Proceedings of the International Conference on Marine and Freshwater Environments (iMFE 2014) - Our Water, Our Future
Editors: Drs. Bing Chen, Baiyu Zhang, Liang Jing, Pu Li, and Yinchen Ma Northern Region Persistent Organic Pollution Control (NRPOP) Laboratory, Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John's, NL Canada A1B 3X5 Marine and freshwater are essential components of the earth's hydrosphere and their protection has been one of the most critical and challenging tasks for all the involved researchers, engineers and decision makers at a global scale. Within a changing global context, effective protection and management of water environments demand continuously improved knowledge and technologies, sound decisions and practices, and benign legal and socio-economic environments. The iMFE 2014 provided a unique international platform for exchange of ideas and experiences amongst researchers, practitioners and regulators in the field. The conference was organized jointly by the 2014 Atlantic Symposium of the Canadian Association on Water Quality, the 2014 Annual General Meeting and 30th Anniversary Celebration of the Canadian Society for Civil Engineering Newfoundland and Labrador Section, the 2014 Annual Conference of the International Society for Environmental Information Sciences, and the 2nd International Conference of Coastal Biotechnology of the Chinese Society of Marine Biotechnology and Chinese Academy of Sciences. This two and half day event was packed with 23 informative sessions, more than 60 oral presentations, and 15 poster exhibitions. Over 100 participants from 9 countries attended the conference to discuss and appreciate of various aspects involved in the protection of freshwater and marine environments as well as sustainable development of natural resources (water, oil & gas, mineral, etc.). The iMFE 2014 conference was able to provide a unique platform for exchange of ideas and experiences amongst decision-makers, managers, researchers and academics from different areas of water environmental protection; to provide a communication forum for scientists and engineers to discuss and appreciate of various aspects involved in the protection of freshwater and marine environments as well as sustainable development of natural resources in coastal areas and oceans, particularly under harsh environmental conditions; and to foster an integrative understanding of water and the environment as well as exploring sound engineering solutions. The wealth of information exchanged at this conference will be of great benefit to all involved with marine and freshwater protection problems. It is also expected to help achieve the following long-term goals: to extend the research network to a national and then an international level; and to help develop long-term research collaborations on water management and sustainable development, especially in harsh environment. The conference proceedings, as shown below, has a total of 48 papers that cover the following areas: Climate Change, Energy Systems and Emission Reduction Environmental and Marine Biotechnology Environmental Modeling, Risk Assessment and Decision Making Marine Oil Spill Response and Countermeasures Marine Resource Management and Sustainable Development Ocean Observation and Pollution Mitigation Oil Spill Environmental Forensics and Chemical Fingerprinting Persistent and Emerging Contaminants Subsurface Contamination and Remediation Water and Wastewater Treatment Water Management in Harsh and Arctic Environments Water Safety and Public Health Watersheds, Wetlands and Estuaries Management This proceedings is devoted to help refine future strategies for effective management of the world’s marine and fresh waters by the summary of recent scientific research on the management of water quality through model- and technology-based investigations and case studies. In summary, all papers represent some of the latest and most promising research results in the field of marine and freshwater quality management. We believe that this proceedings will inspire further research and benefit practice along the same lines. Finally, we thank all the authors for their worthy contributions and the reviewers for their precious time and efforts to help ensure the high caliber of quality.
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An Integrated System Planning and Process Control System for Marine Wastewater Management
An ideal combination of both system planning and process control can greatly reduce system cost and maximize economic and environmental benefits associated with marine oily wastewater treatment. If appropriate process control is not implemented during the system planning procedure, there might be potential benefits lost because traditional planning tends to be more conservative and less risk-taking. However, such integration is oftentimes complicated by many factors such as multi-scale nature of decisions, the lack of knowledge of process dynamics and control, and various types of uncertainties. How to more accurately couple process control with system planning has been a major roadblock in the wide application of the marine oily wastewater treatment systems. To date, there has been no such attempt made to investigate the feasibility and efficacy of coupling system planning and process control on marine oily wastewater treatment. This research therefore aims at demonstrating the possible integration of process control with traditional system planning by using neural networks, genetic algorithm, multistage principle, and Monte Carlo simulation. A case study that is related to offshore water use and wastewater treatment is carried out to demonstrate the efficacy of the proposed approach.
A GIS-based Spatiotemporal Study of the Variability of Water Quality Parameters in the Dubai Creek
High concentrations of nutrients canincrease algal growth in coastal marine systems. The growth of harmful algal blooms (HAB’s) has become common in UAE, especially in late 2008 and early 2009 when a huge HAB event devastated the coasts of the whole country and a significant portion of Arabian Gulf. Nutrient enrichment in Dubai coast has been one of the primary environmental concerns for eutrophication. Increased algal growth normally leads to oxygen depletion by bacteria to decompose the dead algal cells in the bottom leading to low-oxygen water. Such situation normally leads to the killing of different types of fish; lowering the biotic diversity. Dubai Creek, a saltwater lake connected to the coast of Dubai has similar characteristics as the coast and suffers from similar water quality concerns. The paper presents the outcomes of a comprehensive study of the spatiotemporal variability of major water quality parameters in the creek. In-situ water quality data from 10 monitoring stations along the Dubai creek have been used in the study. The results showed unique trends of spatiotemporal variability of chlorophyll-a and nutrients over the creek in the period of study. This result was attributed to the increasing anthropogenic activity in Dubai due to the rapid urban development, shallow water depth in the creek, poor flushing and irregular circulations and wave patterns in the area.
Intelligent Multiparameter Fiber-Optic Sensing for Ocean Observation
With the increasing needs for the protection of marine and fresh water environment, there is surging demand for effective technologies to monitor different environmental parameters. Among different new technologies, fiber-optic sensing technology has found its unique roles in the measurement of different environmental parameters with advantages such as immunity to electromagnetic interference, compact size, low cost, and the possibility of distributed measurement over a long distance. In this study, we demonstrate a novel approach to realize intelligent multiparameter fiber-optic sensing to achieve simultaneous measurement of temperature and other parameters for marine observation, including salinity, flow rate, and chemical sensing. The temperature sensitivities of the acrylate and polyimide-coated fiber sensors are 0.0102 and 0.0094 nm/°C, respectively. The salinity sensitivity of the fiber sensor on potassium chloride concentration is 0.0126 nm/M.
