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In this report we describe the results of astudy conducted to better estimate airbornemicroorganisms present in wastewater treatmentplants (WWTP) environments. Air samples weretaken with the Air Sampler MAS 100 impactor(Merck) at each stage of an activated-sludgeWWTP (pre-treatment, primary clarifiers,aeration basins and sludge processors), inorder to determine levels of contaminationaccording to work stations. Culture methodswere used to investigate heterotrophic platecount, moulds and yeasts, total and fecalcoliforms, Pseudomonas aeruginosa andspecies belonging to Mycobacteriumtuberculosis complex, whereas these lastmicroorganisms were also analysed by PolymeraseChain Reaction (PCR) methods. Statisticalanalysis showed that pretreatment and primaryclarifiers were the stages with the highestemission of bioaerosols, and that bioaerosolconcentration at each stage depended on windspeed and daily inflow at the WWTP. Lowconcentrations of P. aeruginosa werefound isolated at pretreatment and primaryclarifiers; however, species of M.tuberculosis complex were not detected at anystage of the treatment plant.

Most studies focusing on detecting microorganisms in air by polymerase chain reaction (PCR) have used a liquid impinger to sample bioaerosols, mainly because a liquid sample is easy to be processed by PCR analysis. Nevertheless, the use of multiple-hole impactors for the analysis of bioaerosols by PCR has not been reported despite its great utility in culture analysis. In this study we have modified the impaction onto an agar surface sampling method to impaction onto a liquid medium using the MAS-100 air sampler (Merck) (single-stage multiple-hole impactor). To evaluate the recovery of airborne microorganisms of both sampling methods, a suspension containing Escherichia coli was artificially aerosolized and bioaerosols were collected onto Tergitol-7 agar and phosphate-buffered saline (PBS) with the MAS-100. A linear regression analysis of the results showed a strong positive correlation between both sampling methods (r = 0.99, slope 0.99, and y intercept 0.07). Afterwards, the method of impingement into a liquid medium was used to study airborne Legionella pneumophila by PCR. A total of 64 samples were taken at a wastewater treatment plant, a chemical plant, and an office building and analyzed by culture and PCR. Results showed that three samples were positive both by PCR and plate culture, and that nine samples negative by plate culture were positive by PCR, proving that L. pneumophila was present in bioaerosols from these three different environments. The results demonstrate the utility of this single-stage multiple-hole impactor for sampling bioaerosols, both by culture and by PCR.Key words: Legionella pneumophila, bioaerosols, PCR, multiple-hole impactor.

Most studies focusing on detecting microorganisms in air by polymerase chain reaction (PCR) have used a liquid impinger to sample bioaerosols, mainly because a liquid sample is easy to be processed by PCR analysis. Nevertheless, the use of multiple-hole impactors for the analysis of bioaerosols by PCR has not been reported despite its great utility in culture analysis. In this study we have modified the impaction onto an agar surface sampling method to impaction onto a liquid medium using the MAS-100 air sampler (Merck) (single-stage multiple-hole impactor). To evaluate the recovery of airborne microorganisms of both sampling methods, a suspension containing Escherichia coli was artificially aerosolized and bioaerosols were collected onto Tergitol-7 agar and phosphate-buffered saline (PBS) with the MAS-100. A linear regression analysis of the results showed a strong positive correlation between both sampling methods (r = 0.99, slope 0.99, and y intercept 0.07). Afterwards, the method of impingement into a liquid medium was used to study airborne Legionella pneumophila by PCR. A total of 64 samples were taken at a wastewater treatment plant, a chemical plant, and an office building and analyzed by culture and PCR. Results showed that three samples were positive both by PCR and plate culture, and that nine samples negative by plate culture were positive by PCR, proving that L. pneumophila was present in bioaerosols from these three different environments. The results demonstrate the utility of this single-stage multiple-hole impactor for sampling bioaerosols, both by culture and by PCR.

In this paper we describe a simple method, noncorrosive to pipes, for the eradication of Legionella pneumophila from potable water systems. This method is based on the systematic purging of the pipe networks with cold water containing 1 – 1.5 mg residual chlorine/L. In the hot water system, a new pipe bypassing the water heater was installed, whereas in the air conditioning system, the circuit is purged with water from the tap water system. The feasibility of this method was studied in two hotels in which the presence of Legionella was detected despite treatment of the water by the hyperchlorination method. The evolution of the presence of Legionella was studied by culture and polymerase chain reaction. Eighty samples from hotel A and sixty-seven samples from hotel B were analyzed during the time that the eradication method was applied. Our results showed that this method permitted the effective elimination of L. pneumophila after 5 months in hotel A and 7 months in hotel B.Key words: Legionella pneumophila, eradication.

