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The purpose of this investigation was to study the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in seawater (flow velocity from 0 to 0.8 m/s, sediment content from 0 to 0.15 percent), to analyze the effects of the flow velocity and sediment content on the erosion-corrosion process.

A simulated erosion-corrosion test system was set up. Weight loss determinations and electrochemical measurements (such as potentiostat square wave (PSW), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests) were used to study the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in stagnant and flowing seawater with different sediment contents.

Under the test conditions, ZHMn55-3-1 copper alloys had good corrosion resistance to stagnant clear seawater, while increasing the flow velocity and sediment content reduced the corrosion resistance of the material. The difference in the erosion-corrosion mechanism between flow velocity and sediment content was that the former affected both the cathode process and the anode process of electrochemical corrosion, while the latter essentially affected only the anode process.

This paper explains the effects of flow velocity and sediment content on the erosion-corrosion behavior of ZHMn55-3-1 copper alloy in flowing seawater.

The rate of diffusion‐controlled corrosion of the copper walls of a cylindrical agitated vessel in acidified FeCl3 solution was studied by measuring the weight loss and the increase of Cu2+ concentration with time using iodometry. Variables studied were impeller rotation speed, physical properties of the blank solution and oil concentration in the emulsion. The rate of dissolution of copper was found to increase with increase in impeller speed according to the equation: K = a′ V0.1, where K is the mass transfer coefficient, a′ is a function of oil concentration; V is the linear velocity of the impeller. The mass transfer coefficient of the corrosion process in blank solution was related to other variables by the equation: Sh = 0.000575 Re0.1 Sc0.33, where Sh is the Sherwood number, Re the Reynolds number and Sc Schmidt number. This equation could be used in the design stage, to calculate the thickness of the vessel which covers a certain life span in service under a given set of operating conditions.

Purpose – The purpose of this research is to investigate the relationship of lead (Pb) and zinc (Zn) contents in sediment of Faunus ater (F. ater) population density and to analyze the relationship between Pb and Zn accumulation in F. ater with F. ater density in Reuleng River, Leupung, Aceh Besar.

Design/Methodology/Approach – Sampling was conducted in November 2016 until January 2017. Density of F. ater was analyzed by density formula while its relationship to Pb and Zn in sediments and F. ater was conducted by correlation analysis method.

Findings – The results showed that correlation between Pb and Zn in sediments and in F. ater varies at each locations on every month of sampling. Pb and Zn content in sediments found a fluctuating relationship in each month of sampling with density of F. ater. Correlation of Pb content in sediments with F. ater density showed a medium correlation in January 2017 with r-value = 0.665. Zn in sediment has a very strong correlation to F. ater density in November 2016 with r-value = 0.891. Pb in F. ater has a medium correlation to F. ater density in January 2017 with r-value = 0.436. Furthermore, accumulation of Zn in F. ater to its density does show some apparent correlation in each month of sampling.

Research Limitation/Implications – This research gives information about the relationship of Pb and Zn contents in sediment to density of F. ater and to analyze correlation of Pb and Zn in F. ater to density of F. ater in Reuleng River, Leupung, Aceh Besar district.

Originality/Value – This is the first time research is conducted about on the correlation between lead and zinc to obtain the density of F. ater.

The purpose of this paper is to evaluate the historical pollution of the Hostivar Reservoir (largest reservoir in Prague) sediment by metals, polyaromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) and identify the trends in pollution of aquatic environment.

Core samples, 140 cm long, recording the 45-year history of the reservoir, were separated to 5 cm width subsamples (approximately 1.5 years of sedimentation) and analyzed for metals (Cd, Pb, Cu, Zn, Cr, Ni, Al), PAH and PCB. Following methods were used: US EPA 3051 for metals, US EPA 505 and US EPA 8082 A for PCB, and ISO 18287:2006 for PAH.

Most of the contaminants had the highest concentration at the beginning of the existence of the reservoir, suggesting that the contamination results from construction activities. Significant decrease of Pb occurred in the second half of the 1990s. It was caused by termination of the addition of lead as a detonation suppressant to the gasoline. Most concentrations of PAHs, PCBs and metals, except copper do not present eco-toxicological risk.

The results show the volume of priority pollutants removed from the reservoir by sediment extraction, and point risk to the terrestrial environment due to application of the sediment in the construction of a noise protecting wall.

