Modelling the environmental behaviour of pollutants in Algeciras Bay (south Spain)

An environmental study of Algeciras Bay is carried out through numerical modelling. First, a 2D barotropic model is applied to calculate tides and mean circulation. Results of this model are used by a sediment transport model which provides suspended matter concentrations and sedimentation rates in the Bay. It includes three particle classes. An effective diffusion coefficient has been calibrated simulating temperature distribution inside the Bay. An additional validation is obtained from an independent nitrate dispersion simulation. Then heavy metal dispersion patterns are investigated using a model which includes water-sediment metal interactions and uses the outputs of the hydrodynamic and sediment transport models. The metal transport model has been applied to simulate the dispersion of Zn, Cu and Ni. Results from the hydrodynamic, sediment and metal transport models have been compared with measurements. Model results also indicate that transport inside the Bay is relatively weak. Numerical experiments have been carried out to determine flushing times for conservative and non-conservative pollutants. Flushing time is about 20 days for a conservative tracer, and this value is mainly due to the M(2) residual current. Tides are not effective in removing pollutants.     

太湖流域漕桥河小流域水环境容量估算及污染物削减分配

太湖流域漕桥河区域水环境质量日益恶化,成为影响该区域可持续发展的主要问题之一,为此基于漕桥河小流域和水质污染分段的特征,计算了研究区域的水环境容量和污染物削减量,提出河流污染分段控制和流域管理的水环境容量控制模式,建立河流氮磷污染控制的可操作性措施,从而确定重点工程和措施实施的年度计划,形成污染源年度削减方案,可为小流域污染控制管理提供科学依据.     

Spatial stochasticity and correlated effects in dose–response relationships for environmental pollutants: a case study of radiation effects

 Models of dose–response for environmental pollutants generally do not include explicit consideration of the stochastic nature of the spatial pattern of dose delivered to an organ or tissue, or the correlation between events leading to a final health endpoint (such as cancer). The result can be significant errors in risk calculations when these stochastic properties contribute as strongly to the dose–response relationship as do the dose–response relationships for individual cells. The present paper considers the issue of stochasticity of dose and events (initiation, promotion and inactivation) for the case of carcinogenicity following exposure to environmental pollutants, using the case of irradiation by high LET emitters such as radon and progeny from water or air. The model is based on the concepts of hit probabilities and effect-specific track length probabilities (probability of damage per unit track length), and is applied first to in vitro data and then to predictions in vivo. It is shown that inhomogeneity of dose throughout an irradiated tissue or organ volume, and correlation between initiation, promotion and inactivation, can lead to significant differences in predicted risk.     

Benthic infauna variability in relation to environmental factors and organic pollutants in tropical coastal lagoons from the northern Yucatan Peninsula

We examine the abundance and species composition variability of benthic infauna from tropical coastal lagoons in relation to environmental factors and organic pollutants. Sediment samples were collected at 40 sites in four lagoons in the northern Yucatan Peninsula. A total of 7985 individuals belonging to 173 species were sampled. While the eastern lagoons were dominated by polychaetes, the western ones were dominated by crustaceans. Overall, polychaetes had the highest abundance (48%), followed by crustaceans (42%). According to canonical correspondence analysis, species attributes were correlated with water salinity, pH and temperature, but also with sediment pentachlorobenzene, trichlorobenzene, and low molecular weight polycyclic aromatic hydrocarbons. Some pollutants exceeded sediment quality guidelines, representing a potential environmental risk to benthic infauna. Together, environmental factors and pollutants explained 52% of the variance in abundance and species composition among sites.     

Bayesian spatial modeling of Lavaca Bay pollutants

Locational risk of increased mercury and PAH concentrations in Lavaca Bay, Texas sediments and eastern oysters (Crassostrea virginica) harvested from Lavaca Bay, Texas were analysed. Chemical analysis results were evaluated utilizing Bayesian geo-statistical methods for comparison of the model fit of a random effects model versus a convoluted model which included both random and spatial effects. For those results fit best with the convoluted model, continuous surface maps of predicted parameter values were created. Sediment and oyster concentrations of mercury and the majority of measured PAHs were fit best with the convoluted model. The locational risks of encountering elevated concentrations of these pollutants in Lavaca Bay sediments and oysters were highest in close proximity to industrial facilities.     

