RESUMEN

Groundwater in the Yucatan State is the only source of water. The karst aquifer in Yucatan is vulnerable to pollution. Anthropic activities in Yucatan, such as pig farming, are usually related to high wastewater discharges and water pollution. Administrative and logistical issues in developing on-site sampling to evaluate water quality are common in Mexico. The RENAMECA database provides official data related to groundwater quality. However, no analysis based on this database has been reported. A groundwater quality evaluation based on five reference pig farms and the effect of spatial and temporal anthropic activities in the study area was developed. Eighteen wells based on their location concerning the selected pig farms were studied. On-site sampling and laboratory analysis of the supply water and wastewater in the study case farm were done. Fecal coliforms (FC) values (maximum 2850 MPN [100 mL] -1) in most cases for supply water wells exceeded the allowed limit by NOM-127-SAA1-2021. The year of monitoring was significant (P < 0.05) on FC concentrations. Population density and the proximity of wells to population centers affect negatively the presence of total dissolved solids (TDS) and total nitrogen (TN). TDS (maximum value 2620 mg L -1) and phosphorus presence could be related to agricultural activities, human settlements, and local aquifer conditions. A local wastewater treatment issue is evident. Groundwater is not quality for consumption without treatment. Regarding the issues in on-site water monitoring, database analysis provides an approximation of the real situation of groundwater quality.

RESUMEN

Agriculture effluents from cleaning and handling equipment used in pesticide applications can contaminate superficial and groundwater sources when not correctly disposed of. Biobeds using soil enriched with amendments represent a viable technology to control and minimize pesticide pollution of soil and water in farmlands. They are usually installed outdoors without protection, making them vulnerable to rain flooding, lack of moisture, drought, and intense heat or cold. Temperature (T) and moisture (M) of the biomixture are considered two of the most important physical factor affecting pesticide dissipation. This study aimed to evaluate the effect of T and M on the dissipation of five of the most used pesticides (carbofuran, atrazine, 2,4-D, diazinon, and glyphosate) in Yucatan State, Mexico. Three experiments using miniaturized biobeds considering optimal temperature and moisture (T of 30 ± 2 °C and 90% water holding capacity [WHC]) were performed. The optimal dissipation time and the effect of T, M variations, and volatilization was determined. The optimal dissipation time was over 14 days. Carbofuran was the least dissipated pesticide and glyphosate the most. The primary factor affecting pesticide dissipation was T (P < 0.05), reaching rates of dissipation of 99% at 45 °C. Variations of M in the biomixture were not significant on pesticide dissipation (P > 0.05). The white-rot fungi were observed; its presence was related to increments of T. Head Space analysis (at 45 °C) showed low pesticide volatilization (≤0.03%) for all pesticide used were quantified; water vapor condensation could reduce the pesticide volatilization for experimental conditions.

RESUMEN

A growing concern exists over water contamination by veterinary pharmaceuticals from small pig farms in Yucatan, Mexico, where the anaerobic digesters installed as the wastewater treatment system are not operated properly. Therefore, considerable interest exists to develop analytical methods to detect these compounds and characterize their fate in the environment. In this study, the detection of three antibiotics (enrofloxacin, oxytetracycline and sulfamethoxazole) and a ß-agonist (ractopamine) was carried out using fluorescence spectrophotometry, with a semi-quantitative approach and a low environmental impact. Wastewater samples from 10 pig farms were analyzed, detecting concentrations of approximately 0.043 µg mL-1 for enrofloxacin, 1.427 µg mL-1 for oxytetracycline, and 9.748 µg mL-1 for sulfamethoxazole. The detection of these pharmaceuticals in the effluents of treated wastewater from the biodigesters of the pig farms suggests the need to optimize the system and prevent the entry of these compounds into the environment.

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RESUMEN

Biobed systems are an important option to control point pollution in agricultural areas. Substrates used and microbial diversity present in a biomixture perform an essential function in pesticide dissipation. In this study, the effects of soil (50% of volume/volume [V/V] proportion for all biomixtures) and four soil-based biomixtures (miniaturized biobeds; addition of novel substrates from southeastern Mexico) on dissipation of high concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), atrazine, carbofuran, diazinon, and glyphosate and on microbial diversity in biomixtures were evaluated. Small residual amounts of all pesticides at 20 (<2%) and 41 (<1%) days were observed; however, the lowest efficiency rates were observed in soil. Glyphosate was the only pesticide that completely dissipated in soil and biomixtures. Archaea, bacteria, and fungi were identified in biobeds, with bacteria being the most diverse microorganisms according to the identified species. The presence of white-rot fungi (normally related to pesticide degradation in biomixtures) was observed. Effects of the pesticide type and of biomixtures on pesticide dissipation were significant (P<0.05); however, only the effect of biomixtures on microbial diversity was significant (P<0.05); microbial diversity and richness had a significant effect on the residual amount of pesticides (P<0.05). Microbial diversity in terms of phyla was directly related to physicochemical parameters such as organic matter, lignin, water-holding capacity, and pH of soil and biomixtures.

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RESUMEN

Misuse of pesticides in farming activities leads to contamination of drinking water sources and is responsible for animal and human health problems. The biobeds are practicable option to minimize contamination by pesticides during preparation, use and washing of equipment for pesticide treatments. This research aimed at testing substrate mixtures to optimize biobed efficiency to remove pesticides under the climate of the Yucatan (México). Agricultural soil and 11 mixtures adding vegetable compost, sisal pulp, corn stover and seaweed were tested under controlled conditions. Each biomixture was exposed to a mixture of five pesticides (2,4-diclorophenoxyacetic acid "2,4-D" [1.08 mg cm-3], atrazine [2.50 mg cm-3], carbofuran [0.23 mg cm-3], diazinon [0.34 mg cm-3], and glyphosate [0.36 mg cm-3]) in a period of 41 days. Monitoring of the dissipation of pesticide residues showed that pesticides were quickly dissipated in soil at microcosm level experiment, while at two critical times of 20 and 41 days, all mixtures of substrates (biomixtures) were efficient in dissipation of high concentrations of pesticide in a short time (>99%). Time, biomixture and type of pesticide were shown to be the main parameters influencing pesticide dissipation (P < 0.05). Several other physicochemical parameters of the biomixtures, such as organic matter (OM), lignin, water holding capacity (WHC), and pH, were also significant on pesticide dissipation (P < 0.05), being pH the most significant.

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