Mapping of Chlorophyll-A in the Dubai Creek Area Using WorldView-2 Imagery and Field Data
Occurrences of harmful algal blooms (HAB) in coastal regions have been increasing both in frequency and magnitude in the last few decades. The coasts of United Arab Emirates UAE have been affected by massive HABs in 2008 and 2009 that lasted for months and encouraged frequent monitoring of algae and nutrient concentrations in the area. Other small scale algal blooms were also observed in recent years as well. The increasing anthropogenic activities in the Dubai area have led to increased growth of algae in the Dubai Creek. This paper presents the results of a study aimed at mapping of chlorophyll-a, which is a direct indicator of algal growth in the creek. A spectral model of chlorophyll-a was developed from WorldView-2 data of the creek that was acquired in July, 2012. Field data of chlorophyll-a collected at the time when the WorldView-2 image was acquired, have been used for calibration and verification of the spectral model, which showed an 82.7% correlation with field data. Development of such a model is useful for spatiotemporal mapping of algae in the area. Such information is essential for monitoring of the levels of pollution in the Emirate of Dubai coastal area and for planning and decision making activities related to the sustainability of the creek.
Mass Balance Simulation for Wetlands and Estuaries Management
The closed bay formed by a tidal power plant on the west coast of Korea has caused water quality to change due to nutrient increase and salinity alternation. The nutrients of the inner bay are often kept a balance with the aid of the outflow at the mouth of the bay. Hence it is necessary to minimize the environmental effects by forecasting the potential environmental changes caused by a tidal power construction. Seasonal observations of mass balance in the inner and outer Garolim Bay were performed. The low quality nutrients released from sediments, land and river were more dominant than the nutrients released from the outer bay in the study area. It was observed that the tidal power plant construction made water exchange ratio 57%.Various mitigation strategies such as water gates were studied so that the water exchange rate can be reduced. The change in the water exchange ratio is significantly reduced as the cross-section and the number of water gates is increased. The water exchange ratio was decreased by 8%, which increased nutrients in the inner bay. Results of numerical the nutrients decreased with the 7% increase in the inflow while the decrease in outflow discharges. However, it is considered only 0.2% increase in the entire mass balance of Garolim Bay relatively inadequate to mitigate the environmental impact.
Opto-Microfluidics for Monitoring Salinity and Temperature of Sea Water
The success of ocean observation relies on effective monitoring technologies with increased functionalities, minimized size, and reduced cost, which can only be achieved through the development of new technologies. Opto-microfluidics has been increasingly recognized as powerful technologies to realize miniaturized devices for environmental monitoring, biological analyses, and chemical syntheses. By combining microfluidics and optics technologies, roomful laboratory equipment can be integrated into a palm-size chip with merits of versatile functionalities, compactness, minimized waste, and low cost. These opto-microfluidic systems are promising for applications in ocean observation. In this study, opto-microfluidic devices for monitoring salinity and temperature of liquids are proposed and demonstrated with ultrafast laser fabrication and two-photon polymerization techniques. By applying femtosecond lasers as powerful tools to achieve laser microfabrication with unprecedented high precision and quality, a Mach-Zehnder interferometer (MZI) has been fabricated and integrated into a microchannel as a miniaturized opto-microfluidic system. When saline solution or sea water is introduced to the microchannel, different phase shifts in the MZI can be resulted, which allow determination of the salinity and temperature of the solution from output optical spectra and intensities of the MZI corresponding to different phase shifts. The sensitivities of salinity and temperature have been found to be 215.744 nm/RIU and 0.519 nm/oC for the opto-microfluidic systems developed in this study, respectively. The results demonstrate the practicability of opto-microfluidic devices for real-time salinity and temperature monitoring of sea water in harsh environment.
Characterization of Microbial Community Structure Associated with Pollution in Xiaoqing River Sediment
To understand the impacts of anthropogenic activities on structure and composition of microbial communities and evaluate how microbial communities respond environmental gradients at river sediments, the composition of microbial communities in sediments from Xiaoqing River (in spring, summer and autumn) were assessed using DGGE and real-time PCR approaches. Meanwhile, 16S rRNA clone library construction of three sites was constructed to represent the composition and structure of microbial communities in the three distinct site-groups. The gene copy number was ranged from 107-108 cells/g that was most influenced by sample sediment density and medium grain size. Through analysis of DGGE gel profile, there were no distinct variation on richness, evenness and Shannon-Weaver index with all samples, which ranged 3.69-5.21, 1.73-2.30, and 0.56-0.76 respectively. The clustering result on the DGGE patterns showed that the microbial diversity of all samples were more similar than 40%, while the distinction was formed with three groups at a level of 46% similarity. Redundancy analysis revealed that the distribution of microbial composition seemed to be determined by the variables of nitrite, medium grain size and total carbon content. The clone library of three sites revealed that the Proteobacteria was the dominant phylum, which consistent with DGGE bands sequencing result. In addition, members of Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Planctomycetes and Verrucomicrobia were recorded in all three libraries. The distribution of functional populations as denitrifier and anammox bacteria will be the focus of future research.
Offsetting the Destruction of Marine Fish Habitat During Coastal Development Projects in Canada
Under the Fisheries Act of Canada (2012), proponents of development projects are responsible for offsetting the destruction of freshwater and marine habitat if “serious harm” is expected to occur to fish supporting a commercial, recreational or Aboriginal fishery. One method of offsetting lost fish habitat in the coastal marine environment is the creation of artificial reefs. Artificial reefs are constructed with ships, rock or other hard substrate that creates surfaces upon which marine life can grow and seek shelter. We examine the conditions under which an artificial rock reef is equivalent to lost marine habitat and can satisfy the legislated requirement of maintaining or enhancing the productivity of a fishery impacted by a development project. To help achieve the objective of maintaining the productivity of the fisheries impacted by development projects, we recommend that coastal engineering plans for offsetting works incorporate the environmental requirements of the relevant fishery species during the critical juvenile stage of its life history.
Water Resources Assessment and Management for Nuclear Power Plants in China
To deal with global warming and energy shortage, nuclear power plants are constructed or planning to be constructed in China presently. The operation of a nuclear power plant consumes a great amount of water and discharges a lot of radioactive wastewater into nearby marine or freshwater environment. Therefore, water resources assessment and management are crucial to this kind of plants considering their significance to not only marine and freshwater environment protection but also sustainable development of nuclear power industry. This article proposed the contents, procedures and methods of water resources assessment and management for nuclear power plants based on the overview of development process of nuclear power plants in China. Furthermore, the tendency of water resources assessment and management for nuclear power plants in China was also presented. Water resources assessment for a nuclear power plant in China should analyze local water resources, the rationality of water-draw and utilization of a plant, water sources, the impact of water-draw and wastewater discharge as well as water resources safety mainly. The key processes of it may include data collection, compiling a work outline, analyzing local water resources as well as water-draw and wastewater discharge of a plant, and completing and approving the report. The suggested methods of it are referring legal documents, site investigate, model simulation, expert consultation and public participation. Finally, suggestions, including carrying out comparison as well as selection of several optional sites, improving impact assessment of radioactive wastewater discharge and enhancing public participation, are also proposed.
