Animal Waste, Water Quality and Human Health

Exposure 263contact activities, the whole body, including the head is intentionally immersedin the water or wetted by spray. Hence, it is likely that some water will beswallowed (WHO 2003). The most common primary-contact activity isswimming, which includes related actions such as diving or jumping into thewater. Other common examples are wading, surfing, water-skiing, windsurfing,scuba-diving and snorkelling. White-water sports such as canoeing, kayaking,tubing and rafting are also considered to fit in this category. In secondary orincidental contact activities only the arms and legs are intentionally exposed, andgreater contact is unusual (WHO 2003). Examples of secondary-contact activitieswould be rowing, canoeing or kayaking; power boating and fishing. Anotherimportant consideration for the discussion of recreational contact relates to thelocation of potential exposures. Swimming activities occur near shorelines andthus users may be located in closer proximity to contamination inputs. Otheractivities like waterskiing or surfing can have immersion exposures that occur atsignificant distances from shore. Secondary contact activities such as recreationalboating or canoeing may allow bathers to access possibly more polluted watercloser to the source of contamination.Drinking-water exposures in developed countries would be largely restrictedto instances where livestock-contaminated source waters were untreated orincompletely treated prior to human consumption.In developing countries, contact circumstances can be expected to be entirelydifferent from the developed world. Numbers published by the WHO andUNICEF suggest that as of 2000, 1.1 billion people lacked basic access to awater supply within 1 kilometre of their home (Howard & Bartram 2003). Inpoor rural communities water resources can be shared by multiple householdsand would support a variety of sanitary or hygienic and household uses.Expected water contact activities would be bathing and laundering, and otheruses such as drinking or handwashing may also occur if there is inadequatehousehold access to water (Howard & Bartram, 2003). It is also expected that incertain countries a greater number of exposures may arise through occupationalcircumstances. Examples include domestic farmers working in rice paddies, andmilitary personnel on manoeuvres in rural areas. Rescue workers providingrelief in floodwaters produced by natural disasters are a noteworthy example ofoccupational exposure created by unpredictable circumstances. This scenariowould have importance in both the developing as well as the developed world.In interpreting the degree of water exposure associated with this range ofactivities, it is possible that the WHO contact definitions can also be appliedhere. For the examples described, bathing might be considered a primarycontactactivity, while laundering and occupational exposures may be morerepresentative of secondary contact.