Development of a ‘Matrix Scoring Technique’ to determine litter sources at a Bristol Channel beach

Litter at beaches can come from more than one source and determining the proportions to assign pollution to different sources is very complex. There is no widely accepted methodology at present that links litter items to their source. The aim of this study was to create a method of assigning a source to litter found on beaches of the Bristol Channel but which could equally be used on any beach. Various methods that attempt to establish the source of beach litter were evaluated; their strengths, weaknesses, applicability and reliability for use on Bristol Channel, UK beaches were considered. Elements of existing methods coupled with new ideas were utilized in the production of a ‘refined’ methodology: consequently a new method of assigning a source to beach litter was developed. The developed ‘Matrix Scoring Technique’ was applied to data collected at Minehead beach on the Bristol Channel, UK. Several numerical and nomenclature variations were used to produce a system that reflected the various sources and eliminated as much bias as possible. This cross-tabulated matrix scoring system can produce an insight into the contribution of different source groups to litter found on beaches. This novel approach requires further testing with emphasis on a control data set.     

Inorganic mercury and methylmercury in surface sediments and mussel tissues from a microtidal lagoon (Bizerte, Tunisia)

The aim of this study was to investigate the distribution of mercury compounds in marine sediments and mussel tissues collected in the lagoon of Bizerte, Tunisia, during two seasons (summer and winter). Inorganic mercury (Hg²⁺) concentrations in sediments were found to be highly variable, ranging from 0.04 nmol.g¹ to 3.22 nmol.g⁻¹ (dry weight) with a mean value of 0.52 nmol.g⁻¹. Anthropogenic sources of Hg²⁺, most probably metallurgy or tire production industries, have been evidenced. The mean concentration of monomethylmercury (MeHg⁺) in the surface sediments is 2.32 pmol g⁻¹ ranging from below the detection limit (0.45 pmol.g⁻¹) to 14.6 pmol.g⁻¹. No significant variation was observed between winter and summer seasons for both mercury species concentration in the sediments. The Hg²⁺ concentrations in mussel tissues are also variable, ranging from 0.007 to 1.347 nmol.g⁻¹ (dry weight). The mean concentration is 0.70 nmol.g⁻¹. In these tisssues, Hg²⁺ is generally the major compound, making up ca. 88% of total mercury concentrations. However, methylmercury concentrations are significant and homogeneous, ranging from 62 to 121 pmol.g⁻¹ (mean 96 pmol.g⁻¹). The results suggest that a fraction of the inorganic mercury load in the sediments of the lagoon undergoes methylation pathways. MeHg⁺ produced is assimilated in the mussels more readily than Hg²⁺.     

S–O–C isotopic picture of sulphate–methane–carbonate system in freshwater lakes from Poland. A review

Microbial oxidation of organic compounds (including methane), in freshwater sediments, may result in precipitation of carbonates, which may become an important geochemical archive of paleoenvironmental variations. Most probably low δ¹³C value in calcite in eutrophic systems results from an advanced oxidation of organic compounds in turbulent or/and sulphate-rich conditions. Likewise, high δ¹³C value in calcite from organic-rich sediments may evidence low redox potential of the freshwater system. Oxidation of methane and organic matter results in significant isotope effects in sulphates dissolved in water. Therefore, to better understand the origin of carbon isotope signal in carbonates, concentration and stable isotope measurements in dissolved sulphate (water column), bubble methane and calcite (freshwater sediments) have been carried out in 24 lakes, 2 ponds and 4 rivers in Poland. The highest concentration of sulphate has been detected in rivers (85.47 SO₄ ²⁻ mg/l) and an artificial lake (70.30 SO₄ ²⁻ mg/l) located in the extremely SO₄ ²⁻-polluted region called the “Black Triangle”. The lowest concentration of sulphate is found in dystrophic and mountain lakes (from 0.5 SO₄ ²⁻ to about 3 mg/l). The lowest δ³⁴S(SO₄ ²⁻) and δ¹⁸O(SO₄ ²⁻) values occur in unpolluted lakes in eastern Poland (−0.94 and 1.38‰, respectively). The highest S and O isotopic ratios are found in a polluted lake in western Poland (δ¹⁴S(SO₄ ²)=12.95‰) and in a dystrophic lake in eastern Poland (δ¹⁸O(SO₄ ²) = 16.15‰) respectively. It is proposed that δ³⁴SO₄ ²⁻ and (¹⁸O(SO₄ ²⁻) values in lakes represent a good tool to assess and quantify anthropogenic impact by acid precipitation and to monitor variations in the trophic state and redox processes controlled by biodegradation of organic compounds in sediments and water column. In general, increasing depth (up to 12 m) of the water column is associated with decreasing trend the δ¹³C(CH₄) value from about –35 to about –78‰. However, δ¹³C value in sedimentary calcite (δ¹³C vary from –10 to 0.5‰) shows opposite trends as compared to the corresponding methane. This is probably due to redox processes and distribution of heavy isotopes between methane and calcite. Likewise, turbulent water (river) show high δ¹³C value in methane and low δ¹³C value in calcite—this is probably due to an enhanced oxidation of methane producing ¹³C-depleted CO₂. In contrast to clean lakes, it is observed that an increase of the δ¹³C(CH₄) value occurs with increasing depth of the water column in a strongly SO₄ ²⁻-contaminated lake. This is probably due to a loss of biological buffering potential of the lake accompanied by an active oxidation of methane precursors.     

