Microbiological Hygienic Quality of Playground Sand

Wolfgang Kohnen1, Susanne Teske-Keiser1, Rainer Arneth2, Lothar Wendel2, Dieter Kopp3, Harald Mayer2, and Bernd Jansen1

1 Department of Hygiene and Environmental Medicine, Johannes Gutenberg University of Mainz, Mainz, Germany
2 Public Health Authorities Wiesbaden, Wiesbaden, Germany
3 Office for Green Areas, Agriculture and Forests, Wiesbaden, Germany

Corresponding author: Dr. W. Kohnen
    Department of Hygiene and Environmental Medicine
    Johannes Gutenberg University of Mainz
    Hochhaus Augustusplatz
    D-55131 Mainz, Germany
    Telephone: +49-6131-3933159
    Fax number: +49-6131-3936628
    E-mail address: kohnen@mail.uni mainz.de

Key words:
Playground, sand, E. coli, sand exchange, cleaning procedures

CEJOEM 2002, Vol.8. No.4.: 289–297

In the period of March to October 1998, sand samples from 40 playgrounds in the city of Wiesbaden (centre and suburbs) were investigated in order to assess the microbiological hygienic quality of the sand in sand boxes before and after complete removal of the sand, manual cleaning or machine-assisted cleaning and to compare the effectiveness of the various procedures. Total colony count and detection of E. coli, other Enterobacteriaceae (coliforms) and nematodes’ ova were performed. In the case of E. coli, their ability to produce Shiga-like-toxin (SLT), and thus the presence of enterohemorrhagic E. coli (EHEC) strains, were examined. Furthermore, the presence of benzo-a-pyrene was assessed in sand samples from 20 playgrounds. Immediately after complete exchange of sand and after manual cleaning, the total colony count dropped, whereas after machine-assisted cleaning this was not observed. However, at the end of the investigation period the total colony count and detection rate of E. coli and coliforms were similar for all three procedures. Interestingly, ova from Ascaris could only be detected when complete sand exchange had been performed. No EHEC strains or benzo-a-pyrene above the detection level were found in any of the samples. In conclusion, complete exchange of sand once per year is no absolute requirement. Regular aeration of sand and removal of organic debris, either manually or machine-assisted, is of greater importance for maintaining specific levels of microbiological hygienic quality.

Received:  30 July 2002
Accepted:  17 December 2002

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