Chlorination in a wastewater treatment plant: acute toxicity effects of the effluent and of the recipient water body

This study investigates the impact of wastewater treatment plant (WWTP) effluent on the toxicity of the recipient water body and the effectiveness of the disinfection treatment applied (sodium hypochloride) to assure the compliance of both microbiological and toxicological emission limits. No toxicity was found in the majority of samples collected from the recipient river, upstream and downstream of the WWTP, using three different toxicity tests (Vibrio fischeri, Daphnia magna, and Pseudokirchneriella subcapitata). Only three samples presented toxic unit (TU) values with V. fischeri, and one presented TU with P. subcapitata. The influent toxicity ranged from slightly toxic to toxic (TU = 0.68–4.47) with V. fischeri, while only three samples presented TU values with the other tests. No toxicity was found in the absence of chlorination, while the mean toxicity was 3.42 ± 4.12 TU with chlorination in the effluent. Although no toxicity or very slight toxicity was found in the receiving water, its residual toxicity was higher than the US EPA Quality Standard in two samples. Escherichia coli concentration had a lower mean value in the chlorinated effluent: 13,993 ± 12,037 CFU/100 mL vs. 62,857 ± 80,526 CFU/100 mL for the not chlorinated effluent. This difference was shown to be significant (p < 0.05). E. coli in ten chlorinated samples was higher than the limit established by European and Italian Legislation. The mean highest trihalomethanes (THMs) value was found in the influent samples (2.79 ± 1.40 μg/L), while the mean highest disinfection by-products (DBPs) was found in the effluent samples (1.85 ± 2.25 μg/L). Significant correlations were found between toxicity, sodium hypochlorite, THMs, DBPs, E. coli, and residual chlorine. In conclusion, this study highlighted that the disinfection of wastewater effluents with sodium hypochlorite determines the increase of the toxicity, and sometimes is not enough to control the E. coli contamination.     

Surface ozone comparison conducted in two rural areas in central-southern Spain

Purpose  

The purpose of this work is to contribute to the understanding of the photochemical air pollution analysing the levels and temporal variations of surface ozone in two rural areas situated in central-southern Spain.     

Influence of soluble copper on the electrokinetic properties and transport of copper oxychloride-based fungicide particles

This article describes the influence of dissolved copper on the electrokinetic properties and transport of a copper oxychloride-based fungicide (COF) in porous media. The Zeta potential (ζ) of COF particles increases (viz. becomes less negative) with increasing concentration of Cu(2+) in the bulk solution. ζ decreases for COF when the electrolyte (NaNO(3)) concentration is raised from 1 to 10mM. This can be ascribed to ion correlation of Cu(2+) in the electrical double layer (EDL). COF transport tests in quartz sand columns showed the addition of Cu(2+) to the bulk solution to result in increased retention of the metal. Modelling particle deposition dynamics provided results consistent with kinetic attachment. Based on the effect of soluble Cu on colloid mobility, the transport of particulate and soluble forms of copper is coupled via the chemistry of pore water and colloid interactions. Mutual effects between cations and colloids should thus be considered when determining the environmental fate of particulate and soluble forms of copper in soil and groundwater (especially at copper-contaminated sites).     

Transverse limb reduction defects after chorion villus sampling: A retrospective Cohort study

A retrospective cohort study was performed in five Italian obstetrical centres from 1984 to 1991 in order to verify the association between chorionic villus sampling (CVS) and transverse limb reduction defects (TLRDs). TLRD rates by period of gestation at CVS were calculated, and the study's results were compared with data from the general population. Of the 3430 pregnancies for which CVS was performed, 2759 had a known outcome. The overall rate for TLRDs was 1 in 1143 CVS pregnancies, four times higher than that of the general population in Italy (1 in 4458). The rate of TLRDs was 2·9/1000 for CVS performed at 9 weeks' gestation and 1·0/1000 for CVS at 10 weeks' gestation. A scalp defect was detected in a pregnancy in which CVS was performed at 10 weeks. A high proportion of pregnancies lost to follow-up and the poor quality of the data may have affected the results. Nevertheless, our results suggest an association between CVS carried out at less than 10 weeks' gestation and TLRDs which is consistent with the findings of other studies. CVS should not be prepared at less than 10 weeks' gestation until additional evidence is obtained.     

Enhanced biological nitrogen and phosphorus removal from sewage driven by fermented glycerol: comparative assessment between sequencing batch- and continuously fed-structured fixed bed reactor

Environmental Science and Pollution Research - The nutrient biological removal from sewage, especially from anaerobic reactor effluents, still represents a major challenge in conventional sewage...     

Trust via disasters: the case of Chile's 2010 earthquake

Chile has a long‐standing history of natural disasters and, in particular, earthquakes. The latest big earthquake hit Chile on 27 February 2010 with a magnitude of 8.8 on the Richter scale. As an event that had a profound impact on significant portions of the population, the earthquake could theoretically have served to build trust by promoting new trust networks through the enhancement of distant family ties and the interaction between affected neighbours. This study offers an empirical analysis of this theory in the Chilean case. It finds that if initial social capital is very low (thus allowing for post‐disaster looting and violence), then the impact of the trust‐increasing effect is smaller. It also shows that the effect of the disaster was not transitory, but that it persisted and actually increased over time.     

High NOx levels and lack of ozone in downtown Caracas

An evaluation of the NO, NO₂ and O₃ concentrations in downtown Caracas atmosphere at two different heights (1.5 and 56 m ) during the dry and wet season was performed.The qualitative variation of NO and NO₂ concentrations throughout the day was the same for all conditions. The profiles are explained considering the automobile emissions and the fates by photochemical reactions and dispersion. The daily mean averages for NO_x exceed all available air quality standards, making the downtown Caracas air polluted with these compounds at harmful levels.The O₃ concentrations are lower than the natural background levels practically all day long for all conditions. This lack of O₃ is explained mainly by the very high continuous NO emissions occuring in Caracas. NO reacts very fast with O₃ consuming all the O₃ produced by photochemical reactions. Possible health implications of the low O₃ levels are pointed out.     

Effect of wind speed on the atmospheric levels of particles produced by traditional and non traditional sources on the island of curacao

The TSP, SO₄⁼ and Pb levels observed downwind of a large refinery and in the city of Willemstad in Curaçao are presented. The results show that wiht increasing wind speed TSP and SO₄⁼ levels increase while Pb levels decrease. On the other hand, at relatively constant wind speeds a good correlation between TSP and Pb was observed.The correlation observed between TSP, SO₄⁼ and Pb and the wind speed, the effect of rain on the atmospheric levels observed during the sampling period, the lack of secondary pollutants (e.g. ozone, NO₃^?) and the composition of the island background air, allow us to conclude that the SO₄⁼ measured at the monitoring sites is mainly produced as a primary pollutant in the refinery, the high atmospheric TSP levels are due to refinery emissions (traditional source) and the recirculation of street dust particles (non traditional source) produced by traffic and the predominantly high wind velocity.The implication on air quality and control measures are discussed.