Patricia Fragoso, Alberto Pereira, Francisco Bautista y Gonzalo Zapata
The aim of this work was to develop the digital map of soils for Quintana Roo for a printed scale 1:400000 with 1:50000 work scale data, initially with a geopedological approach and subsequently improved to a digital map.
The map was prepared with data from the formative factors of soils using mathematical methods to infer information in the places where these data are not available. Its elaboration included three stages, the first two following the principles of the geopedological approach consisted in the synthesis of the information generated in the characterization of the geomorphological landscapes (vertical dissection, karst geomorphometrics, failures, geology) and soils, in the third stage incorporating the environmental components (climate and vegetation) and related variables through various statistical analysis (cluster analysis, principal component analysis and classification analysis) the procedure allowed to obtain the pattern of distribution of the Soils to finally develop the model and get to the digital map of soils in the study area.
Vertical dissection, karstic forms (dolines, uvalas and poljes), karst faults densities, and the flooding regime for karstic, bodies of water, and age of parental materials, explain 65% of spatial distribution of soils from Quintana Roo, Mexico.
The analysis of classification denotes that above 83% of soil WRB group assignments are correct.
The soil WRB groups that occupies the territory is the Leptosol, Gleysol and Phaeozem, together occupy 75.6% of surface. Other soil WRB groups are Kastanozem, Regosol, Vertisol, Histosol, Solonchak, Arenosol and Fluvisol.
The map developed with data from the soil forming factors and associated with mathematical methods to infer information in the places where there are no data is an important input for the decision making process.
The index of the vulnerability of the Yucatecan karstic aquifer (IVAKY) is proposed.
The IVAKY was built based on a geomorphopedological map scale of 1:50 000, which contains the density and type of karst depressions and soil associations in each geomorphopedological unit. The climate factor is included through the length of the rainy period that considers amount, distribution and intensity of the rain.
The three factors (topography, soils and climate) were weighted with the process of hierarchical analysis (AHP) using ArcGis.
It was identified that the ring of sinkholes and part of the northeast of Yucatan state have the extreme level of vulnerability, where dominated sinkholes in contact with the aquifer and soil as Nudilithic Leptosols, Lithic Leptosols and Rendzic Leptosols, occupying 19% of the state surface.
Low and very low levels of vulnerability are located in southern Yucatan in areas of equal or greater than 50 masl, with low to medium density of karstic depressions (uvala and poljes) and Luvisols, Vertisols and Stagnosols associated with Leptosols ( 12% of the state surface).
In areas with very high levels and high vulnerability, the general population – including producers, entrepreneurs and decision makers – must be informed and made aware that land use is adequately managed, because poor management or activities intensely productive would represent both potential threats and high risks of pollution.
By contrast, in areas with low levels and very low vulnerability, anthropic activities represent a lower risk of aquifer contamination.
Finally, the proposed approach is replicable and could be used to assess the vulnerability of aquifers in regions with similar environmental characteristics in Mexico, Guatemala, Belize, Cuba and the United States of America (Florida).
Aguilar, Y*., F. Bautista, M. Mendoza, O. Frausto, T. Ihl y C. Delgado. 2016. IVAKY: Índice de la vulnerabilidad del acuífero kárstico yucateco a la contaminación. Revisa Mexicana de Ingeniería Química, 15(3): 913-933.
Living almost 15 years in karst has allowed me to know the particularities of its soils, its diversity. For that reason, when I see the maps of soil organic carbon content I am horrified to see such great mistakes made by my colleagues, the same feeling causes me to hear or read that the Yucatan peninsula, is the largest store of organic carbon in the soil in Mexico.
The organic carbon inventories in the soil in karst areas should be done in a very different way to the way they are being carried out. Discontinuity and spatial heterogeneity should be taken into account at short distances of meters. Soil bulk Density data must be generated and the soil depth not to be used beyond the real depth.
The summary of the paper is:
The organic carbon stock in Leptosls with discontinuous distribution in the Peninsula of Yucatan
The SOC estimation requires quantifying the coarse fraction(stones and gravels), bulk density and depth. The soils inventory realized for INEGI didn´t reports the first two parameters, then, the generated SOC maps have considerable doubt SOC.
The objective was to evaluate the spatial variability of soil organic carbon over short distances, as well as to report the contents of organic carbon per unit area in Leptosols from northern of Yucatan Peninsula.
102 samples were taken; organic carbon was analyzed by technique of potassium dichromate; and coarse fragments (coarse gravel, medium and fine gravel) were separated from the fine earth. The Color was recorded dry and wet, bulk density was measured using the amount of fine earth in a volume of 10×10 cm surface by a depth to find the rock.
