MSGID: 1:317/3 647eb678   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    River diversions may cause microplastics to remain longer on land and in   
   streams before reaching oceans    
      
     Date:   
         June 5, 2023   
     Source:   
         University of Birmingham   
     Summary:   
         Diverting streams and rivers to irrigate crops or provide drinking   
         water may significantly extend the time microplastics spend in river   
         catchments before they flow into our oceans, a new study reveals.   
      
      
         Facebook Twitter Pinterest LinkedIN Email   
      
   ==========================================================================   
   FULL STORY   
   ==========================================================================   
   Diverting streams and rivers to irrigate crops or provide drinking water   
   may significantly extend the time microplastics spend in river catchments   
   before they flow into our oceans, a new study reveals.   
      
   Publishing their findings in Water Research, an international group of   
   scientists led by the University of Birmingham, highlight the impact of   
   water management in terms of river diversions for irrigation purposes   
   on microplastic transport.   
      
   These diversions can have significant impact on the estimates of the   
   pollutant's flow towards our oceans, with the diverted water from rivers   
   dispersing the tiny plastic particles across farmland from where they   
   may be flushed back into other watercourses or neighbouring catchments.   
      
   The research team studied two paired rivers in Colorado, United States --   
   the Boulder Creek and its less urbanised tributary South Boulder Creek   
   - - evaluating the effects of urbanisation and flow diversions on the   
   up-to- downstream profiles of local microplastic concentrations as well   
   as microplastic loads, indicating the flow-weighted downstream transport   
   of particles.   
      
   The researchers found that microplastic concentration patterns in both   
   rivers were related to the degree of catchment urbanisation: Data from   
   both streams suggests a link between microplastic concentration and   
   urbanisation, as microplastic concentrations in Boulder Creek with a   
   more urbanised catchment were higher in both surface water and sediment   
   than in South Boulder Creek, and microplastic concentration increased   
   in downstream direction when passing more urbanised areas.   
      
   Lead author Anna Kukkola, from the University of Birmingham, commented:   
   "We discovered strong links between the degree of urbanisation in   
   the river catchment and observed river microplastic concentrations,   
   highlighting how human activities resulted in immediate increase in   
   microplastics in this mountainous catchment.   
      
   "A key novelty of this study is the application of the loading approach   
   which is used here for the first time for the quantification of   
   microplastics fluxes and enabled us to not only identify microplastic   
   sources but also determine the downstream evolution of microplastic   
   transport patterns and in this case also the diversion of microplastics   
   out of the river catchment."  Co-author Rob Runkel, from the United   
   States Geological Survey, added: "These results for microplastics are   
   consistent with our results for other urban- derived elements such as   
   chloride, where we are seeing 3 to 9 times more loading in the more   
   urbanized Boulder Creek watershed."  The international team furthermore   
   discovered that the magnitude of flow diversions from both streams   
   resulted in large quantities of microplastic being removed from each   
   stream and being transported out of their actual catchment.   
      
   They measured microplastic removal through flow diversions of over 500   
   microplastic particles per second (or 1,800,00 per hour) from the two   
   rivers studied.   
      
   To put this into perspective: In 2012, 241 km3 of water were diverted   
   for agricultural purposes in North America alone with 2,670 km3 having   
   been diverted globally. By using conservative estimates based on the >63   
   mym particle threshold of their study, the researchers estimated that   
   this could result in around 41 trillion microplastic particles being   
   redistributed out of river networks into the terrestrial environment in   
   North America every year, with as many as 459 trillion particles being   
   redistributed globally.   
      
   Co-author and Principal Investigator Professor Stefan Krause, from the   
   University of Birmingham, commented: "How we manage our streams and rivers   
   can have a substantial impact on the transport of microplastics, yet   
   these effects have not been incorporated into global models that assume   
   downstream convergence of microplastic fluxes along river networks. Our   
   current models may, therefore, underestimate the quantities and residence   
   times of plastics held in river catchments and overestimate the speed with   
   which microplastics are transported into our oceans."  While toxicity   
   assessment was not a focus of the current study, co-author Professor   
   Iseult Lynch from the University of Birmingham noted: "The results of   
   this study are highly relevant for estimating ecotoxicological impacts   
   on aquatic and terrestrial environments and ecosystems, with enhanced   
   terrestrial residence times resulting in extended (chronic) exposures."   
       * RELATED_TOPICS   
             o Earth_&_Climate   
                   # Water # Floods # Geography # Atmosphere #   
                   Ecosystems # Drought_Research # Environmental_Policy #   
                   Environmental_Issues   
       * RELATED_TERMS   
             o River o Estuary o Levee o Rain o Ocean_current o   
             Water_pollution o Water_scarcity o Glacier   
      
   ==========================================================================   
   Story Source: Materials provided by University_of_Birmingham. Note:   
   Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Anna Kukkola, Robert L. Runkel, Uwe Schneidewind, Sheila F. Murphy,   
      Liam   
         Kelleher, Gregory H. Sambrook Smith, Holly Astrid Nel, Iseult   
         Lynch, Stefan Krause. Prevailing impacts of river management   
         on microplastic transport in contrasting US streams: Rethinking   
         global microplastic flux estimations. Water Research, 2023; 240:   
         120112 DOI: 10.1016/ j.watres.2023.120112   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/06/230605181333.htm   
      
   --- up 1 year, 14 weeks, 10 hours, 51 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 153/7715 218/700 226/30 227/114   
   SEEN-BY: 229/110 112 113 307 317 400 426 428 470 664 700 291/111 292/854   
   SEEN-BY: 298/25 305/3 317/3 320/219 396/45   
   PATH: 317/3 229/426