Ben Wielstra studies hybrid zones, regions in which distinct populations of organisms meet, mate and produce genetically admixed offspring. In the journal Current Biology, he introduces hybrid zones in an accessible way.

Plastic cigarette filters are a major source of litter and microplastics pollution. Legal experts from Leiden University, commissioned by a Dutch ministry, examined policy options to reduce this pollution and whether a national ban is legally feasible.

Ben Wielstra studies balanced lethal systems, in which half of the offspring die before birth. In the journal Current Biology, he explains in an accessible way how such a disadvantage can originate in nature.

14 March 2018 a Citizens’ Dialogue about plastic-use in Europe with First-Vice President Frans Timmermans took place in Utrecht. It was one in a series of dialogues organized by the European Commission held throughout Europe. LAPP-student Emily den Boer joined the evening.

On 27 November 2019, the Royal Netherlands Academy of Arts and Sciences (Koninklijke Nederlandse Akademie van Wetenschappen) organized a symposium on the plastic pollution crisis.

LAPP students Emily den Boer and Louise Floris, together with Esther Kentin, wrote about the proposal for a plastic bottle deposit return system that has been discussed in the Dutch Parliament in April 2019.

The Ben Pauw thesis prize for the best Master’s thesis in the area of Public Affairs was won by student Esther Mangelsdorf of the Institute of Public Administration.

Every Sunday you can help fish plastic and other floating garbage out of the Leiden canals. You can use your own canoe or loan one from Plastic Spotter and join the garbage-fishing fleet. Annetje Ottow, President of Leiden University, was one of the crew on Sunday 4 July.

Leiden University will install over 30 tap water stations in the autumn of 2017 at the various University buildings. The first is already in use.

Shell, our country's largest company, is constructing a vast plastics plant in the United States. And it is doing so at a time when the European Union, led by the Netherlands, is launching a major pact to combat use of plastic.

At the recent UN summit in Geneva, representatives from more than 180 countries failed to reach a global plastics agreement. Esther Kentin, a lecturer at Leiden Law School, spoke to media outlets on the issue: ‘Human health is at stake.’

On 12 September 2025, Dr. Ben Van Rompuy participated in the conference “Playing by the Rules: the Intersection of Competition Law and Sports”, organised by the University of Lausanne.

After studying medicine in Leiden, Diederik Hofstede specialised in plastic surgery. 'I was attracted by its creativity and I enjoy working with my hands.' Cosmetic surgery is just 5% of the work.'

One person can already make a difference, and if all students and academics were eco-friendly, the world would be a much more sustainable place. Plastic Soup Surfer Merijn Tinga opened the academic year in Leiden with this message.

This year will see the start of not one but two citizen science projects in Leiden and The Hague. This is the outcome of a large survey among residents and researchers in both university cities. The Citizen Science Lab will help the winners implement their ideas, with support from the University and…

International trade has played a major role in defining the modern global economy. Trade, however, entangles the environmental pressures of economic sectors, giving the illusion of environmental improvements, while the opposite may be occurring.

At two recent events, Ben Van Rompuy, Assistant Professor of competition law at the Europa Institute in Leiden, discussed current developments in the application of EU competition rules to regulatory aspects of sport.

Ben Van Rompuy participated as an invited expert in the 22nd Annual Meeting of the Association of European Competition Law Judges (AECLJ), which took place in Berlin between 30 May and 1 June 2024. The event was co-organised by the European Commission.

On 19 November 2018, the American Bar Association (ABA), Section of Antitrust Law organized a teleconference “Sports and Antitrust: Breaking the Ice”.

It's now possible to measure how many plastic particles there are in our food. Chinese scientists and Leiden professor Willie Peijnenburg applied their new method to lettuce and wheat. Their results were published January 20 in Nature Nanotechnology.

A memorial stone honouring professor and resistance hero Ben Telders was unveiled on 12 September at the site of the former concentration camp Bergen-Belsen.

Ben Van Rompuy, assistant professor of EU competition law, was an invited expert at the 23th Latin American and Caribbean Competition Forum (LACCF) organised in Quito, Ecuador on 28-29 September 2023.

When the plans for a breakaway Super League in European football were announced this weekend, governing body UEFA threatened to ban all participating clubs and players.

