Chapter 2: Biotechnologies Applied to Environmental Issues PDF

II. Biotechnologies applied to environmental issues II.1-Climate change and ecosystem evolution II.1.1. Definition A climate change, or climate disruption, corresponds to a lasting modification (from decade to million years) of the statistical parameters (average parameters, variability) of the g...

II. Biotechnologies applied to environmental issues II.1-Climate change and ecosystem evolution II.1.1. Definition A climate change, or climate disruption, corresponds to a lasting modification (from decade to million years) of the statistical parameters (average parameters, variability) of the global climate of the Earth or of its various regional climates. Designates the set of variations of climatic characteristics in a given place, over time: warming or cooling. Certain forms of air pollution, resulting from human activities, threaten to significantly modify the climate, in the direction of a global warming. This phenomenon can cause significant damage: elevation of sea levels, accentuation of extreme climatic events (droughts, floods, cyclones,...), destabilization of forests, threats to freshwater resources, agricultural difficulties, desertification, reduction of biodiversity, extension of tropical diseases, etc. According to the IPCC (1995), The Intergovernmental Panel on Climate Change (IPCC) --- in English IPCC for Intergovernmental Panel on Climate Change --- This climate change would be accompanied by:  a disturbance of the water cycle,  an increase in the frequency and intensity of natural disasters of climatic origin (droughts, floods, storms, cyclones),  a threat of disappearance of certain coastal areas, in particular deltas, mangroves, coral reefs, beaches of Aquitaine, etc.  a decrease of 17.5% in the emerged area of Bangladesh, of 1% of that of Egypt,  would favor the resurgence of malaria, and the extension of infectious diseases such as salmonellosis or cholera,  would accelerate the decline of biodiversity: disappearance of animal or plant species, II.1.2. Ecosystem definition In ecology, an Ecosystem refers to "a whole formed by an association or community of living beings (or biocenosis) and its geological, pedological and atmospheric environment (the biotope)." The elements constituting an ecosystem develop a network of interdependencies allowing the maintenance and development of life. Ex. A Forest, a swamp are ecosystems. The ecosystem constitutes a natural system and tends to evolve towards its most stable state, called climax; we speak of ecological regression when the system evolves from one state to a less stable state. An ecosystem is composed of:  all living organisms of a biocenosis (phytocenosis, zoocenosis, microbiocenosis and mycocenosis).  All environmental factors (climatic, edaphic and water factors).  The relationships (interrelations) that exist between the biocenosis and its environment and reciprocally between the environment and the biocenosis. II.2. Management of microbiological, plant and animal resources II.2.1. Biological resources Definition: Includes genetic resources, organisms or parts thereof, populations, or any other biotic component of ecosystems with actual or potential use or value for humanity. The management of microbiological, plant, and animal resources aims to:  organize the collection and conservation of genetic resources of species used and selected by humans in the form of samples of the animal, plant, and microbial genetic heritage;  promote research in the field of resource conservation. Thus, the management of these resources aims to safeguard selected plant varieties, animal breeds, and useful microbiological strains that are part of human history and diet. Its ultimate goal is to counter the increasing erosion of this heritage’s diversity due to the abandonment of older varieties considered less productive and more fragile and the homogenization of productions. The conservation of genetic heritage is done by helping to preserve species in their environment when possible (in situ conservation) and by collecting and/or cryoconserving genetic heritages (ex situ conservation). As far as cultivated plant species are concerned, informal networks involving public and private actors carry out conservation requiring regular multiplication cycles. II.3. Agro-environmental Pollution (Water, Air, Soil) II.3.1. Pollution: Pollution is an unfavorable modification of the natural environment that can directly affect humans or through agricultural resources, water, and biological products. It is of three types:  Air pollution: caused by industrial fumes, means of locomotion, volcanism, etc.  