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2.2.12  Trifluralin  in  the  marine  environment  of  the  North  and  Baltic  Seas
Since  trifluralin  had  a  very  low  LOQ,  it  was  measurable  in  most  water,  sediment  and
fish  liver  samples  from  the  North  Sea  and  Baltic  Sea.  Concentrations  are  very  low  in
summer,  with  a  median  of  15  pg/L  for  water  samples,  10  ng/kg  dw  for  sediments  and
0.42  pg/kg  ww  for  fish  liver.  In  winter,  concentrations  in  water  are  about  10  times
higher.  This  can  be  explained  by  the  preferred  use  of  this  herbicide  as  a  pre-seed  agent
in  winter.  The  detected  trifluralin  concentrations  in  sea  water  are  considerably  lower
than  the  proposed  WFD  EQS  value  of  30  ng/L.
The  concentrations  found  demonstrate  that  trifluralin  is  stable  enough  in  the  marine
environment  of  the  North  Sea  and  Baltic  Sea.  Concentrations  are  highest  during  and
after  the  main  application  season  in  winter.  The  tenfold  lower  concentrations  in  summer
demonstrate  that  trifluralin  degrades  moderately  fast  in  the  (marine)  environment.  The
distribution  patterns  are  best  explained  by  a  general  diffuse  burden  (e.g.  by  atmospheric
deposition)  with  only  minor  local  sources.
Trifluralin  concentrations  in  the  river  Elbe  are  relatively  low  and,  consequently  its
influence  on  the  German  Bight.  Summer  concentrations  of  trifluralin  in  sea  water  are
above  those  of  the  classical  lipophilic  pollutants  such  as  HCB,  DDT,  PCBs  or  PAHs  but
below  those  for  HCHs.  In  winter,  levels  exceed  HCH  concentrations.  Therefore,  it  will
be  worthwhile  continuing  to  study  the  behaviour  of  trifluralin  in  marine  waters.
Compared  to  classical  pollutants,  trifluralin  concentrations  in  sediment  are  10  to  100
times  lower.  For  example,  HCH  isomer  concentrations  ranged  from  10  to  200  ng/kg  at
the  most  polluted  station  in  the  German  Bight  (KS  11).  The  more  lipophilic  DDD  and
CB153  were  in  the  range  of  1000  to  5000  ng/kg.  PAHs  such  as  benzo(a)pyrene  had
sediment  levels  between  40-240  pg/kg.
The  enrichment  factor  of  trifluralin  based  on  the  median  concentrations  in  water  and
fish  liver  is  28’000  (ww)  and  113’000  (lw),  respectively.  The  trifluralin  levels  in  biota
are  comparable  to  those  of  HCH  and  HCB,  but  lower  than  the  concentrations  of  DDTmetabolites
  and  PCB.  Typical  HCH  concentrations  in  the  German  Bight  varied  between