For example, the decomposition of a deer or squirrel carcass in the forest produces some ammonia — and so does the decay of a fallen tree.
Most ammonia in the soil accrues as bacteria break down organic matter. Forest fires, human and animal waste, nitrogen fixation processes, and gas exchanging with the atmosphere can also result in the formation of ammonia. Ammonia exists in either one of two forms. The form ammonia takes in water is highly dependent on the temperature and pH level of the water. Warmer water will contain more of the un-ionized form and less of the ionized form than colder water, as will water with a higher, less acidic pH.
The un-ionized form of ammonia is the one that can be toxic to some forms of life. The ammonium ion does not have the same toxic properties. So, what causes high ammonia levels in water? Ammonia most often comes from agricultural fertilizers and industrial process wastes that contain ammonia that gets into surface water in runoff.
And what is the normal level of ammonia in water? Higher natural levels of up to three milligrams per liter, though, are often found in forests or areas with substantial iron deposits. Surface waters may naturally contain up to 12 milligrams per liter. Higher levels than these can disrupt delicate aquatic ecosystems. In water, some ammonia breaks down to form the ammonium ion plus hydroxide ions.
Ammonia is toxic to aquatic life, but ammonium ions are not. Generally, in water, an equilibrium exists between these two types of ammonia, and molecules change back and forth between the two states depending on pH and water temperatures. At the acidic pH of 6, for instance, the ratio of ammonia to ammonium is about 1 to At the basic pH of 8, that ratio declines sharply to 1 to Warm water also tends to contain more toxic ammonia than cooler water.
Ammonia in water is non-toxic to humans, but it is toxic to aquatic life. Unlike other forms of nitrogen, which can indirectly harm aquatic ecosystems by increasing nutrient levels and promoting algae growth in the process known as eutrophication, ammonia has direct toxic effects on aquatic ecosystems.
Aquatic plants can absorb ammonia and incorporate it into some of the molecules of their structures, such as proteins and amino acids. Once aquatic organisms have absorbed it, it is challenging for them to excrete ammonia from their systems. It tends to build up in their tissues and blood until it kills them. For example, freshwater unionid mussels are highly sensitive to ammonia in water, as are freshwater gill-breathing snail species , along with many other invertebrates, fish, and plants.
Additionally, high levels of ammonia in lakes and streams can promote the growth of algae, which in turn can choke out the growth of other aquatic plants. Bacteria can also convert ammonia in water to nitrate in a process known as nitrification.
Nitrification is a beneficial process if it takes place in the soil — plants can use the produced nitrates as food. However, nitrification tends to lower the dissolved oxygen levels in water, making it harder for fish and other aquatic life to breathe.
Ammonia in drinking water can sometimes create an unpleasant taste and smell, which is caused by the formation of chloramines , which the addition of ammonia helps promote. Chloramines form when both chlorine and ammonia are added to drinking water to disinfect it. However, ammonia is not thought to be toxic to human health at the levels found in drinking water.
Water that has become contaminated with fertilizer, chemical runoff, or animal waste may also contain increased levels of ammonia. Because of its lower toxicity to humans, the U.
Environmental Protection Agency EPA has not set a standard upper limit for ammonia in public water sources. Brown has a Ph. Ingredients in Carburetor Cleaners. What Is Urethane? Isopropanol Alcohol Vs. Isopropyl Alcohol. How to Mix Ammonia with Glycerine. Sodium Carbonate Vs. Sodium Bicarbonate. About Bleach Neutralizers.
Disposal of Boric Acid. Test for Benzene. Toxicity of Household Bleach. S3 in Guo, et al. S1 , which were not carried out by Wang, et al.
When carrying out such an evaluation Fig. Comparing measured and predicted particle-phase fractions e. Cheng, et al. The approach for generating the contour plots of Fig. The equilibrium concentrations of various components e. Data for the contour plots are generated by varying sulfate from 0. The calculation of the sensitivity lines in Fig.
Fang, T. Guo, H. Fine particle pH and the partitioning of nitric acid during winter in the northeastern United States. Longo, A.
Gwynn, R. A time-series analysis of acidic particulate matter and daily mortality and morbidity in the Buffalo, New York, region. Environmental Health Perspectives , — Jang, M. Heterogeneous atmospheric aerosol production by acid-catalyzed particle-phase reactions. Meskhidze, N. Iron mobilization in mineral dust: Can anthropogenic SO 2 emissions affect ocean productivity? Seinfeld, J. Wang, G. Persistent sulfate formation from London Fog to Chinese haze.
Cheng, Y. Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China. Katoshevski, D. A study of processes that govern the maintenance of aerosols in the marine boundary layer. Stockdale, A. Understanding the nature of atmospheric acid processing of mineral dusts in supplying bioavailable phosphorus to the oceans.
Hanisch, F. The heterogeneous reactivity of gaseous nitric acid on authentic mineral dust samples, and on individual mineral and clay mineral components. Dust and pollution: A recipe for enhanced ocean fertilization?
ADS Google Scholar. Fountoukis, C. Cruz, C. The effect of dioctyl phthalate films on the ammonium nitrate aerosol evaporation rate. Dassios, K. The mass accommodation coefficient of ammonium nitrate aerosol.
Fine particle pH and gas—particle phase partitioning of inorganic species in Pasadena, California, during the CalNex campaign. Fine-particle water and pH in the southeastern United States. Tian, S. Size-resolved aerosol chemical analysis of extreme haze pollution events during early in urban Beijing, China.
Weber, R. High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years. You, Y. Atmospheric amines and ammonia measured with a chemical ionization mass spectrometer CIMS. Puchalski, M. Bougiatioti, A. The unappreciated effects of biomass burning on fine mode aerosol acidity, water and nitrogen partitioning.
In review Particle water and pH in the Eastern Mediterranean: Sources variability and implications for nutrients availability. Zou, Y. Arctic sea ice, Eurasia snow, and extreme winter haze in China. Nenes, A.
Stumm, W. Xu, L. Effects of anthropogenic emissions on aerosol formation from isoprene and monoterpenes in the southeastern United States. Hennigan, C. A critical evaluation of proxy methods used to estimate the acidity of atmospheric particles.
Download references.
0コメント