Water pollution: caused by industrial and agricultural discharges and urbanized areas, refineries at sea, etc.  Soil pollution: caused by waste storage, pesticide spreading, etc. II.3.2. Atmospheric Pollution a) Definition from the official journal of the Algerian Republic: “Air pollution means the emission into the atmosphere of gases, smoke, or solid or liquid corrosive, toxic, or odorous particles likely to inconvenience the population, compromise public health or safety, damage plants, agricultural production, and agri-food products, conservation of buildings and monuments, or the character of sites.” Pollution is defined according to two distinct or combined criteria:  A Qualitative criterion: substance foreign to the composition of the air  A Quantitative criterion: where the pollutant is a normal constituent of the air that exceeds set limits, e.g., CO2 > 300ppm. b) Main atmospheric pollutants  Primary pollutants: directly emitted into the atmosphere. These are sulfur dioxide (SO2), nitrogen oxides (NOx), and suspended particles (PES).  Secondary pollutants: primary pollutants can chemically evolve in the atmosphere to form secondary pollutants that are the origin of photochemical pollution and acid rain. c) Main sources of atmospheric pollution: The main sources of pollution are:  Natural sources:  o Natural combustion: Forest fires (CO, CO2) o Volcanic eruption: (dust, SO2, F) o Fermentation processes of organic matter (greenhouse gases: CH4 and NO2) o Oceans and seas: NaCl, CaCl2, MgCl2, KBr  Anthropogenic sources: These sources result from human activity. Among anthropogenic sources, fixed sources emitted by non-mobile installations are often opposed to mobile sources related to transport. o Means of transport (road, air, sea, rail, etc.) o Industry (power plants, incinerators, etc.) o Agriculture (fertilizers, livestock…) o Residential sectors (heating, sanitary products…) d) Ecological impacts of atmospheric pollution  Acid rain by forming strong acids from the reaction of primary pollutants with moisture: H2SO4 and HNO3. They are responsible for the poisoning of trees and disruption of photosynthesis; death of soil microorganisms; erosion of rocks; and monuments.  Photochemical Oxidant Smog (SMOG = mix of smoke and fog) It is the result of typically urban pollution related to transport, characterized by an accumulation of ozone, aldehydes, and peroxyacetyl nitrate with high oxidizing power. This is favored by the introduction of primary pollutants into the atmosphere (NO, Volatile Organic Compounds) as well as unfavorable meteorological conditions (Very weak wind, temperature inversion, strong sunlight). This leads to the accumulation of pollutants in the atmosphere.  Exacerbation of the greenhouse effect “additional greenhouse effect” The greenhouse effect is a natural phenomenon that helps retain some of the solar heat on the Earth’s surface through the absorbing power of certain gases (CO2, CH4, N2O, O3, CFC…). High atmospheric concentrations of these gases lead to an exacerbation of the greenhouse effect with a rise in temperature. As a result, we witness global warming with glacier melting, mechanical increase in sea water volume, an increase in precipitation.   Destruction of the Ozone layer Stratospheric ozone (10 to 50km altitude) is referred to as good ozone because it absorbs solar UV radiation. However, many compounds can cause catalytic destruction (OH , H , NO , Cl , Br , HO2 ) of stratospheric ozone. This increases UV radiation reaching the ground, resulting in increased skin cancer cases and endangering survival on Earth.  Eutrophication Disturbance of the biological balance of soils and waters by excess nitrogen and carbon or phosphorus from the atmosphere. II.3.3. Water Pollution a) Definition: According to the Water Agency: “Water pollution is an alteration that makes its use dangerous and/or disrupts the aquatic ecosystem.” b) Main sources of water pollution:  Agricultural discharges (Nitrates, phosphorus, pesticides…)  Household discharges (foaming products, phosphorus, PAHs, drugs…)  Industrial discharges (metals, PAHs, dioxins…) c) Main water pollutants:  Physical pollutants (turbidity, thermal pollution, radioactive materials)  Chemical pollutants (nitrogen, metals, pesticides, hydrocarbons…)  Organic matter  Microbiological pollutants (bacteria, viruses, fungi) d) Ecological impacts of water pollution  Increase in temperature: Modification of density, viscosity, and vapor tension: impact on evaporation  Turbidity: i.e., the non-transparency of water due to the presence of suspended matter (clays or organic matter): impact on light penetration, hence photosynthesis.  