A New Phosphorus Paradigm for the Baltic Proper

The external phosphorus (P) loading has been halved, but the P content in the water column and the area of anoxic bottoms in Baltic proper has increased during the last 30 years. This can be explained by a temporary internal source of dissolved inorganic phosphorus (DIP) that is turned on when the water above the bottom sediment becomes anoxic. A load-response model, explaining the evolution from 1980 to 2005, suggests that the average specific DIP flux from anoxic bottoms in the Baltic proper is about 2.3 g P m⁻² year⁻¹. This is commensurable with fluxes estimated in situ from anoxic bottoms in the open Baltic proper and from hydrographic data in the deep part of Bornholm Basin. Oxygenation of anoxic bottoms, natural or manmade, may quickly turn off the internal P source from anoxic bottoms. This new P-paradigm should have far-reaching implications for abatement of eutrophication in the Baltic proper.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-013-0441-3) contains supplementary material, which is available to authorized users.     

工业烟气净化系统的风量平衡调节及数值模拟应用研究

为了对某钢铁集团烧结机尾气净化系统的风量平衡进行调节,提出了利用Fluent仿真软件对通风管道内部流场进行数值模拟,在主管和部分支管上设置节流管、调节管径的改进措施。风量模拟结果表明,通风管道的原风量存在严重的不平衡性,吸尘点的风量不平衡率高达75.0%,在部分管道增加节流管可以有效调整管道的风量不平衡性,调整后吸尘点风量的不平衡率为18.8%;对于压力损失较大、风量偏小的管道,可通过管径调节使其风量基本达到设计要求;Fluent仿真软件的风量模拟值与现场实测值有较高的吻合性,数值模拟方法可以为工业烟气净化系统的改造提供参考依据。不仅能够为前期工程设计提供帮助,大大节省工程调试费用,缩短工期,并有助于风量不平衡管道的调节和改造。     

珠江三角洲制鞋行业挥发性有机化合物排放系数研究

采用工艺调查与现场监测相结合的方法,以物料衡算法为依据,通过现场监测结果进行验证,研究了制鞋行业挥发性有机化合物(VOCs)排放系数。结果表明,水性胶粘剂使用企业的VOCs排放系数为(5.25±2.67)g/双,油性胶粘剂使用企业的VOCs排放系数为(30.11±10.60)g/双,根据不同类型胶水在制鞋行业中所占的权重,可得到反映地方特色的制鞋行业VOCs排放系数。     

Seasonal air-water exchange fluxes of polychlorinated biphenyls in the Hudson River Estuary

Polychlorinated biphenyls (PCBs) were measured in the air and water over the Hudson River Estuary during six intensive field campaigns from December 1999 to April 2001. Over-water gas-phase SigmaPCB concentrations averaged 1100 pg/m3 and varied with temperature. Dissolved-phase SigmaPCB concentrations averaged 1100 pg/L and displayed no seasonal trend. Uncertainty analysis of the results suggests that PCBs with 5 or fewer chlorines exhibited net volatilization. The direction of net air/water exchange could not be determined for PCBs with 6 or more chlorines. Instantaneous net fluxes of SigmaPCBs ranged from +0.2 to +630 ng m(-2) d(-1). Annual fluxes of SigmaPCBs were predicted from modeled gas-phase concentrations, measured dissolved-phase concentrations, daily surface water temperatures and wind speeds. The net volatilization flux was +62 microg m(-2) yr(-1), corresponding to an annual loss of +28 kg/yr of SigmaPCBs from the Hudson River Estuary for the year of 2000.     

Mass balance and long-term fate of PCDD/Fs in a lagoon sediment and paddy soil, Niigata, Japan

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in a sediment core and in samples of surface sediment and paddy soil collected from the Toyano lagoon and Kameda basin in Niigata, Japan, were analyzed to elucidate the temporal trends of their concentrations in the lagoon sediment and the relationship between the sediment and the paddy soil. The mass balance of these pollutants was also estimated to determine their long-term fate in surface waters. An analysis by chemical mass balance identified the agrochemicals pentachlorophenol and 2,4,6-trichlorophenyl 4-nitrophenyl ether as the major sources of PCDD/Fs. On the basis of the findings regarding the mass balance in the Kameda basin over the last 40 years, we estimate that more than half the input of PCDD/Fs to the Kameda basin has disappeared. We suggest that the PCDD/Fs that flowed out from the paddy fields have been transferred to the lower basin.     

