Upper layer of the earth's crust, located between the bedrock and the surface, and composed of mineral particles, organic matter, water, air and living organisms. It is the interface between earth, air and water, which makes it capable of performing both natural and usage functions.

Environmental Functionalities of the Soil

Soils are essential for the environmental health of the planet to fulfill essential differ not functions for the maintenance of the biosphere.


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Base function

Soils are the basis of fixation and growth of the flora, influence the development of habitats and play a very important role important in animal diversity on the planet. In turn, contain millions of organisms that are contributing by ecosystems through the decomposition of residues (including toxic), absorption of atmospheric elements, the oxygenation of the same soil or the regulation of the hydrological and carbon cycles.

Water supply

The soil is responsible for the distribution and storage of rainfall and therefore ultimately key in the water supply just as much for ecosystems as for the demands for human uses, consumption, irrigable, industrial use or recreational activities. Similarly, it develops key synergies due to the scarcity of water and droughts, as well as in controlling flood risks.

Climate regulation

Soils help regulate climate by absorbing CO-2 from the atmosphere and storing large amounts of carbon, which contributes to climate change mitigation and adaptation to the same.

Forests and soils

Forests and soils are large greenhouse gas sinks that absorb CO2 through photosynthesis and store it as carbon, turning it into organic matter. The forest biomass, wood and, of course, the soil are great carbon stores. In fact, it is estimated that European soils house 70,000 billion tons of organic carbon.

However, if such sinks emit more carbon than they absorb, they can become a source of greenhouse gases. A loss of only 0.1% of carbon accumulated in European soil to the atmosphere is equivalent to the emission of 100 million more cars on the continent. While forest lands and grasslands they pick up 100 million tons of carbon annually; the lands of cultivation set loose between 10 and 40 million tonnes.

The degradation of the soils can cause part of the CO2 previously absorbed and stored as carbon in the sinks, to be sent back again into the atmosphere. To this environmental problem one must add, in addition, the acid rain that alters the chemical composition of the soil, produces the loss of its neutralizing capacity (acidification) and moves the heavy metals in the soil that prevent vegetation from properly absorbing the water and the necessary nutrients. In addition, these “mobilized” heavy metals may reach sources of consumption, with the consequent impact on the health of the people.

Soils and underground water control strategy in EDP Spain

Protection of soil and underground water is integrated into EDP Spain’s strategy of environmental protection, and it develops through structural and management actions.


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Structural actions

Zoning and paving of activities are basic elements of protection, to which one can add the installation of collection tanks that spill, and beaches of discharged products, networks independent water, etc..

Management measure

Control of leakage and spill containment and collection are the main management measures to minimize the risks of soil contamination, which are developed by means of leak detectors in buried tanks, monitoring and control of groundwater through piezometers, environmental emergency kits with absorbent materials, realization of simulations and continuous training of workers, external means of rapid intervention, etc…

For the monitoring and control of facilities with more risk of soil contamination the installation of piezometers stands out for the regular monitoring of groundwater, so that if a contaminant might be identified, preventive and/or corrective actions can be taken on the potentially polluting agent or the soil itself (remediation).

In these facilities, there has been a campaign of characterization of soil, called Base Report, which will be taken into consideration when it becomes time to dismantle the facilities, given that the site must be maintained suitable for potential future use. Similarly, a Risk Analysis on the health of people has been made, which ensure that under the current conditions of the soils of these centers there is no risk to people, for example by volatile inhalation, or dermal migration risks contaminants to nearby water sources.

The noise is an auditory sensation usually unpleasant.

There is a belief, not confirmed, in which it is said that people living near the Nile Falls complained of being deaf and although this statement has not been proven, the number of references found on this subject suggests that there was at least some concern.

In the late nineteenth century, with the steam engine and the initiation of the industrial age, industrial deafness of workers begins to be documented (PRL).

And more recently, discussions mention “noise pollution” making reference to noise, understood as excessive and annoying sound, caused by human activities (traffic, industry, places of leisure, planes…) that produce negative effects on hearing, and the physical and mental health of living beings.

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How do we perceive the noise?

A Sound is the sensation produced in the ear by the movement of the body and transmitted by an elastic medium, such as air.

The energy produced by a sound source per time unit is called sound power, and when that acoustic energy reaches the receiver (ear or measurement microphone) sound pressure variation occurs.

The minimum threshold of perception of sound by the human ear is 20 micro-pascals and the pain threshold is at 20 pascals. The same applies to frequencies. The human ear only perceives sound waves between 20 and 20,000 Hz.

