78446 - Pollutants in the soil-water-plant system

Course Unit Page

  • Teacher Ilaria Braschi

  • Credits 6

  • SSD AGR/13

  • Teaching Mode Traditional lectures

  • Language Italian

  • Campus of Bologna

  • Degree Programme Second cycle degree programme (LM) in Planning and management of agro-territorial, forest and landscape (cod. 8532)

  • Teaching resources on Virtuale

  • Course Timetable from Sep 21, 2021 to Dec 09, 2021


This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Clean water and sanitation Sustainable cities Oceans

Academic Year 2021/2022

Learning outcomes

At the end of the teaching, students will aquire the expertize to evaluate, to analyze and, from a theoretical point of view, to predict the main depuration processes acted by the soil-plant system against organic and inorganic pollutants by retention and degradation mechanisms. Specifically, students will be able: (i) to correlate the behaviour of pollutants in the soil-water-plant system with their physical and chemical properties and those of the soil and water considered;  (ii) to produce a report on topics related to the behaviour of pollutants in the soil-water-plant system; (iii) to understand scientific reports on the evaluation and prevision of the main phenomena of pollution of soil, water and plants.

Course contents

1. Classroom teaching (36 hours)

1.1. Adsorption of pollutants by soil components (10 hours)

1.1 Soils characteristics and pollutants adsorption. Introduction to the programme. Definitions of pollutant. Partition equilibria among the environmental compartments. Soil texture: structure of expandable and non-expandable phillosilicates and adsorption. Siloxane cavity as nucleophilic reactor. Isomorphic substitutions and hydration rate of clays on the adsorption of organic and inorganic pollutants. Soil organic matter and adsorption. Adsorption on soil oxides and hydroxides. State diagram of hematite and gibbsite. Adsorption as a function of soil pH.

1.2. Pollutant characteristics and soil adsorption. Physical and chemical characteristics: solubility, vapour pressure, Henry constant, Partition cefficient n-octanol/water (Kow), n-ottanolo-acqua (Kow), soil-water partition coefficient (Kd), acid and base dissociation constants (Ka and Kb), pollutant charge effect on soil adsorption.

1.3. Macroscopic effect of pollutant adsorption by soil. Adsorption and desorption isotherms: batch and column techniques. Reversibe and irreversible adsorption mechanisms. Themodinamics of adsorption.

1.4. Soil adsorption and retention at molecular scale. Adsorption mechanisms: Van der Waals interactions, hydrofobic interaction. Adsorption as a cooperative process. Hydrogen bonding. Protonation and adsorption. Cation exchange. Water bridging and cation bridging. Anion exchange. Legand exchange.

1.2. Degradazione of pollutants in soil and water (10 hours)

1.2.1. Abiotic degradation. Potential energy of adsorption (reversible and irreversible adsorption). Adsorption and abiotic degradation. Soil characteristics and degradation. Inner sphere and outer sphere complexes. Isomorphic substitutions and degradation. pH-Dependent homogeneous and heterogeneous hydrolysis. Photolitic trasformations: Direct photolysis and Jablonsky diagramme. Indirect photolysis. Water potabilizazion by titania.

1.2.2. Biotic degradation. Definition and characteristics. Physical and chemical characteristcs of the soil-root interface. Rizosphere gradients: pH, nutrients, redox potential, exudates, microbial and enzimatic activities. Effect od rizosphere activities on the soil mineral structure. Soilcharacteristics and biotic degradation. Direct and indirect microbial degradation. Oxidation, hydrolisis and reduction trasformations. Biological beds.

1.3. Heavy metals (6 hours)

1.3.1. Metals in the soil-water-plant system. Metals and heavy metals. Metal speciation in soil and in the soil water (ions, ionic pairs, organometal complexes). Metal avilability as a function of soil/water pH. Dissolved organic matter and metal tranfer to water bodies. Metal speciation and redox potential. Phytoextraction with chelants. Heavy metal toxicity: Cupper, Cadmium, Arsenic, Nichel and Lead.

