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Fecal pollution events reconstructed and sources identified using a sediment bag grid
Author(s) -
Nix P. G.,
Daykin M. M.,
Vilkas K. L.
Publication year - 1994
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/wer.66.6.8
Subject(s) - sanitary sewer , environmental science , pollution , sampling (signal processing) , plume , hydrology (agriculture) , sediment , combined sewer , fecal coliform , water pollution , stormwater , contamination , storm , environmental engineering , water quality , surface runoff , ecology , geology , geography , engineering , paleontology , oceanography , geotechnical engineering , filter (signal processing) , meteorology , electrical engineering , biology
Conventional microbiological surveys, relying on periodic sampling of the water column, were unable to identify sources of fecal contamination at a local beach in North Vancouver, B.C., Canada. Many sources of human and/or animal wastes to the cove were evident (for example, storm sewers, animal feces on the beach, urban streams, discharges from boats, leaking sanitary sewers) but it was not possible to identify any one source as the cause of the pollution by sampling the water column since the contaminant source was likely episodic (that is, discharging for only brief periods). It was unlikely that any conventional sampling survey would coincide with a pollution event and thereby reveal a pattern of contamination. As a result, a novel sampling strategy was devised using sediment bags (porous bags filled with sand) suspended from buoys and deployed in a grid pattern around the beach. The sand in these bags accumulated fecal bacteria during pollution events and retained them long enough so that they could be analyzed during weekly sampling surveys; in this way, the true pattern of the pollution plume was documented and the source was revealed. Results from an analysis of the sediment bag grid indicated that storm sewers were the principal contaminant sources. The subsequent clean‐up was inexpensive compared with other proposed remedies (for example, diversion of urban creeks, replacement of sanitary sewers).