Sharon van Rouwendaal of the Netherlands, undaunted by tainted water and crashing surf, romped to the women's 10km marathon swimming gold medal at the Rio Olympics on Monday.

Van Rouwendaal slapped the finish marker off the shore of picturesque Copacabana beach in 1hr 56min 32.1sec. 

Aurelie Muller of France crossed the line second but was disqualified with silver going to Italy's Rachele Bruni -- 17.4sec back with Brazil's Poliana Okimoto snaring bronze 19.3 seconds off the lead.