On 27 September the European Commission informed the International Skating Union (ISU) of its preliminary view that its eligibility rules under are in breach of EU antitrust rules.

The last blog of Leiden Law Blog of 2018 was written by Ladislav Kováč. He discusses the proposal for the Single-use Plastics Directive of the EU which was agreed upon on 19 December.

On 25-27 June the Academic Society for Competition Law (ASCOLA) organized its 15th yearly conference discussing the most recent developments in the context of competition law policy.

The new scholarly journal ‘Voetbal- & Sportjuridische Zaken’, published by Boom Juridische Uitgevers, will focus on current legal aspects related to sport with particular attention for football.

On 8 December 2017, the European Commission decided that the International Skating Union (ISU)’s eligibility rules, which impose severe penalties on athletes participating in speed skating competitions that are not approved by the ISU, are in breach of EU competition law.

On 24 October 2018, the European Competition and Regulatory Law Review (CoRe), the Computer and Communications Industry Association (CCIA) and the Vrije Universiteit Brussel jointly organized the second “Competition Policy and Online Markets” conference in Brussels.

Ben Van Rompuy was a guest speaker at the 138th Lunch Talk of the Global Competition Law Centre (College of Europe), which took place in Brussels on 15 January 2024.

On 10 January, Ben Van Rompuy spoke at the New Year's meeting of the Dutch Competition Law Association in Amsterdam.

Dr. Ben Van Rompuy participated as an invited expert in the annual Congress of the International League of Competition Law (LIDC), held this year in Vienna from 9 to 12 October.

LAPP student Heidi Kaarto and project leader Esther Kentin published an article on the right to regulate in relation to an EU ban on microplastics in a special issue on plastic regulation of Review of European, Comparative & International Environmental Law.

A team of students from Leiden and Groningen took the second prize at the European final of the BISC-E sustainability competition. Last June, the team had already won the Dutch finals. The students came up with ‘Suckerspheres’, a natural alternative to the plastic micro-particles that are still frequently…

Shortly before Remembrance Day, a new film was launched about the life and legacy of Ben Telders. Telders was professor of Dutch Law at Leiden University at the start of the Second World War; he was imprisoned in a concentration camp on account of of his protest against the Nazis.

In the Port of Rotterdam, tiny industrial pellets leak into the environment, causing a form of pollution that’s hard to trace but highly persistent. Three students of the LDE Sustainability Honours Programme took on the challenge to identify sources of this pollution.

Promotor: Prof.dr. M.K. Richardson, Co-Promotor: F. Witte

Evolutionary and ecological interactions affect species on genetic and phenotypic levels. This theme aims to understand these processes at multiple levels: from molecules to genomes to populations and to communities. Our research focuses on evolutionary responses to anthropogenic change, the role of…

Lecture, Studium Generale

The Grachtwacht (Canal Watch) conducts research on urban wildlife and the impact of plastic on nature. With our clean-ups, we not only collect waste, but also data. This way we try to find out the source of the waste and turn off the tap on shore. This way there is structurally less plastic in the c…

Below you will find an overview of the publications of The Leiden Advocacy Project on Plastic.

On Tuesday 2 April Vice President of the European Commission, Frans Timmermans, came to Leiden to receive the Plastic Avengers Manifest from Plastic Soup Surfer Merijn Tinga. The Manifest contains five key areas for a new approach to deal with how we use plastic.

This week, the cooperation between the Zwerfinator and Leiden University was in the news because of loose labels on deposit bottles. NOS news reported that the Zwerfinator submitted an enforcement request to the Inspectorate. The Leiden Advocacy Project on Plastic (LAPP) is supporting litter waste expert…

Mapping out the problem of plastic pollution requires a lot of data over a large area. That's why scientists are increasingly turning to volunteers for help, also known as citizen science. But what are the challenges for a researcher when he or she involves the public in research in this way? Four Leiden…

Former clients en projects

Plastics are an intrinsic part of our society. Annually, 400Mt of plastics are produced of which roughly 40% is discarded within a year.

Auke-Florian Hiemstra is the Leidsch Dagblad Person of the Year 2022.

The world is becoming clogged with plastic, with tiny plastic particles found everywhere, from the oceans’ depths to the mountain tops, soil, plants, animals and even inside us. The question is: what harm, if any, are they causing? In a new article on The Conversation, environmental scientists Meiru…