What are the four methods used for water quality testing? (Select all that apply.)Group of answer choicesDirect reading probesLab-tested samplesBioluminescence retractionSensory testingLight refraction devicesColorimetric testing

The four methods used for water quality testing are:

1. Direct reading probes: These are devices that can be inserted directly into the water source to get real-time readings of various parameters like pH, temperature, turbidity, etc.

2. Lab-tested samples: This is the most accurate method of water testing. Samples of water are collected and sent to a laboratory where they are tested for various contaminants and parameters.

3. Sensory testing: This is a basic method of water testing where the taste, smell, and appearance of the water are evaluated.

4. Colorimetric testing: This method involves adding a reagent to a water sample and then comparing the color of the sample to a standard color chart. The color that the sample turns indicates the concentration of the substance being tested.