2.2 Objectives
Since the beginning of the 2010s, research on plastic litter in continental environments has developed, even if it remains limited compared to work on the marine
environment. This research has revealed the widespread occurrence of plastic debris
in environmental compartments including the atmosphere [8] and food: salt [9],
possibly honey [10], mussels [11, 12] and also bottled water [13, 14]. These findings
have raised concerns about the human health effects of plastics [15] but also
receiving systems [16] and aquatic ecosystems [17, 18].
In 2013, the Leesu research unit launched a research project on microplastics in
urban hydrosystems, in partnership with the PIREN-Seine programme and the
Observatoire des Polluants Urbains en Ile-de-France (OPUR), which has expanded
to include the issue of macro-pollution by plastics. This project had several objectives, including (1) the estimation of macroplastic mass fluxes from Paris to the
mouth of the Seine and their dynamics and (2) the identification of the sources and
fluxes of microplastics at the scale of the Parisian Metropolis, from the atmosphere to
the Seine River and the assessment of its plastic contamination from the Paris
conurbation to its mouth.
2.3 Macroplastics in the Seine River
In contrast to microplastics, macroplastic pollution is highly visible. There is a need
to investigate the occurrence and dynamics of macroplastics, in order to implement
efficient multiscale reduction policies in the Marine Strategy Framework Directive
[19]. Various methods have been proposed recently [20, 21], based on waste
production and different leakage rates into the environment; these approaches have
the major interest to allow, relatively easily, for the estimation of estimating
macroplastic flux to the ocean at the global scale.
The evaluation of these methods on data collected in watersheds is obviously the
next step and is currently underway in the Seine River basin. A first rough attempt
estimated the yearly macroplastic mass fluxes between 1,000 and 10,000 metric tons
[22]. More recently, two conceptual modelling approaches, based on the data
available in the Seine catchment, have been implemented [23]. The first one
(CM1) was based on the extrapolation of the retention efficiency of a network of
floating booms installed by the Greater Paris Sanitation Authority since 1994, which
removes 27 tons of plastics yearly [24], accounting for 0.9–6.3% of the total mass of
debris. A significant proportion of these macroplastics consists of food wrappers and
containers and plastic cutlery, most likely associated with recreational activities.
The second approach (CM2), based on the Jambeck and Lebreton methodologies
[20, 21], has calculated the amount of mismanaged plastic waste (MMPW) at the
basin scale, of which 15% and 40% are assumed to be transferred to the English
Channel. MMPW is based on (1) the population (GIS data), (2) the economic level of
358
P. Labadie et al.
Since the beginning of the 2010s, research on plastic litter in continental environments has developed, even if it remains limited compared to work on the marine
environment. This research has revealed the widespread occurrence of plastic debris
in environmental compartments including the atmosphere [8] and food: salt [9],
possibly honey [10], mussels [11, 12] and also bottled water [13, 14]. These findings
have raised concerns about the human health effects of plastics [15] but also
receiving systems [16] and aquatic ecosystems [17, 18].
In 2013, the Leesu research unit launched a research project on microplastics in
urban hydrosystems, in partnership with the PIREN-Seine programme and the
Observatoire des Polluants Urbains en Ile-de-France (OPUR), which has expanded
to include the issue of macro-pollution by plastics. This project had several objectives, including (1) the estimation of macroplastic mass fluxes from Paris to the
mouth of the Seine and their dynamics and (2) the identification of the sources and
fluxes of microplastics at the scale of the Parisian Metropolis, from the atmosphere to
the Seine River and the assessment of its plastic contamination from the Paris
conurbation to its mouth.
2.3 Macroplastics in the Seine River
In contrast to microplastics, macroplastic pollution is highly visible. There is a need
to investigate the occurrence and dynamics of macroplastics, in order to implement
efficient multiscale reduction policies in the Marine Strategy Framework Directive
[19]. Various methods have been proposed recently [20, 21], based on waste
production and different leakage rates into the environment; these approaches have
the major interest to allow, relatively easily, for the estimation of estimating
macroplastic flux to the ocean at the global scale.
The evaluation of these methods on data collected in watersheds is obviously the
next step and is currently underway in the Seine River basin. A first rough attempt
estimated the yearly macroplastic mass fluxes between 1,000 and 10,000 metric tons
[22]. More recently, two conceptual modelling approaches, based on the data
available in the Seine catchment, have been implemented [23]. The first one
(CM1) was based on the extrapolation of the retention efficiency of a network of
floating booms installed by the Greater Paris Sanitation Authority since 1994, which
removes 27 tons of plastics yearly [24], accounting for 0.9–6.3% of the total mass of
debris. A significant proportion of these macroplastics consists of food wrappers and
containers and plastic cutlery, most likely associated with recreational activities.
The second approach (CM2), based on the Jambeck and Lebreton methodologies
[20, 21], has calculated the amount of mismanaged plastic waste (MMPW) at the
basin scale, of which 15% and 40% are assumed to be transferred to the English
Channel. MMPW is based on (1) the population (GIS data), (2) the economic level of
358
P. Labadie et al.