倪琼华博士, 建造、环境及工程学系 Country parks play an important role in nature protection, recreation, and outdoor education. During weekends and holidays, thousands of Hong Kong residents and tourists flock to country parks for camping and hiking. Hong Kong is a densely populated city. Most country parks in Hong Kong are adjacent to busy roads, meaning that the soil may be polluted with heavy metals emitted from the traffic activities nearby. This can pose potential health risks to the park users especially children when visiting the parks, as well as ecological risks to the environment (i.e., biological, chemical or physical stress which can have an adverse response in the environment).There are twenty-four designated country parks in Hong Kong. Dr Edith Ngai from the Department of Construction Technology and Engineering studied four country parks, namely Plover Cove Country Park, Sai Kung West Country Park, Lion Rock Country Park, and Kam Shan Country Park. These selected parks are near busy roads, and people who engage in recreational activities are most vulnerable to the effects of pollution, so it is necessary to study the potential health impact of soil pollution on these sites.Between the wet (Apr to Oct) and dry (Nov to Mar) seasons from 2019 and 2021, 48 topsoil samples were collected from the four country parks. At each location, a stainless-steel soil sample probe was used to collect 0-10 cm of topsoil samples.
使用土壤样品探针採集土壤样本这些土壤样本被送到香港认可化验所进行分析。利用电感耦合等离子体质谱 (ICP-MS) 或电感耦合等离子体原子发射 (ICP-AES) 来检测样品中是否含砷、银、镉、铬、铜、汞、镍、铅和锌等重金属。研究团队使用「汙染负荷指数 (PLI)」 、「平均汙染指数 (PIave)」 、「Nemerow汙染指数 (PINemerow)」 等几个指数来评估土壤样本的汙染程度，透过比较这些指数来评估不同地点的整体土壤质量。
土壤样本结果显示公路边的土壤表面因交通活动而受重金属汙染，重金属浓度并随着交通量而增加。其中金山郊野公园的铬、铜、铅和锌浓度最高， 比其他三个公园的平均浓度高出 7.8 倍。 而 PIave 和 PINemerow 指数显示，金山郊野公园的土壤汙染程度指数在四个郊野公园中亦排行最高 (见表一) 。在土壤状况方面，汙染负荷指数（PLI）显示除了船湾郊野公园外，其馀的三个郊野公园的土壤状况都随着时间的推移而恶化，而导致恶化的原因就是交通量增加。
表一. 香港四个郊野公园的综合汙染指数概要 in Hong KongOverall, the results suggest that the ecological risks in all the parks were acceptable, ranging from low to moderate. Dr Ngai outlines that developing better urban planning can avoid high ecological risks, and to reduce heavy metal pollution in country parks, increasing the height of roadside green plants is a solution.From this study, it is clear that traffic-induced pollution is present on the soil surface of Hong Kong’s country parks. At present, there are no regulatory guidelines and benchmarks for assessing metal pollution in the soils in Hong Kong. Existing guidelines in the industry only focus on the impact of heavy metal pollution from industrial facilities without acknowledging pollution from traffic activities. With many high-polluting industries gradually leaving Hong Kong, vehicular emissions will become the main source of environmental pollution. More research is needed to address the problem of traffic-induced pollution, including research on emission control measures in areas with busy traffic activities to reduce traffic-induced heavy metal pollution.(Acknowledgement: This project was supported by the THEi Seed Grant Scheme, Project No.: SG1819106.)
使用土壤样品探针採集土壤样本这些土壤样本被送到香港认可化验所进行分析。利用电感耦合等离子体质谱 (ICP-MS) 或电感耦合等离子体原子发射 (ICP-AES) 来检测样品中是否含砷、银、镉、铬、铜、汞、镍、铅和锌等重金属。研究团队使用「汙染负荷指数 (PLI)」 、「平均汙染指数 (PIave)」 、「Nemerow汙染指数 (PINemerow)」 等几个指数来评估土壤样本的汙染程度，透过比较这些指数来评估不同地点的整体土壤质量。
土壤样本结果显示公路边的土壤表面因交通活动而受重金属汙染，重金属浓度并随着交通量而增加。其中金山郊野公园的铬、铜、铅和锌浓度最高， 比其他三个公园的平均浓度高出 7.8 倍。 而 PIave 和 PINemerow 指数显示，金山郊野公园的土壤汙染程度指数在四个郊野公园中亦排行最高 (见表一) 。在土壤状况方面，汙染负荷指数（PLI）显示除了船湾郊野公园外，其馀的三个郊野公园的土壤状况都随着时间的推移而恶化，而导致恶化的原因就是交通量增加。| PLI | PIave | PI(Nemerow) | RI | |
| 船湾郊野公园 | 0.99 | 1.08 | 1.81 | 70.78 |
| 西贡西郊野公园 | 2.84 | 1.22 | 1.47 | 67.35 |
| 狮子山郊野公园 | 4.11 | 1.34 | 1.96 | 98.84 |
| 金山郊野公园 | 813 | 3.95 | 8.60 | 192.08 |
