That is what a study by the Universidad de Almería says, confirming for the first time that human excrements contribute to water pollution, primarily with nitrogen and phosphorus.
A team of researchers from the Universidad de Almería (UAL) has estimated the environmental impact of the Spanish diet and role that human excrements play in the life cycle of food. It is the first time that a scientific study of this type incorporates the role played by human excrements.
"Food in Spain produces emissions of around two tonnes of carbon dioxide per person and per year (more than 20% of total emissions per person and per year) and consumes 20 gigajoules of primary energy," main author of the study and researcher at the UAL Iván Muñoz told SINC.
The study, which was published recently in The International Journal of Life Cycle Assessment, analyses the relationship of the food production and consumption chain with global warming and the acidification and eutrophication (excess of nutrients) of the environment, taking what a person in Spain ate in 2005 (881 kilograms) as a reference.
Calculations included agricultural and animal production, industrial food processing, sale and distribution, preparation and cooking at home, solid waste treatment (food remains and packaging), as well as human excretion.
According to the study, producing food from animals, such as meat and dairy products, causes the greatest impact. Agriculture, livestock, fishing and the food industry are the greatest source of carbon dioxide water pollution, but in both cases the effects of human excretion (through breathing or due to waste water treatment) are next on the list.
Human Excretion Contributes Nutrients
"Human excretion contributes significantly to water polluting through providing organic matter and nutrients, such as nitrogen and phosphorus, which fosters the growth of algae, a decrease in the level of oxygen dissolved in the water, bad smells and other problems associated to eutrophication," Muñoz says, "although such effects are minimised by the purification processes performed before wastewaters are discharged into rivers or to the coast."
The researcher makes the point that returning these wastewaters to the environment is not a bad thing in itself, as they are nutrients, just like manure is reused as fertiliser in agriculture.
"The problem is that in many cases our rivers have a very low water level and find it difficult to soak up wastewaters, not only from excrements, but also from other sources such as pesticides and fertilisers used in farming and pollutants from industry," Muñoz indicates.
The researchers have also estimated the CO2 and methane produced by the human metabolism and the energy consumption associated to aspects such as using toilet paper, soap and basin water, together with the treatment of sewage at treatment stations.
As regards emissions, "human excrements have a net null effect on global warming, as they are offset by carbon fixation in photosynthesis. As a result, they do not contribute to increasing the concentration of CO2 in the atmosphere".
Ivan Muñoz, Llorenç Milà i Canals y Amadeo R. Fernández-Alba. "Life cycle assessment of the average Spanish diet including human excretion". The International Journal of Life Cycle Assessment 15(8): 794-805, 2010. DOI: 10.1007/s11367-010-0188-z
SINC | EurekAlert!
Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung
High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy