ARTICLE | doi:10.20944/preprints201809.0600.v1
Subject: Earth Sciences, Environmental Sciences Keywords: emission inventory; livestock; greenhouse gases; air pollutant
Online: 30 September 2018 (06:04:22 CEST)
Livestock farming is a major source of greenhouse gas and ammonia emissions. In this study, we estimate methane, nitrous oxide and ammonia emission from livestock sector in the Red River Delta region from 2000 to 2015 and projection to 2030 using IPCC 2006 methodologies with the integration of local emission factors and provincial statistic livestock database. Methane, nitrous oxide and ammonia emissions in 2030 are estimated at 132 kt, 8.3 kt and 34.2 kt, respectively. Total global warming potential is 9.7 MtCO2eq in 2030, accounts for 33% greenhouse gas emissions from livestock in Vietnam. Pig farming is responsible for half of both greenhouse gases and ammonia emissions in the studied region. Other major livestock for greenhouse gas emission is cattle and for ammonia emission is poultry. Hanoi contributes for the largest emissions in the region in 2015 but will be caught up and surpassed by other provinces in 2030.
ARTICLE | doi:10.20944/preprints201809.0497.v1
Subject: Earth Sciences, Environmental Sciences Keywords: urban lake; sediments; nutrients; landuse; pollutant sources
Online: 26 September 2018 (04:53:40 CEST)
Lake Rawa Besar is an urban lake surrounded by dense settlements and market area. Currently Lake Rawa Besar is experiencing physical and ecology strain. This research’s objectives are to determine the levels of sediment and nutrient, the distribution, also the relation to land use and human activities producing pollutant. Field surveys with 30 sample points and observations was needed scattered within the lake. Measuring the value of each parameter is carried out in national standardized laboratory. The result shows that sediment load of TDS is still below the standard limit for clean water, while TSS levels in the middle of lake exceed the standard limit. Nutrient loads, spesifically nitrate and phospate levels is below the standard limit. While turbidity and BOD levels have a uniform distribution pattern in the lake, exceed the standard limit for clean water, and have a positive correlation. High levels of turbidity and BOD are caused by household waste and human activities producing organic waste such as tofu factory, fowl manure, and garbage dump. Small sewage goes into the lake mediates pollutants inflow. Attention is needed by nearby people, also for the government, to sustain the ecological condition of the lake.
ARTICLE | doi:10.20944/preprints202209.0486.v1
Subject: Mathematics & Computer Science, Applied Mathematics Keywords: wastewater treatment; combinatorial normalization; codec; pollutant indicators; predict
Online: 30 September 2022 (11:07:01 CEST)
Effective prediction of wastewater treatment is beneficial for precise control of wastewater treatment processes. The nonlinearity of pollutant indicators such as COD and TP makes the model difficult to fit and has low prediction accuracy. The classical deep learning methods have been shown to perform nonlinear modeling. However, there are enormous numerical differences between multi-dimensional data in the prediction problem of wastewater treatment, such as COD above 3000 mg/L and TP around 30 mg/L. It will make current normalization methods challenging to handle effectively, leading to the training failing to converge and the gradient disappears or exploding. This paper proposes a multi-factor prediction model based on deep learning. The model consists of a combined normalization layer and a codec. The combined normalization layer combines the advantages of three normalization calculation methods: z-score, Interval, and Max, which can realize the adaptive processing of multi-factor data, fully retain the characteristics of the data, and finally cooperate with the codec to learn the data characteristics and output the prediction results. Experiments show that the proposed model can overcome data differences and complex nonlinearity in predicting industrial wastewater pollutant indicators and achieve better prediction accuracy than classical models.
