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.
7:40 p.m. Three-time Wimbledon champion Novak Djokovic lost the first set of his third-round match against Sam Querrey 7-6 (6). Djokovic, a two-time defending champion at the All England Club, has won four straight major titles and is halfway to a calendar-year Grand Slam.