Possible Impacts of Climate Changes on Freshwater in Coastal Aquifers
Groundwater resources in coastal aquifers constitute a main source of freshwater in many regions around the globe. This is typically true in arid and semi-arid regions where rainfall is scarce and infrequent and the surface water resources are almost absent. The consequences of climate changes and global warming on the freshwater in coastal aquifers have been investigated by several researchers over the last two decades. Due to the expected increase in the global temperature and the associated expansion of water in oceans and seas, the seawater is expected to rise. This seawater rise would lead to land submergence along the coastline and also an increase in the hydraulic head of seawater at the seaside boundary. Investigations revealed the seriousness of the problem and undesirable possible consequences on land loss and degradation of groundwater quality in coastal areas. In addition, groundwater in would be subjected to extensive pumping which may lead to depletion of aquifers. This paper investigates the possible impacts of climate change on two coastal aquifers located in arid regions; namely, the Nile Delta Aquifer, in Egypt and the Wadi Ham aquifer in United Arab Emirates. For the case of the Nile Delta aquifers and due to the low altitude and flat nature of the coastal zone, vast areas will be submerged was seawater. A numerical model, FEFLOW was used to simulate the possible impacts of seawater rise under different pumping scenarios. It is concluded that the groundwater in both aquifers will be affected but with significantly different degrees.
Statistical Downscaling of Rainfall using Large-Scale Predictors: Dynamic Model Outputs vs. Reanalysis Data
A warmer climate is expected to lead to more serious natural disasters, such as heavy storms, prolonged droughts and frequent floods. For a high-density urban region, the flash flood problem may become worse due to possible increasing frequency and magnitude of short-duration rainfalls in the future. A Global Circulation Model (GCM) is a powerful tool to assess the climate change impact. However, the resolution of a GCM output is generally too coarse to be applicable to small regions directly. Two types of approaches, dynamical and statistical downscaling, could be used for bridging the gap between GCM and local climate information. Compared with dynamical downscaling, the statistical approach is more flexible and computationally less intensive. In addition, statistical downscaling tools may be sensitive to the resolution of large-scale predictors. In this study, two downscaling approaches are compared. The first is to use a statistical method (Automatic Statistical Downscaling, ASD) directly to downscale large-scale predictors (i.e. ERA-Interim Reanalysis data) to local rainfall. The second is to combine a dynamical (i.e. MM5) and a statistical method (ASD) to generate the station-level data. The study site is the City of Edmonton and the resolutions of large-scale GCM predictors and dynamical model output are about 150 km and 27 km, respectively. The results show that the downscaled results based on predictors from MM5 is better than that from ERA-Interim, in terms of both accuracy and uncertainty range.
Cuttings Transport Evaluation in Deviated Wells
Cuttings transport efficiency is a measure of the extent to which cuttings are carried to the surface from a drilled hole. It quantifies the success achieved in freeing a well of drilled cuttings. It is also related to the carrying capacity of a drilling mud. Cuttings transport efficiency in vertical and deviated wellbores has been reported to depend on the following factors: hole geometry and inclination, average fluid velocity, fluid flow regime, drill pipe rotation, pipe eccentricity, fluid properties and rheology, cuttings size and shape, cuttings concentration, cuttings transport velocity, rate of penetration and multiphase flow effect. In this study, the effects of mud flow rate, rate of penetration, annular clearance, mud and cuttings densities on annular fluid velocity, transport ratio and mean mud density are investigated for highly deviated wells. Equations are developed and used to generate graphs. These equations and graphs could be applied in the field during directional drilling to determine annular fluid velocity, mud flow rate, transport ratio and mean mud density.
Role of Hydro in Support of Modern Power Grids
This paper summarizes the features of hydropower developments and compares hydro with other renewable energy sources for supply to electric power grids. The particular advantages that hydro plants typically provide for grid operation and reliability are then described. Challenges that hydro developers face are then noted and discussed. The paper then addresses the question about sustainability of hydro power developments particularly those in Canada. The meaning of sustainability as currently presented in public discourse is examined and popular applications of this concept challenged.
Sea-Land Integrated Pollution Control Mode applied to Beidaihe Offshore Area
A Sea-Land Integrated Pollution Control Mode(SLIPCM) is extremely needed as the Beidaihe offshore area experiences the deterioration of water environmental quality and degradation of ecosystem service functions. In this study, a retrospective analysis was used to review the total discharge amount of major pollutants and quality of water environment over the past five years. And it further identified the major water environmental problems and screened out the primary pollution sources. According to lower level of socio-economic development and less power of regional pollution control within the catchment, a set of practical targets regarding freshwater and marine environment protection were made out. Furthermore the SLIPCM was proposed to meet above targets and countermeasures were presented in three dimensions, namely non-point source pollution control, point source pollution control, and water ecological protection and restoration. Moreover, a SWAT model was established to predict the SLIPCM performance in three scenarios. The results showed that the effect of sea-land integrated pollution control scheme was the best and almost can meet the Ⅰclass of water quality standard.
An Agent-based Simulation-optimization Coupling Approach for Device Allocation and Operation Control in Response to Offshore Oil Spills
The efficiency of offshore oil spill response not only relies on an efficaciously global decision/planning in devices combination and allocation, but also depends on the timely control for response devices (e.g., skimmers and booms). However, few study has reported on such decision framework with timely integration of global planning and operation control to support the offshore oil spill recovery. This study developed an agent-based simulation-optimization coupling approach to provide sound decisions for devices combination and allocation for offshore oil spill recovery in a fast, dynamic and cost-efficient manner under uncertain conditions. At the same time, the approach aimed at providing operation control for specific devices, reflecting the site conditions, and correspondingly real-time adjusting the global planning, which was especially helpful to harsh environments prevailing in the Newfoundland offshore areas. In the case study, the developed approach was applied to determine the allocation of 3 response vessels from 7 different locations of the spilled oil slicks. The routes of the response vessels for response operation were optimized and reflected by the principle agent-based programming. The modeling results indicated a minimal time of 21 hours for vessels allocation and recovery operation when only considered oil recovery, leading to an oil recovery rate of 90%. The proposed approach can timely and effectively support optimal allocation of devices and control of operation as well as real-time adjustment of global decision for oil recovery under dynamic conditions and improve recovery efficiency.
Modelling the Effects of Chemical Dispersant on the Fate of Spilled Oil: Case Study of a Hypothetical Spill near Saint John, NB
The proposed Energy East pipeline project has raised concerns about potential oil spills in Saint John, New Brunswick, due to increased tanker traffic. While environmental conditions such as strong tide and current could pose challenges for using mechanical recovery methods if a spill occurs in the area, chemical dispersant could be an alternative oil spill countermeasure. However, the application of chemical dispersant in shallow water and costal zones remains an issue of debate. To study if chemical dispersant could be effective for potential oil spills in Saint John, a 3-dimensional model was used to simulate the transport of oil following a hypothetical release of 1000 m3 Arabian Light crude under winter conditions. A stochastic approach was used to take into account the uncertainties of environmental inputs. The results show a significant reduction of oil ashore, and enhanced biodegradation with dispersant application, but these effects were accompanied by an increase of oil in sediment and water column, which is a concern. While the results are only conclusive for the selected scenarios of winter release, the method could be extended to other months and seasons of the year to support more detailed net environmental benefit analysis regarding dispersant application.