The pressure value is associated with intensity, high or low sounds, while the sound frequency is related to acute or bass (high or bass frequencies, respectively) for the same level of sound pressure, a noise is respectively more annoying depending on the proportion of high frequencies that it contains.

In addition, in the studies made on people one can see that a listener cannot give a reliable indication of the intensity of a sound, nevertheless, if one has them hearing two different sounds, it is capable of distinguishing the difference in intensity.

How do we measure the noise?

To measure the noise one uses the decibel, since this expresses a ratio between quantities and not quantity: a bel is equivalent to 10 decibels and represents a power increase of 10 times on the magnitude of reference (0 bels), 2 bels an increase of 100 times, and so on (logarithmic scale).

In addition, the decibel A (dBA) was defined, a unit of sound level measured with a filter that removes part of the low and very high frequencies (weighted A), leaving only the most harmful frequencies for the ear.

The equipment used to measure noise is the sound level meter, that among other things, gives us the measure in dBA.

Thus, the human ear is capable of supporting corresponding sounds at levels of sound pressure from 0 (low threshold) and 140 dBA (threshold of pain).

Propagation of noise: sound waves

In case of a point source, it is considered that all noise emission power is concentrated at one point and acoustic waves spread uniformly in all directions as if it was the case of waves of a pond.

As the waves move away from the source, they are attenuated due to absorption into the air of part of the acoustic energy (transforming it into heat): in a homogeneous medium, whenever the distance is doubled, the level of sound pressure decreases by 6 dB. This attenuation It depends on the frequency of sound, temperature and the humidity of the air.

On the other hand, if we double a sound power (two equal sound sources) the resulting value of sound pressure will increase by 3 dB, treating it on a logarithmic scale. Although it might seem that the increase in loudness is significant, the human ear does not perceive it as such:

Power source

Sound pressur (dB)

Increased noise

2X+3Barely perceptible
5X+750% noisier
40X+16Three times
100X+20Four times
Acoustic Contamination

According to the law 37/2003 noise, noise pollution are those noises or vibrations no matter what the generation that are considered a nuisance, risk or harm to people and the development of their activities or cause significant effects on the environment.

Today, with the growth of urban centers -more than 70% of the European population lives in cities- noise pollution has become one of the most important environmental factors to directly impact on the quality of life of the citizens.


Spanish law by Royal Decree 1367/2007, set 2 types of controls on noise. The new acoustic emitters (further to the RD1367) must not exceed certain values acoustic emission limit (VLI), and the Administration should ensure that in each acoustic area, all acoustic emitters located in said area, do not exceed certain stated global values. Acoustic quality objectives.


It is noteworthy that the new transmitters, as well as having stricter limits the measurements made with the meter are penalized with up to 9dBA if low frequency components are detected, impulsive and/or tonal (values La + Ki =Lk).


But, for existing acoustic transmitters (prior to 2007), State law doesn\u2019t set concrete values, leaving its regulation in the hands of autonomous communities. Facilities that have not been that have not been designed not to emit noise above certain determined values, once implemented, have serious difficulties to achieve effective noise reductions.


Royal Decree

New acoustic emittersObjectives of acoustic quality
Lk dayLk afternoonLk nightLk dayLk afternoonLk night
Zona residencial







Zona industrial








Measures with penalty:Up to
+9 dBA

Overall measurements of all
acoustic emitters


If some of these values are not met, the acoustic transmitters should implement plans to minimize noise.

Measures for minimizing noise in EDP Spain

To combat noise pollution, EDP acts continuously on three fronts: new projects, minimizing sound existing sources and implementation of best practices in operation.

Any project such as the implementation of new equipment and systems, are modeled acoustically to check if their sound emissions would raise the noise outside, so that the situation can be corrected right from the design phase. This is the case, for example, for the denitrification plants of Aboño 2 and Soto 3 (2016 and 2017, which came into operation respectively).

On the other hand, to reduce noise of operating plants, EDP analyzes which equipment is the noisiest and defines minimization plans. Thus, they have invested only between the thermal stations of Soto Aboño Ribera over 1.5 million euros in the last decade. The company introduced mufflers, replaced equipment and installed acoustic screens. These studies as well as the implementation of measures of noise minimization are being carried out with expert third-party firms in this area, coordinating and collaborating with different areas of EDP.

The awareness and education of all staff members is very important because it ensures the effectiveness of investments. In addition to plans for preventive and corrective maintenance of equipment and attenuation systems, the application of good practices, as simple as keeping doors, windows and gates permanently closed, is fundamental.