RESUMO
The presence of pharmaceuticals in the environment is known to have multiple origins; livestock activities comprise one scarcely studied source, both globally and specially in Latin-America. This work aims to study the occurrence of pharmaceuticals in wastewater from swine farms and their surrounding surface waters, in a highland livestock production area of Costa Rica. The monitoring of 70 pharmaceutical active compounds resulted in the detection of 10 molecules in farm wastewater (influents and effluents of the on-farm treatment system), including compounds of animal and human use. A 57% of effluents showed high hazard (ΣHQ > 1), mainly due to the compounds risperidone, ketoprofen, ibuprofen and naproxen. Additionally, ecotoxicological tests with Daphnia magna and Microtox classified at least 21% of the effluents as very toxic (10 < TU ≤ 100); likewise, 86% of effluents exhibited germination index (GI) inhibition values over 90% for Lactuca sativa. Seven molecules were detected in surface water, six of them of human use (1,7-dimethylxanthine, caffeine, cephalexin, carbamazepine, gemfibrozil, ibuprofen) and one (acetaminophen) of dual (human and veterinary) use; nonetheless, most of the detections were found in sampling points closer to human settlements than animal farms. Considering the set of molecules and their distribution, the livestock influence on surface water seems minimal in comparison with the urban influence. Only 16% of surface water samples showed high risk, mainly due to ibuprofen, gemfibrozil and caffeine; similarly, 45% samples presented GI inhibition >20% (no toxicity was determined towards Daphnia magna or Microtox). These findings in surface water suggest an incipient environmental risk in the area.
Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água , Animais , Costa Rica , Monitoramento Ambiental , Fazendas , Suínos , Águas Residuárias , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidadeRESUMO
Biopurification systems are useful in the management of pesticide residues and provide an option to dispose wastewaters of agricultural origin derived from pesticide application practices. The analysis of pesticide residues in the biopurification system biomixture is necessary to determine whether the removal of the target compounds occurs with reliable results. In this study, the pesticide extraction methodology was optimized and validated in a biomixture composed of coconut fiber, compost and soil, to determine a total of 43 molecules, distributed among triazines (10), triazoles (13) and organophosphates (20) using liquid chromatography coupled to a triple quadrupole mass spectrometer. For the validation, the parameters of linearity, matrix effect, limit of determination (LOD), specificity, selectivity, precision, trueness and robustness in the proposed biomixture were evaluated. The analyses of those parameters revealed satisfactory results of the method for most of the compounds, with the exception of diclorvos and ciromazine, for which the development of an alternative method is recommended. Once the extraction methodology was validated, the removal of eight molecules was assayed in a biopurification system used for the simultaneous treatment of a mixture of pesticide commercial formulations. Although most of the compounds were at least partially removed, none of them was eliminated at levels below the LOD. The removal pattern of ametryn, atrazine, chlorpyrifos, malathion and terbutryn was comparable to those obtained in other efficient biomixtures, and the highly recalcitrant triadimenol was eliminated; nonetheless, tebuconazole and diazinon were not significantly removed.
Assuntos
Biodegradação Ambiental , Resíduos de Praguicidas/análise , Triazinas/análise , Triazóis/análise , Poluentes Químicos da Água/análise , Cromatografia Líquida/métodos , Limite de Detecção , Modelos Lineares , Resíduos de Praguicidas/química , Resíduos de Praguicidas/isolamento & purificação , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos , Triazinas/química , Triazinas/isolamento & purificação , Triazóis/química , Triazóis/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificaçãoRESUMO
Biopurification systems (BPS) have been barely explored for removing complex mixtures of pesticides. In this study, the potential of a biomixture to remove simultaneously a mixture of herbicides (triazines), fungicides (triazoles) and insecticides (organophosphates) is presented. Also, a BPS using the same biomixture was used for treating a pesticide testing laboratory wastewater containing a mixture of 38 compounds. Ecotoxicological assays were conducted on the BPS elutriates to investigate the mixture detoxification. A mixture (concentrations of 4-8â¯mgâ¯kg-1) run in small-scale biomixture systems (SSB) for 128â¯d showed 59.3% removal of triazines, 68.5% of organophosphates and no elimination of triazoles. The treatment of the laboratory wastewater (individual concentrations range: 0.0036-0.25â¯mgâ¯kg-1) in the pilot-scale BPS for 281â¯d resulted in the elimination pattern of organophosphates (90.0%)â¯>â¯triazoles (73.4%)â¯>â¯carbamates (71.3%)â¯>â¯triazines (54.3%). Complete detoxification towards Daphnia magna and partial detoxification in Lactuca sativa seeds germination occurred in the BPS. Although the pesticide mixture complexity is higher in the BPS, the lower concentrations found in this matrix, could explain removal differences between SSB and BPS and the apparent inhibition in the elimination of carbamates and some triazines observed in the latter. These findings suggest that disposal of pesticide-containing laboratory-wastewater should be done in separate containers, according to chemical groups before their treatment in separate BPS, in order to reduce treatment periods. Monitoring the treatment process in the BPS with a battery of ecotoxicological tests is strongly recommended.
