粤港澳大湾区污染场地土壤风险管控制度体系建设与思考

防范污染场地环境风险和保障人居环境安全是粤港澳大湾区建设世界级城市群面临的重要挑战和工作内容之一.由于粤港澳在政治制度和土地管理等方面的差异,以及珠三角9市内部城市化水平、产业结构以及环境管理能力的差别,大湾区各地污染场地风险管控模式有明显的差异,分析粤港澳大湾区典型城市污染场地风险管控特点,对加强污染场地风险管控技术交流与合作,优化大湾区污染场地风险管控制度具有重要意义.本文在简述我国污染场地风险管控制度体系的基础上,重点介绍了广州、深圳、东莞、香港和澳门的污染场地风险管控制度体系、监管对象、污染评估与整治程序等的特点,对其风险管控制度体系进行了分析与对比,并针对土地规划、政策反馈、信息公开及联盟机制探索等提出了思考与建议.总体来看,香港及珠三角部分地市构建了行之有效的污染场地风险管控制度体系,且体现了一定的地方特点,但随着污染场地的进一步开发再利用,打造粤港澳大湾区世界级城市群的建设目标将对污染场地风险管控策略的安全性、精细化和时效性等提出更高的要求,互相借鉴和充分学习,加强大湾区2区9市污染场地风险管控上的技术交流与合作,是实现大湾区污染场地安全再利用与高效开发的有效路径.     

江苏省印染污泥现状分析

对江苏省四大纺织基地进行调研,掌握了17家典型的印染企业污水处理量、污泥脱水及处置方式.同时,取样分析了印染污泥中重金属镉(Cd)、铅(Pb)、总铬(Cr)、铜(Cu)、锌(Zn)和镍(Ni)及含水率、低位热值、灰分和氯离子含量的变化情况.研究表明:采用板框压滤脱水的印染污泥平均含水率可达66.42%,便于焚烧处置;将近1/2的污泥低位热值低于污泥助燃焚烧的限值,需对污泥处理工艺和脱水方式加以改进;污泥处理过程中含氯药剂的加入使得Cl-含量波动较大,焚烧时需加强对二英的监测;17家印染企业污泥中重金属平均含量均低于江苏省城市污泥重金属平均含量,但Zn的含量却远高于评价标准.本文可为江苏省印染污泥焚烧及污染防治工作提供技术支持.     

Effects of water regime,crop residues,and application rates on control of Fusarium oxysporum f. sp. cubense

Biological soil disinfestation is an effective method to control soil-borne disease by flooding and incorporating with organic amendments, but field conditions and resources sometimes limited its practical application. A laboratory experiment was conducted to develop practice guidelines on controlling Fusarium wilt, a widespread banana disease caused by Fusarium oxysporum f. sp. cubense (FOC). FOC infested soil incorporated with rice or maize straw at rates of 1.5 tons/ha and 3.0 tons/ha was incubated under flooded or water-saturated (100% water holding capacity) conditions at 30°C for 30 days. Results showed that FOC populations in the soils incorporated with either rice or maize straw rapidly reduced more than 90% in the first 15 days and then fluctuated till the end of incubation, while flooding alone without organic amendment reduced FOC populations slightly. The rapid and dramatic decrease of redox potential (down to − 350 mV) in straw-amended treatments implied that both anaerobic condition and strongly reductive soil condition would contribute to pathogen inactivation. Water-saturation combined with straw amendments had the comparable effects on reduction of FOC, indicating that flooding was not indispensable for inactivating FOC. There was no significant difference in the reduction of FOC observed in the straw amendments at between 1.5 and 3 tons/ha. Therefore, incorporating soil with straw (rice or maize straw) at a rate of 3.0 tons/ha under 100% water holding capacity or 1.5 tons/ha under flooding, would effectively alleviate banana Fusarium wilt caused by FOC after 15-day treating under 30°C.     

非均质条件下河流包气带水分运移的原位试验

围绕非均质条件下河流包气带水分运移,选择渭河河漫滩开展原位试验。在渭河原位试验点开挖7 m×1 m×2.8 m的探坑,以一侧剖面为研究面,刨光成垂直平面并对剖面做保护工作,方便观测。在不同层位按不同深度、在不同岩性的层位上打孔,分别安装MP-917时域反射仪与水银压力计,监测含水率及地下水压力势,并采用自制Bauwer渗水仪做持续5 d的有压入渗试验,研究非均质条件下河流包气带水分运移规律及入渗速度与水头高度的关系。结果表明,包气带介质含水率分布与包气带结构有关,受岩性渗透系数制约,其中弱透水层的存在阻滞了水分的运移,包气带很难达到饱和,在弱透水层以上形成上层滞水并以非饱和流形式入渗。入渗速度随水层的厚度增大而增大,且入渗速度与水头高度呈对数关系。     

Slope,aspect and climate: Spatially explicit and implicit models of topographic microclimate in chalk grassland

The slope and aspect of a vegetated surface strongly affects the amount of solar radiation intercepted by that surface. Solar radiation is the dominant component of the surface energy balance and influences ecologically critical factors of microclimate, including near-surface temperatures, evaporative demand and soil moisture content. It also determines the exposure of vegetation to photosynthetically active and ultra-violet wavelengths. Spatial variation in slope and aspect is therefore a key determinant of vegetation pattern, species distribution and ecosystem processes in many environments. Slope and aspect angle may vary considerably over distances of a few metres, and fine-scale species’ distribution patterns frequently follow these topographic patterns. The availability of suitable microclimate at such scales may be critical for the response of species distributions to climatic change at much larger spatial scales. However, quantifying the relevant microclimatic gradients is not straightforward, as the potential variation in solar radiation flux under clear-sky conditions is modified by local and regional variations in cloud cover, and interacts with long-wave radiation exchange, local meteorology and surface characteristics.     

