Evaluation of the Toxicity of Municipal Effluents from a Locality in the State of Mexico Using Hyalella azteca as a Bioindicator

Abstract

Agriculture is a dominant component of the world economy since this primary activity allows us to have access to the food required by the populations; however, this need for food has led to the expansion of irrigation and an increasing use of fertilizers and pesticides in order to achieve and maintain higher yields and has become a significant source of organic pollution in most countries, which has caused a significant and generalized dysfunction of ecosystems through the various toxic effects induced in organisms. According to WHO reports, nitrogen levels in groundwater have increased in many parts of the world as a result of “intensification of agricultural practices”; in some parts of Europe, nitrate levels have increased to the point that more than 10% of the population drinks water with nitrate levels above the norm of 10 mg/L, along with other activities related to agriculture which have an impact on water quality, such as the application of fertilizers, manure, and pesticides, which cause high levels of pathogens, metals, phosphorus, and nitrogen. The ecological, recreational, and tourist state park “Hermenegildo Galeana” is located in the southern part of the state of Mexico, specifically in the municipality of Tenancingo, State of Mexico; this park is important because in this there are about 30 different species of plants, ferns, mosses, and different fungi, as well as housing species such as lynx, jaguarundi, coyote, tuza, Peter squirrel, skunk, rabbits, opossum, Cozumel badger, armadillo, fox, buzzard, red-tailed hawk of Tres Marias, carpenter, hummingbird, sparrow (finch of Guadalupe), swallow, quail, heron, lizard, snake, salamander, and viper; in addition there are two perennial river currents, one corresponds to La Fabrica, located at the east end of the park, and another is located westward called Puentecillas, and the rest of the fluvial network that make it up are intermittent; also within the park you can distinguish other bodies of water, such as the spring located south of the limit, near the town of Monte del Pozo and San Antonio Agua Bendita, and near the park in which small boards have been created to store water that serves for irrigation of the agricultural area, occupied mostly by greenhouses with flower production, which can represent a risk to the ecosystem by releasing various types of contaminants such as pesticides and metals. Due to this, the objective of this work was to evaluate the toxicity induced by effluents from the Hermenegildo Galeana Park (HGP) in a sentinel organism, Hyalella azteca, using biomarkers of oxidative stress as hydroperoxide content, lipoperoxidation degree, and carbonylated protein content, in addition to the activity of antioxidant enzymes superoxide dismutas and catalase.