Admission requirements
This course is taught in 2025-2026
Description
How do you determine the impact of a microplastics or chemicals on the environment? How are organisms impacted by contaminants? And how do you translate the results obtained from the lab to the field? And, how can a student run hackathon inform policy?
In this course we will provide students with an introduction to the field of environmental toxicology: the study of the fate and effects of contaminants in ecosystems. The foundation of the course is Environmental Risk Assessment, which is a key tool for scientist and policy makers to assess the potential risk of contaminants to the environment. What is the difference between risk assessment and risk management? In order the truly understand risk assessment, students will gain both theoretical knowledge as well as practical skills in this fast-moving and important field of study.
For the theoretical component, the course provides students with a framework in order to assess the risk of environmental contaminants. Basic principles of ecotoxicology will be discussed, including i) fate of chemicals and substances, ii) uptake, bioaccumulation and elimination of contaminants, iii) dose-response models, and iv) responses to chemicals at different biological levels – organism to community organisms. v) lab-field extrapolations, vi) field realistic testing. Environmental pollutants that will be discussed include classic chemical contaminants (e.g. pesticides, persistent organic pollutants and metals), as well as emerging contaminants (e.g. nanoparticles, endocrine disruptors and plastics).
For the practical component, we will collectively practice the process of conducting collaborative scientific research in the field of ecotoxicology in a Hackathon: starting with hypothesis formulation, to design, sampling, analysis and dissemination of findings through a variety of scientific contexts and practical. These practical components will be done based on input from the Dutch Authorisation Board of pesticides. Together, we will search for a real case chemical problem for which we will perform a Hackathon. The Hackathon consists of hands-on experiments that are designed by the students themselves based on tools and procedures discussed in class. It is generally anticipated that ecotoxicological tests should provide data useful for making realistic predictions of the fate and effects of chemicals in natural ecosystems.
This Hackathon is in scope of the fact that in spite of the considerable amount of work devoted to pollution and the wide range of test methods being used, there is still reason to question whether current procedures for testing accurately predict the risks of contaminants. In the Hackathon we will use our shared creativity to explore methods to more effectively collect data which can be used in Environmental Risk Assessment.
Course objectives
Learning Objectives:
Skills
At the end of this course, students can:
Synthesize the scientific literature (reading, lectures, discussions) to gain a detailed knowledge of the sub-discipline area of ecotoxicology; and use it in their assignments
Apply knowledge of ecotoxicological theory to new environmental situations;
Interpret, summarize, validate and critique ecotoxicological data from the scientific literature;
Design an study, collecting and analyzing field and/or laboratory data;
Understand the difference between risk assessment and risk management, and discuss how (informed) management decisions are made based on data;
Work as part of a team to design, plan, carry out, analyze and report the findings of an experiment in ecotoxicology;
Content:
Students can define and discus the concept of Environmental Risk Assessment
Students are able to describe and discuss important principles in ecotoxicology, such as including i) fate of chemicals and substances, ii) uptake, bioaccumulation and elimination of contaminants, iii) dose-response models, and iiii) biomarker responses that can be observed in organisms, iv) lab-field extrapolations, v) research questions, design, interpretation.
Students can discuss strengths and shortcomings of different lab-based, field-based, model-based approaches to assess environmental impacts.
Timetable
To access the timetables for all courses and degree programs at Leiden University, please use the [MyTimetable] (https://rooster.universiteitleiden.nl/schedule) tool (login required). Any teaching activities that you have successfully registered for in MyStudyMap will automatically be displayed in MyTimetable. Additionally, any timetables you manually add will be saved and shown the next time you log in.
MyTimetable offers the convenience of integrating your timetable with popular calendar apps such as Outlook, Google Calendar, Apple Calendar, and other smartphone calendar apps. Any changes made to the timetable will be automatically synced with your calendar. If desired, you can enable email notifications for timetable changes in the "Settings" section (after logging in).
For more information, please watch the instructional video or visit the "help-page" within MyTimetable. Note that Joint Degree students from Leiden/Delft will need to merge their two separate timetables into one. A video tutorial is available to guide you through the merging process.
Mode of instruction
The main mode of instruction will center around lectures and labs. We have the approach that students are a member (co-creator) in the course and not a client. This means you have to actively participate in both the lectures and the labs, as we discuss a lot, and there are often hands on assignments during the lectures. Therefore, we expect you to be in class unless you have a good reason not to make it, in which case you inform us ahead of time.
Addition, students are required to complete individual and group assignments. To facilitate completion of these assignments, there will be some time set aside during lectures to discuss and work on assignments (the remainder of the work is conducted outside class hours). MAKE SURE TO BRING A NOTEBOOK AND A PEN TO CLASS!
Absence: It will be compulsory to attend some parts of the course. This includes the course introduction, interactive sessions, lab-sessions and guest lectures. These compulsory parts are indicated in the weekly schedule. Failure to attend these course components, may result in an additional individual assignment, or failing the course.
Assessment method
Exam: 40%
Practical (experimental work and reporting): 60%
Minimum grade:
Courses require a minimum, unrounded 5.5 grade to complete.
If a course has 2 or more written partial exams, the minimum grade only applies to the weighted average of the exams.
For partial grades from components other than exams (e.g. practicals, seminars, writing assignments), the bottom grade does apply to the individual components.
Please refer to the Student Charter for an overview of regulations.
Reading list
C.A.M. Van Gestel (Editor), F.G.A.J. Van Belleghem (Editor), N.W. Van den Brink (Editor), S.T.J. Droge (Editor), T. Hamers (Editor), J.L.M. Hermens (Editor), M.H.S. Kraak (Editor), A.J. Löhr (Editor), J.R. Parsons (Editor), A.M.J. Ragas (Editor), N.M. Van Straalen (Editor), M.G. Vijver (Editor): https://maken.wikiwijs.nl/147644/Environmental_Toxicology__an_open_online_textbook and scientific articles will be made available prior to the class in Brightspace.
Registration
All students have to register for courses with the enrollment tool MyStudyMap. There are two registration periods per year: registration for the fall semester opens in July and registration for the spring semester opens in December. Please see this page for more information.
Please note that it is compulsory to preregister your participation for every exam and retake. Not being registered for a course means that you are not allowed to participate in the final exam of the course.
Extensive FAQ's on MyStudymap can be found here.
Contact
Coordinator: Prof. dr. M.G. Vijver
Email: Vijver@cml.leidenuniv.nl
Remarks
It will be compulsory to attend some parts of the course. This includes the course introduction, interactive sessions, lab-sessions and guest lectures. These compulsory parts are indicated in the weekly schedule. Failure to attend these course components, may result in an additional individual assignment.