Characterization, chemodynamics and environmental impact assessment of leachates from complex organic materials

More than 65,000 organic chemicals are currently in commercial production with approximately 1000 added each year. Many chemicals are released into the environment as organic mixtures derived from complex hazardous or solid wastes. Of these, more than 1000 chemicals are of environmental concern because of their production quantities, toxicity, persistence, and tendency to bioaccumulate. To manage the impacts of these chemicals to the environment, the environmental chemodynamics of such Complex Organic Mixtures (COMs) or Solid Waste Materials (SWMs) must be predicted accurately. Required information includes the molecular organic composition of SWMs/COMs and/or their leachates, the transport processes and migration in and between the various multimedia environments, chemical and biochemical transformation processes, and effects on the interacting organisms. A technique is developed to predict the potential impact of SWMs/COMs based on the organic chemical composition of the extracts from such complex materials and/or their leachates. In addition, the methodology can be used to estimate the potential hazards of organic pollutants in such complex mixture, ultimate fate and environmental toxicity. This technique consists of three fundamental approaches: characterization and source partitioning, chemodynamics and Environmental Impact Assessment (EIA) models. The characterization and source partitioning model of SWMs/COMs and their leachates are based on their lipid molecular marker (MM) signatures. Chemodynamics (i.e., Fate-Transport) model is based on experiments such as leaching, sorption, volatilization, photolysis, and biodegradation. These experiments are carried out for different SWM leachates and a group of polycyclic aromatic hydrocarbons (PAHs) that are characteristic to the studied leachates. The Environmental Impact Assessment (EIA) model estimates the probability of 96-hr fresh water alga Selenastrum capricornutum chronic toxicity of EPAH-containing SWMs/COMs using a combination of leaching kinetics, equilibrium partitioning, QSPR-QSAR, toxic unit, multicomponent joint toxic effect of mixtures (i.e., additivity, synergism, or antagonism) and dose-response models. The EPAH model is verified by comparing both predicted and observed toxicity in different waste materials. Molecular Connectivity-Quantitative Structure Activity Relationship (MC-QSAR) techniques then are used to develop a predictive model to estimate the concentrations of PAH components in mixtures derived from SWMs/COMs leachates that would jointly cause 50% inhibition of alga Selenastrum capricornutum toxicity.Keywords: Environmental Chemo dynamics, Environmental Pollution, Leschates, Characterization of organic compounds, Environmental Impact Assessmen

Discerning natural and anthropogenic organic matter inputs to salt marsh sediments of Ria Formosa lagoon (South Portugal)

Sedimentary organic matter (OM) origin and molecular composition provide useful information to understand carbon cycling in coastal wetlands. Core sediments from threors' Contributionse transects along Ria Formosa lagoon intertidal zone were analysed using analytical pyrolysis (Py-GC/MS) to determine composition, distribution and origin of sedimentary OM. The distribution of alkyl compounds (alkanes, alkanoic acids and alkan-2-ones), polycyclic aromatic hydrocarbons (PAHs), lignin-derived methoxyphenols, linear alkylbenzenes (LABs), steranes and hopanes indicated OM inputs to the intertidal environment from natural-autochthonous and allochthonous-as well as anthropogenic. Several n-alkane geochemical indices used to assess the distribution of main OM sources (terrestrial and marine) in the sediments indicate that algal and aquatic macrophyte derived OM inputs dominated over terrigenous plant sources. The lignin-derived methoxyphenol assemblage, dominated by vinylguaiacol and vinylsyringol derivatives in all sediments, points to large OM contribution from higher plants. The spatial distributions of PAHs (polyaromatic hydrocarbons) showed that most pollution sources were mixed sources including both pyrogenic and petrogenic. Low carbon preference indexes (CPI > 1) for n-alkanes, the presence of UCM (unresolved complex mixture) and the distribution of hopanes (C-29-C-36) and steranes (C-27-C-29) suggested localized petroleum-derived hydrocarbon inputs to the core sediments. Series of LABs were found in most sediment samples also pointing to domestic sewage anthropogenic contributions to the sediment OM.EU Erasmus Mundus Joint Doctorate fellowship (FUECA, University of Cadiz, Spain)EUEuropean Commission [FP7-ENV-2011, 282845, FP7-534 ENV-2012, 308392]MINECO project INTERCARBON [CGL2016-78937-R]info:eu-repo/semantics/publishedVersio

Integrated assessment of contaminants and monitoring of an urbanized temperate harbor (Montevideo, Uruguay): a 12-year comparison

AbstractSituated opposite the Freshwater Front, Montevideo city with its more than 1.5 million inhabitants encircles Montevideo Bay, where one of the most active and polluted harbors in South America is located. Faecal sterols, trace metals, organochlorine compounds and petroleum derivatives in the sediments of Montevideo Harbor were evaluated and their spatial distribution inside the harbor as well as in the input of two main tributary streams analyzed. Specifically for the harbor sites, a temporal comparison of metal and hydrocarbons was made with previous measurements taken 12 years ago. Clear changes were observed at these sites. The concentration of metals such as Pb, Cr and Zn have diminished, while aliphatic hydrocarbons have increased their values at almost all of the stations studied. Differences were observed between summer and winter suggesting sedimentation, input or hydrodynamic changes in the area. These results help one to understand the present situation and develop the management measures needed to improve the environmental quality of the harbor and bay

The Natural environment and the biogeochemical cycles

430p. : ill. ; 25 cm

BIOCHEMICAL STUDIES OF HIPPOCAMPAL GENE EXPRESSION OF BRAIN-DERIVED NEUROTROPIC FACTOR AND TOLL-LIKE RECEPTOR-4 IN DIABETIC RATS EXPOSED TO CHRONIC STRESS: EFFECTS OF ANTIDEPRESSANT DRUGS

  Objective: Depression and diabetes are closely associated in a reciprocal manner, leading to significant morbidity and mortality with an evidence of a pro-inflammatory state underlying pathophysiology of both diseases. Unfortunately, little information is available about the effects of antidepressant drugs on hippocampal brain-derived neurotrophic factor (BDNF) and toll-like receptor-4 (TLR-4) expression in diabetes.Methods: We investigated the effect of chronic administration of fluoxetine (FLU) and imipramine (IMIP) on behavioral, metabolic, and inflammatory abnormalities in diabetic and non-diabetic rats exposed to chronic restraint stress (CRS).Results: Both diabetes and CRS induced depressive-like behavior which was more prominent in diabetic/depressed rats; this was reversed by chronic treatment with FLU and IMIP. Diabetic and non-diabetic rats exposed to CRS showed a significant increase in hippocampal expression of TLR-4 and pro-inflammatory cytokines alongside a decrease in BDNF expression. FLU and IMIP ameliorated these inflammatory abnormalities.Conclusion: Diabetes mellitus (DM) and chronic stress induced a depressive-like behavior associated with an increase in hippocampal expression of TLR-4, tumor necrosis factor-α, and interleukin-1ß with a significant correlation to decreased BDNF expression. FLU and IMIP showed comparable effects regards the improvement of depressive and inflammatory abnormalities associated with DM