Nitrogen chemical pollution: Excess nitrogen products reduce water quality and cause plankton proliferation. It causes toxicities after nitrogen is transformed into nitrate and then into nitrites: risk of methemoglobinemia for pregnant  women and infants and risk of stomach cancer due to transformation into nitrosamines.  Organic pollution (hydrocarbons, persistent organic compounds like PAHs, PCBs, dioxins): persist in the environment, accumulate in the tissues of living organisms. They lead to the pollution of ground water.  Detergents form a non-biodegradable residue, and foam forms an impermeable screen to oxygen above the water.  Medications rejected after absorption and metabolism or in the raw state load the water with residues of antibiotics (ATB), hormones... with the development of multiple resistances to antibiotics and endocrine disruptions in humans.  Eutrophication: it is an imbalance that results from an excessive supply of nutrients (nitrogen, carbon, phosphorus). A lake receives quantities of nutritive materials brought by torrents and runoff waters. Certain algae grow and multiply excessively in the layers of superficial waters due to the need for light. These excess algae increase the biodegradable organic materials at the bottom of the lake. Aerobic bacteria that feed on these materials proliferate in their turn, consuming more and more oxygen until depletion of O2. These latter can no longer degrade all the dead organic matter and this accumulates in the sediments. It is then said that the lake is aging. II.3.4. Soil Pollution  Definition: It is the accumulation of toxic compounds: chemicals, salts, radioactive materials, or pathogens having harmful effects on plant growth and animal health.  Types of soil pollution: o Diffuse pollution (over large soil areas): Results from the spreading of solid or liquid products and atmospheric fallout. o Localized pollution (localized presence of dangerous substances in soils and subsoils): Spills, leaks, or waste disposal.  Main pollutants: o Heavy metals: From agriculture and diffuse atmospheric fallout. o Cyanides: Come from herbicides.  o Nitrates: Poorly adsorbed in soil, they are denitrified and carried to the waters. o Sodium salts (herbicides, irrigation water): Cause soil salinization and reduce fertility. o Pesticides: Can dissolve in soil solutions and gradually move towards groundwater. Their lifespan varies greatly; for example, DDT is very persistent. o Pathogenic organisms: Animal diseases can be transmitted to humans through soil, such as tetanus, botulism, brucellosis, foot-and-mouth disease, etc. o Radioactive pollution: Natural (e.g., radon), industrial, medical, accidental (e.g., Chernobyl), or military from atomic bomb tests (e.g., Reggane, Algeria from February 13, 1960, to April 25, 1961).  Ecological impact of soil pollution: o Acidification: Caused by acidic atmospheric deposits and inputs of acidifying fertilizers; this causes acidification of watercourses and disrupts flora and fauna. o Eutrophication o Soil compaction: Pressures exerted on the soil surface reduce porosity, leading to a lack of aeration and drainage. o Soil erosion and salinization o Greenhouse effect: Increased by methane produced by bacteria from organic matter, N2O from denitrification, and CO2. II.3.5. Environmental Biotechnology, a Path to Sustainable Development The main areas of activity currently concerned with environmental biotechnology are the decontamination of polluted sites, the treatment and recycling of waste and odors, water treatment, monitoring of pathogens in the environment, and renewable energies. A. Sustainable Waste Management  Bioremediation techniques can be used in various applications, including soil decontamination, wastewater treatment, pollutant gas treatment, and solid waste.  Unpleasant odors can also be treated using biological systems.   The purified products are discharged into the air, sewers, or landfilled. They can eventually be reused, such as biogas or compost from municipal waste.  This ensures maximum relief of landfills and leads to socially, economically, and environmentally sustainable waste management. B. Cleaning at the Molecular Level  The biofilm encompasses the cells it contains and a matrix of polymeric substances they secrete, which keeps them attached to the surface and to each other.  Bacteria in biofilms often acquire specific physiology and become much more resistant to external aggressions such as biocides and antibiotics.  Biofilms also promote the release and dissemination of variant strains during the so-called dispersion phase.