Nitrates are organic compounds that consist of one nitrogen atom and three oxygen atoms. We consume nitrates everyday in meats and vegetables. Groundwater, our drinking water, typically has a nitrate concentration less than 2mg/L, which is safe for consumption. If nitrate levels rise above 2mg/L, the water is considered harmful to humans and wildlife because it can cause nitrate poisoning.
Often caused by fertilizer runoff, excessive nitrates seep into our drinking water. Because Florida has extensive waterfront property, it is common for rain to wash landscape fertilizer from yards directly into waterways. Nitrates are not only tied to fertilizer, however, as they also increase in concentration due to leakage from wastewater, landfills, and septic systems.
Increased nitrate levels can cause methemoglobinemia, or “blue baby” syndrome (BBS). In BBS, high nitrate levels (from contaminated water) decrease the amount of hemoglobin transporting oxygen throughout the body. Without sufficient oxygen, the baby turns blue. Due to frequent water quality monitoring, this syndrome is not common, but it given enough reason to constantly regulate nitrate levels in drinking water. When nitrate levels increase in nearby waterways, it signals the presence of contaminants and the overall decrease in water quality.
While regulating nitrates, scientists also seek to regulate pH because the two go hand in hand. Scientists use pH to determine if solutions, like water, are acidic, basic, or neutral. Higher nitrate concentrations can lower the pH, making the water more acidic.
Most aquatic life can only tolerate a pH from 6-9, but if pH fluctuates out of this range, it could signal either a change in nitrate concentration or a change in dissolved carbon dioxide concentration. (See the chart above to see where household objects fall on the pH scale.) Even a slight change in pH can be devastating for marine life.
Strong acids have the potential to burn or melt through metals. Imagine what would happen to an ocean if it became too acidic. It wouldn’t be a pretty sight (and would probably feel even worse to the fish!). Even if a larger fish could survive a change in pH, the microorganisms wouldn’t be able to adapt to the changes. Without these microorganisms, a domino effect takes place where animals all along the food chain begin to suffer the consequences. pH can fluctuate from acid rain; the more acid rain, the more dissolved carbon dioxide (CO2), and the lower the pH becomes. (Acid rain is precipitation with acidic components, such as sulfuric or nitric acid.)
Both pH and nitrate levels are critical for determining water quality. Constant measuring and record keeping reveals trends in values and the effects of human actions. Generally speaking, a healthier body of water is one where pH and nitrate levels are close to its natural state. Save Crystal River works tirelessly each week to restore the Crystal River water quality, but they can’t do it alone. It is also up to us to be good stewards and to practice safe fertilizing. Crystal River, like all waterways near populated areas, needs our help to restore and maintain its natural state.
I’ll see you on the water,
Walker A. Willis
Nitrate Chart: Beta Analytic Inc.
pH Scale: Science News for Students