Modelling the responses of the Lagoon of Venice ecosystem to variations in physical forcings

A Finite Element Ecological Model for the Lagoon of Venice (VELFEEM) has been used to test the responses of the Lagoon of Venice ecosystem to variations in physical conditions.The model is obtained by coupling a finite element hydrodynamic model, that computes the velocity fields of water, an energetic model to compute the water temperature fields, and an ecological model that simulates the dynamic of phytoplankton, zooplankton, nutrients (ammonia, nitrate and phosphate) organic detritus (organic nitrogen, organic phosphorous and CBOD) and dissolved oxygen.The transport model is a two-dimensional barotropic finite element model which allows for a better resolution of the lagoon morphology.The ecological model has been developed by starting from the ecological module EUTRO of WASP (Water Analysis Simulation System released by US EPA), and by adapting it to the peculiarity of the Lagoon of Venice.A reference condition has been identified by running a 1-year simulation under climatologic condition. Then, the sensitivity to physical forcing (tide and wind) and to the input of macronutrients has been investigated, by comparing model predictions of spatial and temporal evolution of major state variables and of an aggregate index of Water Quality Trophic Index (TRIX).     

基于监测样本信息的水环境系统权重分配方法

针对水环境系统权重分配问题，从建筑系统客观背景入手，以环境因子监测样本资料为信息源，通过构造关联信息矩阵，并采用旋转正交转变换的主成分分析法，定量地描述了交五因子在整体系统的贡献，最后依贡献量大小识别对应各个因子的权重值，实例表明，该方法物理意义清晰结果客观合理。     

国内外水环境管理体制对比分析

水环境管理体制建设是一项复杂的系统工程；即使在发达国家，水环境管理模式也随着认识水平的提高与需求的不断变化，处于逐步完善的过程。本文收集了国际上在水环境管理方面比较有代表性的国家，包括美国、英国、法国、荷兰、加拿大、澳大利亚、前苏联、日本、韩国、以色列与印度等水环境管理体制方面的资料，系统分析了这些国家在国家级、流域级与区域级的水环境管理体制与主要采取的水环境管理模式；并针对我国水环境管理体制的结症所在，提出了我国水环境管理体制改革所需遵循的基本原则。     

无锡市水环境的卫星遥感分析

利用计算机图像处理和多元统计方法处理了无锡市卫星遥感数据,形象直观地显示了无锡市水环境的宏观面貌,较好地反映了无锡水网主干河道的水质空间分布特征。研究表明,卫星遥感技术作为地面监测方法的一种有效补充,可提供丰富的遥感水质信息。     

造纸用水中菌尘的控制探讨

分析了民丰造纸厂生产用水中存在菌尘的问题 ,认为水源污染、水温和浊度等因素是处理水菌类大量生长的原因。通过试验和实验运行 ,提出降低出水浊度和采用混合杀菌剂的解决办法 ,获得了很好的效果。     

潘谢矿区导水裂隙带发育高度与采厚关系回归分析

根据淮南潘谢矿区最近几年导水裂隙带的实测资料,使用功能强大的数学分析软件Origin对其导水裂隙带与采厚关系进行数学回归分析,并对照现有规范中的关系通式,总结出更适合淮南矿区的预测公式,为以后淮南矿区防水煤柱的留设提供更可靠的理论依据。     

应用电化学方法处理印染废水

本文简要介绍了电化方法的原理、特点及其在印染废水处理中的应用．