Microbial Quality of Irrigation Water of Public Parks in Dubai, United Arab Emirates

In this study, the microbial quality of treated wastewater used for irrigation of three public parks in Dubai was evaluated. A total of 23 samples of TWW （treated wastewater） and 12 samples of irrigated soils from three public parks were collected and tested for Legionella, Salmonella, traditional bacterial indicators, Cryptosporidium oocyst and Giardia cysts using membrane filtration and direct immune-fluorescence assay. The majority of the tested water samples were found contaminated with LLO （Legionella like organisms）, Salmonella and traditional bacterial indicators. Both Cryptosporidium oocysts and Giardia cysts were detected in these samples with a higher occurrence ofCryptosporidium oocysts （96%） than Giardia cysts （35%）. The fecal coliform bacteria were detected in 60.8% of water samples and 58% of soil samples. Total coliform bacteria were detected in most of the water and soil samples with a higher occurrence than the fecal coliform bacteria. The results of this study indicate that microorganisms are surviving the chlorination method used for disinfecting wastewater, and are further multiplying in the public parks irrigation network system. Therefore, monitoring the treated wastewater for bacterial pathogens, protozoan parasites and controlling their growth at the point of end use are vital to reducing the risk of environmental contamination with microbial pathogens.

Analysis of magnetic elements in otoliths of the macula lagena in homing pigeons with inductively coupled plasma mass spectrometry

Objective The macula lagena in birds is located at the apical end of the cochlea and contains many tiny otoliths. The macula lagena is innervated and has neural projections to the brainstem, but its physiological function is still unclear. It remains disputable that it is because otoliths in the lagena are rich in elements Fe and Zn that birds can obtain geomagnetic information for homing. To clarify this issue, we carried out a study to determine whether or not otoliths in the lagena of homing pigeons are richer in magnetic elements than those in the saccule and the utricle. Methods The contents of ferromagnetic elements （Fe, Co, Ni） and other metal elements in lagenal otoliths of adult homing pigeons were precisely analyzed with inductively coupled plasma mass spectrometry （ICP-MS） of high sensitivity, and then they were compared with those in saccular and utricular otoliths （all the contents were normalized to Ca）. Results In adult homing pigeons, the contents of ferromagnetic elements （Fe, Co, Ni） in lagenal otoliths were less than 0.7% （normalized to Ca element） and were the same order in magnitude as those in saccular and utricular otoliths. The content of Fe in lagenal otoliths was not significantly different from that in utricular otoliths and was even lower than that in saccular otoliths. The content of Co in lagenal otoliths was lower than that in saccular otoliths and higher than that in utricular otoliths. The content of Ni in lagenal otoliths was not significantly different from that in saccular otoliths and was higher than that in utricular otoliths. The contents of other metal elements Na, Mg, K, Al, Mn and Pb in lagenal otoliths were not significantly different from those in utricular and saccular otoliths. The contents of metal elements Zn, Ba and Cu in lagenal otoliths were lower than those in saccular otoliths. Conclusion The contents of magnetic elements in lagenal otoliths of homing pigeons are not much higher than those in utricular and saccular otoliths, which does not support the hypothesis that birds depend on high contents of Fe and Zn in lagenal otoliths for sensation of geomagnetic information. Similarities in morphology, element ingredient and element content between lagenal otoliths and utricular otoliths suggest that the two types of otolithic organs may play similar roles in sensing gravitational and acceleration signals.