三峡水库蓄水运行初期(2003—2012年)水环境演变特征的“四大效应”

自2003年三峡水库首次蓄水至2012年工程竣工验收启动,针对三峡水库蓄水运行初期的水环境演变研究较多,但整体性、综合性科学认识仍然缺乏.基于水环境多要素跟踪观测研究,综合采用现场观测、室内试验、数理统计、模型模拟、同位素及保守离子示踪等技术手段,系统剖析了特大型、高变幅水位水库运行背景下水动力变异及其所伴生的水环境演变特征,从水动力、水质、水生态、污染物输移角度,提出了三峡水库水环境演变过程中的“四大效应”,主要包括干支流水动力特性的“分化”效应、上游-干流-支流水质演变“同步”效应、水动力变化对藻类水华暴发的“胁迫”效应、水动力变化对同等负荷条件下污染源危害的“迭加”效应等.考虑到大型水库生态系统的演替和稳定是一个长期过程,建议继续强化长江上游梯级水电开发影响下的三峡水库水环境演变跟踪调查研究,适时开展三峡工程对库区水环境影响的后评估.      

长江流域总磷污染:分布特征·来源解析·控制对策

针对长江流域总磷污染,开展总磷污染时空特征分析,选择长江流域总磷污染最严重的上游地区岷江和沱江为典型区,分析总磷来源,提出总磷污染控制对策.研究表明:2016年开始总磷成为长江流域主要污染因子,其中上游污染最重,中游污染最轻,总体呈降低趋势;长江流域枯/平水期总磷污染较重,丰水期污染较轻,说明流域主要污染负荷来自点源.总体来说,造成长江流域总磷较高的原因有:磷矿开采和磷化工的污染源高负荷排放,造成部分河段水质严重超标;基础设施建设滞后,城镇生活污染源排放影响河流水质;畜禽养殖废物资源化利用不足;生态流量不足,加剧水污染问题;水污染治理导向不全面和污染源监管措施不系统,影响总磷水质同步改善.针对长江流域总磷污染特征,按照"分区控制、分类治理""突出重点、精准施策"原则,提出长江流域总磷污染控制建议:①抓住长江流域上游重点片区,开展流域总磷污染整治. ②抓住磷化工、城镇生活和畜禽养殖等三类涉磷重点污染源的治理,控制磷污染负荷排放. ③抓住环境监管有效手段,进一步完善水环境标准和监管体系.      

黄河流域氮磷营养盐动态特征及主要影响因素

收集了黄河流域下游主要干流监测站近40a来(氮数据)或20a(磷数据)来的水质数据,同时,收集了流域各省人口、氮肥磷肥施用量(折纯)及工业废水排放量等数据,研究了黄河氮磷营养盐通量(或浓度)的多年变化趋势,并统计了水质变化与流域人口、化肥用量和工业废水排放量等社会经济指标的关系.结果表明,黄河氮输送通量近40a来有不断升高的趋势,但1990s后期受黄河断流影响有明显下降;同时,由于下游引黄灌区大量取水使得花园口-利津之间的氮通量相对入海口的氮通量为负值.黄河总磷含量在一定范围内波动,没有呈现趋势性变化,受断流影响1990s后期总磷含量值也明显减小.进一步分析表明,黄河氮输送通量的变化主要受流域内人口、氮肥施用量的影响,而与工业废水排放量没有统计上的相关性;黄河总磷含量和流域人口、磷肥施用量和废水排放量均无相关性,而与黄河水体中悬浮物含量显著相关.回归分析结果表明,黄河水体悬浮物中的总磷含量为0.54g·kg-1,与黄土高原总磷背景值十分接近.由于黄河悬浮物主要来自黄土高原,故判断黄河总磷输送的主要影响因素是黄土高原的水土流失.查明黄河流域氮磷输送量多年变化情况和主要影响因素可为流域和海域污染控制及负荷分配提供依据.     

基于生态管理的流域水环境功能区划——以浑河流域为例

从环境战略管理的高度,提出了一种基于生态管理的流域水环境功能区划分方法.在现行水环境功能区划的基础上,结合生态管理理念及相关理论,并充分考虑我国水环境管理能力及发展趋势,进行流域水环境功能区划分.流域水环境功能区划以流域水生态分区为基础,根据参考条件评估水体的生态状况,考虑水体生态保护功能和最小生态需水量,提出新的流域水环境功能区划的理论基础和技术方法体系.首次将水生态分区、水生态保护目标和生态需水量引入水环境功能区划之中,对原水环境功能区划的内涵进行了拓展.该方法以浑河流域为案例做了实证研究.     