The paper presents unique data about historical contamination of the largest reservoir in Prague, the capital of Czech Republic. It shows how the watershed and the construction phase of the dam cause a pollution of the reservoir sediment and possible environmental risk for aquatic biota.

The Suez Irrigation Canal is the source of drinking water to a large community. Complaints have been raised regarding the odor and unpleasant taste of drinking water. The problems encountered reveled enrichment of the Canal with nutrients, degraded water quality and nuisance caused by algal growth. This paper aims to investigate these claims by evaluating the interaction between water and sediment with ecological indicators.

Bioassessments were used as a primary tool to evaluate the biological conditions and identify the degree of water quality degradation in the Suez Irrigation Canal. The monitoring program integrates biological, chemical, and physical data assessment. Several field surveys were carried out to these areas during the period between March 2003 and February 2005 (over 23 months) for acquiring all possible information about the current situation and to explore the impact of human activities along the canal banks on the canal ecosystem. Seasonal variations of phytoplankton and zooplankton standing crop, species diversity as well as physico‐chemical characteristics of water, sediment, fish and aquatic weeds at the intakes of drinking plants and from the discharge of agricultural and domestic drains into the Canal were investigated.

Preliminary field investigations showed great amounts of discharged wastes at several locations to the canal water creating unique conditions, which vary with changes of volume and properties of the discharged wastes. Rotifer and green algae for example demonstrated seasonal variable response to the ecological variations. Myriophyllum spicatum, Potamageton nodsus and Polygonum Salicfolium were the most common types of recorded weed. The Myriophyllum spicatum is the dominant submerged plant. The canal was characterized by high concentrations of HCO₃^‐ as well as high pH >8.2 which provides a favorable habitat for the growth of Myriophyllum spicatum. The results illustrated the ability of using the aquatic weed as biomarkers for monitoring heavy metals contaminates in the canal. The evidence suggests that there is a degree of selectivity in metals uptake and partitioning within the plant compartments.

The current paper adopts the idea of utilizing multiple organism groups in the bioassessment to effectively detect ecological change when they occur in one of the most important waterways in Egypt. These different organism groups are suited for detection various stressors, providing warnings and detection of stress impacts at different scales. The study presented provides decision makers with important information that can assist them in making objective decisions related to the design of monitoring programs based on scientific research.

Reviews compound physico‐chemical properties and water and soil properties influencing the transport and distribution of organochlorine pesticides, polychlorinated biphenyls (PCBs) and chlorophenols in a water and soil environment. As highly hydrophobic compounds of low water solubility, organochlorine pesticides and PCBs are rapidly and strongly sorbed by most soils and sediments. The sorption of weakly acidic chlorophenols comprises both molecular and ionic forms and depends not only on the soil/sediment organic matter content but also on the pH and ionic strength of the aqueous phase. Briefly describes the analytical methods for trace analysis of organocholorine pesticides, PCBs and chlorophenols in water and soil/sediment samples. Presents some results of those micropollutants’ analysis in surface, ground and drinking waters, soils, river sediments and wet depositions in Croatia.

The purpose of this paper is to describe the investigation of distribution of metals in water and sediment samples of Poydras‐Verret wetland, an area that has received approximately 40 years input of secondarily treated municipal effluent.

Water and sediment samples were analyzed for metals for a period of 18 months. These metals were also monitored for the secondarily treated effluent, and at a reference/control wetland that does not receive wastewater. Analysis of variance (ANOVA) and Student Newman‐Keuls post‐hoc ANOVA analysis were conducted to evaluate the pattern of metal distribution within the Poygras‐Verret wetland and compare results to the reference wetland. Heavy metal criteria established by United States Environmental Protection Agency (USEPA) and State of Louisiana were also used to assess the potential chronic and acute health impacts of heavy metals in the Poydras‐Verret wetland.

Concentrations of metals of the Poydras‐Verret wetland water are not different from those found in the reference wetland water, suggesting no observed accumulation of these metals within the receiving wetland water. All metals are below the acute criteria.

Historical data regarding metal accumulation in wetlands in the published literature is limited. This paper provides supporting evidence that using wetlands to assimilate wastewater could be a long‐term, practical solution with the side benefits including wetland restorations and protection from wave erosion and storm surge.

There has been a general promotion of small and medium sized dams as the solution to supply water for domestic, sanitation and other livelihood purposes in the less industrialised countries of the world. This paper aims to communicate and share ideas and experiences with policy makers and other engineering practitioners in issues related to the sedimentation of, and the development of small and medium sized dams so that relevant issues are taken into account in the planning, design and implementation of such small and medium sized dams.