Transportation of oil and gas and oil spills are two potential risks posed to the marine environment. This paper mainly focuses on the use of Computational Fluid Dynamics (CFD) at Oceanic Consulting Corporation (OCC). With OCC’s extensive CFD experience in Marine Engineering, it is expected that we could expand our expertise into the area of oil spill forecast and response or other related areas. Under support of the Atlantic Innovation Fund (AIF), Oceanic has been engaged in a project “Numerical Simulation of Hydrodynamic Loads for the Safe Production and Transportation of Oil and Gas in Harsh Marine Environments” since 2008. This paper presents some CFD studies taken from this project, which includes: 1) 3-dimension flow simulation; 2) Sloshing prediction of a U-tube tank in a vessel; and 3) Moored structure motion in waves and visualization. It also includes an introduction to some commercial CFD and in-house codes used in Oceanic.
Bio-dispersant produced by a Rhodococcus erythropolis mutant as an oil spill response
Bio-dispersants have been considered as superior alternatives of currently used dispersants as they are generally more biodegradable, less toxic, and better at enhancing biodegradation. However, the application of bio-dispersants is limited by the availability of economic products and the corresponding producers that can work effectively. Hyperproducers generated by metabolic engineering of biosurfactant producers are highly desired to overcome this obstacle. A Rhodococcus erythropolis SB-1A strain was isolated from Newfoundland offshore oily water samples. One of its mutant derived by random mutagenesis with ultraviolet radiation, producing high levels of biosurfactants was selected by the oil spreading technique. The mutant produces biosurfactants with critical micelle dilutions (CMD) approximately 4 times of the parent strain. The results obtained with thin layer chromatography (TLC) indicated the produced biosurfactant remained unchanged between the mutant and the parent strain. In addition, the produced biosurfactants were recovered with solvent extraction method and applied as the oil spill response agents to effectively disperse oil slick. Based on the baffled flask test (BFT) results, the dispersion efficiency of the biosurfactants produced by the mutant is higher than that induced by the parent strain and Corexit 9527 while comparable to the Corexit 9500.
Comparison of Autoregressive Moving Average and State Space Methods for Monthly Time Series Modelling of Labrador and South-East Quebec River Flows
Time series data such as monthly stream flows can be modelled using time series methods and then used to forecast flows for short term planning. Two methods of time series modelling were reviewed and compared; the well-known autoregressive moving average (ARMA) method and the State- Space Time-Series (SSTS) method. ARMA has been used in hydrology to model and simulate flows with good results and is widely accepted for this purpose. SSTS modelling is a method that was developed in the 1990s and is relatively unused for modelling river flow time series data. The work described in this paper focuses on modelling the stream flows from basins of different sizes using these two time series modelling methods and comparing the results. Three rivers in Labrador and South-East Quebec were modelled; the Romaine, Ugjoktok and Alexis Rivers. These rivers are located in various areas of the study region, having different drainage aspects and differing basin sizes. Both models were compared for accuracy of prediction, ease of software use and simplicity of model to determine the preferred time series methodology approach for modelling these rivers.
Development of a risk rank model for environmental risk assessment of abrupt water pollution accidents - with the case of Laoguan River Basin
In recent years, abrupt water pollution accidents have broken out frequently in watersheds and caused huge environmental and economic losses. These accidents have become one of the most serious environmental problems in China. Abrupt accidents in watersheds involve large scale, multiple sources, multiple stressors and complex risk spread relationships. An appropriate environmental risk assessment method that can solve these problems is needed to protect water quality and the safety of people and property. In this paper, we have adopted a risk rank method in ecological risk assessment and modify it to assess the risk of abrupt water pollution accidents in watersheds, and take a reach of Laoguan River in Xichuan County, Nanyang city as an example. After identifying risk factors and their relationships, the risk rank model is established accordingly, and then risk values are calculated. Finally, the assessment result is displayed and specific risk management decisions are provided.
Evaluation of the Causal Relationship between Variables Using a Probabilistic Approach for Water Quality Management
In aquatic environments, complex interplay exists among physical, chemical, and biological water quality parameters, which are further influenced by exogenous factors such as hydrological, meteorological and geological conditions. To understand the spatial and temporal variations of water quality, and furthermore, the relationships between the variables of interest is hence a challenging task. Given the large data matrix, one category of methods frequently employed in the literature is multivariate analysis such as cluster analysis, principal component analysis, and factor analysis. These techniques are straightforward and intuitive to identify the qualitative associations among variables. However, a quantitative evaluation from a probabilistic perspective is favorable since it defines a measurable causality among variables so that more efficient water management strategies can be formulated. This paper will illustrate a new way to discover the relationship between two variables by estimating their joint distribution which fully interprets the statistical dependence. A multivariate Gaussian mixture model was employed to describe the data. The model parameters were determined using the developed expectation maximization algorithm, which is capable of dealing with multiple variables and censored data. The joint distribution of two variables of interest and the conditional distributions were used to describe the complete statistical distribution of water quality parameters, which are subject to the effects of hydro-meteorological conditions. The method was demonstrated using data from the Bow River in Alberta. The results shed light on how one variable affects the distribution of the other variable under complex environments in a probabilistic context.
Lattice Boltzmann Method for the Advection and Diffusion Equation in Shallow Water
Solute transport exists in most natural flows, which can be described by the advective-diffusive equation. In numerical modeling of such phenomenon, it is important to deal with irregular boundary and angular boundary points for hydrodynamic and water quality modeling. However, there is no clear control method for corner points in water quality modeling in existing literature. In this study, two-dimensional symmetrical flow in a cubic cavity with contaminant transport is investigated based on the presented control mechanisms: the lattice Boltzmann method for the advection and diffusion equation. For corner points of square cavity, a corner points controlling method proposed in this study shows great validity and reliability in the application of models.
Long-Term Dependence of Annual Peak Flows of Canadian Rivers: Two Decades Later
Both short- and long-term dependence of the peak flow series of 90 Canadian rivers were analyzed two decades ago. It showed that although short-term dependence was practically absent for most of the flow series, significant long-term dependence was present for a large number of rivers tested. With 20 or more years of additional data available today, the authors analyzed 57 rivers (only 57/90 were suitable for analysis) for: a) short-term dependence using several parametric and non-parametric tests; b) long-term dependence using a resampling-based Hurst’s K; and c) trend using Mann-Kendall’s test. Results showed that as expected, short-term dependence is practically absent in all rivers before or after the additional data. However, the percentage of rivers showing long-term dependence remains high. The trend test showed that most of the rivers showed no trends before or after the additional records were added. However, several rivers showed a downward trend, and a few showed an upward trend before and after the additional records were added. This study showed that sample statistics and the associated statistical significance tests can change unpredictably over time. Hence engineering decisions made in the past need to be re-visited and cannot assumed to remain unchanged especially when dealing with natural phenomenon such as annual peak flows.