Leptosols presented SOC values below 100 t ha-1 reported for this area, with mean values of 32.85, 37.57, 43.72, and 61.93 t ha-1, for dark brown soils, very dark brown, blacks and very dark grays respectively. Coarse fragments ranging from 6.7% to 96.4% with an average of71.15%.
The amount of edaphic organic carbon is in agreement with the values reported in percentage but lower than those reported in unit of surfaces, which is why it is being overestimated.
The spatial analysis of the soils at short distances reveals a high discontinuity and variability in the percentage of carbon, as well as in the depth and quantity of coarse fragments.
The comparison in the COS content between soils should consider the spatial discontinuity and the amount of COS in kilograms per hectare.
In the soil organic carbon inventories in the north of the Yucatán Peninsula, there has been an overestimation of the organic carbon of the soil that must be corrected considering the discontinuity of the soil and its shallow depth.
Delgado C, Bautista F, Calvo-Irabien LM, Aguilar-Duarte Y y Martínez-Tellez J. 2017. El carbono orgánico en Leptosols con distribución discontinua en la península de Yucatán. Ecosistemas y Recursos Agropecuarios. 4(10): 31-38.
By A. Sanchez, F. Bautista, R. Cejudo, A. Goguichaishvili, J. Reyes, F. Solis and J. Morales
Many studies have shown that the magnetic increase in urban dust is related to the heavy metal pollution. Urban dust contains heavy metals circulating in the atmosphere of the cities. The skin contact, oral intake, and breathing of urban dust is related to serious health problems such as cancer. Chronic exposure of the population to urban dust is a public health problem. The objective of this work was the assessment of pollution using the magnetic increase in urban dusts.
Assessments of magnetic increase on urban dust samples collected on different surfaces, mostly paved and unpaved roads, were performed in order to evaluate the environmental contamination in Mexicali City (medium-sized city on the Mexico-USA border). Rock and mineral magnetic techniques consisted of systematic measurements of mass-specific magnetic susceptibility and isothermal remanent magnetization at 0.7 T.
Magnetic increase was estimated by comparing magnetic concentration for each sample relative to reference value obtained from the site with almost no human activity also known as conservation area in the suburb of town. Additional magnetic parameters as the S-200 ratio and Curie temperatures were used to identify predominant magnetic carriers.
Figure 1. Magnetic susceptibility and Saturation Isothermal Remanent Magnetization in urban dust from divers soil urban uses
Figure 2. Map of the mangnetic increace as pollution indicator.
Geostatistical analysis and interpolation techniques (experimental variogram and ordinary Kriging, respectively) were carried out in order to determine the spatial distribution of magnetic enhancement and relative levels of environmental contamination.
The results indicate that impure magnetic is the main mineral in most studied samples, other results are:
- The background values of the magnetic signal is located in the Conservation Area
- At sites with different levels of pollution, the magnetic signal was dominated by non-stoichiometric magnetite and grain coarse. Particles are essentially anthropogenic combustion product.
- The highest level of the magnetic increase occurred in areas of high traffic as well as in industrial, commercial and services areas.
- In the map we show the most polluted areas in which it should take remedial action.
Sánchez-Duque, A., F. Bautista, A. Gogichaishvili, R. Cejudo-Ruiz, J. Reyes-López, F. Solís-Domínguez y J. Morales-Contreras. 2015. Evaluación de la contaminación ambiental a partir del aumento magnético en polvos urbanos – Caso de estudio para la ciudad de Mexicali, México. Revista Mexicana de Ciencias Geológicas, http://satori.geociencias.unam.mx/en_prensa/SanchezDuque-ENPRENSA.pdf
By West Marrin, Ph.D.
Conventional seawater desalination, wastewater recycling, geoengineering, and transcontinental water importation are a few of the solutions that have been proposed to address the shortage of available freshwater. While useful for a limited timeframe or in certain locations, these technologies have drawbacks related to energy requirements, environmental effects and long-term sustainability.
Contributors to atmospheric carbon dioxide are recommending the “sequestering” of carbon in the oceans or underground in saline aquifers that frequently involves capturing greenhouse gases and relocating them to environments that are not in direct contact with the atmosphere. Ocean sequestration can have devastating effects on marine chemistry and biodiversity, whereas underground sequestration can pollute potable groundwater aquifers.
