Seite - 137 - in Freshwater Microplastics - Emerging Environmental Contaminants?
Bild der Seite - 137 -
Text der Seite - 137 -
measured concentrations include both primary and secondary plastics (i.e., pro-
duced and fragmented/weathered particles, respectively), whereas themodel only
includedprimaryplastics,whichmayhave interferedwith the reportedvalidation.
Current knowledgeon theuseof nano- andmicroplastics in consumerproducts
is limited, soagenericapproachwithmanyassumptionswasused in thismassflow
modeling study, contrastingwith the approaches usedwithmore advancedmulti-
mediamassbalancemodels, lifecycleperspectivemodels,orprobabilisticmaterial
flow models. More reliable data to feed the models are needed to improve the
emission estimates [90].
4.2 GlobalRiverModels
Riverpollution isaworldwideproblem.Humanactivitieson the landpollute rivers
in all continents.Anumber of global river pollutionmodels exist. One of these is
the Global NEWS (Nutrient Export fromWaterSheds) model [101, 102]. Global
NEWS is a model that calculates river export of nutrients from land to sea as a
function of human activities on the land.GlobalNEWS includesmore than 6,000
riverbasinsusinghydrologyfromthewaterbalancemodel [103]. Itcalculates river
exportat the rivermouth.Themodel input ismostlyonagridof1degree longitude
by 1 degree latitude. It has been used to simulate trends in river pollution for the
period1970–2050, taking intoaccount change in landuse, foodproduction,urban-
ization, and hydrology [103–105]. Results indicate that over time, most rivers
worldwidebecomemorepolluted.
Global river exportmodels for nutrients, likeGlobal NEWS, have been under
developmentformorethan20years.Forotherpollutantsglobalriverexportmodels
donot have such a longhistory.As a result, theGlobalNEWSapproachhas been
takenasanexampleandinspirationforotherpollutants [44].Nutrients inriverscan
havepointsources(e.g.,pipesdrainingintotheriver)ordiffusesources(e.g., runoff
fromsoilsoratmosphericdeposition[65]).This is thecasefornutrients,butalsofor
other pollutants, like plastic debris. Model structures for point sources of one
pollutant can easily serve as an example for other pollutants. The same holds for
diffuse sources.
A river exportmodel formicroplastics, inspiredby theGlobalNEWSmodel, is
currently under development (Table 1). Preliminary results for point source inputs
of microplastics to European seas have been presented [91]. This plastic model
calculatespoint source inputsofmicroplastics fromsewage to rivers. Inaddition, it
simulates river transport of microplastics as a function of population, sewage
connection, wastewater treatment, and river retention. River retention is derived
from [36]. First results indicate that car tires are important point source inputs of
microplastics inEuropean rivers.
Modeling theFate andTransport of PlasticDebris inFreshwaters:Reviewand. . . 137
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