Lincoln Fok

Plastic waste in the marine environment: A review of sources, occurrence and effects.

This review article summarises the sources, occurrence, fate and effects of plastic waste in the marine environment. Due to its resistance to degradation, most plastic debris will persist in the environment for centuries and may be transported far from its source, including great distances out to sea. Land- and ocean-based sources are the major sources of plastic entering the environment, with domestic, industrial and fishing activities being the most important contributors. Ocean gyres are particular hotspots of plastic waste accumulation. Both macroplastics and microplastics pose a risk to organisms in the natural environment, for example, through ingestion or entanglement in the plastic. Many studies have investigated the potential uptake of hydrophobic contaminants, which can then bioaccumulate in the food chain, from plastic waste by organisms. To address the issue of plastic pollution in the marine environment, governments should first play an active role in addressing the issue of plastic waste by introducing legislation to control the sources of plastic debris and the use of plastic additives. In addition, plastics industries should take responsibility for the end-of-life of their products by introducing plastic recycling or upgrading programmes.

Hong Kong at the Pearl River Estuary: A hotspot of microplastic pollution

Large plastic (>5mm) and microplastic (0.315-5mm) debris were collected from 25 beaches along the Hong Kong coastline. More than 90% consisted of microplastics. Among the three groups of microplastic debris, expanded polystyrene (EPS) represented 92%, fragments represented 5%, and pellets represented 3%. The mean microplastic abundance for Hong Kong was 5595items/m(2). This number is higher than international averages, indicating that Hong Kong is a hotspot of marine plastic pollution. Microplastic abundance was significantly higher on the west coast than on the east coast, indicating that the Pearl River, which is west of Hong Kong, may be a potential source of plastic debris. The amounts of large plastic and microplastic debris of the same types (EPS and fragments) were positively correlated, suggesting that the fragmentation of large plastic material may increase the quantity of beach microplastic debris.

Impacts of land use and water quality on macroinvertebrate communities in the Pearl River drainage basin, China

The East River (Dong Jiang), a major tributary of the Pearl River (Zhu Jiang, the second largest river in China by discharge), is situated in southern China, which has the highest rates of urbanization and development on Earth. The East River also provides 80% of Hong Kong’s water supply. However, there have been no ecological studies to examine the combined impacts of changes in land use and water quality degradation on this river ecosystem. We tested the hypothesis that land-use disturbance and water quality degradation would significantly reduce benthic biodiversity in the East River by investigating macroinvertebrate community composition and relating it to data on water quality and catchment condition. The percentage of total impervious area within each catchment (%TIA—an indicator of land-use disturbance) was negatively related to a composite water quality index—the ERWQI—we developed for the East River. Modeling by partial least squares projection to latent structures (PLS) showed that family richness and relative abundance index (RAI) of macroinvertebrates were strongly influenced by both %TIA and ERWQI. Multi-response permutation procedure (MRPP) tests showed highly significant differences in family richness composition and RAI of macroinvertebrates among sites in the upper, middle, and lower course of the East River. MRPP also revealed differences in the family richness composition of nighttime drift samples between upper and middle site groups. Abundance (individuals m−3) and total family richness of drifting macroinvertebrates at each site were positively related to %TIA (range: 1.0–8.5%), while drift biomass was negatively related to dissolved oxygen and positively related to total suspended solids. Thus, human disturbances associated with land-use changes (increasing %TIA) and nutrient inputs severely degraded ecosystem integrity and the water quality of the East River and thereby reduced aquatic biodiversity.

Seasonal variation in the abundance of marine plastic debris in the estuary of a subtropical macro-scale drainage basin in South China

Marine plastic debris, including microplastic debris (0.315-5mm) and large plastic debris (>5mm), was collected from 25 beaches in Hong Kong during a wet summer season (June-August 2014) and the following dry winter season (January-March 2015). Wilcoxon signed rank tests were used to compare the abundances and weights of seven categories of plastic debris between the two seasons. The results showed that the abundances and weights were significantly higher (p<0.05) in the wet season than in the dry season. Additionally, seasonal differences were detected only at the sites that were located on the west coast of Hong Kong and not at the sites on the east coast. These results suggest that the Pearl River Estuary on the west of Hong Kong plays a prominent role in the abundance and distribution of plastic debris in Hong Kong. In addition, the study indicates that estimates of microplastic abundance may be biased if samples are collected only during the wet or dry season if the sample locations are strongly influenced by a seasonal variation of riverine inputs, such as from the Pearl River.

