The abundance of karst depressions in Yucatán has been widely recognized, but they have not been classified or quantified despite their importance in land-use planning. Our objective was to study the types and areas of the sinkholes, uvalas, and poljes and identify their patterns of spatial distribution. We used 58 topographic maps (1:50,000) from INEGI, from which we extracted the depressions and bodies of water. For typology, we used a circularity index and the shape and area of the depressions. For single-density analysis, we extracted the centroids and added an inventory of karst features (cenotes, caves). We counted 6717 depressions with a total area of 454 km 2 and 750 karst features. We identified 4620 dolines (34 km 2 ), mainly in plateaus below 30 masl. In number, they are followed by uvalas (2021) and poljes (76), occupying together a similar area (210 km 2 ) and dominating in elevations higher than 30 masl. Eighty percent of the dolines were automatically labeled. The density of depressions allowed us to identify the "ring of cenotes" and the "field of dolines" according to two main types of factors, structural and climatic. The typology and density of the depressions could be used as geomorphological differentiation criteria in the vast plateaus of central and eastern parts of the state.

The design of proxy techniques is an innovative tool to monitor the potentially toxic elements of pollution in road dust. This study evaluated the use of road dust color as a proxy methodology to identify samples contaminated with presumably contaminating elements. FRX determined the concentrations of Fe, Ti, Rb, Sr, Y, Cu, Zn, and Pb in eighty-five road dust samples. The appliance of the RGB system and the Munsell color cards identified five color groups of road dust samples. The discriminant analysis validated these groups by colorimetric indices and presumably contaminating elements. The “very dark gray” color of road dust contains the highest concentrations of Pb, Cu, Zn, and Y. The redness and saturation rates showed high correlations with presumably contaminating elements in “dark gray” and “very dark gray” color samples. The color of road dust, as a proxy technique, allows identifying samples contaminated with presumably contaminating elements.

Cities occupy a relatively small percentage of the Earth’s surface. However, they influence the entire biosphere, affect biodiversity and environmental conditions, which end up affecting human health and well-being. Therefore, it is necessary to evaluate the level of contamination by heavy metals in urban environments, as well as the possible ecological and human health risks. In this study, the urban dust of six Mexican cities was analyzed and it was found that all studied cities were contaminated, except for Mérida, when soil world background value was used as reference. In contrast, Mérida and Morelia were the most contaminated when a local background was used (decile 1). The concentrations in the cities for the metals Cu, Pb and Zn, decreased in the order CDMX > San Luis Potosí > Toluca > Morelia-Ensenada > Mérida. In the particular case of Cu and Pb, SLP accompanied CDMX as the most polluted city. For Mn and Fe concentrations, the order was CDMX > Toluca > Ensenada > SLP > Morelia-Mérida. No potential ecological risk was found due to contamination by Cu, Pb, and Zn, in the urban dust of the studied cities. However, the higher metal contribution to the potential ecological risk in all the cities was from Pb; and it represented a moderate ecological risk of more than 25% on CDMX, SLP, and Toluca sites. Pb can also be a potential risk for children’s health. In addition, chronic exposure to Fe and Mn could trigger many ailments. In the future, it is important to identify the main sources of Pb in cities and seek mitigation strategies to reduce the possible adverse effects that this metal may be causing.

<p><strong>Background. </strong>Pig farms are an important economic activity in the state of Yucatán, but they cause great environmental damage, such as groundwater contamination, air pollution, and soil degradation, which together affect both health and economy of local populations. <strong>Objective:</strong> The aim of this work was to spatially identify the surface suitable for the establishment of pig farms in the state of Yucatán where damage to the environment and human health are not a serious problem. <strong>Methodology:</strong> For the elaboration of the cartographic model, four maps were used as inputs that represent the evaluation variables, they are: altitude, karst depressions, soils and duration of the rainy season. They were converted to raster formats and handled in a geographic information system. Five classes of territorial aptitude for the establishment of pig farms were defined, 1 = very low; 2 = low; 3 = mean; 4 = discharge; and 5 = very high. The index and superposition method were used to integrate the four variables in a territorial aptitude model. To assign weights to each variable, a multi-criteria decision technique called "analytical hierarchies’ method" was used. <strong>Results:</strong> The surface area of the territory of the state of Yucatán according to the suitability classes for the establishment of pig farms was: a very low with 21%; low with 50%; medium with 15%; high with 6%; and the very high zone with 8%. The areas of high and very high suitability for the establishment of pig farms are located in the south of the state. <strong>Implications:</strong> the map of the suitability for the establishment of pig farms on a regional scale will be an important input for updating the "program of ecological land management" of the state of Yucatan. However, due to the particularities of the karst, it is very necessary to carry the analysis to scales greater than 1:50 000 for the development of specific pig projects. <strong>Conclusions:</strong> The land evaluation model for the establishment of pig farms in the state of Yucatán on a regional scale, allows spatially identifying suitable and highly suitable areas for such activity. The most suitable territories are located in the south of the state, so it would be recommended that the growth of pig farming be those territories after consulting with the native populations.</p>

<p><strong>Introduction</strong>: The state of Yucatán is the third national producer of pork meat due to a large number of pig farms, there are them of all sizes from very small to mega-farms with more than 30 000 pigs, many of which generate environmental and social problems. <strong>Objectives</strong>: The analysis of the operation of pig farms in Yucatán; identification of environmental problems; and proposals for mitigating damage to the environment and human health. <strong>Results</strong>: The environmental problem is generated by the large amount of water with which they operate to clean the farms and cool the pigs during high-temperature days. In addition to the large volumes of water extraction, large volumes of wastewater are generated that are not properly treated and that contaminate air, soil, and groundwater. In this work, the traditional way of operating farms is documented, emphasizing environmental damage. The particularities of karst landscapes and their environmental vulnerability are explained. <strong>Implications</strong>: Ways of reducing environmental problems are proposed with the idea that they are taken into account to move towards sustainable management of pig farms in the state of Yucatán, for example, selection of the best sites for pig farming (relief, soils, climate, and depth of groundwater), reduction of extracted water, treatment through artificial wetlands and agricultural use of wastewater through sprinklers in soils of the Luvisol, Nitisol and Vertisol groups. <strong>Conclusions</strong>: For the transit of contamination to Sustainability in the management of pig farms in the state of Yucatán requires knowledge, innovations to solve problems, social commitment with local communities, and environmental regulations. It will not be easy but it is possible.</p>