Numerical simulations of oil spill trajectories in the Danjiangkou Reservoir in China
Oil spills in surface water happen each year in the world and significantly damage water quality and ecosystems. Numerical simulation of oil spill trajectories is helpful for risk assessment and risk controlling. Previous research for tracking oil spills generally focused on the sea, and not on the great reservoir. Danjiangkou Reservoir, the source reservoir of China’s South-to-North Water Diversion Middle Route Project, will flood impounded areas and raise the water to 170 m, a much higher level. The result will be convenient for waterway transportation, but it will also increase the risk of oil spills into the reservoir. In order to efficiently protect the reservoir’s water quality and ecosystem, a numerical simulation based, oil spill tracking model was developed and utilized for trajectory simulations of oil spills from five possible sites. Scenarios analysis method was applied to studding the effects of multiple environmental factors on the trajectories of oil parcels in the reservoir. The results indicated that initial water level, wind speed, wind direction and dam operation can obviously affect the spread trajectories of oil parcels in the reservoir. The results can be useful for risk assessment and risk controlling of the oil spills in the reservoir.
Optimal PM2.5 emission reduction strategies for an industrial park based on China’s 12th five-year plan on air pollution prevention and control
Over the past decades, China has been undertaking extremely rapid industrialization and urbanization. Along with economic boom, many adverse environmental effects are emerging. Among them, it is of great significance for the country to deal with air pollution such as PM2.5. As a compound pollutant, PM2.5 is composed of many significant pollutants (e.g., SO2, NOx, and TSP) that are closely related with many industrial activities in China. Till now, there have been few studies exploring and managing relationship between PM2.5 emission reduction and the associated industrial park that is a park to multiple industries such as power plants and manufacturing industries. This research introduced a supply-chain mechanism to systematically evaluate PM2.5 emission of industrial parks. To tackle the problems of PM2.5 emission reduction and industrial park management, an optimization model was proposed. Then the proposed model was applied into a pulp and paper industrial park to support the formulation of optimized strategies that can help fulfill the national plan. The results indicated that the reduction amounts of SO2, NOx, and TSP should be 126, 247, and 146 t per year in the manufacturing plant (i.e., a pulp mill in this research), and the reduction amounts of SO2, NOx, and TSP should be 291, 31, and 61 t per year in paper-making mill. Therefore, the proposed model was useful for management of air pollution as a decision tool in the level of a industrial park.
Optimizing Water Quality Sampling Through Application Of Real Time Ionic Concentration Regression Models
The Water Resources Management Division of the Department of Environment and Conservation performs routine water sampling to measure the physical and chemical parameters of select water bodies in Newfoundland and Labrador. Ionic concentration parameter measurement is performed during routine water sampling to complement some of the key indicator parameters measured in real time at these select water bodies. The collection, laboratory analysis and measurement of water samples are a time consuming process. Some of the common conducting ions measured during routine sampling are sodium, calcium, chloride and sulphate. These conducting ions can be estimated using continuously measured specific conductance after observing the effect of flow. The estimated measurement will help identify the quality of water at a given point in time and hence save time and resources in performing routine sampling. It will also help estimate the quality of water in remote locations where routine sampling is not feasible. This paper compares four water bodies on the island part of Newfoundland and Labrador and estimates the ionic concentration using continuously measured specific conductance.
Parametric functional analysis of variance for fish biodiversity
The conservation and restoration of biodiversity in the marine environment is a crucial aspect of fishing and related activities. Human activities cause changes in fish population and deep transformation in the type and quality of the water. Fishing, restocking and pollution often bring to reduction and distribution changes of indigenous fish species to the benefit of the diffusion of exotic species. In this context protection and management of water environments become a primary objective. Therefore it is necessary to implement initiatives for protecting and restoring the quality and integrity of native species. Any decision-making process must be based on a careful analysis of the collected data. In this paper we propose a parametric functional approach to study the biodiversity in marine environment.
Peak flow prediction using fuzzy linear regression: Case study of the Bow River
The 2013 floods in Alberta highlighted the need for better flood prediction. Though the mechanisms behind floods and extreme events in urban areas are understood and documented, the uncertainty in data during these events makes it difficult to accurately predict and assess the risk of floods. In this research, a fuzzy number based linear regression model is proposed that incorporates uncertainty and characterizes risk of extreme events in the Bow River at Calgary, Alberta, Canada. The proposed model uses a fuzzy linear regression model to predict peak flow rate using mean daily flow rate. Lagged data from one to seven days is also considered. Results of the research show that using a fuzzy number approach to predict uncertain extreme events outperforms traditional regression methods in the Bow River at Calgary. The developed model can accurately predict daily peak flow, including a flood event in 2005, up to 7 days in advance. In addition to this, fuzzy number model output can be used to further characterize the risk of peak flow magnitude. These results are extremely beneficial for water resource managers who implement flood mitigation and defence strategies.
Predicting Dissolved Oxygen Concentration in Urban Watersheds: A Comparison of Fuzzy Number Based and Bayesian Data-Driven Approaches
Dissolved Oxygen (DO) concentration is significantly and adversely impacted by urbanisation. However, the processes that govern DO concentration in riverine environments are complex, difficult to understand and to model. In the Bow River in Calgary, AB, Canada there is a need to predict DO concentration as part of the overall goal to improve river health for downstream users. In this research three data-driven models are used to predict DO concentration in the Bow River are compared. Fuzzy linear regression performed better than both simple linear regression and Bayesian linear regression. The fuzzy number based model was better able to capture the daily variability in DO in the Bow River and substantially improved low DO predictions.
System Dynamics Modeling Of Socioeconomic Development Mode Associated With Water Usage In Baiyangdian Lake, Northern China
With continual increase of environmental pressure from human activities, it has become necessary to study the process of socioeconomic water usage influencing the water quality. Based on the system dynamic model developed before to display the whole related flowing processes and the integrated influencing mechanisms of socioeconomic water usage influencing total phosphorus (TP) and total nitrogen (TN), we set 4 types of different socioeconomic development modes (i.e., type of continual status, type of economic development, type of water quality protection, and type of integrated harmonious development) to dynamically simulate and analyze the impact of socioeconomic and ecological water system on TP and TN. Moreover, it indicated that the type of integrated harmonious development was relatively more conducive to balance the water quality condition and economic development, compared to other three modes. Thus, the research could provide a reference to the water resources planning and management, as well as the eutrophication control.
