Restorating marine coastal ecosystem health as a new goad for integrated catchment management in Tolo Harbour,Hong Kong,China

Abstract

The paper demonstrates why it is necessary to take the restoration of marine coastal ecosystem health as a new goal for integrated catchment management, in coastal area of the Tolo Harbour. The present goal of integrated catchment management (ICM) in the Tolo Harbour is to meet with Water Quality Objectives. The performance of an ICM plan, Tolo Harbour Action Plan (THAP), is evaluated by using marine coastal ecosystem health indicators including stress indicators and responses indicators. Since the implementation of THAP in 1988, some significant reduction in pollution loading has been observed—reduction of 83% of BOD load and 82% of TN between 1988 and 1999. There has been an improvement in the health state of Tolo Harbour marine coastal ecosystem as evidenced in the trends of the physical, chemical and biological indicators, although some reverse fluctuations in some periods exist. However, this can only be considered as the first sign of the ecosystem health restoration, since ecosystem health covers not only physical, chemical and biological aspects of an ecosystem, but also ecosystem-service-function aspect. It is recommended to take the restoration and protection of marine coastal ecosystem health as a new goal, instead of water quality objective management, for integrated catchment management in Tolo Harbour catchment. Steps to further improve the marine coastal ecosystem health of Tolo harbour are discussed in the paper.     

Discussion of Population Modernization Theory and Actuality Analysis of Population Modernization in China

Abstract

This paper discusses the basic concept and connotation of population modernization.

The author briefly analyzes the actuality of population modernization in China, gives some advice and puts forward some measures.     

Effects of the "Conversion of Cropland to Forest and Grassland Program" on the water budget of the Jinghe River catchment in China

In 1999 China adopted the "Conversion of Cropland to Forest and Grassland Program" (CCFGP), a nationwide ecological recovery program, to minimize wide-scale soil erosion and vegetation degradation in China, as well as to improve water budgeting results. In the 10 yr since implementation, the CCFGP has resulted in the recovery and reforestation of >100,000 km of cropland and bare land, though the quantitative effect of this program on catchment water budget is not entirely clear. Therefore, we used the Soil and Water Assessment Tool to evaluate and quantify the effects of the CCFGP on the water budget of the Jinghe River catchment, a tributary of the Yellow River covering the central region of the Loess Plateau. Our results indicated that precipitation had dropped by 12.0% from the 1970s (611.6 mm) to the 2000s (538 mm) and that there was a corresponding 25.2% decrease in humidity index from 0.48 to 0.36. Before the CCFGP's implementation, forest and grassland had been decreasing, while bare land, cropland, and shrub land had been increasing. After the implementation of the CCFGP, the opposite trend was observed. Moreover, streamflow increased by about 15 and 20% for the upstream and middle stream subbasins, respectively, while soil water content also showed an obvious increase. Over the same period, evapotranspiration decreased by 5.2 and 13.5 mm and runoff decreased by 37.5 and 38.6% in the two subbasins. The same trends were obtained in the downstream subbasin, where changes were even greater. As a result of the reduced runoff and evapotranspiration, utilization of water resources was more efficient and ecological environment was improved under the CCFGP policy. Our results indicate the CCFGP resulted in a favorable ecological impact and should therefore be maintained.     

Anomalous Ba/Ca signals associated with low temperature stresses in Porites corals from Daya Bay, northern South China Sea

Barium to calcium (Ba/Ca) ratio in corals has been considered as a useful geochemical proxy for upwelling, river flood and other oceanic processes. However, recent studies indicated that additional environmental or biological factors can influence the incorporation of Ba into coral skeletons. In this study, Ba/Ca ratios of two Porites corals collected from Daya Bay, northern South China Sea were analyzed. Ba/Ca signals in the two corals were ‘anomalous’ in comparison with Ba behaviors seen in other near-shore corals influenced by upwelling or riverine runoff. Our Ba/Ca profiles displayed similar and remarkable patterns characterized by low and randomly fluctuating background signals periodically interrupted by sharp and large synchronous peaks, clearly indicating an environmental forcing. Further analysis indicated that the Ba/Ca profiles were not correlated with previously claimed environmental factors such as precipitation, coastal upwelling, anthropogenic activities or phytoplankton blooms in other areas. The maxima of Ba/Ca appeared to occur in the period of Sr/Ca maxima, coinciding with the winter minimum temperatures, which suggests that the anomalous high Ba/Ca signals were related to winter-time low sea surface temperature. We speculated that the Ba/Ca peaks in corals of the Daya Bay were most likely the results of enrichment of Ba-rich particles in their skeletons when coral polyps retracted under the stresses of anomalous winter low temperatures. In this case, Ba/Ca ratio in relatively high-latitude corals can be a potential proxy for tracing the low temperature stress.     

