GEOCHEMISTRY

Geochemistry studies the chemical composition of the Earth and examines the chemical processes exchanging matter and energy between the different geochemical spheres: rocks and soils (lithosphere), surface and underground waters (hydrosphere), gases (atmosphere) and the biotic component (biosphere). The Geochemistry course for the Degree in Environmental Sciences provides the basis for understanding many geological and environmental processes such as (i) the chemical and chemical-physical processes that generated and shaped the Earth's crust, (ii) the processes leading to the current spatial distribution of the elements and nuclides in the different geochemical spheres; (iii) the current composition of the atmosphere and hydrosphere, (iv) the biogeochemical cycles and their interactions, and (v) the anthropic forcing and its impact on biogeochemical cycles. Knowing Geochemistry improves our understanding of the Earth, allowing us to reconstruct the past and to understand the present. In addition, human activities have a strong impact on the climate and geochemical cycles regulating the functioning of ecosystems. The application of geochemical concepts also allows understanding and predicting the behavior of the elements in an anthropized environment (a fifth sphere -the anthroposphere- has recently emerged).

This teaching aims to provide the basic knowledge of Geochemistry necessary to understand the environment. The teaching focuses on the evolution of the planet Earth, on the processes of generation, transport and transformation of matter, on the behavior, distribution and biogeochemical interactions of the elements occurring on the Earth's surface. The concepts of Geochemistry will be applied to different environmental matrices such as rocks, sediments, soils, surface and underground waters, gases and atmospheric particulates. In addition, this teaching aims to provide a multidisciplinary view of the environment by applying chemical and chemical-physical principles to explain the mechanisms controlling the geological systems and affecting the biological sphere.

The course aims to provide the student with a broad and comprehensive introduction to the basic concepts and principles of Geochemistry. The teaching explores arguments and chemical concepts to understand geological, hydrological, atmospheric, biological processes and their potential interactions. Attendance and participation in training activities (lectures, seminars, reading sessions, understanding and discussion of scientific articles, analysis of case studies, and exercises with geochemical datasets) will allow the student to:

1. Knowledge and understanding
1a. Knowing the main concepts of Geochemistry and knowing correct geochemical terminology;
1b. Understanding the processes that shaped the Earth to the current form, composition;
1c. Understanding the mechanisms regulating the geochemical spheres;
1c. Understanding the fluxes of matter and energy and the anthropic pressures that have (and will increasingly have) important impacts on the environment and on the climate;

2. Ability to apply knowledge and understanding
2a. Knowing how to correctly use terminology and geochemical principles in all application and communication processes of Environmental Sciences;
2b. Knowing how to identify and quantify the geochemical processes that shaped the Earth and its geochemical spheres;
2c. Knowing how to identify and discriminate the geochemical processes between natural and anthropized environments;

3. Ability to judge
3a. Knowing how to formulate and argue hypotheses on the basis of the concepts learned during the lessons;
3b. Knowing how to apply geochemical knowledge and tools to explain natural phenomena and to solve environmental problems;
3c. Knowing how to apply a critical and multidisciplinary approach to the assessment of complex environmental problems;

4. Communication skills
4a. Knowing how to communicate geochemical concepts in science, using appropriate terminology;
4b. Knowing how to interact with different professional figures that a graduate in Environmental Sciences will find during his/her professional career, such as biologists, chemists, geologists, physicians, epidemiologists, as well as with figures of non-scientific fields (politicians, economists, etc.);
4c. Knowing how to simplify and summarize the concepts of Geochemistry for the dissemination of data to the general public, using simple and direct terminology;

5. Learning skills
5a. Knowing how to apply the concepts of geochemistry to real case studies;
5b. Knowing how to read environmental processes with a geochemical perspective;
5c. Knowing how to critically consult the reference texts and how to interpret the bibliography that will be proposed during the course;
5d. Knowing how to process geochemical data and apply appropriate statistical and geostatistical analyzes during exercises.

Basic knowledge acquired during the courses of the first year of the three-year degree course in Environmental Sciences, e.g., inorganic chemistry, physics and Earth Sciences.

The teaching is divided into 7 sections.

Section 1 (basic concepts) briefly introduces and summarizes key concepts for the remaining parts of the course, i.e. the atom structure, isotopes, periodic properties, valence states, chemical bonds, state functions (Entropy , Enthalpy, Gibbs Free Energy), phase diagrams and chemical potential. The influence of the periodic properties of the elements on their geochemical behavior is examined.

Section 2 (cosmochemistry and origin, evolution and structure of Planet Earth) describes the nucleosynthesis, the origin and evolution of the solar system and terrestrial planets with an introduction on the composition of meteorites. The origin of the Earth, the processes of condensation, homogeneous /heterogeneous accretion, the internal structure of the Earth, and the genesis and evolution of the Earth's crust. Key concepts of Geochemistry are presented, such as the geochemical differentiation of the Earth and the origin of its oceans and atmosphere, the Goldschmidt rules and the geochemical classification of elements in atmophiles, lithophiles, siderophiles and chalcophiles.