Uncertainty analysis for propagation effects from statistical downscaling to hydrological modelingUncertainty analysis for propagation effects from statistical downscaling to hydrological modeling
To understand the water balance and environmental effects under climate change condition, hydrological models are always used to simulate the hydrological cycle and predict future scenarios by using global climate models (GCMs) outputs. Due to the mismatch of the spatial resolution problem, different downscaling techniques are usually applied to GCMs outputs to generate the high resolution data for fitting the data requirement of hydrological models. As it is known, hydrological modeling always suffers from a number of uncertainties and leads to inaccuracy and unreliability of prediction. Uncertainties associated with climate change have been described as irreducible and persistent, and downscaling GCM outputs using downscaling methods also lead to considerable uncertainties. The purpose of this study is to quantify the propagation effects of uncertainties from statistical downscaling to hydrological modeling for improving the accuracy and reliability of hydrological prediction. A real-world case study has been provided in this study to demonstrate the feasibility of the proposed method. Statistical downscaling model (SDSM) was applied to downscale H3A2a (A2 emission scenario in Hadley Centre Coupled Model 3) outputs for uncertainties evaluation during hydrological modeling when the GCM outputs are used as inputs of a distributed hydrological model.
Water Supply-Demand Management under Climate Change
This study aimed to investigate optimal multiple reservoir operations and water demand management considering climate change impact. In this study, conditional density estimation network creation and evaluation (CaDENCE) method was used for downscaling precipitation, and support vector machine (SVM) was used for downscaling temperature. The Bayesian neural network (BNN) model was applied to simulate the monthly reservoir inflows, which was used as the input to the optimization model. A multi-reservoir system was used for methodology demonstration, where three reservoirs were delivering water to an urban area. Several water-saving measures including long-term and short-term measures were involved in the optimization model to mitigate water shortage problem. The model aimed to maximize the total revenue obtained from water release of three reservoirs subject to constraints of available water supply, demand of water users, and cost of water demand management. The optimal water release schemes and adoption of water-saving measures under current and future climate-change conditions were obtained. The results showed that the water releases would increase at spring and decrease at winter under HadCM3 A2 emission scenario compared to the current condition.
Biosorption of Silver using Metal-Imprinted Thiourea-Modified Glutaraldehyde-Crosslinked O-Carboxymethyl Chitosan Beads
Chitosan, an abundant biopolymer obtained from deacetylation of chitin, has been proved to be a promising biosorbent for metal uptake. Grafting new functional groups on the chitosan backbone was also reported to be efficient in increasing either the sorption capacity or sorption selectivity for the target metal. In this study, silver-imprinted thiourea-modified glutaraldehyde-crosslinked O-carboxymethyl chitosan beads were prepared to selectively adsorb Ag (I) from a bimetallic aqueous solution. The biosorbent was synthesized by using prepared O-carboxymethyl chitosan beads to first absorb Ag (I) ion, then crosslinking with a polymeric Schiff’s base of thiourea/glutaraldehyde. To obtain the best performance sorbent, the degree of carboxymethylation substitution, and the amount of crosslinking agent used were studied. Results indicated the highest selective uptake capacity of Ag (I) occurred when a molar ratio of amino group of chitosan to carboxymethylation agent to crosslinking agent of 6:15:16 is used in the synthesis. Batch sorption tests were carried out for isotherm and kinetic studies using the sorbent which provides the best selective uptake capacity of Ag (I). All isothermal and kinetic experiments were performed at 25 °C. The maximum uptake of Ag (I) was found to be 137.5 mgg-1 at pH 5.0 with the initial concentration of Ag (I) being 1.75mmolL-1. The sorbent demonstrated extremely good selectivity towards Ag (I) as equal mole of Cu (II) present in the solution was scarcely absorbed over a pH range from 1.0 to 6.0. The experiments also revealed that the biosorption process of Ag (I) fits well with a Langmuir model and Lagergren’s Pseudo-second-order kinetic.
Cu, Zn and As pollution of river insect, plant and water along the metal mine tailing in Waidani area, Okayama prefecture, Japan
Comparing metal concentration and distribution for river insect larva in metal contaminated and not contaminated areas, dobsonfly was clarified to be an effective indicator for metal contamination. The Waidani area was selected as metal contaminated area. Although the maximum concentration of effluent for Cu, Zn and As was 0.18, 1.5 and 0.07 mg/l, under the Japanese Effluent Standard, the maximum metal load for Cu, Zn and As reached 35, 250 and 9 kg per year, abundant of Japanese diving beetles, were only found and then specialized condition was thought to be made by the effluent. Cu, Zn and As concentrations of dobsonfly and the other river insect larva were measured in the mine areas including the Waidani mine, limestone area and not contaminated area. Dobsonfly, just one specie, Protohermes grandis, was able to cover wide concentration range for Cu (several 10 to several 1000 ppm), Zn (several 100 to several 1000 ppm) and As (0.000 to 400 ppm) and had a wide distribution. Then, its concentration was depended on metal contamination. Although the other insects had wide concentration ranges and wide distributions as well as dobsonfly, they have many kinds of species. Therefore, their concentration did not depend on metal contamination but also species.
Membrane fouling remediation in ultrafiltration of latex contaminated water and wastewater
The goal of the present study was to remediate membrane fouling of latex effluent by altering the membrane surface charge or the ionic strength of simulated latex effluent either through the pH change or using anionic surfactants. Hydrophilic Polysulfone and Ultrafilic flat membranes, with MWCO of 60,000 and 100,000, respectively, as well as hydrophobic Polyvinylidene Difluoride membrane with MWCO of 100,000, were used under a constant flow rate and cross-flow mode in ultrafiltration of latex solution. The effect of Linear Alkyl Benzene Sulfonate (LAS) on the ionic strength of the latex solution and the zeta potential of latex particles at different LAS concentrations was investigated. LAS was also used, at different concentrations and various treatment times in order to improve the antifouling properties of membrane surface. The results obtained indicate that increasing the ionic strength of latex effluent was achieved by increasing its pH from 7 to 12, resulted in an increase of the zeta potential negativity of the latex particles from -26.61 to -42.66 mV, while LAS had an opposite effect even at high concentration and for long treatment times. The optimum enhancement of membrane surface hydrophilicity occurred in the LAS treatment at a concentration of 1x10-4 g/L. However, the optimum treatment time was different for each membrane. Increasing the ionic strength of latex effluent or enhancing the membrane surface hydrophilicity caused a significant increase in the cumulative permeate flux, a substantial decrease in the total mass of fouling, and a noticeable decrease in the specific power consumption.