This study develops a method for solid-phase microextraction (SPME) of eight organophosphorus pesticides, diazinon, fenthion, fenitrothion (sumithion), methyl-parathion, parathion, methyl-trithion, ethion and triazophos, from water. Determination is carried out by gas chromatography with nitrogen-phosphorus detection. To perform the SPME, poly(dimethylsiloxane) and polyacrylate fibers were initially compared on the basis of their absorption capacities for the selected pesticides, and polyacrylate was selected to accomplish the rest of assays. The main factors affecting the SPME process such as memory effect, stirring rate, extraction temperature and absorption-time profile were studied. The proposed method requires 2 ml of sample and reaches limits of detection ranging between 6 ng/l for fenthion and 136 ng/l for methyl-parathion, with relative standard deviations at the 500 ng/l level between 2% for diazinon and 13% for ethion. The method was applied to spiked tapwater, seawater, wastewater with high dissolved organic matter content (DOC = 212 mg/l) and water containing 15 mg/l of sodium lauryl sulfate (SDS), which were previously analyzed to control interferences. Recoveries for diazinon, fenthion and methyl-trithion were better from seawater than from Milli-Q water. Recoveries for fenthion and ethion increased with the presence of SDS and those for methyl-parathion and triazophos decreased from the wastewater because of the presence of the organic matter. Finally, a wastewater from a pesticide producer industry was analyzed showing the presence of diazinon and ethion at concentrations of 0.97 μg/l and 0.67 μg/l, respectively. Results were in concordance with those obtained using a standard liquid-liquid extraction method.

The ICP-MS for simultaneous trace element determination in human blood has prevailed as the most suitable methodology for clinical aims because of its rapidity, detection limits and minimal sample quantity needed for analysis. As the proteic matrix is high, it is necessary to fine-tune the ICP-MS Agilent 7500i with autosampler CETAC ASX-500 and ISIS System connected, and further we have to the sample pre-treatment in order to obtain good results. The study of the results shows that the best pre-treatment for blood serum samples consists of a basic treatment by 1/10 dilution with a solution of EDTA and NH4OH, with a detection limit of the order of μg/L and a reduction of the necessary patient sample volume to 2 mL.

The genus Legionella is represented by 48 species and Legionella pneumophila includes 15 serogroups. In this work, we have studied the intergenic 16S-23S spacer region (ITS) in L. pneumophila to determine the feasability of using amplification polymorphisms in this region, to establish intraspecies differences and to discriminate Legionella species. The amplification of this region, using 16S14F and 23S0R primers, and the analysis of amplicons by the analysis of fragments technique showed that all the L. pneumophila serogroups studied presented the same electrophoretic pattern. Moreover, the analysis of different Legionella species showed that the amplification polymorphisms obtained were species-specific. In order to study the sequence variability of this region, the existence in L. pneumophila of three ribosomal operons was determined by pulsed field gel eletrophoresis (PFGE). Two of the 16S-23S rRNA ITS presented a tRNA Ala and the third one a tRNA Ile. Nevertheless, the variability expected in this region of the operon was not found and the rest of the ITS contained only punctual mutations.

Fiber/water partition coefficients (Kfw) of 52 pesticides, including triazines, organophosphorus pesticides, organochlorine pesticides, and polychlorinated biphenyls (PCBs) were experimentally calculated for the five polymeric coatings poly(dimethylsiloxane) (PDMS), polyacrylate (PA), poly(dimethylsiloxane)-Divinylbenzene (PDMS-DVB), Carboxen-poly(dimethylsiloxane) (CAR-PDMS), and Carbowax-divinylbenzene (CW-DVB) commercially available for solid-phase microextraction coupled to gas chromatography. The equilibrium-time profiles for the five coatings were previously studied in order to establish the time needed for equilibrium. To calculate Kfw the amount of analyte extracted at equilibrium was obtained by gas chromatographic analysis of spiked water samples. In the case of mixed coatings in which adsorption processes are involved the term partition coefficient is not strictly correct and partition coefficient apparent is used in these cases. For the triazines, small partition coefficients were found, showing that PDMS-DVB permits the best extraction for these compounds. PA and PDMS-DVB gave the highest mean partition coefficients for the organophosphorus pesticides. Organochlorine pesticides in general gave high Kfw with all five coatings, with strong differences depending on the compound. In the case of PCBs a decrease in the partition coefficient with the increase of the number of chlorines substituted was observed. The results obtained indicated that the polarity of the fibers is not the main factor affecting the extraction. The presence of DVB in the mixed coatings seems to increase the uptake, probably due to adsorption processes instead of absorption. In general the PDMS-DVB coating proved to be a good choice for the analysis of the compounds under study.