Validation of a methodology by LC-MS/MS for the determination of triazine, triazole and organophosphate pesticide residues in biopurification systems.

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.

Evaluación de los Niveles de Mercurio en Productos Pesqueros en Costa Rica, Durante 2003-2013, como insumo para recomendar una ingesta semanal tolerable / Evaluation of Mercury Levels in Fishery Products in Costa Rica, During 2003-2013, as an Input to recommend a tolerable weekly intake

ResumenLos peces y mariscos pueden acumular mercurio en sus tejidos. En este trabajo se establecen recomendaciones de consumo de productos pesqueros para los residentes de Costa Rica, a partir de la evaluación de los niveles de mercurio en pescados y mariscos analizados durante los años 2003-2013.Objetivo: Evaluar los niveles de mercurio (en mg/kg) en muestras de productos pesqueros, analizadas por el Laboratorio Nacional de Servicios Veterinarios (LANASEVE) del Servicio Nacional de Salud Animal (SENASA) de Costa Rica, durante el período 2003-2013, para sugerir un valor de Ingesta Semanal Tolerable Recomendada (ISTR) de pescados y mariscos.Materiales y métodos: Los ensayos de mercurio se realizaron, bajo un esquema de análisis de riesgo determinado por el Programa Nacional de Residuos del SENASA, en pescados y mariscos. Las muestras de músculo fueron recolectadas por personal del SENASA y enviadas al LANASEVE para evaluar los niveles de Hg. Las concentraciones de mercurio fueron luego comparadas con los dos valores límite establecidos por la normativa nacional e internacional para productos pesqueros: 1 mg Hg/kg para pescados depredadores y 0,5 mg Hg/kg para otros productos pesqueros.Resultados: Se encontró que aproximadamente el 85 % de las muestras de pescados depredadores cumplió con el valor límite de 1 mg Hg/kg. Por su parte, el 93 % de los otros productos pesqueros evaluados, mostraron niveles de mercurio por debajo de 0,5 mg Hg/kg.Conclusión: Para mujeres embarazadas se establecieron valores de ISTR de 171 g de pescados depredadores o 889 g de otros productos pesqueros, en tanto para niños los ISTR recomendados fueron 100 g de pescados depredadores y 519 g de otros productos pesqueros.

AbstractFish and seafood can accumulate mercury in their tissues. This work establishes fishery products intake recommendations for the residents of Costa Rica, based upon the evaluation of mercury levels on fish and seafood analyzed during years 2003-2013.Objective: To evaluate mercury levels (in mg/kg) in fishery samples, as analyzed by the National Veterinary Services Laboratory (LANASEVE) of the National Animal Health Service (SENASA) of Costa Rica, during the 2003-2013 period, to suggest a Tolerable Weekly Intake Recommendation (TWIR) for fish and seafood.Methods: Mercury assays were performed, under a risk-analysis scheme determined by the National Residue Program of SENASA, in fish and seafood. Muscle samples were collected by SENASA staff and sent to LANASEVE for evaluation of Hg contents. Mercury concentrations were then compared to two limit values established by national and international regulations for seafood: 1 mg Hg/kg for predatory fish, and 0,5 mg Hg/kg for other fishery products.Results: It was found that, approximately, 85 % of predatory fish samples complied with the 1 mg Hg/kg limit value. Meanwhile, 93 % of the other fishery products analyzed, showed mercury levels below 0,5 mg/kg.Conclusion: For pregnant women TWIR values were established at 171 g for predatory fish and 889 g for other fishery products, while for children the TWIR values were 100 g for predatory fish and 519 g for other fishery products.