Sludge Blanket Anaerobic membrane bioreactor (SB-AnMBR) Treatment of Prehydrolysis Liquor from the Dissolving Pulp Industry
Performance of innovative sludge-blanket anaerobic membrane bioreactors (SB-AnMBRs) was evaluated at mesophilic (35oC for 400 days) followed by thermophilic (55oC for 330 days) temperatures for the treatment of the pre-hydrolysis liquor (PHL) waste stream from a dissolving pulp production plant. PHL with an average total chemical oxygen demand (COD) of 100 g/L was generated from the steam hydrolysis of wood and mainly consisted of sugars (hemicelluloses), acetic acid, furfural and lignin. The bioreactors were fed with PHL at organic loading rates (OLR) ranging from 0.8 to 7.5 kg-COD/m3-d to study the performance with respect to the COD removal, methane (bio-energy) production, effluent characteristics, and membrane fouling. Average COD removal of 91% and specific methane yield of 0.36 m3/kg-CODremoved/day were achieved during the pseudo-steady period of the continuous mesophilic operation at each loading rate. The effluent lignin concentration showed an increasing trend (0.2 g/l to 2.7 g/l) with an increase in the OLR. At thermophilic condition, the AnMBR exhibited accumulation of volatile fatty acid (VFAs), the presence of slow-degrading lignin in the effluent and lower COD removals (less than 60%) possibly due to the one-step increase in the temperature (from 35 to 55oC) exerting temperature stress on biomass during the first sixty days of the operation. Subsequently, it was observed that the methane yield slowly increased to 0.38 m3/kg-CODremoved/day. This phenomenon can be ascribed to the shift in the population increase of thermophilic anaerobic bacteria. There was no sugar and furfural found in the effluent of the SB-AnMBR at both temperatures during the stable period. This suggested good potential of using the AnMBRs for the treatment of PHL as well as production of bio-energy. Flat-sheet membranes were used in the SB-AnMBRs. Membranes did not show significant fouling based on monitoring of temporal variations in the trans-membrane pressure at a sustained flux of 0.1 m3/m2/d during the aprox. 700 days of the continuous operation.
Photocatalytic degradation of naphthalene in offshore produced water: comparison of immobilized and suspended TiO2
Offshore oil and gas industry has produced and discharged a considerable amount of produced on a daily basis. However, current treatment methods such as gravity separation are not effective in removing dissolved organic matters before discharge. As the increasing environmental awareness and stringent regulation, it is necessary to develop more effective approaches to remove dissolved organics. Photocatalysis has been introduced in water and wastewater treatment and can effectively remove organic pollutants non-selectively. However, the separation of catalysts after treatment is difficult and costly. Thus, the immobilization of catalyst could be an alter approach that avoids any post-treatment. In this study, produced water was irradiated under UV-C (254 nm) for 12 h with the presence of catalysts. A commercial catalyst, Aeroxide® P25 was immobilized on glass plates by a heat attachment method. The P25 powder was used as a referent catalyst. Naphthalene was selected as an indicator owing to its abundance in produced water and typical chemical property of polycyclic aromatic hydrocarbons (PAHs). The results showed that the immobilized catalyst has a better enhancement to photo-oxidation. The turbidity was significantly reduced compared with suspended system.
Potential Health Risks of Contaminants in Private Groundwater Sources in Newfoundland and Labrador
The Government of Newfoundland and Labrador regularly tests public drinking water supplies to ensure the absence of any microbiological, physical or chemical contaminants. Private water supplies, including wells however, fall outside the mandate of these testing regimes and thus monitoring becomes the sole responsibility of the individual well owner. There are over 40,000 wells in Newfoundland and Labrador servicing approximately one fifth of the total population. Limited information on private well water quality is available, especially of physical and chemical contaminants. A scan of provincial government water quality reports of public wells was performed to create a proxy model of the potential risk of private well contamination. Our results show potential problems with toxic levels of arsenic, barium, cadmium, chromium, lead, mercury and selenium. Lead and arsenic pose the greatest risk with 13% and 10% of public wells having shown contamination at least once. Our model finds 8,544 people at risk for exposure to toxic levels of arsenic, 11,232 people at risk of exposure to toxic levels of lead, and 3,840 people at risk for exposure to the remaining contaminants from drinking water from private wells. In total, this model shows 5% of the province’s population at risk of exposure to toxic drinking water contaminants. A review of the literature was conducted to assess the health risks from each of these individual contaminants. Health risks on account of chronic exposure to these seven contaminants include cancer, cardiovascular disease, kidney damage, diabetes, as well as neurological and developmental conditions, among others.
Trace Element Analysis of Water with Inductively Coupled Plasma-Mass Spectrometry
Trace element analysis of the drinking water in the area of St. John’s, Newfoundland, Canada has been investigated by an Agilent 7700X inductively coupled plasma-mass spectrometry (ICP-MS). 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Water Insecurity in Indigenous Canada: A Case Study of Illness, Neglect, and Urgency
Water insecurity in Northern Indigenous communities in Canada is pervasive and complex with multiple dimensions and impacts. Yet the relevant literature is sparse, especially for Labrador. Our case study aimed to understand the multiple dimensions, health risks, and coping strategies of long-term water insecurity in the Southern Inuit island community of Black Tickle-Domino, Labrador, where there is no household running water system and people rely on an under-funded potable drinking water unit (PDWU) and unmonitored shared shallow wells. Using qualitative and quantitative methods, our exploratory work included research on water quality, access, contamination, uses, preferences, and cultural interpretations. In Black Tickle water security was chronically and severely compromised and the community did not meet the World Health Organization (WHO) guidelines for safe drinking water. Some water samples had contaminants and there were past records of outbreaks of water-borne illnesses. Water insecurity was linked to poverty, food insecurity, men’s health, and mental health and poses major health risks. There is an urgent need for a sustainable strategy to improve water quality and quantity in these communities, such as that outlined by WHO in 2005. Yet these communities lack the economic and political means to implement such strategies. Our materialist approach and ongoing commitment to this work has led to early-stage work with engineers and the community to identify possible solutions.
Water Resources Security Evaluation Based on Matter Element Model in the Yellow River Basin
Water resource is a major limitation of human survival and development. Water security assessment is an important task in the environmental protection and control of water. The solution to assess the grade of water security in the Yellow River Basin is to study based on the theory of matter element of extension method. Considering the factors of water resources, water environment and social economic aspects, the assessment index system of water security is established . Based on the defining of assessment level, water security assessment based on matter element model is developed exerted both qualitative and quantitative analysis. According to the calculation of correlation degree in the matter element model, the assessment result is represented by the quantitative data that can reflect water security situation in the Yellow River Basin briefly.The result shows that: water security in Qinghai and Sichuan province is in security level, that in Henan province is in the relative security level, that in Shaanxi and Shandong province is in the security threshold level, that in Shanxi province is in the relative insecurity level and that in Gansu, Ningxia and Inner Mongolia province is in insecurity level. The result of matter element model is scientific and reasonable, simple and easy, and can meet the factual data. matter element model can be used in water security assessment and can reveal the complementary information of every single assessment index.
This research investigated the potential application of blue-green algae to improve the quality of composts generated from multiple waste streams including- fly ash, fish waste, and sludge from a local wastewater treatment plant. The alga strain used is called Anabaena 387, which was obtained from the Canadian Phycological Culture Centre. Different mixture ratio of fly ash, fish waste compost, sludge and algae and different reaction period were tested to generate different levels of compost products. The parameters including trace elements concentration, carbon to nitrogen ratio, pH level, moisture content, organic matter, and germination index were monitored for evaluating the quality of composts. Three different levels of compost were generated, which are Type AA, A, and B. The algae treated compost could be used as an amendment for agriculture application.
