ENVIRONMENTAL TOXICITY
Detergents to be harmful to the environment must penetrate the surface and ground water. If present in high concentration and if they are intercepted by the purifiers, pass in natural environments because of their toxicity by accumulation in the environment or become harmful to aquatic systems (and hence for the equilibrium of ecosystems) and human health when they enter the food chain.
From studies conducted in the laboratory shows that a detergent concentration of only 2 ppm can cause fish to absorb double the amount of chemicals that absorb under normal conditions (the surfactants act on the surface tension of water), but in general we can say which is never quite so high that it affects the fish directly.
Detergents can be toxic to all forms of aquatic life if present in sufficient quantity (concentration of from 5 ppm), even in the case of biodegradable detergents: they act on the outer layers of mucus that protect fish from bacteria and can cause severe damage to the gills, also reduce the surface tension of water making organic chemicals, including pesticides and phenols, more easily absorbed by fish.
Surfactants can cause eutrophication: forming a layer floating on the water surface that prevents oxygen exchange with the atmosphere and the passage of gaseous substances that are formed from the decomposition of substances in water.
The phenomena observed depend on the type of detergent and the presence or absence of cleaners. In the case of traditional detergents, synthetic or non-biodegradable substances that do not degrade easily are today excluded by law in the case of surfactants, for other non-biodegradable, however, does not constitute an absolute constraint to their use.
These substances, although in lesser amounts accumulate in the water, if not intercepted by the purifiers, and adversely affect ecosystems. The substances with toxic effects, however, are prohibited by law.
The cleaning of plant origin, in general, are more degradable in the choice of surfactants, which for the lower number of other additional substances. But often the biodegradability is not absolute, because the plants are treated with surfactants or synthetic products as a percentage up to 30%. The only cleaning agents that do not use non-biodegradable substances, and any synthetic product are organic.
Not insignificant is the contribution of sewage and wastewater treatment systems that limit the dispersal of chemicals into the environment. Not always there is the presence of both, even in countries with stronger industrialization and not always where they exist, they are highly efficient. This makes difficult the exact evaluation of pollution caused by the use of chemicals.
Not all treatment plants, however, are able to remove or detect the various components of detergents. The primary ones, tied to small companies, it removes only a fraction of sludge deposition. The secondary use biological processes, such as activated sludge, to accelerate the biodegradation of many substances. The tertiary also reduce non-biodegradable components of the chemical process more complex and expensive.
In any case, the most common purification techniques are not able to remove substances such as boron, if not reducing it to simpler components.
For the considerations made so far, therefore, a detergent should be evaluated not only for its effectiveness, including:
that it contains (the ingredients);
for any problems that can cause tissue and areas with prolonged use;
for its possible toxicity to humans, in the case of prolonged contact and allergies;
for the possible entry into the food chain;
for harmful amounts that reach the waterways.
THE CHOICE OF THE COMMUNITY ‘EUROPEAN
European legislation requires chemicals to eliminate the toxicity of which has been established. For substances in use, whose effects on our body are not yet clear, the European Community Directive issued in 2007 with the aim of REACH in 2020 analyzing all the chemicals already in use and newly introduced and regulate the use, both domestic and industrial. Even the detergents / cleaners are fully included in the scope of the Directive.
For the first objective biodegradability imposed by law was to drastically limit the use of phosphates, non-biodegradable and cause massive eutrophication. In particular, the maximum percentage of compounds of phosphorus (and its derivatives) in laundry detergents has been fixed in 1%. However, greater tolerances are allowed in dishwashing detergents.
Law 136 of 1983 has imposed on the biodegradability of detergents to 90% (28 days) only for the four types of surfactants providing that all detergents, including ecological ones, return the following statement: “Caution, this product can pollute seas, lakes, rivers. Do not overuse. 90% biodegradable. “
The new law distinguishes between October 2005:
Biodegradability, refers exclusively to the surface and set at 90%. The analysis of the biodegradability have a margin of error of + – 10%. Therefore no one can write that a product is 100% biodegradable, but at most 90%.
Mineralization related to the ultimate aerobic biodegradability of surfactants or other substances (compounds transformation in a non-aggressive as H2O, carbon dioxide, inorganic salts). It ‘set at 60% in 28 days.
The law thus leaves unresolved the problem for 40% of the product and does not take into account the possible negative effects on ecosystems that may occur in the grace period of 28 days.
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