ARTICLE | doi:10.20944/preprints202107.0292.v2
Subject: Chemistry, Analytical Chemistry Keywords: Activated carbon; adsorption; ciprofloxacin; pollutant; pumpkin seed; thermodynamics
Online: 14 July 2021 (14:12:02 CEST)
Antibiotics are among the most critical environmental pollutant drug groups. One of the methods used to remove this pollution is adsorption. In this study, activated carbon was produced from the pumpkin seed shell and then modified with KOH. This adsorbent obtained was used in the re-moval of ciprofloxacin from aqueous systems. Fourier Transform-Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), elemental, X-ray Photoelectron Spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and Zeta analyzes were used for the characterization of the ad-sorbent. In particular, the surface area was found to be a very remarkable value of 2730 m2/g. The conditions of the adsorption experiments were optimized based on interaction time, adsorbent amount, pH and temperature. Over 99% success has been achieved in removal works carried out under the most optimized conditions. In addition, it was determined that the Langmuir isotherm is the most suitable model for the adsorption interaction.
ARTICLE | doi:10.20944/preprints202108.0300.v1
Subject: Engineering, Other Keywords: clinker; used tires; pollutant gases; energy savings; environment impact
Online: 13 August 2021 (15:11:16 CEST)
The objective of this work is to compare how the gases emitted during the manufacture of the clinker vary in a cement plant, using two types of fuel: petroleum coke and unusable tires (UTs). The study is based on a case study using real time data on more than 40 process variables. Gases are analysed from two points of the production process: Sintering Kiln, main focus of emission to the atmosphere by chimney, and Preheater. The variation of CO and NOx depending on the oxygen and fuel type is studied. The SO2 levels are also analyzed, observing a decrease when using the UTs. The quality of the Clinker has been compared depending on the fuel type. The results are compared, on the one hand, with the quality of the clinker, determined by the content of the majority (C3S, Alite) and minority (Free CaO) phases, and, on the other hand, with the Kiln sintering temperature, the most influential parameter in the productive process. It is verified that Clinker quality is maintained, regardless of the type of fuel used. Concluding that the use of UTs as fuel can generate an important economic and environmental benefit for cement companies and their environment.
ARTICLE | doi:10.20944/preprints201904.0036.v1
Subject: Earth Sciences, Environmental Sciences Keywords: compost, nutrient leaching; pollutant removal; stormwater quality, system modeling
Online: 2 April 2019 (15:35:29 CEST)
Filter Media (FM) sourced from recycled organic and mineral material offers a low cost and effective means of treating urban stormwater. Using recycled materials rather than from an increasingly scarce source of virgin materials (typically sandy loam soil) can ensure a sustainable long-term economy and environment. This paper presents results from the laboratory analysis and mathematical modeling to highlight the performance of recycled organic and mineral material in removing nutrients and metals from stormwater. Analysis included physical and chemical characterisation such as particle size distribution, saturated hydraulic conductivity (Ksat), bulk density, effective cation exchange capacity, and pollutant removal performance. Design mixes (DM), comprising a combination of organic and mineral materials, were characterised and used to develop/derive modelling design within the Model for Urban Stormwater Improvement Conceptualisation (MUSIC v6) . Comparison is made to the Adoption Guidelines for Stormwater Biofiltration Systems - Summary Report  which were based on the Facility for Advancing Water Biofiltration (FAWB) guidelines to assist in the development of biofiltration systems, including the planning, design, construction and operation of those systems. An observed outcome from over two decades of biofiltration guideline development has been the exclusion of alternative biofilter materials due to claims of excessive leaching. Results from this study indicate that high nutrient and metal removal rates can be achieved over a range of hydraulic conductivities using design mixes of recycled organic and mineral materials that have a demonstrated equivalence to existing guideline specifications.