Biosurfactant Production by Rhodococcus Erythropolis Sp. SB-1A Isolated from North Atlantic Ocean: Study on the Influence of Environmental Conditions
Biosurfactant production by Rhodococcus erythropolis SB-1A was studied based on Atlas oil agar medium in a batch reactor. The strain was isolated from a water sample collected from Northern Atlantic Ocean. Several parameters including carbon source (n-hexadecane, 0.5, 2, 3.5 and 5 v/v%), nitrogen source (NH4NO3,0.4, 0.7, 1 and 1.3 g/L), pH (5,6, 7 and 8) and salinity (NaCl, 13, 26, 39 and 52 g/L) were analyzed to optimize cultural and environmental conditions for biosurfactant production. Surface active properties of biosurfactants in the cell-free broth were monitored periodically. Results showed that the crude biosurfactants in the media cultivated under experimentally defined conditions reduced surface tension by 40 dynes/cm within 10 hours of cultivation. The research outputs demonstrated the possibility of using biosurfactants produced by Rhodococcus erythropolis SB-1A for remedying hydrocarbon contamination in North Atlantic Canada and beyond.
Research on Passive Contaminant Transport in a Vegetated Channel
Vegetation plays an important role in the physical, ecological, and hydraulic functions of streams, rivers and many other water bodies and can affect the transport of water, sediment and nutrients both within the channel and to or between the riparian zones. This research studied the momentum and passive contaminant transport mechanism in a vegetated channel with a floodplain. Three dimensional numerical simulation and physical experimentations were conducted for turbulent flow in the presence of model vegetation. A non-linear k-ε model with a vegetation model for turbulent flow and an algebraic flux model (DH model) for contaminant transport were adopted. An in-house code developed by the authors was implemented for numerical simulations. Model vegetation zones were prepared in the channel to predict the mixing mechanism. The numerical results were compared with corresponding experimental observations. A good agreement between the simulated and experimental results was observed in terms of pollutant concentration.
Influence of Soil Drought Stress on C, N and P Stoichiometry of Tamarix Chinensis Lour. in Yellow River Delta, China
Taking the one-year-old T. chinensis (Tamarix chinensis Lour.) in Yellow River Delta as the study object, the variations of C, N and P stoichiometry in T. chinensis under drought stress was studied using pot experiments. The results showed that, carbon (C), nitrogen (N) and phosphorous (P) contents and their stoichiometric ratios in the root, stem and leaf of T. chinensis exhibited large variations. The variation of the root C content presented an increasing trend with the gradual intensification of the drought stress while that in leaf and stem revealed different degrees of decrease. Both N and P contents in leaf, stem and root reduced when T. chinensis was under slight drought stress and showed a trend of first increasing and later decreasing with the intensification of the stress. The values of C : N, C : P and N : P ratios represented the same variation trend when T. chinensis suffered drought stress. They increased slightly when the T. chinensis was under slight stress and showed a trend of first decreasing and later increasing with the intensification of the drought stress. Slight drought stress did not have significant influence on the growth of T. chinensis. T. chinensis took competitive and defensive life-history strategies when suffering moderate and severe drought stresses, respectively. Thus, from the standpoint of ecological stoichiometry, T. chinensis had strong drought tolerance. And a certain degree of drought stress could help for the growth of T. chinensis.
Behavior of Corexit dispersants in the Gulf of Mexico after the Deepwater Horizon oil spill
Offshore Oil spills are of tremendous concern due to its enormous harm to economic and ecological systems. Corexit dispersants are used as an important combating agent for oil spills as they can dilute oil downward to water column and promote its biodegradation. They were extensively used during the Deepwater Horizon oil spill and dispersed 16% of the spilled oil. The aims of this paper was to illustrate the transport and fate of the key ingredient of Corexit dispersants, dioctylsulfosuccinate, sodium salt (DOSS), in the Gulf of Mexico after the Deepwater Horizon oil spill. Relevant data were collected from literature and governmental databases. Subsequently, the distribution of DOSS was correlated with distributions of the flow of diverse hydrocarbons. The results indicated that DOSS had highest distribution correlation coefficients with gases and BTEX. The smaller molecular gases and aromatic compounds have higher distribution correlation coefficients while larger molecular alkanes have higher distribution correlation coefficients. The obtained correlation would provide useful information on the fate and behaviour of Corexit dispersants.
A Study on Pollution in Livestock and Poultry Breeding in Shiyan City
With the investigation and research of agricultural ecology situation, the pollution characteristics of livestock manure were indicated by the statistical analysis of data as well as the effect of livestock and poultry breeding on agricultural ecology of Shiyan City. Livestock and poultry breeding industry local pollution load of Shiyan City and the local pollution load ratio of pollution sources from different agriculture industries show that livestock and poultry breeding industry should be comprehensive managed and in strict control as the focus of agricultural pollution sources.
Study on Water-Atmosphere Interface Distribution and Concentration Fluctuation Intensities of Polybrominated Diphenyl Ethers in Great Lake
In this study, the water-atmosphere interfaces distribution and concentration fluctuation intensities of polybrominated diphenyl ethers (PBDEs) in Great Lake were analyzed. Based on the selected significant quantum descriptors, bromination pattern descriptors (NPBS) and temperature descriptors by combination of variable important for projection (VIP) and correlation analysis, 35 experimental Henry’s law constants of PBDEs (transformed as lgH, represented the water-atmosphere interfaces distribution) at different temperatures were divided into modeling set (25 samples) and testing set (10 samples) to establish the quantitative structure-parameter relationship (QSPR) model for lgH at different temperatures via the optimal subset method firstly. Then, the Henry’s law constants of other unknown PBDEs at different temperatures were predicted and the water-atmosphere interfaces distribution regularity were analyzed from views of chemical quantum descriptors and substituent pattern respectively. At last, the concentration fluctuation intensities in Great Lake were discussed based on the correlation analysis between the detected concentration data and experimental Henry’s law constants. The established optimal QSPR model has shown a good fitness and predictive ability for Henry’ law constants of PBDEs, with the R2 and R2 pred of 0.985 and 0.978 respectively. From the view of chemical quantum descriptors, the lgH of PBDEs is positive correlative with EHOMO, indicating the ability to provide electron of congener molecule has played a leading role in governing the exchange ability between water-atmosphere interface; from the view of bromination pattern, both number of relative positions and each position have great influence on the water-atmosphere interface distribution, especially N2(6) and No can decrease the release of PBDEs from water to atmosphere in Great Lake. The concentration fluctuation intensity is negative correlated with the lgH linearly, the bigger solubility of congener in Great Lake, and the stronger water-atmosphere interface exchange ability and fluctuation intensity.