Occurrence of bromate, chlorite and chlorate in drinking waters disinfected with hypochlorite reagents. Tracing their origins.

Bromate was first reported as a disinfection by-product from ozonated waters, but more recently it has been reported also as a result of treatment using hypochlorite solutions worldwide. The aim of this study was to study the scope of this phenomenon in the drinking waters (n=509) of Castilla y León, Spain, and in the hypochlorite disinfectant reagents. Two thirds of the treated waters monitored were found to have bromate concentrations higher than 1 microg/l, and of them a median value of 8 microg/l and a maximum of 49 microg/l. These concentrations are higher than those reported so far, however, a great variability can be found. Median values for chlorite were of 5 microg/l, and of 119 microg/l for chlorate. Only 7 out of 40 hypochlorite feedstock solutions were negative for bromate, the rest showing a median of 1022 mg/l; and 4 out of 14 calcium hypochlorite pellets were also negative, the rest with a median of 240 mg/kg. Although bromate is cited as potentially added to water from calcium hypochlorite pellets, no reference is found in scientific literature regarding its real content. Chlorite (median 2646 mg/l) and chlorate (median 20,462 mg/l) and chlorite (median 695 mg/kg) and chlorate (median 9516 mg/kg) were also monitored, respectively, in sodium hypochlorite solutions and calcium hypochlorite pellets. The levels of chlorite and chlorate in water are considered satisfactory, but not those of bromate, undoubtedly owing to the high content of bromide in the raw brines employed by the chlor-alkali manufacturers. Depending on the manufacturer, the bromate concentrations in the treated waters may be very heterogeneous owing to the lack of specification for this contaminant in the disinfectant reagents -the European Norms EN 900 and 901 do not mention it.

A multi-year survey of organic disinfection by-products in drinking waters of Castilla y León, Spain. The need and difficulty to comply with the legal limit of 2009.

This article explains the general difficulties of the Spanish source waters and climatic conditions regarding a control of trihalomethanes (THMs), as reflected by the case of Castilla y León, and how the median values of 75 and 163 microg L(-1) of years 1999 and 2002 gave way to the more moderate of 31 and 47 microg L(-1) of years 2006 and 2007, respectively--both the latter being measured during the warmer season. Particular circumstances such as raw surface water--with frequently high total organic carbon (T.O.C) values--being the source for 80% of population served, the moderate-to-high water temperatures during the warm seasons and the high chlorine dosages frequently applied account for such as high levels. The median global value (n = 98) for raw water T.O.C. was 4.26 mg L(-1) (90th percentile of 9.81 mg L(-1)) and a median T.O.C. removal of 30% was observed during the treatment, but with an enormous variety (a 90th percentile in the order of 70%). Regression analysis associated the variables raw water temperature, prechlorination dosage and raw and finished water T.O.C. with the THMs measured in the finished waters and in the distribution systems. A certain linear correlation exists between THMs and haloacetic acids (HAAs) contents. However, a shift on their profile is noticeable with the temperature of the water, so that above 11.12 degrees C, THMs concentration tends to be higher than that of HAAs, and vice versa.

Aflatoxins and ochratoxin A in red paprika for retail sale in Spain: occurrence and evaluation of a simultaneous analytical method.

Aflatoxins are the only mycotoxins with legal limits for spices in the European Union. A further limit for ochratoxin A is expected to be adopted soon. Thus, rapid simultaneous methods for quantifying the five mycotoxins are sought. Liquid extraction, immunoaffinity column cleanup, and HPLC-FD with a wavelength program were optimized for the analysis of the five mycotoxins in paprika, a complex fatty matrix. The limits of detection ranged from 0.3 to 0.6 microg/kg. Repeatability (RSDr) ranged from 7.9 to 13.4%, and recoveries were between 61.4 and 77.8%, in both cases at the lower spike level. Aflatoxins, when found, were far below the two legal limits of 5 microg/kg for aflatoxin B 1 and 10 microg/kg for total aflatoxins. Ochratoxin A was more frequently found, with a mean of 11.8 microg/kg, and in a more varied range (SD = 18.9 microg/kg). When an automation of the precolumn derivatization step was attempted, the procedure proved to be unfeasible, but experience derived from this trial and from the general employment of this reaction enables some comments on the possibilities and limitations of this procedure and on research for an alternative one to be made.