Animal Waste, Water Quality and Human Health

448Animal Waste, Water Quality and Human Healththan 30 per cent of the investigated sites: wastewater from combined stormwateroverflow (CSO), wastewater discharge from boats and marinas, bathers and pets atbeaches, and bird colonies near recreational bathing locations. The last column inTable 12.2 shows the number of recreational bathing locations where specificsources of pollution can not be excluded as a determining factor, because it is notpossible to prove that they are non-existent. For instance, untreated sewerage can beshown to be a determining factor at one third of all the locations investigated, andcannot be excluded as a determining factor at two-thirds of the locations.Table 12.2 Results from the assessment of sources of pollution of bacteriologicalcontamination at a random sample of bathing sites in the Netherlands.Source of pollution# bathing locationswhere the source wasproven to be a factorof influence# bathing locationswhere the source couldnot be excluded as afactor of influenceDischarge of untreated1 2sewerageCSO without7 4measuresCSO with measures 0 3Insufficiently treated1 2discharge from WWTPManure from farm 0 1Manure from agricultural0 2landManure from cattle0 2drinking at water sideWastewater discharge at6 5marinasWastewater discharge9 3from recreationalboatsWastewater discharge3 2from commercial shipsPets in water or at6 8bathing water locationBathers 12 7Bird colonies at or near9 7bathing locationLarge international rivers 1 0Source: Brouwer & Bronda (2005).