The course will be focused on the chemistry of the environmental spheres and on their mutual influence through mass and energy transfer processes. It will be extended to the effects of pollutants on the chemical equilibria throughout the various spheres and, vice versa, on the action that these equilibria have on the pollutants, with a particular focus on the consequences on the biosphere and the natural ecosystems.
(a) Stanley E. Manahan Environmental Chemistry 10th Edition, Lewis Publishers. (b) Colin Baird and Micheal Cann Chimica ambientale, Zanichelli.
Additional texts and lectures will be recommended during the course.
Learning Objectives
At the end of the course the student will be familiar with the structure of the terrestrial environment, its partition in spheres, and with the chemical processes, the reactions and the conditions occurring in it.
He will be able to connect the different aspects of the environmental chemistry and the reciprocal influence among the spheres; to analyze the effects of human activity on the biogeochemical cycles globally and at the level of the natural systems.
He will be able to make examples of new chemical approaches for the development of processes with low environmental impact and for the treatment and the restoration of compromised area
Prerequisites
bases of general and organic chemistry
Teaching Methods
taught lessons with discussions and group activities
Further information
Type of Assessment
oral exam with presentation of a theme starting from a scientific article. The theme will be one the subjects of the lectures and the presentation will have to extend that subject also through a bibliographic research. Moreover, the exam will include a discussion with questions aimed at evaluating the ability of the student to critically discuss the topics of the course.
Course program
Introduction to environmental chemistry. Definition of environmental spheres and exchanges of matter and energy among spheres. Biogeochemical cycles of the main chemical elements. The natural capital and human action. Characteristics of each sphere and their interconnection. Bibliographic research: databanks, searching via keywords and subject headings, critical analysis of a scientific article. Short review of general and organic chemistry: measure of concentration, reaction equilibria, solubility and solubility product, acid-base reactions and buffer systems, alkalinity. The hydrosphere and the chemistry of hydrosphere: circulation of chemical species and reactions aqueous systems. Life in water. Importance of water for living organisms. Water’s civil rights for its protection? Importance of kinetics in the reactions in water and biochemical oxygen demand. The carbonate system. Acidity of water and the ability of carbonate system to maintain a pH suitable for life. Predominant species of the carbonate system as a function of pH. Alkalinity vs basicity, pH dependence. Fertility of water as a function of alkalinity and pH. Metals in water and acid-base and complexation reactions. Role of calcium in the chemistry of water. Phosphates and phosphonates. Humic substances. Heavy metals in the environment: mangroves and phytoremediation. Endocrine disruptors and their effects on fauna: the case of the cane toad. Persistent organic pollutants in the hydrosphere: formation, fate and degradation of hexachlorocyclohexane. Redox reactions in the hydrosphere. Standard potential and the Nernst equation. Relationship between pE and pH. pE-pH diagrams of species in water. Redox and humic substances. Solids and gas in water: solubility, dissolution. Formation of sediments. Colloids. Exchange of ions and transport of different species by colloids. Aquatic biochemistry: microorganisms in water. Classification of microorganisms, their importance in aquatic chemistry, metabolism. Bacteria that produce methane. Fermentation reactions. Biodegradation of organic compounds such as hydrocarbons and pesticides. Microbic transformation of nitrogen. Microbic transformation of halogens and of chlorine-containing organic compounds. Redox reactions involving microorganisms. Ocean’s acidification and the carbonate system. Plastics, microplastics and the effects on natural environments. New water pollutants (nanomaterials, siloxane, disinfection by-products, antibiotics, pharmaceuticals, persistent organic compounds, radionuclides.). Heavy metals and metalloids: mercury, cadmium, lead and arsenic.
The atmosphere: structure and composition. Matter and energy transfer in the atmosphere. Chemical and photochemical reactions. Ions and radicals in the atmosphere: the OH radical. The oxygen cycle. Acid-base reactions in the atmosphere. The solar radiation and the ozone layer. Reactions of formation of ozone. How to measure the ozone concentration. Half-life of ozone and ozone cycle. Effects of the UV radiation on the biosphere and its biogeochemical cycles. The ozone hole and the Montreal protocol. Chlorofluorocarbons and ozone destruction, their persistence and alternative products. Acid-base reactions in the atmosphere and acid rain. Gases responsible of acid rain and formation of strong acids in the atmosphere. Effects of acid rain on biosphere, hydrosphere and geosphere. Damages to the cultural heritage. Actions to contrast acid rains. The solar radiation and black body radiation. Solar radiation and Earth temperature. Albedo, aerosol and radiation joining the Earth surface. Loss of energy from Earth surface. Emission of infrared radiation. The greenhouse effect and the absorption of radiation. Why some gases absorb radiation and others not. The most important greenhouse gases. Measure of the concentration of CO2. Keeling curve and patterns of CO2 concentration, the prove of CO2 greenhouse effect. Effects of global warming on climate and on life on Earth. Solutions: CO2 capture and storage: different proposed methods. Production of H2 as fuel. Chemical and physical properties of CO2 and implication for storage in the ocean. Storage under the Earth surface. Biofuels, bioethanol and biodiesel. The geosphere and its composition. Types of rocks and the rock cycle. Weathering and chemical reactions involved. Structure and importance of clays. Sediments. Groundwater. Wells and arsenic pollution. The geosphere and the natural capital. Soil and its chemistry. Water in soil and the water cycle. Organic substances in soil and their importance for soil fertility. Humic substance in soil and its role in the interactions with proteins and in nutrients exchange with plants. Soil contamination by chlorinated biphenyls and diffusion of these pollutants in all environmental spheres. Biomagnification. Examples of persistent organic pollutant and their diffusion in the environment. Detergents: structure, persistence and biodegradation. Environmental problems. Pesticides: classes of pesticides and their diffusion. Pollution from pesticides and recycle in the environmental speres. Neonicotinoids in honey. Example of a pesticide of medium persistence: environmental distribution and degradation. Green pesticides: efficacy, persistence and safety. Dioxins: formation and toxicity, their diffusion and the “problem“ of the incinerators. Biodegradable detergents: structure and biodegradability, diffusion and presence in sewage sludge used in agriculture. Analitical techniques in environmental chemistry: volumetric analysis, gravimetric analysis, electrochemical analysis, spectroscopic analysis, chromatographic analysis, mass spectroscopy.