ARTICLE | doi:10.20944/preprints201712.0197.v1
Subject: Mathematics & Computer Science, Information Technology & Data Management Keywords: air pollutant prediction; multi-task learning; regularization; analytical solution
Online: 28 December 2017 (09:09:20 CET)
In this paper, we tackle air quality forecasting by using machine learning approaches to predict the hourly concentration of air pollutants (e.g., Ozone, PM2.5 and Sulfur Dioxide). Machine learning, as one of the most popular techniques, is able to efficiently train a model on big data by using large-scale optimization algorithms. Although there exists some works applying machine learning to air quality prediction, most of the prior studies are restricted to small scale data and simply train standard regression models (linear or non-linear) to predict the hourly air pollution concentration. In this work, we propose refined models to predict the hourly air pollution concentration based on meteorological data of previous days by formulating the prediction of 24 hours as a multi-task learning problem. It enables us to select a good model with different regularization techniques. We propose a useful regularization by enforcing the prediction models of consecutive hours to be close to each other, and compare with several typical regularizations for multi-task learning including standard Frobenius norm regularization, nuclear norm regularization, ℓ2,1 norm regularization. Our experiments show the proposed formulations and regularization achieve better performance than existing standard regression models and existing regularizations.
ARTICLE | doi:10.20944/preprints202109.0298.v1
Subject: Earth Sciences, Environmental Sciences Keywords: Arabian/Persian Gulf; Lagrangian model; pollutant transport; tide; baroclinic circulation
Online: 17 September 2021 (08:07:30 CEST)
A rapid-response Lagrangian model for simulating the transport of a chemical pollutant in the Arabian/Persian Guls is described. The model is well suited to provide a fast response after an emergency due to an accident or a deliberate spill. Baroclinic circulation was obtained from HYCOM ocean model and tides were calculated using a barotropic model. The interactions of pollutants with sediments (uptake/release processes) were described using a dynamic approach based on kinetic transfer coefficients and a stochastic numerical method. Some examples of model applications are shown.
ARTICLE | doi:10.20944/preprints201912.0204.v1
Subject: Engineering, Automotive Engineering Keywords: diesel engines; numerical simulation; pollutant emissions prediction; computational fluid dynamics
Online: 16 December 2019 (05:09:55 CET)
In this paper an integrated methodology for the coupling between 1D- and 3D-CFD simulation codes is presented, which has been developed to support the design and calibration of new diesel engines. The aim of the proposed methodology is to couple 1D engine models, which may be available in the early-stage engine development phases, with 3D predictive combustion simulations, in order to obtain reliable estimates of engine performance and emissions for newly designed automotive diesel engines. The coupling procedure features simulations performed in 1D-CFD by means of GT-SUITE and in 3D-CFD by means of Converge, executed within a specifically designed calculation methodology. An assessment of the coupling procedure has been performed by comparing its results with experimental data acquired on an automotive Diesel engine, considering different working points including both part load and full load conditions. Different multiple injection schedules have been evaluated for part-load operation, including pre and post injections. The proposed methodology, featuring detailed 3D chemistry modeling, was proven to be capable to properly assess pollutant formation, specifically to estimate NOx concentrations. Soot formation trend was also well-matched for most of the explored working points. The proposed procedure can therefore be considered as a suitable methodology to support the design and calibration of new Diesel engines, thanks to its ability to provide reliable engine performance and emissions estimations from the early-stage of a new engine development.
ARTICLE | doi:10.20944/preprints201809.0128.v1
Subject: Life Sciences, Biotechnology Keywords: Bacillus subtilis; bioemulsifier; cassava wastewater; removal pollutant; methylene blue dye.
Online: 7 September 2018 (10:55:52 CEST)
In this work was investigated the potential of Bacillus subtilis UCP 0146 in the bioconversion of the medium containing 100% of cassava flour wastewater to obtain bioemulsifier. The evaluation of the production was carried out by the emulsification index (IE24) and surface tension (TS). The ionic charge, stability (temperature, salinity and pH measured by IE24 and viscosity), ability to remove and disperse oil and textile dye were investigated. B.subtilis produced an anionic bioemulsifier in the medium containing 100% of cassava wastewater in condition 4 of the factorial design (9% of the inoculum, at 35 °C and agitation of 100 rpm) with surface tension of 39mN/m, IE24 of 95.2 % and yield 2.69 g.L-1. Stability at different pH (2-8), temperatures (0-120ºC) and NaCl, dispersed (55.83 cm2-ODA) and reduced the viscosity of the burned engine oil (90.5 cP) , removed 94.4% petroleum and demonstrated efficiency in methylene blue removal (62.2%). The bioemulsifier and its synthesis from bacteria and also emphases on the role of surfactants in oil remediation.
