Why is pH significant in surface water quality?

pH is a crucial factor in surface water quality primarily because it influences nutrient availability and pollutant toxicity. The pH level of water affects the solubility and chemical form of many nutrients, such as nitrogen and phosphorus, which are vital for aquatic plants and algae. When pH is too low (acidic) or too high (alkaline), it can hinder the availability of these essential nutrients, potentially leading to poor plant growth and alterations in the ecosystem.

Moreover, pH significantly impacts the toxicity of various pollutants. Many harmful substances, such as heavy metals and pesticides, can become more toxic to aquatic life at specific pH levels. For instance, certain metals may dissolve more readily in an acidic environment, increasing their bioavailability and toxicity to organisms. Therefore, maintaining a balanced pH is essential for ensuring the health of aquatic ecosystems, as it governs both nutrient dynamics and the potential risks posed by pollutants.