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.

Benzene and formaldehyde in air of two Winter Olympic venues of "Torino 2006".

The 20th edition of the Olympic Winter Games took place in Torino, Italy and in other 7 winter sport sites belonging to Torino district in February 2006. The Olympic Winter Games had competitions for 15 different sports, and involved around 2500 athletes, 650 judges and umpires, thousands of accredited journalists, and almost 2 million spectators. Aiming to conduct an environmental health survey related to this important event, and taking into account their known or suspected carcinogenicity properties, benzene (B) and formaldehyde (FA) were analyzed in air in two venues of the Torino Olympic Games: Torino and Pragelato. Air-FA and air-B were measured for a whole year with two fixed samplers and, during a whole competition day, with individual passive samplers worn by two groups of supporter volunteers chosen to represent the two sites. Air fixed measurements were simultaneously carried out in Torino and Pragelato all months from May 2005 to April 2006 while individual sampling were performed from 8 A.M. to 6 P.M. on the 22th February 2006. On the whole, comparing Torino and Pragelato, air-B progress shows a significant and positive correlation (r=+0.572, p<0.01). The behaviour of air-FA is similar but not so evident. The secondary and primary origins of formaldehyde can justify the summer peak (June, July, and August 2005) but partially also January 2006. Comparing for Torino each February from 2005 to 2009 the "Olympic impact" on the quality of air is underlined but for benzene only. With a public health approach and considering the two venues, findings obtained by the individual samplers clearly show higher air pollution and, consequently, higher risk due to closer contact to several specific pollutant sources or environmental conditions.

The endocrine disrupting activity of surface waters and of wastewater treatment plant effluents in relation to chlorination.

The present study investigated the biological quantification of estrogenic activity in the effluent of a wastewater treatment plant (WWTP) and in the recipient river in north-western Italy. Samples of the WWTP effluent and those of river water upstream and downstream the WWTP were taken from September 2006 to May 2007. The effluent was evaluated in the presence and absence of chlorination. The E-screen assay, with human estrogens receptor-positive MCF-7 BUS breast cancer cells, was performed on samples after solid-phase extraction to determine the total estrogenic activity by measuring the 17beta-estradiol equivalent quantity (EEQ). In order to study the correlation between estrogenicity and toxicity, untreated samples were also assayed with the acute toxicity test Microtox. Furthermore, to determine the efficiency of the chlorination process, all the samples were analysed for disinfection by-products (trihalomethanes) and Escherichia coli. The mean EEQs were 5.0 ng/L (+/-6.1 ng/L) upstream of the plant, 6.7 ng/L (+/-7.4 ng/L) downstream from the plant and 23.3 ng/L (+/-20.4 ng/L) in the WWTP effluent. The difference between upstream and downstream of the treatment plant was not significant. Chlorinated water samples had lower estrogenic activity and E. coli concentrations, but had greater toxicity and higher trihalomethane concentrations. Estrogenic activity was not correlated with toxicity. These results suggest that the WWTP effluent had little impact on the estrogenic activity of the recipient river.

Faecal sterols determination in wastewater and surface water.

A simplified method to detect faecal sterols, as an alternative assessment of environmental faecal pollution is proposed. The aim of this study is the development of a method to determine sterols in water samples avoiding sample filtration through glass fibre filter. The method is based on a liquid-liquid extraction and a final GC-FID determination. The quantified sterols are coprostanol and 24-ethylcoprostanol, while 5alpha-cholestane is used as internal standard. The recovery of coprostanol and 24-ethylcoprostanol in wastewater ranges from 90 to 100% and the detection limit is 1-2 microgl(-1). Moreover the method proved to be useful for the sterols determination in surface water too.