ARTICLE | doi:10.20944/preprints201607.0033.v1
Subject: Earth Sciences, Environmental Sciences Keywords: industrial pollutant emissions; urbanization; the spatial panel model; Chinese case
Online: 14 July 2016 (12:12:25 CEST)
Urbanization is considered as a main indicator of regional economic development due to its positive effect on promoting industrial development; however, many regions, especially developing countries, are troubled by its negative effect — the aggravating environmental pollution. Many researchers have indicated that rapid urbanization stimulated the expansion of industrial production scale and increased industrial pollutant emissions. However, this judgement contains a grave deficiency in that urbanization not only expands industrial production scales but can also increase industrial labour productivity and change the industrial structure. To modify this deficiency, we first decompose the influence which urbanization impacts on industrial pollutant emissions into the scale effect, the intensive effect and the structure effect by using the Kaya Identity and the LMDI Method; second, we perform an empirical study of the three effects’ impacts by applying the spatial panel model with data from 282 Chinese cities between 2003 and 2013. Our results indicate that (1) there are significant reverse U-shapes between Chinese urbanization rate and its industrial pollutant emissions; (2) the scale effect and the structure effect have aggravated Chinese industrial waste water discharge, sulphur dioxide emissions and soot (dust) emissions, while the intensive effect has generated a decreasing and ameliorative impact on that aggravated trend. The definite relationship between urbanization and industrial pollutant emissions depends on the combined influence of the scale effect, the intensive effect and the structure effect; (3) there are significant spatial autocorrelations of industrial pollutant emissions between Chinese cities, but the spatial spillover effect from other cities does not aggravate local urban industrial pollutant emissions, we offer an explanation to this contradiction that the vast rural areas surrounding Chinese cities have served as sponge belts and have absorbed the spatial spillover of cities’ industrial pollutant emissions. According to the results, we argue that this type of decomposition of the influence into three effects is necessary and meaningful, it establishes a solid foundation for understanding the relationship between urbanization and industrial pollutant emissions, and effectively helps to meet relative policy making.
ARTICLE | doi:10.20944/preprints202212.0434.v1
Subject: Chemistry, Analytical Chemistry Keywords: Adsorption; β-agonists; Magnetic-composite; Metal-Organic Frameworks; Pollutant; Removal; Terbutaline
Online: 23 December 2022 (01:51:10 CET)
Mechanochemical production of copper (II) isonicotinate Metal-Organic Framework ([Cu (INA)2]-MOF) and its modified magnetic iron composite ([Cu (INA)2]-MOF@Fe3O4]) allowed for the adsorptive removal of Terbutaline from water. A variety of characterization techniques, including Fourier, transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM), were used to elucidate the distinct chemical and morphological features of the two advanced materials. The optimal adsorption conditions were determined by investigating a wide range of adsorption-related variables, including contact time, initial Terbutaline concentration, adsorbent dosages pH, and temperature. The chemistry involved in the adsorption process between the adsorbents and the adsorbate molecules was evaluated using the best-fitting models, such as kinetics, isotherms, and thermodynamics, and the regeneration study was performed to evaluate the adsorbents' reusability. Incredibly maximum adsorption capacities (Qmax) of 1667 and 2500 mg L-1 were attained within 40 minutes under alkaline pH 11 by the [Cu (INA)2]-MOF and the [Cu (INA)2]-MOF@Fe3O4, respectively. The adsorbents have been proven to be good for the adsorption of Terbutaline as a priority pollutant in an aqueous solution, with pseudo-first order and Langmuir as the best-fitting models for the kinetic and isotherm models respectively.