Evidence of microbeads from personal care product contaminating the sea

Plastic microbeads in personal care products have been identified as a source of marine pollution. Yet, their existence in the environment is rarely reported. During two surface manta trawls in the coastal waters of Hong Kong, eleven blue, spherical microbeads were captured. Their sizes (in diameters) ranged from 0.332 to 1.015mm. These microbeads possessed similar characteristics in terms of colour, shape and size with those identified and extracted from a facial scrub available in the local market. The FT-IR spectrum of the captured microbeads also matched those from the facial scrub. It was likely that the floating microbeads at the sea surface originated from a facial scrub and they have bypassed or escaped the sewage treatment system in Hong Kong. Timely voluntary or legislative actions are required to prevent more microbeads from entering the aquatic environment.

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.

The motivations and environmental attitudes of nature-based visitors to protected areas in Hong Kong

Understanding nature-based visitors’ motivations and environmental attitudes is important for the development of appropriate visitor management strategies for protected areas. This study categorised Hong Kong nature-based visitors of protected areas into different subgroups according to their visiting motivations and environmental attitudes. The association between their motivations and environmental attitudes was also assessed. A total of 585 completed responses were collected from on-site questionnaire surveys, and three subgroups of protected area visitors, according to their visiting motivations, i.e. travel for novelty, travel for recreation and travel to escape, have been identified. Similarly, three subgroups, namely conservation and development, conservation priority and leisure rights, were identified based on visitors’ environmental attitudes. Results showed that visitors’ environmental attitudes and their motivations were found to be closely related, indicating that visitors with higher environmental concerns tended to travel for novelty and those exhibiting a lower environmental concerns travel to escape.

Evaluating the impact reduction strategies for the tropical cyclone hazard in Hong Kong

Tropical cyclones are one of the major natural hazards that affect the population of Hong Kong on an annual basis. However, the existing loss reduction strategies for the hazard in Hong Kong have rarely been systematically evaluated. In this paper, by adopting Smith and Petleys (2009) framework, the loss reduction strategies currently adopted by the Hong Kong government are evaluated. The known strategies include the implementation of wind resistance design in buildings, the establishment of a state-of-the-art forecast and warning system, and a comprehensive contingency plan. Through the continuous application of those combined strategies, the vulnerability of the Hong Kong population to the tropical hazard has been greatly reduced in recent decades. Nevertheless, there are two issues of concern. First, the issuance of the tropical cyclone signal is not solely determined by wind speed. It is also mediated by the associated indirect economic loss. Second, the strengthened protection helps Hong Kong citizens to develop a strong sense of security towards the tropical cyclone hazard. But, the sense of security may be too strong which results in a general insensitivity to the potential risks of the tropical cyclone hazard. Based on the above findings, it is suggested that in addition to the existing loss reduction strategy for the tropical cyclone hazard, a strategy which enhances the risk perception of the community towards the hazard should be developed.

Recreational specialization and ecologically responsible behaviour of Chinese birdwatchers in Hong Kong

ABSTRACT Birdwatching is a popular nature-based recreational activity that has millions of participants worldwide. Hong Kong is an important birdwatching destination in Southeast Asia, and the number of birdwatchers visiting Hong Kong has steadily increased in recent decades. This study investigated the influences of recreational specialization on the pro-environmental attitudes and ecologically responsible behaviour of Chinese birdwatchers. Questionnaire surveys were conducted in Hong Kong, and 387 completed questionnaires were collected. The results of structural equation modelling indicate a direct positive association between the birdwatchers’ specialization and pro-environmental attitudes and an indirect positive association between their specialization and ecologically responsible behaviour. These findings suggest that understanding birdwatchers’ specialization is essential for predicting birdwatchers’ behaviour when visiting ecologically sensitive destinations. Birdwatcher specialization levels could be used to formulate visitor management strategies at birdwatching sites and to mitigate visitor impacts on avian species.

TIME LAG IN THE CLIMATE CHANGE, WAR, AND POPULATION RELATIONSHIP: A QUANTITATIVE ANALYSIS

Abstract Wars became more frequent in a cold climate at the macro-historical scale. However, war peaks and their associated population collapses appeared ~20–30 years after the commencement of a cold climate. Following Zhang et al.s (2007a) conceptual model, this paper sought to further examine the climate-war-population time lag by using mathematical means. Result was: the relatively slow natural population adjustment to the climate-induced fluctuations in agricultural production generated the time lag between the climate, war, and population cycles in historical agrarian societies. This finding may lend a new dimension to the classic Malthusianism and have current implications to the less developed countries near the tropics.