洱海主要污染物允许排放总量的控制分配

基于环境流体动力学模型EFDC(Environmental Fluid Dynamic Code),建立了洱海湖泊及湖湾的三维水动力水质模型.利用洱海2001 2011年连续11年的水动力水质监测数据对模型进行了率定和验证,模拟结果与实测资料吻合度较好,表明水动力水质模型计算结果较为合理.在考虑水质环境背景浓度的前提下,通过水质模型量化各个入湖排污口对水质控制点的贡献率,并对各水质控制点和入湖排污口的浓度进行约束限制,最终利用单纯形法求解得到各入湖排污口的允许排污量.计算结果表明,北区三条河流弥苴河、永安江、罗时江本身流量相对较大,所以允许排放总量也较大,总氮、总磷和COD_Mn的允许排放总量分别占到整个洱海允许排放量的47%、53%和49%.洱海主要污染物允许排放总量的控制分配研究对于洱海流域的环境综合整治具有十分重要的意义.     

Historical records of organic pollutants in sediment cores

Analyses of sediment core samples are primary sources of historical pollution trends in aquatic systems. Determining organic compounds, such as POPs, in the dated sediments enables the estimation of their temporal concentration changes and the identification of the contaminant origin in local regions. Wars, large-scale fires, economical transitions, and bans on certain chemicals are reflected in the sediment organic compound concentrations. The high POP concentrations in surficial sediments suggest that these chemicals, even after being banned, remain in the environment. Furthermore, vertical profiles can help in understanding the sedimentation process and in estimating effective countermeasures against pollution. Moreover, studies published during the period 1991–2013 on PAHs, PCBs, OCPs, dioxins and dioxin-like compound concentrations in sediment core samples are reviewed.     

滇池东北岸生态修复区的环境效应——Ⅱ.污染净化效应

研究了滇池东北沿岸带生态修复区去除水体中污染物和营养盐的能力．对修复区在重富营养水体迎风岸、无陆源污染情况下通过收获水生植物和促进悬浮物沉降方式去除的湖泊内源污染物质进行了定量的监测分析．结果显示,修复区对外来的悬浮物质具有强大的凝集、固定作用,植被区内每平方米湖面平均年沉积量达118．9 kg(干重),其中的氮、磷、有机碳含量分别达120 g／(m2·a)、70 g／(m2·a)、1080 g／(m2·a):修复区内的底质环境得到明显改善,表层沉积物中氮和有机碳含量比原初提高了4倍以上;修复区内水生植被具有极高的生产能力,仅2002年修复区就收割打捞水生植物113t(干重),由此去除氮、磷分别为30．0 g／(m2·a)和4．8 g／(m2·a).因此,沿岸带生态修复完全可以作为湖泊内源污染净化的一项工程措施在滇池东北沿岸或类似重污染水体推广应用．     

The temporal variation of indoor pollutants in photocopying shop

The paper includes the identification of the main factors responsible for the temporal variations of indoor pollutants during three daily intervals in a photocopying shop. The measurements of concentration levels of total volatile organic compounds, ozone, carbon monoxide, carbon dioxide, nitrogen dioxide, ammonia, perchloroethylene and non-methane hydrocarbons were performed. The individual concentrations of target pollutants were subjected to principal component analysis (PCA) using a software XLSTAT 2014.1.10. Pearson correlation model indicated the relatively weak correlation between the investigated pollutants in a photocopying environment. PCA extracted three principal components (PCs) from the indoor air pollution data set. Obtained PCs explained 56.72 % of the total variance. The summarized biplots showed which pollutants are responsible for photocopying indoor pollution per sampling day/sampling point/time interval/number of measurement. The results pointed out that the main PCs were related to the usage of toners, electrostatic discharge, heating of photocopiers as well as general intensifying of photocopying processes.