1.3.2. Acidi rain. Formation, evolution and effects on the soil-plant sistem. Acdification and buffering of soil components (carbonates, organic matter, base metals). Aluminum mobilization: formation of free species, effect on rootmucigel and on plant cell wall.

1.4. Pollution of soil-water system and plant contamination (10 hours)

1.4.1. Soil pollution. Groundwater Ubiquity Score Index. Mitigation of soil and water pollution. Directives on soil and water pollution. Ecosustainable decontamination strategies: Chemical and physical approaches, cation exchange, composting, phytremediation.

1.4.2. Plant uptake. Phytostabilization: Root concentration factor and pollutant Kow. Phytodegradation:  Transpiration Stream Concentration Factor and pollutant Kow. Plant translocation of acid pollutants: Ionic trap theory. Enzymatic phytotransformation: phase I (ossidation, hydrolysis, reduction), phase II (conjugation with low MW molecules), Phase III (conjugation with high MW molecules). Phytovolatilization.

2. Laboratory activities (24 hours)

Le activities of the following Courses:

  • Pollutants in the soil-water-plant system
  • Soil Quality Indexes
  • Application Of Microbiology In The Environmental Field

will deal with the elaboration of analytical, microbiological and agronomic data regarding animal manure exposed to treatments for antbiotic and pathogen abatement and with their field use as fertilizers.

These activities will allow students to approach the antibiotic environmental fate and antibiotic-resistance issues through a multidisciplinary approach, by making connections among chemical, microbiological and agronomic aspects learned during the classes of the three Courses.

If permitted by the pandemic conditions, students will be allowed to attend the laboratory facilities and tools for a number of credits that will be eventually communicated by the teachers.

Lab activities are held at the Laboratory of Chemistry, Biochemistry and Food technologies (Lab CBA).


Periodic table of the elements.

All the handouts will be available. If needed, handouts in english are available for foreign students.
The following books/chapters are suggested:
Agrofarmaci - Conoscenze per un uso sostenibile, Gruppo Perdisa Editore, II Parte (pg. 151-377). the book can be freely downloaded at http://www.grifa.org/Documenti/AGROFARMACI%20-%20Conoscenze%20per%20un%20uso%20sostenibile.pdf
Marschner H., Mineral Nutrition of Higher Plants. Academic Press, London, 1995. Chapter 15: The soil/root interface.

Teaching methods

During the classroom teaching, the students will acquire the knowledge of the main pollution/depuration mechanisms of the soil-water-plant system, the main techniques to preserve the quality of soil and water bodies and the strategies available to mitigate some pollutions case studies. The knowledge acquisition and the comprehension of students will be monitored along the entire teaching period through a continuous interactions between the teacher and students through a problem solving approach. The teacher-student interaction is also finalized to improve the development of the evaluation skills and to increase the communication ability ofthe students.

During the laboratory activities, the students will learn: (i) to define the rationale of the laboratory trials; (ii) the knowledge of the techniques adopted to conduct the trials, (iii) handling the samples and evaluate the treatment of the soil/water/plant samples; (iv) the collection and elaboration of collected results; (v) the interpretation of results into the light of the knowledge acquired during the teaching activities in the classroom. At lab scale, some pollution scenarios will be presented and the students, in small groups or alone, will select a possible strategy to follow. At the end, a report will be produced and will be defended at the oral exam.

Assessment methods

The knowledge of the main topics will be evaluated by considering the quality of the laboratory report and the strategy adopted to solve the case study. At the same time, specific questions will be asked to verify the comprehension of the main topics considered during the teaching activities. The final quotation has to be at least equal to 18/30. The final quotation of the Course "Chemical and Biochemical Quality of Soil" will be the mean of this quotation and that obtained for the Course of "Indexes of Soil Quality" (27562). You can, on request, sustain the final exam in English. Teaching tools

Teaching tools

Blackboard, Projector, Handouts, slides, Periodic Table of the Elements

Office hours

See the website of Ilaria Braschi