A liter of water weighs a kilogram so 15 mg/kg = 15 ppm on a mass over mass basis. If that is the flavor of ppm you want, done. But ppm can also be computed on a volume basis, molar ratio, etc. It is better tio use a clear form with units that identifies the basis such as mg/kg.
Serena Williams knocked off Lucie Safarova in the final of the women's draw at the French Open, and Bovada has her listed as the clear favorite on the odds to win Wimbledon this year; Williams sits as the 7/4 chalk on those betting lines.
Serena Williams wins 6th Wimbledon title. LONDON -- Serena Williams let herself briefly bask in the joy of a sixth Wimbledon championship, 21st Grand Slam singles trophy overall and fourth consecutive major title Saturday, even balancing the winner's silver dish atop her head -- Look, Ma, no hands! -- as she sauntered off Centre Court.