Chapters authored
Heavy Metal Contamination in a Protected Natural Area from Southeastern Mexico: Analysis of Risks to Human Health
In this chapter, a little of the history of Carmen City, Mexico is addressed; this island is immersed in a Protected Natural Area and in the “Campeche Sound” an oil extraction site. Fishing natural resources were for many years the pillar of the development of the area; the most commercially important species are still shrimp, oysters and scales. Nowadays, although the volumes of capture have decreased considerably, different species of high commercial value are still extracted. The considerable development of the oil industry has brought with its economic development and a better quality of life for its inhabitants; however, the ravages of pollution, rapid population growth, and deforestation have been the unwanted factor. This chapter addresses the effects of heavy metals on human health through a risk analysis, based on the criteria of the US Environmental Protection Agency (USEPA) that was carried out for different commercial species based on carcinogenic factors and not carcinogenic; the results show that the risk from consumption of these species is “potentially dangerous” for human health, especially in those species that, due to their eating habits (mollusks, bivalves, clams) tend to bio-accumulate heavy metals, such as cadmium, which it has been considered by the International Agency for Research on Cancer (IARC) as a risk factor; for this reason, the importance of periodically evaluating and monitoring oyster extraction banks, clams and, in general, all fishery products. Mexican legislation and various international legislations dictate the maximum permissible and tolerable levels of heavy metals in fishery products; the organisms considered in this study exceeded the permissible limits in copper and nickel, which represents a risk for human consumption.
Part of the book: Heavy Metals
Quantification of Heavy Metal Levels in Sediments of the “Palizada” River in a Protected Natural Area of Southeastern Mexico
This chapter shows the results of the determination of the levels of Copper (Cu), Iron (Fe), Magnesium (Mg), Manganese (Mn), and Cadmium (Cd) in sediments of the “Palizada River”; evaluated by atomic absorption. The results show high levels of Fe, Mg, and Mn concerning previous studies and are directly related to agricultural and livestock activities in the area. The metal-metal correlation analysis show significant values, suggesting that the generation source is the same. Some of the pollutants produced by industrial or population centers; end up in natural water bodies; by different physical processes, such as precipitation, complex formation, and others. These contaminants can bioaccumulate in aquatic organisms and reach humans through the food chain. Certain heavy metals such as cadmium (Cd) produced by human activities have been found in the oceans and the tissues of different organisms; which constitutes a risk for consumption; Cd is classified as an element that predisposes to the presence of Cancer. Therefore, the study of sediments is fundamental for determining the degree of contamination of an ecosystem.
Part of the book: Environmental Impact and Remediation of Heavy Metals
Purification of Rainwater Using a Photocatalysis Technique to be Applied to Communities in Ciudad del Carmen, Campeche, Mexico
Small communities far from the municipal seat do not have access to drinking water, so many children suffer from various gastrointestinal diseases, which cause these children to grow up with nutritional deficiencies. In the state of Campeche, there are 300 sunny days. This energy can be used to install water treatment systems to make it drinkable. Therefore, a treatment system with heterogeneous photocatalysis was proposed using a zinc oxide catalyst doped with silver nanoparticles. The reactor has a metal structure with a flat plate where clay plates support the catalyst. Samples were taken every 2 h to carry out the corresponding analyses and in a period of 8 h of reaction. For the characterization of rainwater adhered to Mexican regulations. The results showed that there was 6400 NMP/100 mL for fecal coliforms at the beginning, and after 4 h, this parameter goes to <2 NMP/100 mL. Initially, the same happened for fecal coliforms; 9200 NMP/100 mL was determined. After 4 h, this parameter drops to <2 NMP/100 mL. The same behavior was observed with chlorides, hardness, and total alkalinity, which showed a tendency to decrease significantly. This confirms that the system works properly to eliminate organic compounds and purify rainwater.
Part of the book: Water Purification