Mass balance-based regression modeling of Cd and Zn accumulation in urban soils of Beijing

Accumulation of heavy metals in urban soil can pose adverse impacts on public health and terrestrial ecosystems. We developed a mass balance-based regression model to simulate the heavy metal accumulation in urban soils as a function of time and to explore connections between metal concentration and urbanization processes. Concentrations of Cd and Zn in 68 residential soil samples in the urban area of Beijing were used. The background concentrations, the loss rates and the input fluxes of Cd and Zn in urban soils of Beijing during the last three decades were estimated using a regression of the time series of accumulations of the metals. Based on the regression estimates, we simulated the general trends of Cd and Zn accumulation in the soils from 1978 to 2078. The concentrations of Cd and Zn in urban soil generally increased with the population growth, vehicle use and coal consumption. The mean concentrations of Cd and Zn in urban soil of Beijing would increase by 3 fold over the next 70 years for the current development scenario. The mass balance-based regression approach, which is able to reconstruct the history data of urban soil pollution, provides fundamental information for urban planning and environmental management.     

城市复合生态系统碳氧平衡分析——以沿海城市厦门为例

通过综合城市复合生态系统内社会经济活动的主要排碳、耗氧行为,以及城市区域内湿地、淡水、海洋、森林和农田5种遗留自然生态系统的固碳释氧功能,构建了城市碳氧平衡分析模型（UCOB）,并估算了城市社会经济活动和城市中自然生态系统的碳氧收支,对城市生态系统平衡状况进行定量化指征.最后,以中国东南沿海城市厦门为例进行研究.结果显...     

多功能型城市人工湿地水体汞分布特征及其量变分析

以重庆某集接纳生活污水处理厂出水、水质净化、休闲娱乐为一体的城市湿地公园为研究对象,根据水流流向设点采样,分析了湿地公园内污水处理区、湖泊深度净化区中总汞(THg)和甲基汞(MeHg)的分布特征,并探讨了其源汇关系.结果表明,污水处理区出水THg质量浓度范围为1. 98～38. 03 ng·L~(-1)[平均值为(9. 10±5. 84) ng·L~(-1)],出水MeHg质量浓度范围为0. 09～0. 84 ng·L~(-1)[平均值为(0. 34±0. 08) ng·L~(-1)];湖泊深度净化区THg质量浓度范围为0. 37～85. 69 ng·L~(-1)[平均值为(6. 76±2. 29) ng·L~(-1)],MeHg质量浓度范围为0. 04～1. 47 ng·L~(-1)[平均值为(0. 35±0. 17) ng·L~(-1)],人为活动对汞浓度的干扰较为明显.水体总汞、甲基汞垂直分布规律具有一致性,均表现出表层深层.通过物料衡算,表明该湿地系统水体总汞每年降低155. 50 g,水体甲基汞每年降低1. 65 g,对下游水体具有保护作用.     

北京气象塔夏季大气O3,NOx和CO浓度变化的观测实验

以北京325m气象塔为观测平台,于2002年夏季进行了大气污染物臭氧(O₃)及其前体物氮氧化物(NO_x)和气象要素加强期的同步观测.对观测资料做了详尽的分析,结果表明:边界层内存在明显的臭氧浓度(用体积分数表示)垂直差异;中午120m高度层存在O₃浓度最大值;低层O₃浓度呈明显的日变化,且昼夜振幅较大;夜间高层(280m)O₃的湍流混合和化学消耗较弱,可维持较高的浓度;局地光化学生成是白天边界层O₃的主要来源;降水天气过程可造成O₃及其前体物浓度的显著变化.     

三峡库区1980～2005年农业用地氮平衡时空变化研究

利用三峡库区分区县农业统计资料,对OECD土壤表观氮平衡模型进行适当改进,计算分析三峡库区1980~2005年农业用地氮平衡时空变化格局及驱动机制.结果表明,1980~2005年库区氮总输入和总盈余量呈显著增长趋势,分别从23.4万t和14.4万t增长到45.6万t和30万t;氮总输出量1980~1995年呈增加趋势,从9.0万t到16.7万t,1995年后基本保持稳定趋势;单位面积氮盈余量1980~1998年总体呈持续增加趋势,从133.4 kg/hm2增长到310.3 kg/hm2,1998年后逐步趋向稳定,但空间分布区域差异性增强,主要集中在库中和库首区县,与库区移民数量空间分布具有一定的相似性;氮输入贡献主要来源于化肥、牲畜粪便、人粪尿和生物固氮,累计占总输入90%以上;1995年前库区氮平衡变化主要受国内大量使用化肥宏观环境影响,1995年后受水库淹没和移民影响较大,但其具体影响程度有待进一步分析;建议考虑适当发展副业、改变农业种植结构或进行生态移民等措施减少氮排放量.