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addition,fiberscomingfromdryweatheratmosphericfalloutcouldbere-suspended
bywindorwashedduring the roadsandstreets cleaning, limiting theaccumulation
between two rain events.
While only fibers were detected in atmospheric fallout, runoff contained also
fragments. It suggests that fibers can be transported by air, while the larger
fragments seem to fall directly on surfaces and wait to be transported by the
urban runoff, if not cleaned by road cleaning services.We can suppose that the
fragmentsstemfromthedegradationof largerdebris,but thishypothesisstillneeds
verification.
WWTPs were also studied as potential sources ofMPs. Fibers were found in
washing machine effluents and consequently in wastewater. Mechanisms and
dynamics thatfibersundergo insideof a sewage systemareup tonownot reported
in the literature. The roughly estimated flux of fibers enteringWWTPs lies in the
same range as the amounts supposedly discharged by washing machines. The
estimation range is however large and fluxes could be potentially lower. Because
the transport duration in the sewer systems is probably short (max. 48–72 h), it is
considered that no fragmentation occurs. On the other hand, a sedimentation
process during dry weather periods in the sewage network is possible. WWTP
effluentsareperhaps themost investigatedsources to thereceivingsystems.For the
differentParisianWWTPs, theestimatednumberofMPfibersevenwitharemoval
of fibers between 80 and 95% is higher than the fibers coming from atmospheric
fallout.TheWWTPeffluentsseemtobethemajorsourceoffibers incomparisonto
otherMPs.
In contrast, CSOs contain both high fragments and fiber concentrations. It
appears that CSOs are themain andmajor input ofMP fragments into the fresh-
water.Moreover, the fact that it presentsconcentrationsoffibers sometimeshigher
than wastewater tends to confirm a re-suspension of sewer deposits during wet
weather periods.
The knowledge on the various dynamics and mechanisms of MPs in urban
catchments is still very coarse. For instance, conditions driving the fibers suspen-
sion, the aerial transport, and the fallout processes are unknown. If some sources
andfluxes have been identified, it is necessary to compare the results obtained on
theParisMegacity onother case studies all over theworld.
4 MonitoringMicroplastics in theRiverSeine
4.1 Overviewof theApproach
Inapreliminarystudypublishedatearlystagesof thiswork,wetested twodifferent
meshsizenets tosample theriverSeine[18]. Ithighlighted thedifferencesbetween
asmall (80μm)andalargermeshsize(330μm).Fibersarehighlyconcentratedand
78 R.Dris et al.
Freshwater Microplastics
Emerging Environmental Contaminants?
- Titel
- Freshwater Microplastics
- Untertitel
- Emerging Environmental Contaminants?
- Autoren
- Martin Wagner
- Scott Lambert
- Verlag
- Springer Open
- Datum
- 2018
- Sprache
- englisch
- Lizenz
- CC BY 4.0
- ISBN
- 978-3-319-61615-5
- Abmessungen
- 15.5 x 24.1 cm
- Seiten
- 316
- Kategorien
- Naturwissenschaften Chemie