Swimming's governing body FINA has insisted athletes are responsible for monitoring their own dietary supplements as it prepares to appeal a decision by Brazil not to sanction four swimmers who tested positive for a banned substance.
Brazil's world and Olympic freestyle champion Cesar Cielo was among the quartet who tested positive for the banned diuretic furosemide after the South American country's national championships in May.
The 24-year-old Cielo, Nicholas Santos, Henrique Barbosa and Vinicius Waked, all escaped censure from their national body, but FINA appealed that decision to the Switzerland-based Court of Arbitration for Sport (CAS).
CAS are to hear the appeal on July 20 at a special meeting in Shanghai, with its final decision due no later than July 22, just two days before the marquee pool competition begins.
Cielo, who won gold in the 50 and 100 metres freestyle at the 2009 Rome world championships and is the Olympic 50 metres freestyle champion, said the positive test had been caused by a supplement he took regularly that had become contaminated.
FINA executive director Cornel Marculescu, however, said while he did not want to comment directly on Cielo's case, it did highlight the fact that swimmers needed to be vigilant on what they were taking.
"As always, when you take a supplement you must be sure that you have done everything that the supplement does not contain any contamination by any kind of thing," Marculescu told reporters in the Oriental Sports Centre on Saturday.
"That is always the risk when you take supplements.
"You don't have to take supplements. In modern sports it is possible (to perform without them)."
FINA will undertake the normal urine testing on the more than 2,200 athletes attending the 14th edition of the biennial championships, but will also conduct random blood tests for substances like EPO (erythropoietin) and human growth hormone.
"I hope there are no doping tests I know we have very clean athletes," Marculescu said. "This (testing) is not something we just conduct in the championships... we test year round and this is one step in our fight against doping."
The championships opened in low-key fashion with FINA president Julio Maglione facing a virtually empty press hall with about 30 reporters sparsely dotted throughout an arena that could seat more than 200 as he made his official welcome speech.
Maglione then went on to highlight the "most extensive" broadcasting arrangements in place for the championships and the large media contingent who were expected to attend... "just not yet".
