Chlorophenol tolerant and degradative bacteria isolated from a river receiving pulp mill discharges

A screening was carried out in a river receiving pulp mill discharges (BioBio river, central Chile) to study the bacterial population able to tolerate and degrade chlorophenols. In four selected stations and at different seasons, water samples were taken from the river. Total bacterial population and the number of chlorophenol tolerant bacteria were counted. Bacterial tolerance to 25, 50, 100, 200 and 400 μg/ml of 2,4‐dichlorophenol (DCP), 2,4,6‐trichlorophenol (TCP) and pentachlorophenol (PCP) was determined. Strains able to tolerate at least 400 μg/ml chlorophenols were found. Eighteen bacterial strains able to use chlorophenols as the sole carbon source were isolated: five of them were Pseudomonas fluorescens, two Alcaligenes sp., one Citrobacter freundii, one Aeromonas sp. and nine unidentified Gram negative bacilli. A good correlation (r ² = 0.758) between the logarithm of DCP tolerant bacteria and the content of adsorbable organic halogen (AOX) at low dilution in the river water was established. Four groups of tolerant bacteria were found: growing on PCP and DCP, growing on PCP and TCP, growing only on PCP and growing only on TCP.     

Total organic halogen (TOX) in human urine: A halogen-specific method for human exposure studies

Disinfection by-products(DBPs) are a complex mixture of compounds unintentionally formed as a result of disinfection processes used to treat drinking water. Effects of long-term exposure to DBPs are mostly unknown and were the subject of recent epidemiological studies. However,most bioanalytical methods focus on a select few DBPs. In this study, a new comprehensive bioanalytical method has been developed that can quantify mixtures of organic halogenated compounds, including DBPs, in human urine as total organic chlorine(TOCl), total organic bromine(TOBr), and total organic iodine(TOI). The optimized method consists of urine dilution, adsorption to activated carbon, pyrolysis of activated carbon, absorption of gases in an aqueous solution, and halide analysis with ion chromatography and inductively coupled plasma-mass spectrometry. Spike recoveries for TOCl, TOBr, and TOI measurements ranged between 78% and 99%. Average TOCl, TOBr, and TOI concentrations in five urine samples from volunteers who consumed tap water were 1850, 82, and 21.0 μg/L as X~-, respectively.Volunteers who consumed spring water(control) had TOCl, TOBr, and TOI average concentrations in urine of 1090, 88, and 10.3 μg/L as X~-, respectively. TOCl and TOI in the urine samples from tap water consumers were higher than the control. However, TOBr was slightly lower in tap water urine samples compared to mineral water urine samples, indicating other sources of environmental exposure other than drinking water. A larger sample population that consumes tap water from different cities and mineral water is needed to determine TOCl, TOBr, and TOI exposure from drinking water.