Khadija Aboulfadl

Ozone oxidation of pharmaceuticals, endocrine disruptors and pesticides during drinking water treatment.

This study investigates the oxidation of pharmaceuticals, endocrine disrupting compounds and pesticides during ozonation applied in drinking water treatment. In the first step, second-order rate constants for the reactions of selected compounds with molecular ozone (k(O3)) were determined in bench-scale experiments at pH 8.10: caffeine (650+/-22M(-1)s(-1)), progesterone (601+/-9M(-1)s(-1)), medroxyprogesterone (558+/-9M(-1)s(-1)), norethindrone (2215+/-76M(-1)s(-1)) and levonorgestrel (1427+/-62M(-1)s(-1)). Compared to phenolic estrogens (estrone, 17beta-estradiol, estriol and 17alpha-ethinylestradiol), the selected progestogen endocrine disruptors reacted far slower with ozone. In the second part of the study, bench-scale experiments were conducted with surface waters spiked with 16 target compounds to assess their oxidative removal using ozone and determine if bench-scale results would accurately predict full-scale removal data. Overall, the data provided evidence that ozone is effective for removing trace organic contaminants from water with ozone doses typically applied in drinking water treatment. Ozonation removed over 80% of caffeine, pharmaceuticals and endocrine disruptors within the CT value of about 2 mg min L(-1). As expected, pesticides were found to be the most recalcitrant compounds to oxidize. Caffeine can be used as an indicator compound to gauge the efficacy of ozone treatment.

Analysis of natural and synthetic estrogenic endocrine disruptors in environmental waters using online preconcentration coupled with LC-APPI-MS/MS.

This paper describes a fully automated online method for solid-phase extraction coupled with liquid chromatography and tandem mass spectrometry using atmospheric pressure ionization (LC-LC-APPI-MS/MS) to simultaneously detect selected dissolved natural and synthetic hormones at concentrations as low as 5 ng/L from aqueous matrices. The method shows excellent performance for the direct analysis of water and wastewater with respect to calibration curve linearity, analytic specificity, sensitivity, and carryover, as well as overall method accuracy and precision. With a runtime of 15 min, a minimum of 200 samples were analyzed using a single online solid-phase extraction (SPE) column without noticeable differences in system performance. Because of the ruggedness and simplicity of this system, generic methods can be easily developed and applied for the high-throughput analysis of a wide variety of compounds without the need to resort to laborious offline SPE sample preparation.

Evaluating pharmaceuticals and caffeine as indicators of fecal contamination in drinking water sources of the Greater Montreal region.

We surveyed four different river systems in the Greater Montreal region, upstream and downstream of entry points of contamination, from April 2007 to January 2009. The studied compounds belong to three different groups: PPCPs (caffeine, carbamazepine, naproxen, gemfibrozil, and trimethoprim), hormones (progesterone, estrone, and estradiol), and triazine herbicides and their metabolites (atrazine, deethylatrazine, deisopropylatrazine, simazine, and cyanazine). In the system A, B, and C having low flow rate and high TOC, we observed the highest detection frequencies and mass flows of PPCPs compared to the other compounds, reflecting discharge of urban contaminations through WWTPs and CSOs. However, in River D, having high flow rate and low TOC, comparable frequency of detection of triazine and their by-products and PPCPs, reflecting cumulative loads of these compounds from the Great Lakes as well as persistency against natural attenuation processes. Considering large differences in the removal efficiencies of caffeine and carbamazepine, a high ratio of caffeine/carbamazepine might be an indicative of a greater proportion of raw sewage versus treated wastewater in surface waters. In addition, caffeine appeared to be a promising indicator of recent urban fecal contaminations, as shown by the significant correlation with FC (R(2)=0.45), while carbamazepine is a good indicator of cumulative persistence compounds.