Section 3 (lithosphere) analyzes the abundance and distribution of the elements in the Earth's crust. The weathering, the chemical alteration of minerals and rocks (dissolution, oxidation, hydration and hydrolysis), the solubility of CO2, the abundance and chemical speciation of carbon in solution, and the role of carbonates. Introduction to the properties of clay minerals, introduction to soils, introduction to the organic geochemistry.

Section 4 (atmosphere) deals with the origin, evolution, structure and chemical composition of the atmosphere, with particular attention to the troposphere and stratosphere. Solubility and reactivity of the gaseous species present in the atmosphere, geochemistry of the aerosol system, the role of atmospheric (aeolian) transports of crustal material in the geochemical cycles, the role of volcanoes on climate, the role of volcanic activity on the composition of the atmosphere and on aerosol, urban and regional air pollution, health effects and influence of airborne particles on climate change.

Section 5 (hydrosphere) deals with the structure and properties of water, chemical equilibria in the aqueous phase and presents the geochemistry of ocean, continental and meteoric waters. The origin of dissolved components, particulates and colloidal systems, geochemical mobility, the role of ionic potential, pH, Eh, and humic substances.

Section 6 (biosphere and geochemical cycles) introduces the (bio)geochemical cycles, analyzing the reservoirs and the pathways that chemical elements follow in the surface and crust of the Earth. The main cycles are treated: water, carbon, nitrogen, phosphorus, sulfur. The interactions between the various geochemical cycles are discussed.

Section 7 (anthroposphere) discusses the anthropic impact on the geochemical cycles with the analysis of some case studies. Some real case studies are presented and are interpreted starting from the geochemical associations of the elements. Some methods of statistical and geostatistical data processing are also briefly presented. Some geochemical datasets will be analyzed with statistical tools and geographic information systems (GIS).

Reference text:

Dongarrà, G., Varrica, D., Geochimica e Ambiente. EdiSES ed., Napoli, 2004. ISBN: 978-8879592826 [https://www.edisesuniversita.it/default/geochimica-e-ambiente.html ]

Some optional books and supplementary readings are available at the University library system (Scientific campus, alpha building) or upon request to the teacher:

1) Holland, H.D., Turekian K.K. (Eds.), Treatise On Geochemistry. Volumi 3-6, 8 e 9. Elsevier, 2003. ISBN: 978-0080437514 [https://www.sciencedirect.com/referencework/9780080983004/treatise-on-geochemistry ]
2) McSween H.Y., Richardson S.M. Jr, Uhle M.E., Geochemistry: Pathways and Processes. Columbia University Press, 2003. ISBN: 978-0231124409 [http://cup.columbia.edu/book/geochemistry/9780231124409 ].
3) Ryan P., Environmental and Low Temperature Geochemistry. Wiley-Blackwell, 2014. ISBN: 978-1-405-18612-4 [https://www.wiley.com/en-us/Environmental+and+Low+Temperature+Geochemistry-p-9781405186124 ]
4) White W.M., Geochemistry. Wiley-Blackwell ISBN: 978-0-470-65668-6 [https://www.wiley.com/en-us/Geochemistry-p-9780470656686 ]

Oral test divided into two parts. The first part deals with the concepts presented during the lectures and the case studies analyzed in the classroom. In the second part, students will have to exhibit, critically analyze and discuss a scientific article. This article will be assigned by the teacher at the end of the teaching period and will be chosen on the basis of the preferences expressed by the students. A maximum of 20 points on the total of the final mark is assigned to the first part, a maximum of 10 points to the second one. Non-attending students are invited to contact the teacher to have a scientific article assigned at least 15 days before the exam date.

The teaching is structured in classroom lessons with possible seminars of teachers and researchers inside or outside the University. In addition to the lectures, the teaching also includes some discussion sessions where students are strongly encouraged to examine and review the learned concepts, testing their understanding through the critical reading of scientific literature, and the analysis and interpretation of cases study. These discussion sessions bring multiple benefits to the students (i) helping them to better understand the learned concepts, (ii) encouraging them to stay up to date during the entire teaching period, (iii) allowing them to identify misunderstandings or gaps in preparation, (iv) providing them with the tools to face scientific discussions with a high degree of autonomy, (v) helping them to improve communication skills using appropriate terminology, and (vi) preparing them for the second test of the final exam. Some geochemical datasets (various environmental matrices) will also be analyzed during the last lessons; the goal is becoming familiar with geochemical data and their interpretation.

All lessons are provided as PowerPoint presentations and are distributed at weekly-basis to students by using the Moodle teaching platform. In the same way, the case studies discussed during the lessons and the tracks to perform the exercises will also be provided.

Students are invited to periodically consult Moodle to be up to date on lessons.

Italian

oral

This subject deals with topics related to the macro-area "Natural capital and environmental quality" and contributes to the achievement of one or more goals of U. N. Agenda for Sustainable Development