Pollution of lakes and rivers. A paleoenvironmental perspective

The effectiveness of diatomite as the low-cost sorbent in the removal of polycyclic aromatic hydrocarbons (PAHs) from water was investigated. The effects of ionic strength, pH, dissolved organic matter, and temperature on sorption of phenanthrene (PHE) to two types of diatomite clay (DM 545 and DM 577) were systematically studied. The maximal information coefficient (MIC) was calculated to reveal the linearity/nonlinearity in the sorption process under the influences of aqueous chemistry parameters. Results indicated that the solution parameters played an essential role in the PHE sorption behavior at the aqueous/diatomite interface. The sorption isotherms of PHE on diatomite at different temperatures could well fit the Freundlich equation. Thermodynamic studies confirmed that the sorption behavior of PHE on diatomite was spontaneous and exothermic from 283 to 303 K. The calculation of MIC revealed the linear relationship between the aqueous PAHs and sorbed PAHs at the water/diatomite interface. The results can be used to support the potential application of diatomite for the treatment of PAH-contaminated effluents.

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Sorption of Phenanthrene onto Diatomite under the Influences of Solution Chemistry: A Study of Linear Sorption based on Maximal Information Coefficient

Due to the increasing impact of human activities, water conservation has become a primary aim of environmental management policies. In this context, fish biodiversity represents a good measure of water quality because changes in ecological factors involve qualitative modifications in species composition. For this reason, the analysis of the interaction between biodiversity and environmental characteristics becomes crucial. This paper aims to analyse the effects of habitat and seasonality on fish biodiversity in freshwater environments. In particular, we applied functional data analysis to the beta diversity profile. The proposed approach allows us to overcome the limitations of the classical biodiversity indices, highlighting its multidimensional aspect. More in detail, our research focuses on the functional data analysis of variance in order to quantify the effects exerted on a functional observation by some factors. This model is applied to a real data set concerning ichthyic biodiversity of 104 streams in the province of Arezzo (Central Italy). We consider first the fish zonation and then the seasonality as factors; the results show that species diversity fluctuates seasonally whereas the zonation has no significant effect in influencing the biodiversity. Our proposal is a powerful tool for the analysis of the relationship between qualitative variables and a functional response. Since the diversity profile is a function of the relative abundance vector in a fixed domain, this method is particularly suited to the beta profile and it could be very helpful to monitor or to identify areas of high environmental risk.

/pdf/parametric-functional-analysis-of-variance-for-fish-2ktvpdsmev.pdf

Parametric Functional Analysis of Variance for Fish Biodiversity Assessment

The Laurentian Great Lakes of North America contain approximately 20% of the earth’s fresh water. Smaller lakes, rivers and channels connect the lakes to the St. Lawrence Seaway, creating an interconnected freshwater and marine ecosystem. The largest delta system in the Great Lakes is located in the northeastern portion of Lake St. Clair. This article focuses on the geovisualization of total mercury pollution from sediment samples that were collected in 1970, 1974 and 2001. To assess contamination patterns, dot maps were created and compared with surfaces that were generated using the kriging spatial interpolation technique. Bathymetry data were utilized in geovisualization procedures to develop three-dimensional representations of the contaminant surfaces. Lake St. Clair generally has higher levels of contamination in deeper parts of the lake, in the dredged shipping route through the lake and in proximity to the main outflow channels through the St. Clair delta. Mercury pollution levels were well above the Probable Effect Level in large portions of the lake in both 1970 and 1974. Lower contaminant concentrations were observed in the 2001 data. Lake-wide spatial distributions are discernable using the kriging technique; however, they are much more apparent when they are geovisualized using bathymetry data.

https://www.mdpi.com/2077-1312/4/1/19/pdf

Geovisualization of Mercury Contamination in Lake St. Clair Sediments

Immobilization of phenanthrene onto gemini surfactant modified sepiolite at solid/aqueous interface: Equilibrium, thermodynamic and kinetic studies

The Great Lakes Water Quality Agreement between Canada and the United States has identified the Buffalo River as an Area of Concern. The watershed has a long history of heavy industrial activity that contributed to its overall pollution. Sediment core data collected by the New York State Department of Environmental Conservation in 2005 were used to determine lead sediment contamination in a section of the Buffalo River. The ordinary kriging spatial interpolation technique was used to generate surface and subsurface sediment contamination estimates. Due to the meandering nature of the river, two kriging models were used to analyze surface contamination: a global kriging model and a regional kriging model, consisting of three separate sections. The results show that both the global and regional kriging models display similar interpolated surfaces and do not vary significantly. Within the sediment, lead contamination in the surface layer is lower than at the various subsurface depths. In 2011, habitat restoration efforts commenced to remediate environmental damage due to years of pollution inputs from various sources. Sediment dredging operations were initiated that are expected to be completed in 2015. The goal of these operations is to remove heavily contaminated sediments and rehabilitate the Buffalo River. The kriging results provide area-wide estimates of contamination. When compared to the dredging plan, the results indicate that additional removal of contaminated sediments may need to be considered where no dredging has occurred or is not currently planned.

/pdf/assessing-lead-contamination-in-buffalo-river-sediments-4lehr52vpd.pdf

K. W. Forsythe

Papers

Assessing Lead Contamination in Buffalo River Sediments