Fecal coliforms, caffeine and carbamazepine in stormwater collection systems in a large urban area

Water samples from streams, brooks and storm sewer outfall pipes that collect storm waters across the Island of Montréal were analyzed for caffeine, carbamazepine and fecal coliforms. All samples contained various concentrations of these tracers, indicating a widespread sanitary contamination in urban environments. Fecal coliforms and caffeine levels ranged over several orders of magnitude with a modest correlation between caffeine and fecal coliforms (R(2) value of 0.558). An arbitrary threshold of 400 ng caffeine L(-1) allows us to identify samples with an elevated fecal contamination, as defined by more than 200 colony-forming units per 100 mL (cfu 100 mL(-1)) of fecal coliforms. Low caffeine levels were sporadically related to high fecal coliform counts. Lower levels of caffeine and fecal coliforms were observed in the brooks while the larger streams and storm water discharge points contained over ten times more. The carbamazepine data showed little or no apparent correlation to caffeine. These data suggest that this storm water collection system, located in a highly urbanized urban environment, is widely contaminated by domestic sewers as indicated by the ubiquitous presence of fecal contaminants as well as caffeine and carbamazepine. Caffeine concentrations were relatively well correlated to fecal coliforms, and could potentially be used as a chemical indicator of the level of contamination by sanitary sources. The carbamazepine data was not significantly correlated to fecal coliforms and of little use in this dataset.

Temporal variability of combined sewer overflow contaminants: Evaluation of wastewater micropollutants as tracers of fecal contamination

A monitoring program was initiated for two sewage outfalls (OA and OB) with different land uses (mainly residential versus institutional) over the course of a year. Eleven CSO events resulting from fall and summer precipitations and a mixture of snowmelt and precipitation in late winter and early spring were monitored. Median concentrations measured in CSOs were 1.5 × 10(6)Escherichia coli/100 mL, 136.0 mg/L of Total Suspended Solids (TSS), 4599.0 ng/L of caffeine (CAF), 158.9 ng/L of carbamazepine (CBZ), in outfall OA and 5.1 × 10(4)E. coli/100 mL, 167.0 mg TSS/L, 300.8 ng CAF/L, 4.1 ng CBZ/L, in outfall OB. Concentration dynamics in CSOs were mostly related to the dilution by stormwater and the time of day of the onset of overflows. Snowmelt was identified as a critical period with regards to the protection of drinking water sources given the high contaminant concentrations and long duration of events in addition to a lack of restrictions on overflows during this period. Correlations among measured parameters reflected the origins and transport pathways of the contaminants, with E. coli being correlated with CBZ. TSS were not correlated with E. coli because E. coli was found to be mostly associated with raw sewage whereas TSS were additionally from the resuspension of in-sewer deposits and surface runoff. In receiving waters, E. coli remained the best indicator of fecal contamination in strongly diluted water samples as compared to WWMPs because WWMPs can be diluted to below their detection limits.

Time-dependent integrity during storage of natural surface water samples for the trace analysis of pharmaceutical products, feminizing hormones and pesticides

Monitoring and analysis of trace contaminants such as pharmaceuticals and pesticides require the preservation of the samples before they can be quantified using the appropriate analytical methods. Our objective is to determine the sample shelf life to insure proper quantification of ultratrace contaminants. To this end, we tested the stability of a variety of pharmaceutical products including caffeine, natural steroids, and selected pesticides under refrigerated storage conditions. The analysis was performed using multi-residue methods using an on-line solid-phase extraction combined with liquid chromatography tandem mass spectrometry (SPE-LC-MS/MS) in the selected reaction monitoring mode. After 21 days of storage, no significant difference in the recoveries was observed compared to day 0 for pharmaceutical products, while for pesticides, significant losses occurred for DIA and simazine after 10 days (14% and 17% reduction respectively) and a statistically significant decrease in the recovery was noted for cyanazine (78% disappearance). However, the estrogen and progestogen steroids were unstable during storage. The disappearance rates obtained after 21 days of storage vary from 63 to 72% for the feminizing hormones. Overall, pharmaceuticals and pesticides seem to be stable for refrigerated storage for up to about 10 days (except cyanazine) and steroidal hormones can be quite sensitive to degradation and should not be stored for more than a few days.