大坝下游河段的河流生态径流调控研究

了分析大坝工程对河流径流情势的影响,以三峡大坝下游河段的宜昌站为例,计算了三峡坝下河段的生态水文季节、生态需水和其它径流情势特征参数。计算结果表明,长江宜昌江段枯水期为1~3月份、副汛期为4~6月份和10~12月份,而洪水期为7~9月份;枯水期、副汛期和洪水期的最小生态需量占同期来水总量分别为24%~27%、30%~50%和30%~45%;适宜的生态需水在枯水期、主汛期分别占同时期来水总量为30%~42%、50%~70%;四大家鱼和中华鲟产卵、繁殖期内的适宜生态流量范围分别为 6 540~12 700 m3/s 和 16 300~9 130 m3/s,大约占同时期来水总量的50%~70%;涨水次数平均值分别为5.3和3.4,落水次数平均值分别为50和5.1等,这为三峡水库在四大家鱼和中华鲟产卵、繁殖期内的调度提供了保护的依据。〖     

Profile of Methane Concentrations in Soil and Atmosphere in Alpine Steppe Ecosystem on Tibetan Plateau

The methane concentration profile from -1.5m depth in soil to 32m height in air was measured in alpine steppe located in the permafrost area. Methane concentrations showed widely variations both in air and in soil during the study period. The mean concentrations in atmosphere were all higher than those in soil, and the highest methane concentration was found in air at the height of 16m with the lowest concentration occurring at the depth of 1.5m in soil. The variations of atmospheric methane concentrations did not show any clear pattern both temporally and spatially, although they exhibited a more steadystable state than those in soil. During the seasonal variations, the methane concentrations at different depths in soil were significantly correlated （R^2〉0.6） with each other comparing to the weak correlations （R^2〈0.2） between the atmospheric concentra- tions at different heights. Mean methane concentrations in soil significantly decreased with depth. This was the compositive influence of the decreasing production rates and the increasing methane oxidation rates, which was caused by the descent soil moisture with depth. Although the methane concentrations at all depths varied widely during the growing season, they showed very distinct temporal variations in the non-growing season. It was indicated from the literatures that methane oxidation rates were positively correlated with soil temperature. The higher methane concentrations in soil during the winter were determined by the lower methane oxidation rates with decreasing soil temperatures, whereas methane production rates had no reaction to the lower temperature. Relations between methane contribution and other environmental factors were not discussed in this paper for lacking of data, which impulse us to carry out further and more detailed studies in this unique area.     

三峡工程蓄水后荆江河段河势变化及生态护岸研究

三峡工程蓄水以来,进入长江中下游河道的水沙过程发生明显改变,从而导致中下游河道尤其是荆江河段冲刷、崩塌,局部河段河势调整较为剧烈,并导致主流顶冲部位发生变化,可能会引起新的崩岸发生。分析了荆江河段河势变化特点,列举了各种传统护岸方法,分析了传统护岸的特点和适用性,针对传统护岸工程的不足,提出生态护岸理念,在满足整体性、稳定性、适应变形等要求下,采取工程措施与植物措施共同护岸,并为河道与河岸之间水分交换提供条件,建立了水生生态系统和陆地生态系统之间的联系,实现了河流原本完整的结构和作为生态廊道的功能,进而保证整个生态系统的稳定,有利于生态环境的保护和水土保持,实现生态理念,满足生态需要,达到人与自然和谐发展。     

红壤坡地水土保持植物措施下柑橘林地水文生态效应

根据江西水土保持生态科技园2001～2008年不同处理措施柑橘林地径流小区的降雨产流产沙的定位观测资料及2010年土壤含水量测试数据,分析了坡面尺度水土保持植物措施下柑橘林地的产流产沙及土壤水分的特征,研究了狗牙根带状覆盖、狗牙根全园覆盖、果园清耕3种措施下的蓄水保土效应。结果表明：有草被覆盖的柑橘林小区的产流产沙量明显小于柑橘清耕小区,狗牙根带状覆盖小区减流减沙效果最好,减流率为98.21%,减沙率为99.84%。在大部分土层深度,草被带状覆盖下的土壤水分含量最高,均大于清耕措施,而全园覆盖由于植物蒸腾耗水量大水分含量反而低于带状覆盖。条带植草是防治柑橘林地水土流失的有效措施,具有明显的减流减沙效应和蓄积水分作用