REVIEW | doi:10.20944/preprints201908.0012.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: zebrafish diet; heavy metals; contaminant; toxin; development; behavior; persistent organic pollutant
Online: 1 August 2019 (10:28:59 CEST)
Dietary contaminants are often an over-looked factor in the health of zebrafish. Typically, water is considered to be the source for most contaminants, especially within an aquatic environment. For this reason, source water for zebrafish recirculating systems is highly regulated and monitored daily. Most facilities use reverse osmosis or de-ionized water filtration systems to purify incoming water to ensure that contaminants, as well as pathogens, do not enter their zebrafish housing units. However, diets are rarely tested for contaminants and, in the case of manufactured zebrafish feeds, since the product is marketed for aquaculture or aquarium use it is assumed that the feed is acceptable for animals used for research. The following provides examples as to how contaminants could lead to negative effects on development and behavior of developing zebrafish.
BRIEF REPORT | doi:10.20944/preprints202202.0337.v1
Subject: Engineering, Energy & Fuel Technology Keywords: pollutant emissions; hydrogen combustion; alternative fuels; CFD; NOx emissions; greenhouse gasses; aviation
Online: 25 February 2022 (13:37:28 CET)
The present is a study of the CFD simulations intended to simulate the emissions of pollutants that are generated after the combustion of proposed alternative aircraft fuels (Hydrogen, Ethanol and Methane) to compare with the emissions generated after the combustion of Kerosene and Benzene in a 2D cylindrical combustion chamber. Given that air traffic is a main contributor to not only 3% of man-made greenhouse effects but also of the generation of smog over heavy air traffic urban areas generating an impact on the air quality and the population of those areas.
ARTICLE | doi:10.20944/preprints201807.0322.v1
Subject: Earth Sciences, Environmental Sciences Keywords: stormwater; monitoring; gross pollutant generation rates; suspended solids; nitrogen; phosphorus; heavy metals
Online: 18 July 2018 (09:07:46 CEST)
Urban stormwater runoff from a medium-density residential development in southeast Queensland has been monitored in the field since November 2013. A treatment train installed on the site includes rainwater tanks collecting roofwater, 200-micron mesh baskets installed in grated gully pits and two 850 mm high media filtration cartridges installed in an underground 4 m3 vault. A monitoring protocol developed by research partners, Queensland University of Technology (QUT), guided the monitoring process over a 4.5-year period. Heavy metals were included in the list of analytes during the monitoring period as the catchment is within 1 km of the environmentally-sensitive Moreton Bay, Queensland. Removal efficiencies observed at this site for the regulated pollutants; total suspended solids (TSS), total phosphorus (TP) and total nitrogen (TN) for the pit baskets were 61%, 28% and 45% respectively. The cartridge filters removed 78% TSS, 59% TP, 42% TN, 40% total copper and 51% total zinc. As the measured influent concentrations to the cartridge filters were low when compared to industry guidelines, the dataset was merged with international field results for TSS (n=39) and TP (n=32) but truncated within anticipated guideline levels. The combined dataset for the media filter demonstrates performance at 89% TSS, 66% TP and 42% TN. The total gross pollutant generation rate from the medium-density residential catchment was observed to be 0.24 m3/Ha/year, with a corresponding air-dried mass of 142.5 kg/Ha/year. Less than 2% of the gross pollutant mass was anthropogenic. The findings of this research suggest that the treatment train, and in particular the media filter, holds promise for the removal of total copper and total zinc, in addition to TSS, TP and TN, from urban stormwater runoff. Based on a maximum, low risk trigger TN concentration of 1.5 mg/L, the field test data from 4.5 years of operation and standard maintenance, suggests a 5.5-year replacement interval for the media filters.
