What is the equivalent of 4 PPM in mg/L?

The conversion between parts per million (PPM) and milligrams per liter (mg/L) is straightforward, as they are equivalent in water-based solutions. This equivalence is because 1 PPM is defined as 1 milligram of substance per liter of water.

Therefore, when you have a concentration of 4 PPM, it directly translates to 4 mg/L. This means that for every liter of solution, there are 4 milligrams of the dissolved substance present.

Understanding this equivalence is essential for interpreting concentrations in environmental science and wastewater management, where measurements often rely on these units. The other options do not represent accurate conversions from PPM to mg/L, making them unsuitable in this context.