1 In general, the total dissolved solids concentration is the sum of the cations (positively charged) and anions (negatively charged) ions in the water.  Parts per Million (ppm) is the weight-to-weight ratio of any ion to water.
If you refrigerate the rice, and you want to eat it cold, its perfectly fine. People eat cold rice salads all the time. Cold rice pudding is fine. Its just sitting around at room temperature that is the problem.
You can add a bunch of water to your cooked rice and cook it again, then you can add things like left over chicken, spinach, eggs, really whatever is laying around the fridge and you can make a nice porridge that is especially warming in these cold months.