RESUMEN
Honey has multifaceted nutritional and medicinal values; however, its quality is hinged on the floral origin of the nectar. Taking advantage of the large areas that they cover; honeybees are often used as bioindicators of environmental contamination. The focus of the present paper was to examine the quality of honey from within the vicinity of an abandoned pesticide store in Masindi District in western Uganda. Surficial soils (<20 cm depths) and honey samples were collected from within the vicinity of the abandoned pesticide store and analysed for organochlorine pesticide (OCP) residues using gas chromatograph coupled to an electron capture detector (GC-ECD). The mean level of ∑DDTs in all the soil samples was 503.6 µg/kg dry weight (d.w). ∑DDTs contributed 92.2% to the ∑OCPs contamination loads in the soil samples, and others (lindane, aldrin, dieldrin, and endosulfans) contributed only 7.8%. Ratio (p, p'-DDE+p, p'-DDD)/p, p'-DDT of 1.54 suggested historical DDT input in the area. In all the honey samples, the mean level of ∑DDTs was 20.9 µg/kg. ∑DDTs contributed 43.3% to ∑OCPs contamination loads in the honey samples, followed by lindane (29.8%), endosulfans (23.6%) and dieldrin (3.2%), with corresponding mean levels of 14.4, 11.4 and 1.55 µg/kg, respectively. Reproductive risk assessment was done based on the hazard quotient (HQ) and hazard index (HI) procedure. In our study, the calculated HIs for adults (102.38), and children (90.33) suggested high potential health risks to the honey consumers. Lindane, endosulfan and p, p'-DDD detected in the honey samples at levels exceeding the acute reference dose (ARfD) are known risk factors for spontaneous abortion, reduced implantation, menstrual cycle shortening, impaired semen quality, and prostate cancer in exposed individuals and experimental animal models.
Asunto(s)
Exposición Dietética/estadística & datos numéricos , Miel/análisis , Hidrocarburos Clorados/análisis , Residuos de Plaguicidas/análisis , Adulto , Aldrín/análisis , Animales , Niño , DDT/análisis , Diclorodifenil Dicloroetileno/análisis , Dieldrín/análisis , Endosulfano/análisis , Biomarcadores Ambientales , Monitoreo del Ambiente/métodos , Femenino , Hexaclorociclohexano/análisis , Humanos , Masculino , Plaguicidas/análisis , Salud Reproductiva , Análisis de Semen , Suelo , UgandaRESUMEN
Naturally occurring phyllosilicate minerals such as talc and vermiculite in conjunction with n-tetra butyl ammonium bromide (TBAB) co-catalyst were found to be efficient in the coupling of CO2 with epoxides to form cyclic carbonates. The reaction was carried out in a pressurized autoclave reactor at moderate pressures of 10-35 bars and temperatures of 100-150 °C. The optimized catalyst system exhibited > 90% conversion of the epoxides and > 90% selectivity for the desired cyclic carbonates, in the presence or absence of a solvent. The selectivity of the catalytic system could be improved with heat pre-treatment of the phyllosilicates albeit this resulted in slightly lower epoxide conversion. The results obtained using the heat treated phyllosilicates strongly support the hydrogen bond assisted mechanism for the cycloaddition of epoxides and CO2. The cycloaddition reaction could also be carried out in the absence of TBAB, although lower cyclic carbonate yields were observed. The phyllosilicate part of the catalyst system is heterogeneous, easy to separate after completion of reactions and reusable a number of runs without loss of activity.
RESUMEN
The study carried out a primary validation of Charm II tests for the detection of antimicrobial residues in aquaculture fish. The validation was performed according to European Commission Decision 2002/657/EC and the parameters determined included: detection capability, repeatability, reproducibility, specificity and robustness for the detection of antimicrobial residues in fish. Fish materials from different species including cat fish, trout, salmon, sea bass, tilapia, lingue and pangasius, were spiked with varying concentrations of selected antimicrobials including sulfonamides, ß-lactams, macrolides, tetracyclines and aminoglycosides to determine the detection capabilities and other validation parameters of the Charm II tests. Results of the validation showed that the detection capabilities for the tetracyclines ranged from 25 to 100 µg/kg, while the sulfonamides and aminoglycosides were detected at 25 µg/kg for all species under study. The detection capabilities for the beta-lactams ranged from 25 to 300 µg/kg; and was 100 µg/kg for the tested macrolides. Results of the study showed that there was no significant difference between counts for samples read immediately after addition of the scintillation liquid and those read 14 h after addition of the scintillation liquid, provided that there was good vortexing before analysis. There was also no significant difference between counts for the same samples analyzed in different runs under repeatability and reproducibility conditions at the same spiking concentrations for the different fish species analyzed. The relative standard deviation for both repeatability and reproducibility ranged from 1.2 to 15.1%. The Charm II tests were found to be 100% group specific, as none of the antimicrobials kits, gave false positive results when testing non-target antimicrobial drugs. Results of this study demonstrate the suitability of the Charm II technique as a rapid screening tool for detection of antimicrobial residues in a variety of fish species at maximum residue limits (MRL) established in the EU guidelines, with the exception of tilmicosin which was detected at 2 MRL. The results also prove the robustness, specificity, reliability and precision of the Charm II assay in the detection of various antimicrobial residuals in fish and its applicability for the rapid evaluation of the quality of aquaculture fish for safety and trade purposes.