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.
The most women's Grand Slam titles of all-time is a record Serena Williams appears to be closing in on, following her latest dominant stretch of tennis. With Serena Williams' victory over Lucie Safarova in the French Open, she has moved into third place all-time for the most women's Grand Slam titles.