ARTICLE | doi:10.20944/preprints202110.0409.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Air Pollutant Emissions; Rice Cultivation; Agricultural Machinery; Tier 1 Methodology; Geographic Information System
Online: 27 October 2021 (13:22:08 CEST)
In Korea, rice is a major staple grain and is mainly cultivated using various agricultural machinery. Air pollutants emitted from agricultural machinery have their origins mainly from the exhaustion of internal combustion engines. In this study, emission characteristics of five main air pollutants by European Environment Agency's Tier 1 method for rice cultivation was analyzed. Diesel is a main fuel for agricultural machinery and gasoline is generally used only for rice transplanters as a fuel in Korea. Tractors consume 46% of total fuel consumption and 56% of diesel fuel consumption. Gasoline used for rice transplanters accounts for 17% of total fuel consumption each year. Tractors and rice transplanters are emitting 82% of all total pollutants. From 2011 to 2019, the total amount of air pollutant emissions was decrease by 15%. That accounted for the reduction of rice cultivation fields in those periods. Rice transplanting operation was in charge of 42% of total emissions. Then, harrowing, harvesting, tilling, leveling, and pest control operations generated 10%, 10%, 8%, 8% and 7% of total emissions, respectively. The contribution of each air pollutant held 54% of CO, 39% of NOx, 5% of NMVOC, and 2% of TSP from the total emission inventory. The three major regions emitting air pollutants from mechanized agricultural practices were Jeollanam-do, Chungcheongnam-do, and Jeollabuk-do, which consume 55% of total fuel usage in rice farming. The total amount of air pollutant emissions from rice cultivation practices in 2019 was calculated as 8,448 Mg in Korea.
ARTICLE | doi:10.20944/preprints202103.0243.v1
Subject: Earth Sciences, Atmospheric Science Keywords: wildfires; summer 2019-2010; WRF-Chem; pollutant transport; air quality effect; health impact
Online: 9 March 2021 (09:03:10 CET)
The 2019-2020 summer wildfire event on the east coast of Australia was a series of major wildfires occurring from November 2019 to end of January 2020 across the states of Queensland, New South Wales (NSW), Victoria and South Australia. The wildfires were unprecedent in scope and the extensive extend of the wildfires has caused smoke pollutants transported not only to New Zealand but across the Pacific Ocean to South America. At the height of the wildfires, smoke plumes were injected into the stratosphere at height up to 25km and hence transported across the globe. Based on meteorological and air quality simulation using WRF-Chem model, air quality monitoring data collected during the bushfire period and remote sensing data from MODIS and CALIPSO satellites, the extend of the wildfires and the pollutant transport, and their impacts on air quality and health on exposed population in NSW can be analysed. The results showed that WRF-Chem model using Fire Emission Inventory from NCAR (FINN) predicts the dispersion and transport of pollutants and the predicted concentration of PM2.5 and other pollutants from wildfires reasonably well when compared with ground-based and satellite data. The impact on health endpoints such as mortality, respiratory and cardiovascular diseases hospitalisation across the modelling domain is then estimated. The estimated health impact is comparable with previous study based only on observation data, but the results in this study provide much more detailed spatially and temporally with regards to the health impact from the 2019-2020 wildfire.
ARTICLE | doi:10.20944/preprints201804.0024.v1
Subject: Earth Sciences, Environmental Sciences Keywords: pollutant transport modelling; metals transport modelling; free surface water bodies; toxics-reaction equation
Online: 2 April 2018 (11:27:40 CEST)
This paper describes the development of a two-dimensional water quality model that solves hydrodynamic equations tied to transport equations with reactions mechanisms inherent in the processes. This enable us to perform an accurate assessment of the pollution in a coastal ecosystem. The model was developed with data drawn from the ecosystem found in Mexico's southeast state of Tabasco. The coastal ecosystem consists of the interaction of El Yucateco lagoon with the Chicozapote and Tonalá rivers, that connect the lagoon with the Gulf of Mexico. We present the results of pollutants transport simulation in the coastal ecosystem, focusing on toxic parameters for two hydrodynamic scenarios: wet and dry seasons. As it of interest in the zone, we study the transport of four metals: Cadmium, Chromium, Nickel and Lead. In order to address our objectives we solved numerically a self-posed mathematical problem,which is based on the measured data. The performed simulations show to characterise metal transport within the acceptable range of accuracy and in accordance with the measured data. The performed simulations show to characterise metals transport with an acceptable accuracy, agreeing well with measured data in total concentrations in four control points along the water body. Although for the accurate implementation of the hydrodynamic-based water quality model herein presented, boundary (geometry, tides, wind, etc.) and initial (concentrations measurements) conditions are required, it poses as an excellent option when the distribution of solutes with high accuracy is required, easing environmental, economic and social management of coastal ecosystems.