地下金属矿山安全标准化系统信息平台的构建与应用

以金属非金属地下矿山安全标准化系统的管理思想为理论指导和主要目标,按照安全标准化14个要素的运行要求,构建地下矿山安全标准化系统信息平台,对安全标准化的具体建设内容进行相应的信息化管理.针对地下矿山的特点,开发采场安全管理和尾矿库安全管理2个特色模块.结合矿山企业的实际需求,将信息平台划分为工作管理、图形统计、报表分析、公共事务和系统管理等5个模块,并详细探讨各模块所实现的功能.信息平台的应用保障了地下矿山安全标准化系统的有效实施与运行.     

Intraspecific variation in cadmium tolerance and accumulation of a high-biomass tropical tree Averrhoa carambola L.: implication for phytoextraction

Averrhoa carambola L., a high-biomass tropical tree, has recently been shown to be a strong accumulator of cadmium (Cd) and has great potential for Cd phytoextraction. In the present study, field studies and a controlled-environment experiment were combined to establish the extent of variation in Cd tolerance and accumulation at the cultivar level using 14 to 19 cultivars of A. carambola. The results indicated that all cultivars tested could accumulate Cd at high but different levels, and that Cd tolerance also varied greatly between these cultivars. It is confirmed that the high Cd tolerance and accumulation capacity are species-level and constitutional traits in A. carambola. However, no correlation was detected between tolerance index and accumulation of Cd in different cultivars, suggesting that the two traits are independent in this woody Cd accumulator. More importantly, cultivar Wuchuan Sweet (WCT) was shown to have the highest Cd-extraction potential; it yielded a high shoot biomass of 30 t ha(-1) in 230 d, and extracted 330 g ha(-1) Cd in the aerial tissues grown in Cd-contaminated field soil, which accounted for 12.8% of the total soil Cd in the top 20 cm of the soil profile.     

Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface soils from the Qinghai-Tibetan plateau

Eighty eight surface soil samples were collected from the Qinghai-Tibetan Plateau (QTP) for determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs). The measured concentrations were 51.8 ± 38.5 ng g(-1), 0.329 ± 0.818 ng g(-1), and 0.467 ± 0.741 ng g(-1) as means and standard deviations of PAHs, DDXs, and HCHs, respectively, which were 1-2 orders of magnitude lower than those reported for eastern China. Significant differences were also revealed among four sub-areas within QTP. PAHs detected in the samples from the remote sub-areas of T'ang-ku-la/Hoh Xil Mountains and along the Qinghai-Tibet highway in the west and northwest of QTP were 1 order of magnitude lower than those from Lhasa and east Qinghai. The differences in soil OCPs among the sub-areas were 2-7 times. Soil PAHs were significantly correlated with emission density and soil organic carbon content (SOC), while OCPs were correlated significantly with the population density and SOC. Based on the calculated backward air mass trajectories and geographical distributions of emission and population, it was revealed that PAHs and OCPs accumulated in the soils in the west and northwest QTP were primarily from long-range transport and may represent the background levels of East Asia. This part of QTP can also serve as an important receptor area for regional or even global long-range transport study. The elevated concentrations of PAHs and OCPs in Lhasa and east Qinghai were mainly from local sources, while PAHs from adjacent Lanzhou area also contributed considerably to the accumulation of PAHs in east Qinghai.     

