RESUMEN
Chlorination was investigated as a treatment option for degrading and thus removing saxitoxins (paralytic shellfish poisons, PSPs) produced by cyanobacteria (blue-green algae) from water. It was found to be effective with the order of ease of degradation of the saxitoxins being GTX5 (B1) approximately dcSTX > STX > GTX3 approximately C2 > C1 > GTX2. However the effectiveness of chlorine was pH dependent. Degradation as a function of pH was not linear with the degree of degradation increasing rapidly at around pH 7.5. At pH 9 > 90% removal was possible provided a residual of 0.5 mg l(-1) free chlorine was present after 30 min contact time. The more effective degradation at higher pH was unexpected as chlorine is known to be a weaker oxidant under these conditions. The more effective degradation, then, must be due to the toxins, which are ionisable molecules, being present in a form at higher pH which is more susceptible to oxidation. The feasibility of using chlorine to remove saxitoxins during water treatment will therefore depend strongly on the pH of the water being chlorinated. Degradation may be improved by pH adjustment but may not be a practical solution. Although saxitoxins were degraded in that the parent compounds were not detected by chemical analysis, there is no indication as to the nature of the degradation products. However, acute toxicity as determined by the mouse bioassay was eliminated.
Asunto(s)
Cloro/química , Cianobacterias/química , Saxitoxina/química , Abastecimiento de Agua/análisis , Animales , Concentración de Iones de Hidrógeno , Mariscos , Purificación del Agua/métodosRESUMEN
We report a case of transfusion-mediated Yersinia enterocolitica septicemia in a 43-y-old woman with homozygous beta-thalassemia. Two h after transfusion of 3 units of red blood cells the patient suffered high-grade fever and shaking chills. Y. enterocolitica serotype O3 grew in blood cultures. Prolonged treatment with i.v. ceftriaxone plus ciprofloxacin led to a favorable outcome. Transfusion-associated Y. enterocolitica septicemia has not previously been reported in an adult beta-thalassemic patient from the Mediterranean area. Our report is particularly important, because of the high incidence of chronically transfused thalassemic patients in Mediterranean countries.