REVIEW | doi:10.20944/preprints202112.0451.v1
Subject: Chemistry, Applied Chemistry Keywords: Dendritic Polymers; Dendrimers; Metal Nanoparticles; Photocatalysis; Water Purification; dye discoloration; pollutant degradation; nanoparticle catalysis; decomposition; semicoductors
Online: 28 December 2021 (14:19:11 CET)
Radially polymerized dendritic compounds are nowadays an established polymer category next to their linear, branched and cross-linked counterparts. Their uncommon tree-like architecture is characterized by adjustable internal cavities and external groups. They are therefore exceptional absorbents and this attainment of high concentrations into their interior renders them ideal reac-tion media. In this framework they are applied in many environmentally benign implementa-tions. One of the most important among them is water purification though pollutant decomposi-tion. Simple and composite catalysts and photo-catalysts containing dendritic polymers and ap-plied in water remediation will be discussed jointly with some unconventional solutions and fu-ture prospects.
Subject: Life Sciences, Cell & Developmental Biology Keywords: environment; virus; pollutant; evolution; exaptation; stem cells; transposons; APOBEC; ADAR,; ORF2p; cancer; Eco-Evo-Devo; symbiosis; ecological genomics; environmental stress; genetic recombination; biological plasticity; hypermutation; epigenetics; fractal systems; natural selection
Online: 19 July 2020 (19:35:46 CEST)
This article challenges the notion of the randomness of mutations in eukaryotic cells by unveiling stress-induced human non-random genome editing mechanisms. To account for the existence of such mechanisms, I have developed molecular concepts of the cell environment and cell environmental stressors and, making use of a large quantity of published data, hypothesized the origin of some crucial biological leaps along the evolutionary path of life on Earth under the pressure of natural selection, in particular, 1) virus-cell mating as a primordial form of sexual recombination and symbiosis; 2) Lamarckian CRISPR-Cas systems; 3) eukaryotic gene development; 4) antiviral activity of retrotransposon-guided mutagenic enzymes and finally; 5) the exaptation of antiviral mutagenic mechanisms to stress-induced genome editing mechanisms directed at “hypertranscribed” endogenous genes. Genes transcribed at their maximum rate (hypertranscribed), yet still unable to meet new chronic environmental demands generated by “pollution”, are inadequate and generate more and more intronic retrotransposon transcripts. In this scenario, RNA-guided mutagenic enzymes (e.g. AID/APOBECs), which have been shown to bind to retrotransposon RNA-repetitive sequences, would be surgically targeted by intronic retrotransposons on opened chromatin regions of the same “hypertranscribed” genes. RNA-guided mutagenic enzymes may therefore “Lamarkianly” generate single nucleotide polymorphisms (SNP) and copy number variations (CNV), as well as transposon transposition and chromosomal translocations in the restricted areas of hyperfunctional and inadequate genes, leaving intact the rest of the genome. CNV and SNP of hypertranscribed genes may allow cells to surgically explore a new fitness scenario, which increases their adaptability to stressful environmental conditions. Like the mechanisms of immunoglobulin somatic hypermutation, non-random genome editing mechanisms may generate several cell mutants, and those codifying for the most environmentally-adequate proteins would have a survival advantage and would therefore be Darwinianly selected. Non-random genome editing mechanisms represent a link between environmental changes and biological novelty and plasticity, and provide a molecular basis to reconcile gene-centered and “ecological” views of evolution.