Plastic pollution | EPFL Graph Search

Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are categorized by size into micro-, meso-, or macro debris. Plastics are inexpensive and durable, making them very adaptable for different uses; as a result, manufacturers choose to use plastic over other materials. However, the chemical structure of most plastics renders them resistant to many natural processes of degradation and as a result they are slow to degrade. Together, these two factors allow large volumes of plastic to enter the environment as mismanaged waste and for it to persist in the ecosystem. Plastic pollution can afflict land, waterways and oceans. It is estimated that 1.1 to 8.8 million tonnes of plastic waste enters the ocean from coastal communities each year. It is estimated that there is a stock of 86 million tons of plastic marine

Marine transport of plastic fragments from dolly ropes used in demersal fisheries in the North Sea

Florence Marie Renée Cuttat

Dolly ropes (DR) are used in beamtrawling and other types of fishing to protect the nets from being ripped by the sea bottom. They constitute an important source of plastic pollution in the regions where this type of fishing prevails. The aim of this project is to assess spatially, quantitatively and qualitatively the extent of the pollution caused by this gear. For this, a hydrodynamic model will be created containing the following information: â¢ Hydrodynamic properties of the north sea. An already existing model will be used for this part. â¢ Spacial distribution of the free floating sampled DR. The coordinates of each DR sampled by Bastian Huwer will be inputted in the model to represent the actual spatial distribution of the DR. Additionally and if possible, some of the sampled DR will be analyzed with electron microscopy to allow qualitative dating of the object. The intensity of fishing using this gear will be spatially estimated to be inserted into the model as a source of DR pollution. â¢ Physical properties of the DR. The DR collected were weighed and measured. A laboratory experiment will be conducted to assess potential vertical distribution of the objects and the plastic composition and its properties will be assessed. â¢ Interaction with biosphere will be implemented into the model based on available literature.

2018

Pollution plastique dans les eaux suisses: caractérisation et quantification de leurs micropolluants

Colin Demars

Numerous researches showing various environmental impacts are done on marine plastic pollution. In turn the situation for superficial fresh water is poorly known. In order to measure this pollution in Switzerland three different lake samples (lake Geneva, lake Maggiore and lake Constance), beach samples and rejection pellets from limnic birds have been analyzed. The samples are divided into micro- (1-5mm) and macroplastics (>5mm). The plastic’s composition is the following: polyethylene (x̄=62 %, σ=15 %), polypropylene (x̄=21 %, σ=16 %), polystyrene (x̄= 8 %, σ=9 %), polymer mixes (x̄=5 %, σ=7 %), acetate cellulose (x̄=2 %, σ=3 %) and others (x̄= 2 %, σ=4 %). The concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), mirex, hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs), nonylphenol (NP) and bisphenol A vary between 1 – 6’000 ng/g, the one for phthalates ranges from 500 – 100’000 ng/g depending on the samples. Strong variations in micro pollutants are observed among the particles. Microplastics show higher concentrations than macroplastics. Furthermore surface water samples tend to have higher concentrations than the ones from beaches. The presence of these micropollutants at the measured doses does not directly respond to the question whether there is an eco-toxicological impact or not.

2014

Electrical spinal cord stimulation protocols to regulate neurological functions after spinal cord injury

Salif Axel Komi

Spinal cord injury (SCI) is a life-changing event. People who suffer from it lose their abilityto move normally and are subject to life-threatening symptoms. When the insult is not toosevere, partial recovery is possible. Otherwise, for severely affected people, the perspectives toever retrieve normal functions is almost non-existent. A critically important window to promoteplasticity is in the acute phase after the trauma (weeks to months). However, at this stage,people cannot take active part in rehabilitation programs due to their incapacity to activate theirlimbs and to the apparition of severe autonomic symptoms such as orthostatic hypotension.Hence, current activity-based treatments are of little help for this population. Consequently, SCIdramatically affects their autonomy and quality of life on the life-long term.Continuous Epidural Electrical Stimulation (EES) of the spinal cord has been proposed as amethod to reactivate dormant neural networks innervated below the site of injury. It enablesrobust control over locomotion and autonomic functions. In animal models of severe lesion,continuous EES promoted long lasting recovery of motor abilities when coupled with an intensivetraining. In human, its recent application indeed supported overground walking in chronicallyand severely injured people, but only showed limited plastic effects when compared to animals.Why? Recent advances support that continuous EES abolishes proprioceptive feedback thatis essential to promote recovery. Moreover, late treatment of severe injuries consistently fail apromoting recuperation of functions. Alternatively, over the last decade, our laboratory developeda spatio-temporally patterned approach to EES. In addition to restore fine control over motorfunctions, this technique avoids the caveats of continuous EES, and hypothetically opens a windowof opportunity for plasticity to happen. In this thesis, we propose a translation of this concept tohumans. We first demonstrate that spatio-temporal EES restores robust and versatile locomotorcontrol in people with chronic incomplete, though severe, SCI. Furthermore, the results supportan aptitude of this approach to promote long lasting recovery of functions without stimulationafter 5 months of intensive training. We then report on a patient-tailored technology, thatincludes personalized computational models enabling precise pre-operative planning strategies, anew electrode-lead and control softwares. This technology enables restoration of various motorfunctions in people with chronic and motor-complete injuries within few hours after beginningof therapy. Finally, we transfer this targeted approach to the control of blood pressure. Wedemonstrate that closed-loop stimulation protocols support a precise control over arterial bloodpressure in rodents, non-humane primates and humans with severe SCI submitted to challengingcardiovascular conditions. Combined, the results presented in this manuscript open a clinicallyrealistic perspective for the application of EES acutely after injury and to potentially promoterobust recovery in severe SCI.

EPFL2021

Electrical spinal cord stimulation protocols to regulate neurological functions after spinal cord injury

Salif Axel Komi

EPFL2021