answered regarding the readiness and willingness of schools to engage with ESD. In China, on the other hand, ESD is being promoted mainly through its Green School Program administered by the State Ministry of Education (MOE) and sponsored by the State Environmental Protection Agency (SEPA). This chapter provides an in-depth description and comparison of the history, development, and the theoretical framework of ESD for schools in Hong Kong and Mainland China.

Everyday-ing Health Literacy and the Imperative of Health Communication: A Critical Agenda

Health literacy is an increasingly important issue amongst scholars of health studies and medical practitioners. This essay seeks to understand how health knowledge is co-constructed by different agencies and the role of health communication in this process can contribute to everyday-ing health literacy. In addition, this essay attempts to understand how health communication becomes an everyday practice in identifying disease-specific needs.

Realising Sustainability Leadership

In the last few decades, the Asia Pacific region has faced unprecedented social, economic, political and environmental challenges. These in turn have prompted the necessity for partnerships on order to realise sustainable development in the region.

Hong Kong, China Employers’ Perspectives on a Carbon-Constrained Economy and How Technical and Vocational Education and Training Should Respond

Climate change is generating economic and environmental threats with the pressures set to increase in the coming years. However, these threats also provide opportunities for those cities and regions that seek to address climate change by pursuing lower emission technologies. Where environmental concerns were once associated with problems of high costs and inefficiency, responding to the climate crisis is now rapidly becoming a high-growth industry where profits and returns are increasingly attractive. Research by the Environmental Protection Department identified electricity generation, property development, construction, transport and hospitality as ‘carbon-vulnerable’ industries in Hong Kong, China. This chapter has identified the potential workforce skills needed for Hong Kong, China, in these industries to create new and alternative economic opportunities through a shift to low-carbon technologies, aiming at identifying the changes in vocational training that are required to respond to the skills needs of industry and businesses resulting from climate change.