Effectiveness of amendments on re-acidification and heavy metal immobilization in an extremely acidic mine soil

Previous studies have shown that the application of soil amendments is efficient in reducing acidity and heavy metal bioavailability in mine soils. However, it remains a challenge for environmentalists to predict accurately and control economically the re-acidification in re-vegetated mine soils. In this study, net acid generation (NAG) test and bioassay technique were employed to assess the effectiveness of the amendments [including lime, N-P-K (nitrogen, phosphorous and potassium) fertilizer, phosphate and river sediment] on re-acidification and heavy metal immobilization in an extremely acid (pH < 3) mine soil. Our results suggested that NAG test was a rapid and accurate approach to assess the effectiveness of the amendments on re-acidification potential of the mine soil. Interestingly, it was found that phosphate and river sediment played quite specific roles in preventing the re-acidification in the mine soil. In addition, the results also indicated that the addition of 25 t ha(-1) lime combined with river sediment (30%) might be an economical method to successfully control the acidification and re-acidification in the extremely acid mine soil, allowing the re-establishment of the plants. Collectively, our results implied that the combined use of NAG test and bioassay assessment was effective in evaluating a reclamation strategy for extremely acidic mine soils.     

生物炭施用对紫色土旱坡地土壤氮流失形态及通量的影响

明确生物炭施用对紫色土旱坡地土壤氮流失形态及通量的影响,为提升紫色土旱坡地耕地质量及减少紫色土旱坡地农业面源污染发生风险提供科学依据.以油菜/玉米轮作农田生态系统为研究对象,通过田间试验,研究了不施肥(对照)、常规施肥、优化施肥及生物炭(化肥减量配施生物炭)这4个处理对紫色土旱坡地地表径流和壤中流氮素流失形态及通量的影响.结果表明:①在各施肥处理中,常规处理总径流量最大,为16 133 L·a~(-1),生物炭处理总径流量最小,为11 893 L·a~(-1).各施肥处理以壤中流为主要径流方式,壤中流流失量占总流失量的61.80%～68.60%;与对照(不施肥处理)相比,其余各施肥处理泥沙流失量均有所降低,其中常规处理降低的效果最明显.②铵态氮主要通过地表径流流失,占总流失通量的86.51%～96.58%;铵态氮流失通量最大的为施生物炭处理[0.69 kg·(hm~2·a)~(-1)].③各施肥处理产流中的颗粒态氮浓度均高于对照处理,且常规施肥处理的颗粒态氮流失通量最大,为2.87 kg·(hm~2·a)~(-1).④各施肥处理的壤中流和地表径流中的全氮浓度和硝态氮浓度均存在极显著正相关关系(P0.01).硝态氮是全氮流失的主要形态,且二者均以壤中流为主要流失途径;全氮通过壤中流流失占比为72.86%～89.13%,且常规施肥处理的全氮总流失通量最大,为35.58 kg·(hm~2·a)~(-1),而施生物炭处理全氮总流失通量最小,为21.49 kg·(hm~2·a)~(-1).化肥减量配施生物炭能明显降低径流量和氮的流失通量,可有效阻控农业面源污染发生的风险.     

区域大气环境模式RegAEMS中二次气溶胶的改进模拟研究

为了提升二次气溶胶的模拟精度,在区域大气环境模式RegAEMS中加入了硫酸盐气溶胶的两种新生成机制（NO₂+SO₂化学过程和过渡金属催化氧化（TMI））以及二次有机气溶胶（SOA）生成的挥发性有机物基集（VBS）方法.模拟了2020年1月上海市两次中度污染过程,并与观测数据进行对比验证.研究发现,两次污染过程硫氧转化率（SOR）均大于0.4,PM_2.5主要组分为SO₄^2-、NO₃^-、NH₄⁺等水溶性离子,占比为61.25%~63.85%.SOA占比为2.92%~3.0%.加入NO₂+SO₂化学过程和过渡金属催化氧化（TMI）后,硫酸盐模拟精度明显提升（相关系数（R）从0.49~0.63提升至0.58~0.67,相对标准偏差（NMB）从-35.0%~-36.5%提升至-17.3%~-14.2%）.两种化学过程在污染发展阶段平均贡献占比为23.3%~27.9%,这可能是造成污染条件下SO₄^2-浓度迅速增加的主要原因.VBS机制能够较好地模拟出SOA的变化趋势（相关系数为0.53~0.56）,由于硫酸盐和SOA生成机理的改进,RegAEMS在PM_2.5的模拟精度上有所提升（相对标准偏差（NMB）从-13.5%~-6.0%提升至-9.0%~-3.3%）.