Technologies such as cloud seeding have long been hyped as a potential means of increasing local rainfall and, although potential side effects are often minimal, their reliability is still in question. Fertilizing the oceans with soluble iron and creating tropical tree plantations have been proposed to limit the rise in atmospheric carbon dioxide levels, but their effects on soil productivity, ecosystem stability and critical water quality parameters are unknown. Those who recommend geoengineering techniques often believe that the immediate consequences of climate change are more of a concern than are the potential longer-term negative effects.
The reuse of wastewater can produce potable water, although treatment to drinking water standards is both energy- and water-intensive. Constructed wetlands, or living machines (wetland-like systems), and various types of treatment lagoons that utilize aquatic plants or microalgae to remove pollutants from wastewater streams are significantly more efficient than are conventional treatment facilities. Conventional or and centralized treatment facilities utilize chemicals and electrical energy to clean wastewater, while wetlands and lagoons primarily utilize plants and microorganisms. Although constructed wetlands cannot produce potable water, they can produce water suitable for irrigation, cooling, and other household purposes.
Water reuse and conventional seawater desalination may eventually become expensive necessities for providing potable water to drought-stricken regions; however, exploring more energy-efficient alternatives that produce fewer wastes may be prudent in the interim.
Figure 1. Seawater desalanization is a non sustainable solution
Alternative Energy Sources.
Conventional energy sources (e.g., fossil fuels, nuclear, hydroelectric) are major users and/or polluters of water, but a number of supposedly “green” energy sources are nearly as water inefficient. Hydrogen gas is often touted as a substitute fuel, but most hydrogen gas is produced by reacting steam with natural gas, a process that is both water consumptive and polluting.
Bioethanol is even more water unfriendly as a result of its dependence on cultivating starchy plants that have the same irrigation demands as food crops and that pollute waters with pesticides, fertilizers and processing wastes. Moreover, the global production of bioethanol has been linked to regional food shortages. Alternatively, the combined actions aquatic algae and bacteria can produce hydrogen gas in a complex process that generates a renewable fuel.
Bulk Water Imports.
A common response to drought is moving water from where it is to where it is not. Much of the U.S. Southwest was developed (or overdeveloped) using this tactic, and now the hunt is on for water from more distant sources. Beyond the enormous energy demands of transporting water through pipelines or canals and the staggering costs of building the required infrastructure, importing entire water supplies is neither sustainable nor secure.
Figure 2. Import water is a non sustainable solution
Similarly energy inefficient and unsustainable is the proposed shipping of bulk water (via large tankers) between continents or towing of icebergs from Polar Regions. Questions remain as to whether shipping a more limited volume of bottled drinking water is even energy efficient.
The diversity of soil also called pedodiversity and edafodiversity is a basic concept in soil science, it is the recognition of differences between soils using some taxonomic scheme as Soil Taxonomy (USDA) or the World Reference Bases of Soil Resource (WRB) (Figure 1).
Figure 1. An example of the diversity of soils in Latin America
Along with the identification of soil profile (taxon, name), recognizing the occupied surfaces is required, this activity is called soil geography. The product is a soil map.
What follows is the recognition of the potential use of soils and recognizing the environmental and ecological functions performed by each soil, each soil area. The product is the map of soil functions.
One of the environmental functions of soils is water purification, its function as a natural reactor as plant wastewater treatment.
As it can be seen in Fig. 2 Soils best filter and purify water are Vertisols. However, Luvisoles work best in the decomposition of the soluble organic matter.
Figure 2. Application of wastewater to different soil columns. In flasks below, you can see the differences in water quality after passing through the soil column. ARP = swine wastewater
Vertisols absorb the soluble organic matter; however, the decomposition of organica matter is slow. On the other hand, Luvisols absorb soluble organic matter in mean quantities; but the organic matter decompose faster.
Now you know one environmental function of soils: water purification capacity you use and drinking.
More information, http://www.actswithscience.com/assofu-2/
- Bautista F., A.J. Zinck.y S. Cram. 2010. Los suelos de Latinoamérica: retos y oportunidades de uso y estudio. Boletín del Sistema Nacional de Información Estadística y Geográfica. 2: 93-142.
- Aguilar Y. y Bautista F.. 2011. Extrapolating the suitability of soils as natural reactors using an existing soil map: application of pedotransfer functions, spatial integration and validation procedures. Tropical and subtropical agroecosystems. 13: 221- 232. http://www.veterinaria.uady.mx/ojs/index.php/TSA/article/view/810/0
- Aguilar Y., Bautista F., and E. Díaz-Pereira.2011.Soils as natural reactors for swine wastewater treatment. Tropical and subtropical agroecosystems. 13: 199- 210.http://www.ccba.uady.mx/ojs/index.php/TSA/article/view/815