Time-integrated monitoring of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in urban and industrial wastewaters using a ceramic toximeter and the CALUX bioassay

Abstract

The ceramic toximeter as a passive sampler in combination with the CALUX bioassay was utilized as a time-integrated pollution-assessment technique for dioxin-like PCDD/Fs in wastewaters. Toximeters filled with XCARB and enclosed in stainless steel cages were submerged in wastewater of Belbeis drainage-canal and EMAK paper-mill, located in Egypt, for 28 days. Two samplers were removed every week from each site. Extracts from toximeters, from bottom-sediments, and from paper-mill sludge were analyzed by the CALUX. Results showed a regular increase in the amounts of PCDD/Fs trapped by the toximeters as sampling time increased. Time-weighted average concentrations (TWA) of PCDD/Fs in the wastewaters of the drainage-canal and paper-mill were 231 (214-281) and 26 (24.1-32.6) pg-BEQ L-1, respectively. Compared to literature data, this means a high pollution level for the drainage-canal water, while the pollution level in the paper-mill wastewater is similar to that reported for other paper mills. The PCDD/Fs levels in the drainage-canal bottom-sediments and in the paper-mill sludge were 8.3 and 14.6 pg-BEQ g-1 dry-weight, at the lower end of internationally reported values in similar compartments. The sampling rate of the tested toximeters for dissolved PCDD/Fs was about 3.6 mL d-1. Sediment/water partitioning coefficient log Kd of PCDD/Fs in the drainage-canal and the paper-mill was 1.42 and 2.70 respectively. The organic-carbon normalized partition coefficient log Koc was 4.17 and 3.19 respectively, and is lower than the reported values for other sites.

Time-integrated monitoring of dioxin-like polychlorinated biphenyls (dl-PCBs) in aquatic environments using the ceramic toximeter and the CALUX bioassay

“…A value of m =2.0 was previously determined and used in field applications with ceramic-based passive samplers [12-14], but according to the results obtained on our testing solution of PCB-126, the value of m was set to 2.5. Since in this experiment only PCB-126 is present, a D e of 2.59 10 -7 will be used (see also Table 3 for diffusion coefficients of dl-PCBs).…”

“…The ceramic cylinders were manufactured by ATECH Innovations (Germany) [12]. The XCARB (activated carbon 1% w/w on celite) was from Xenobiotic Detection Systems (USA).…”

“…The XCARB and glass wool for the toximeters were conditioned by fluxing in toluene as described previously [12]. The ceramic cylinders were sintered at 750°C for 24 hours to eliminate possible organic traces.…”

“…More details about the sampling locations can be found elsewhere [12]. Wastewater effluents of the paper mill were sampled by applying the toximeters before the primary wastewater treatment process inside the factory.…”

“…Ceramic-based passive sampling devices have been previously used for monitoring dissolved polychlorinated dibenzo-ρ-dioxins and polychlorinated dibenzofurans (PCDD/Fs) [11, 12], polycyclic aromatic hydrocarbons (PAHs) and volatile organic contaminants (VOCs) in surface and ground water [13, 14], and flame retardants in river water [15]. The ceramic toximeter is based on the free flow of analyte molecules from the sampled medium through a ceramic diffusion membrane towards a suitable receiving phase, under the effect of a chemical-potential difference [16].…”