Phosphates may be created by substituting some or all of thehydrogen of a phosphoric acid by metals.
Depending on the number ofhydrogen atoms that are replaced, the resulting compound is described asa primary, secondary or tertiary phosphate. Primary and secondaryphosphates contain hydrogen and are acid salts. Secondary and tertiaryphosphates, with the exception of those of sodium, potassium andammonium are insoluble in water. Tertiary sodium phosphate is valuableas a detergent and water softener. The primary phosphates tend to bemore soluble. Phosphates, which are an important component to metabolism inboth plants and animals, help in the first step in oxidation of glucosein the body.
Primary calcium phosphate is an ingredient of plantfertilizer. Phosphates have caused increasing attention recently. The focusis on the environmentally harmful effects in household detergents. Wastewater, from laundering agents, contains phosphates, which are saidto be a water pollutant.
Most laundry detergents contain approximately 35% to 75% sodiumtriphosphate (Na5P3O10), which serves two purposes. Providing analkaline solution (pH 9. 0 to 10. 5) is necessary for effective cleansingand also to tie up calcium and magnesium ions found in natural watersand prevent them from interfering with the cleansing role of thedetergent. Eutrophication is the progressive over-fertilization of water,in which festering masses of algae’s blooms, choking rivers and lakes.
Phosphorus compounds act as a fertilizer for all plant life, whetherfree-floating algae or more substantial rooted weeds, and are implicatedin eutrophication. Many countries control phosphate levels, whereasSwitzerland has banned the use of phosphates. The marine environment is both fragile and more resistant thanthe terrestrial ecosystem. It is fragile for the reasons that nutrientsare generally present in very low concentrations, permanently consumedby living organisms and pollutants diffuse rapidly. Lakes and rivers are extremely complex ecosystems.
Nutrients aretaken up by both algae and rooted weeds. The weeds act as a shelter forfish larvae and zooplankton, both of which eat algae and are, in turn,eaten by larger fish. Scientists have concluded that unpolluted lakescan absorb surprisingly large amounts of phosphates without uncertainty. When a fertilizer, such as a phosphate, is added more algae will grow,and consequently will the populations of zooplankton and fish.
Difficulties only arise when the lake is already impure. Zooplankton aresensitive to their environment and many substances are toxic to them. Ifany of these substances, including phosphates, are present thezooplankton population cannot increase. Adding phosphates to thispolluted system will case algae growth. The floating masses cut off thelight supply. Weeds die and decompose using up dissolved oxygen, andcausing sulfurous smells and plagues.
Deprived of shelter and food, thefish larvae starve. The lake is well on the way to catastrophe. Without wetlands there would be a minimal amount of freshdrinking water due to the fact that wetlands filter the waters of ourlakes, rivers and streams, sequentially reducing contamination of water. The plant growth in wetlands removes phosphates and other plantnutrients washed in from the surrounding soil, consequently restrictingthe growth of algae and aquatic weeds. This growth is a serious problemin some of Canadas major waterways, where dead and decaying algaedeprive the deeper waters of their oxygen. Researches at Lancaster University have studied lakes whoseplant and animal life has been killed by acid rain.
The excess acid inthe lakes can be neutralized easily by adding lime, but this makes thewaters rich in calcium. Life will gradually return to the lake but, asthese lakes should have low calcium levels, it will not be the same kindof life that existed in lakes before pollution. The answer, they haveconcluded, is to add phosphates. These phosphates work by shielding the water. This depends uponnitrate ions in the lake. Contradictory, these ions also are produced byacid rain, contain oxides of nitrogen from combustion sources.
Thesefertilizers do not alter the pH level of the water. Instead, theystimulate the growth of plants. The plants absorb the dissolvednitrates, generating hydroxide ions, which in return neutralize theexcess acid. Removal of phosphates from detergent is not likely to slow algaegrowth in containing substances.
It may actually prove disastrous. Itsreplacement with borax will definitely be disastrous. Scientists areunsure of borax role in plant growth. It is not required by algae andother micro plants, but it is essential to higher plants. However inexcessive quantities, about 5 micrograms of boron per gram of water,boron severely damages plant life.
Highly alkaline substances, gelproteins and sodium hydroxide is hazardous substances. Another concern is the fact that each year thousands of children swallowdetergents resulting in serious injuries or death. In conclusion, the only way to overcome the disastrous effectsof phosphates is to find an alternate. However, an acceptable substitutefor phosphates has not yet been found.
Washing only with syntheticdetergents would require so much detergent that the cost per wash wouldincrease significantly. Another alternative is the substitution ofsynthetic nonionic detergents for ionic detergents in use. Nonionicdetergents are not precipitated by Calcium of Magnesium ions.Thiswould reduce the risk contaminating our lakes and rivers.