饮用水源水质预警监控断面设置方法及其应用

为进一步保障饮用水源水质安全,以北江的广东辖区段(下称北江)为案例区,研究构建了饮用水源水质预警监控断面设置方法,并开展应用研究. 研究结果:①系统提出了饮用水源水质预警监控断面设置思路. 从断面类型上,划分为入境断面、控制断面、预警断面、目标断面4类;从断面功能上,分别定位为入境水质监控、源头影响控制、早期水质预警、目标水质保障;从断面的风险覆盖范围上,分别在面尺度、线尺度、点尺度3个层面保障水源水质安全;从而构建分类多级的饮用水源水质预警监控站网. ②提出了饮用水源水质预警监控各类断面的设置方法. 如入境断面的设置执行“属地管理”原则,与跨省(市)界断面保持一致;控制断面的设置遵循“快速响应”原则,在高风险源及河段下游就近布设;预警断面的设置遵循“应急缓冲”原则,断面与取水口距离的核算公式是预留的水团迁移时间、设定水文条件下水流流速2类参数的函数,预留迁移时间需要满足不小于当地区域应急响应时间的约束条件;目标断面则直接位于取水口. ③北江流域饮用水源水质预警监控断面初设136个,优化核定后共计111个,包括入境断面6个、控制断面71个、预警断面26个、目标断面16个,其中有8个断面具有多重监控功能属性. ④经验证,该研究中所述方法具有可操作性.      

辽东湾近岸海域石化产业环境风险综合评价

为探究临港石化产业对海洋生态环境造成的不利影响,以2014-2018年辽东湾近岸海域生态环境监测数据为基础,结合环境灾害学理论体系与数理统计法构建了环境风险评价模型.并借助ArcGIS空间矢量叠加分析技术,开展了辽东湾近岸海域环境风险状况评价研究.结果表明:辽东湾近岸海域环境风险承载能力整体较为脆弱,从远海至近岸海域环...     

溶解性有机碳的主要组成对青鳉鱼铜急性毒性的影响

为揭示溶解性有机碳(DOC)的组成对生物配体模型(BLM)预测铜的生物毒性准确性的影响,研究了不同浓度黄腐酸(FA)、腐殖酸(HA)和两者不同浓度比例混合物影响铜对青鳉急性毒性。结果表明:在相同水质条件下,黄腐酸或腐殖酸浓度增加时,铜对青鳉的LC50均增加;两者共存时,当腐殖酸质量百分比从10%增至90%时,铜对青鳉的LC50也增加。当天然水中DOC的组成不确定时,可假设HA和FA的组成比例为1∶1,此时BLM预测铜对青鳉的LC50的偏差最小。     

Distribution,sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface water in industrial affected areas of the Three Gorges Reservoir,China

Water samples were collected from wastewater treatment plant (WWTP), drain water (DW), major tributaries (MT), and main course of the Yangtze River (MY) in areas of three industrial parks (IPs) in Chongqing city in the Three Gorges Reservoir (TGR). Sixteen EPA priority polycyclic aromatic hydrocarbon (PAH) pollutants were quantified to identify the effects of industrial activities on water quality of the TGR. The results showed that 11 individual PAHs were quantified and 5 PAHs (naphthalene (Nap), acenaphthylene (Acy), benzo[k]fluoranthene (BkF), indeno[1,2,3-cd]pyrene (InP), and benzo[g,h,i]perylene (BgP)) were under detection limits in all of the water samples. Three-ring and four-ring PAHs were the most detected PAHs. Concentrations of individual PAHs were in the range of not detected (nd) to 24.3 ng/L. Total PAH concentrations for each site ranged from nd to 42.9 ng/L and were lower compared to those in other studies. The mean PAH concentrations for sites WWTP, DW, MT, and MY showed as follows: DW (25.9 ng/L) > MY (15.5 ng/L) > MT (14.0 ng/L) > WWTP (9.3 ng/L), and DW contains the highest PAH concentrations. Source identification ratios showed that petroleum and combustion of biomass coal and petroleum were the main sources of PAHs. The results of potential ecosystem risk assessment indicated that, although PAH concentrations in MT and MY are likely harmless to ecosystem, contaminations of PAHs in DW were listed as middle levels and some management strategies and remediation actions, like strengthen clean production processes and banning illegal sewage discharging activities, etc., should be taken to lighten the ecosystem risk caused by PAHs especially risks caused by water discharging drains.     

Emissions of ammonia and greenhouse gases during combined pre-composting and vermicomposting of duck manure

Combined pre-composting and vermicomposting has shown potential for reclamation of solid wastes, which is a significant source of ammonia (NH₃), and greenhouse gases (GHG), including nitrous oxide (N₂O), methane (CH₄), and carbon dioxide (CO₂). Earthworms and amendments may both affect physico-chemical characteristics that control gas-producing processes, and thus affect NH₃ and GHG emissions. Here, we used two-way ANOVA to test the effects of addition of reed straw and combined addition of reed straw and zeolite on NH₃ and GHG emissions during pre-composting of duck manure, either with or without a follow-up phase of vermicomposting. Results showed that cumulative N₂O, CH₄, and CO₂ emissions during pre-composting and vermicomposting ranged from 92.8, 5.8, and 260.6 mg kg^?1 DM to 274.2, 30.4, and 314.0 mg kg^?1 DM, respectively. Earthworms and amendments significantly decreased N₂O and CH₄ emissions. Emission of CO₂ was not affected by earthworms, but increased in responses to addition of reed straw. Cumulative NH₃ emission ranged from 3.0 to 8.1 g kg^?1 DM, and was significantly decreased by reed straw and zeolite addition. In conclusion, combined pre-composting and vermicomposting with reed straw and zeolite addition would be strongly recommended in mitigating emissions of N₂O, CH₄, and NH₃ from duck manure. Moreover, this method also provides nutrient-rich products that can be used as a fertilizer.