RESUMO
Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC) in fillet samples showed values of 0.007-0.014 and 0.01-0.02 Bqâkg-1 wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16-3.26, 0.70-1.13 and 0.93-1.37 Bqâkg-1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13-0.39, 0.005-0.126 and 0.009-0.08 mgâkg-1 ww, respectively, while in gill samples they were 0.11-0.43, 0.002-0.039 and 0.02-0.26 mgâkg-1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 Lâkg-1 in fillet and gills, respectively, and BAFU total = 1.5 Lâkg-1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 Lâkg-1 in fillet and gills, and BAFPb = 6.5 and 22 Lâkg-1 in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat.
Assuntos
Peixes , Contaminação de Alimentos , Metaloides/toxicidade , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Poluentes Radioativos da Água/toxicidade , Adulto , Animais , Monitoramento Ambiental , Peixes/metabolismo , Brânquias/química , Brânquias/metabolismo , Humanos , Fígado/química , Fígado/metabolismo , Metaloides/análise , Metaloides/metabolismo , Metais Pesados/análise , Metais Pesados/metabolismo , México , Medição de Risco , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Poluentes Radioativos da Água/análise , Poluentes Radioativos da Água/metabolismo , Abastecimento de ÁguaRESUMO
UNLABELLED: Since 2000, the city of Chihuahua had a distribution system of treated wastewater for irrigation of green areas and has replaced this water for processes that do not require the consumption of drinking water. This replacement was necessary in order to meet the growing demand for potable water which has exceeded the current supply of 700 L (184,88 gallons) per second. Nowadays it is necessary to identify and assess the risks to public health and the environment due to the substitution of drinking water by treated wastewater in the last 10yr. Treated wastewater contains compounds whose effects have not been evaluated when used for irrigation in public green areas. Therefore, it is not known whether there is a danger to the health of park visitors due to exposure and/or inhalation of the emitted gases, accidental ingestion of water, or impact to the environment. The purpose of the research, using an experimental prototype, is to identify the changes from nitrogen present in the treated wastewater to nitrous oxide. The research objective is the generation of data to simulate a regional scale at this stage, which will be analyzed and statistically validated using Minitab and Origin software. The experiment was performed using three different samples to compare water quality: drinking water treated wastewater, and water with nitrogen-based fertilizer (urea). Prototypes were filled with two types of soil: sand and clay Each type of water was sprinkled on the prototype, grass was planted in it, and the prototype was equipped with samplers to capture the gas in the root zone. The authors found high emissions of nitrous oxide in the clay-filled lysimeters, and climate and growing conditions of vegetation were the most important factors for producing nitrous oxide. IMPLICATIONS: Major problems in the ecosystem arise from solutions that are not based on environmental public policy research or experimentation. For example, before application a specific policy or regulation, research should be performed to evaluate long term effects to the ecosystem and this can be done through close monitoring. This study raises awareness about the public policy of substituting potable water with treated wastewater for irrigation of green areas in Chihuahua City. The present study was performed during a sufficient period of time in order to assess the impact to the environment.