What are the four methods used for water quality testing?Group of answer choicesDirect Reading ProbesSensory TestingColorimetric TestingBioluminescence RetractionLight Refraction DevicesLab-tested Samples

The four methods used for water quality testing are:

1. Direct Reading Probes: These are devices that are inserted directly into the water source. They provide immediate results and can measure a variety of water quality parameters such as pH, temperature, dissolved oxygen, and conductivity.

2. Sensory Testing: This method involves using the senses to assess water quality. For example, visual observations can detect cloudiness or color changes in the water, while smell can detect the presence of certain chemicals.

3. Colorimetric Testing: This method involves adding a reagent to a water sample that causes a color change. The intensity of the color change can then be measured to determine the concentration of a specific substance in the water.

4. Lab-tested Samples: This is the most accurate method of water quality testing. Samples of water are collected and sent to a laboratory where they are analyzed for a variety of parameters. This method can detect substances at very low concentrations and can also identify specific types of bacteria or other microorganisms.