A Survey of Diving Behavior and Accidental Water Ingestion among Dutch Occupational and Sport Divers to Assess the Risk of Infection with Waterborne Pathogenic Microorganisms

Article excerpt

Divers may run a higher risk of infection with waterborne pathogens than bathers because of more frequent and intense contact with water that may not comply with microbiologic water quality standards for bathing water. In this study we aimed to estimate the volume of water swallowed during diving as a key factor for infection risk assessment associated with diving. Using questionnaires, occupational and sport divers in the Netherlands were asked about number of dives, volume of swallowed water, and health complaints (nausea, vomiting, diarrhea, and ear, skin, eye, and respiratory complaints). Occupational divers, on average, swallowed 9.8 mL marine water and 5.7 mL fresh surface water per dive. Sport divers swallowed, on average, 9.0 mL marine water; 13 mL fresh recreational water; 3.2 mL river, canal, or city canal water; and 20 mL water in circulation pools. Divers swallowed less water when wearing a full face mask instead of an ordinary diving mask and even less when wearing a diving helmet. A full face mask or a diving helmet is recommended when diving in fecally contaminated water. From the volumes of swallowed water and concentrations of pathogens in fecally contaminated water, we estimated the infection risks per dive and per year to be as high as a few to up to tens of percents. This may explain why only 20% of the divers reported having none of the inquired health complaints within a period of 1 year. It is highly recommended that divers be informed about fecal contamination of the diving water. Key words: Campylobacter, divers, enteroviruses, risk of infection, volume of water. doi:10.1289/ehp.8523 available via http://dx.doi.org/ [Online 16 February 2006]


Exposure to waterborne pathogens in surface water may lead to health complaints among recreants such as bathers, divers, surfers, kayakers, and anglers. In the Netherlands, because of discharges of raw and treated sewage and manure runoff from agricultural land, pathogenic microorganisms may enter surface waters (e.g., Lodder and de Roda Husman 2005; Schijven et al. 2004; Van den Berg et al. 2005). Swallowing this water may lead to infection, which may lead to symptoms such as nausea, fever, and diarrhea or more severe illness. Campylobacter species and waterborne viruses are of major importance in that respect (de Roda Husman 2001; Schijven 2003). In addition, there are pathogens indigenous to surface water, such as Pseudomonas aeruginosa, Vibrio, amoebae, and cyanobacteria. In the Netherlands, skin complaints, followed by gastrointestinal complaints, were reported most often among water recreants (Leenen and de Roda Husman 2004; Schets and de Roda Husman 2004). Skin complaints were especially ascribed to cercaries and cyanobacteria. In 1994 and 1995, ear complaints caused by P. aeruginosa (otitis externa) were important incidents in the Netherlands involving large numbers of patients (Van Asperen et al. 1995).

Water-associated health complaints may occur despite the fact that the microbiologic quality of the bathing water complies with European Union (EU) Directive 76/160/EEC (1976), which sets limits for fecal indicator bacteria and is primarily aimed at protecting the bather against gastrointestinal complaints and acute febrile respiratory illness, but not against eye, skin, and ear complaints. Epidemiologic studies have demonstrated that these legal standards protect bathers insufficiently (Kay et al. 1994; Van Asperen et al. 1998; Wiedenmann et al. 2006). The proposed new EU bathing water directive COD 2002/0254 (2002) aims to better inform the water recreants on the risks of bathing by means of bathing water profiles. This proposed directive also addresses the fact that water activities other than bathing, such as diving, surfing, and kayaking, have strongly developed since 1976. Divers, surfers, and kayakers may be exposed to a greater extent to waterborne pathogens than are bathers because of more often and longer contact with surface water that need not be recreational water and that may be more fecally contaminated than are recreational waters. …