Assuntos
Organofosfatos/análise , Triazinas/análise , Triazóis/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Animais , Biodegradação Ambiental , Carbamatos , Daphnia , Ecotoxicologia , Fungicidas Industriais/análise , Herbicidas/análise , Inseticidas , Praguicidas/análise , Águas Residuárias/químicaRESUMO
This study used the Canadian Water Quality Index (CWI) to characterize water sampled at three points within the Purires River micro basin, Costa Rica. The first sampling point is located in a high zone with domestic agricultural activities, the second point around the mid-point of the flow of the river, and the third point at the lowest zone with extensive agricultural activities mainly centered on the production of fresh vegetables. Eleven physicochemical parameters (As, Cd, Cr, biochemical oxygen demand (BOD), chemical oxygen demand (COD), NH4 +, NO3 -, Pb, pH, percent saturation of dissolved oxygen (PSO), and total suspended solids (TSS)) and two microbiological parameters (fecal coliforms and enterococci) were evaluated. We evaluated three different Canadian Water Quality Indexes (CWIs): CWI-1 included only physicochemical parameters, CWI-2 included CWI-1 parameters plus fecal coliforms, and CWI-3 included CWI-2 in addition to enterococci. Statistical analysis of individual parameters showed significant differences between sampling sites. CWI-1 was unable to discriminate between the three sampling points, and characterized the water quality as 'fair'. CWI-2 was only able to discriminate when the water contained high levels of chemical and microbiological contaminants, while CWI-3 adequately discriminated water quality at each of the sampling points. The evaluation of enterococci together with more traditional water quality parameters enabled better categorization of surface water quality.
Assuntos
Enterococcus/crescimento & desenvolvimento , Rios/microbiologia , Microbiologia da Água , Qualidade da Água/normas , Costa Rica , Monitoramento AmbientalRESUMO
Drinking water utilities are relying more than ever on water sources impacted by wastewater effluents. Disinfection/oxidation of these waters during water treatment may lead to the formation of several disinfection by-products, including the probable human carcinogen N-nitrosodimethylamine (NDMA) and the regulated trihalomethanes (THMs). In this study, the potential of ion exchange resins to control both NDMA and THMs precursors in a single treatment is presented. Two ion exchange resins were examined, a cation exchange resin (Plus) to target NDMA precursors and an anion exchange resin (MIEX) for THMs precursors control. We applied the resins, individually and combined, in the treatment of surface and wastewater effluent samples. The treatment with both resins removed simultaneously NDMA (43-85%) and THMs (39-65%) precursors. However, no removal of NDMA precursors was observed in the surface water with low initial NDMA FP (14 ng/L). The removals of NDMA FP and THMs FP with Plus and MIEX resins applied alone were (49-90%) and (41-69%), respectively. These results suggest no interaction between the resins, and thus the feasibility of effectively controlling NDMA and THMs precursors concomitantly. Additionally, the effects of the wastewater impact and the natural attenuation of precursors were studied. The results showed that neither the wastewater content nor the attenuation of the precursor affected the removals of NDMA and THMs precursors. Finally, experiments using a wastewater effluent sample showed that an increase in the calcium concentration resulted in a reduction in the removal of NDMA precursors of about 50%.
Assuntos
Dimetilnitrosamina/química , Trialometanos/química , Purificação da Água , Resinas de Troca Iônica , Poluentes Químicos da ÁguaRESUMO
The main objective of this study was to examine the roles of powdered activated carbon (PAC) characteristics (i.e., surface chemistry, pore size distribution, and surface area) in the removal of N-nitrosodimethylamine (NDMA) formation potential (FP) in surface and wastewater-impacted waters. Also, the effects of natural attenuation of NDMA precursors in surface waters, NDMA FP concentration, and carbon dose on the removal of NDMA FP by PAC were evaluated. Finally, the removal of NDMA FP by PAC at two full-scale DWTPs was monitored. Wastewater-impacted and surface water samples were collected to conduct adsorption experiments using different PACs and activated carbon fibers (ACFs) with a wide range of physicochemical characteristics. The removal efficiency of NDMA FP by PAC was significantly higher in wastewater-impacted than surface waters. Adsorbable NDMA precursors showed a size distribution in the waters tested; the adsorbable fraction included precursors accessing the pore size regions of 10-20 Å and <10 Å. Basic carbons showed higher removal of NDMA FP than acidic carbons on a surface area basis. The overall removal of NDMA FP by PAC on a mass basis depended on the surface area, pore size distribution and pHPZC. Thus, PACs with hybrid characteristics (micro and mesoporous), higher surface areas, and basic surface chemistry are more likely to be effective for NDMA precursor control by PAC adsorption. The application of PAC in DWTPs for taste and odor control resulted in an additional 20% removal of NDMA FP for the PAC doses of 7-10 mg/L. The natural attenuation of NDMA precursors through a combination of processes (biodegradation, photolysis and adsorption) decreased their adsorbability and removal by PAC adsorption.