This paper, which is a viewpoint, utilises the findings of various research work carried out in Zimbabwe and findings from other regional and international literature as a basis for discussion and arriving at some engineering and other developmental policy recommendations. The research work utilised and analysed in this paper is based on actual field work carried out by others as cited.

The paper concludes that the following policy and technical issues should always be borne in mind in the promotion of small and medium sized dams: the predicted increase in rainfall intensities due to climate change/variability requires the review of existing small and medium sized dam spillway capacity designs; an increase in the minimum storage ratios of small and medium sized dams should be made from the current recommended 0.1‐0.3; further research work is required to validate the postulation that rainfall intensities are increasing due to the effects of climate change/variability resulting in increased sedimentation of reservoirs; whilst sediments are required for ecosystem sustenance, they can also be viewed as a pollutant in respect of certain other human water supply needs; do not build small dams on large catchments as such small dams will silt‐up quickly and thereafter pose challenges in the management and disposal of the accumulated sediments and nutrients when decommissioning/rehabilitating them; every dam site, irrespective of the resultant dam size, should be developed to its maximum potential in respect of the dam site's water yield and/or prevailing topography; WHO predicts that road traffic injuries will rise to become the fifth leading cause of death by 2030. The “vulnerable road users” and/or their estates should also receive like attention and timely compensation benefits as advocated for the large dam's “disadvantaged and vulnerable” people.

Every year, about 1 per cent of the world's reservoir capacities are lost to sedimentation. Most researchers postulate that an increase in the intensity of rainfall due to climate change/variability is imminent and will result in increased sediment loads with resultant negative impacts on dam reservoir life‐spans and usefulness. This paper discusses the advantages, disadvantages and efficiency of small and medium sized dams in satisfying the various beneficiary needs in the less industrialised countries of the world. The technical issues that have to be considered in the design and construction of such small and medium sized dams in order to minimise the negative impacts of sedimentation in their development are also presented and discussed. The opinions and conclusions drawn in the viewpoint are those of the author.

This paper aims to present the implementation of a multi-layer radiation propagation model in simulations of multi-phase flow and heat transfer, for a dissociating methane hydrate reservoir subjected to microwave heating.

To model the induced heterogeneity due to dissociation of hydrates in the reservoir, a multiple homogeneous layer approach, used in food processes modelling, is suggested. The multi-layer model is incorporated in an in-house, multi-phase, multi-component hydrate dissociation simulator based on the finite volume method. The modified simulator is validated with standard experimental results in the literature and subsequently applied to a hydrate reservoir to study the effect of water content and sand dielectric nature on radiation propagation and hydrate dissociation.

The comparison of the multi-layer model with experimental results show a maximum difference in temperature estimation to be less than 2.5 K. For reservoir scale simulations, three homogeneous layers are observed to be sufficient to model the induced heterogeneity. There is a significant contribution of dielectric properties of sediments and water content of the reservoir in microwave radiation attenuation and overall hydrate dissociation. A high saturation reservoir may not always provide high gas recovery by dissociation of hydrates in the case of microwave heating.

The multi-layer approach to model microwave radiation propagation is introduced and tested for the first time in dissociating hydrate reservoirs. The multi-layer model provides better control over reservoir heterogeneity and interface conditions compared to existing homogeneous models.

The purpose of this paper is to address the case of toxic metal contamination of Sepetiba Bay caused by the Ingá Company. The paper reviews the history of the contamination and discusses the current presence of metals in the bay sediments, demonstrating that the toxic metals are clearly enriched. Sepetiba Bay is prone to significant dredging activities that make metals available in the food chain, affecting human populations, mainly fishermen communities.

The study presents the case of the Ingá Company based on international literature and data provided by previous studies.

Through the analysis and compilation of diverse data from the literature, this study demonstrates that the Ingá Company is a major source of Cd, Pb and Zn due to its calamine processing activities used to obtain high purity Zn.

This study highlights important research to complete the historical scenario of heavy metal contamination of the Sepetiba Bay by Ingá Company. The results indicate that the contaminants from the Ingá Company can indeed be traced in the sediments of Sepetiba Bay. These data have the utmost value for the environmental management of this coastal system, because such high concentrations of toxic metals in marine sediments have serious implications for the environmental quality of the bay and may negatively affect biota and human health. Therefore, this study suggests that it is now necessary to monitor this region for contamination continuously.