Trace metal distribution in the bed, bank and suspended sediment of the Ravensbourne River and its implication for sediment monitoring in an urban river

Purpose This study aims to identify a suitable sediment compartment for sediment quality monitoring by: (a) studying the concentration of trace metals (Cd, Cu, Ni, Pb and Zn) in the bed, bank and suspended sediment compartments of the Ravensbourne River to establish any differences in trace metal concentrations with compartment; (b) determining the influence of sediment particle size fractions ( 0.05) in the concentrations of metals between the suspended sediment and the < 63 μm bed sediment fraction, but there was a significant difference (p < 0.05) between the suspended sediment and the < 63 μm bank sediment fraction. There were also significant differences between the concentrations of metals in the < 63 μm and the 63 μm–2 mm fractions. Generally, the Ravensbourne River did not comply with the draft UK sediment quality guidelines for the metals analysed. Conclusions This study shows the importance of identifying a suitable sediment compartment to sample for compliance with sediment quality standards. The bed and suspended sediments are the most widely used sediment compartments for sediment monitoring, but collecting sufficient mass of the < 63 μm sediment fraction for monitoring presents a challenge for urban gravel bed rivers like the Ravensbourne River. It seems appropriate to establish individual monitoring regimes for different rivers

Attachment of freshwater bacteria to solid surfaces

The initial stages of the permanent attachment of selected freshwater bacteria, particularly Pseudomonas fluorescens, Enterobacter cloacae, a Chromobacterium sp and a Flexibacter sp, to a hydrophobic and a relatively hydrophilic polystyrene surface was investigated. Changes in the nutrient conditions and growth rates of the bacteria caused differences in cell surface characteristics, measured by hydrophobic and electrostatic interaction chromatography and saline contact angle measurements on lawns of cells, and changed attachment levels to the two substrata in both buffer and nutrient media. The effects were different for each species, varying independently with surface, and were, largely, related to changes in predicted physicochemical interactions. However, the Flexibacter sp, a gliding bacterium, showed an increase. in attachment with increased growth rate, i. e. metabolic activity, possibly indicating an active attachment process. Peaks in the attachment of E. cloacae, P. fluorescens and the Chromobacterium sp to both substrata occurred between pH 6 and 7.5 and 20°C and 25°C, while the Flexibacter sp decreased attachment with increasing pH and temperature. These changes in attachment for each species were related to physico-chemical rather than physiological effects. Varying the electrolyte concentration and valency of the attachment solution showed that permanent attachment was independent of diffuse electrical double layer thickness. Similarly, attachment levels could not be predicted thermodynamically using liquid, solid and cell surface tensions, indicating the involvement of electrostatic interactions in the attachment of these species. Estimates of the hydrophobicity of the cell surfaces, by hydrophobic interaction chromatography, showed that hydrophobic interactions did not dominate in bacterial attachment. Thus, attachment of these four species was a multifactorial interaction involving a range of physico-chemical interactions. The attachment of individual species was also found to be affected by the presence of other bacterial species. Thus in natural aquatic systems a variety of biological, environmental and physico-chemical parameters will affect levels of bacterial attachment and hence biofilm composition and development

I. L'eau : réguler une ressource naturelle dans un climat économique changeant

McEldowney John, McEldowney Sharron. I. L'eau : réguler une ressource naturelle dans un climat économique changeant. In: Droit et gestion des collectivités territoriales. Tome 30, 2010. Les enjeux de la gestion locale de l'eau. pp. 259-274

Environmental law

Environmental Law is an exciting new textbook that explores all areas of the law relating to the environment in context. Legal principles and key cases are discussed alongside historical, social and economic influences, an approach which is particularly important at a time when environmental issues are making their way up the global political agenda. Key areas of development such as human rights and carbon trading are included alongside more traditional areas of environmental law such as planning and air pollution. A number of in-chapter features encourage critical thinking and aid understanding

Pollution : ecology and biotreatment /

Includes bibliographical references and index