RESUMO
In this study, we assessed the suitability of using a standard reference material (SRM) other than National Institute of Standards and Technology (NIST) 2710a or NIST 2711a in USEPA Method 1340 to determine arsenic (As) and lead (Pb) in vitro bioaccessibility (IVBA) and the capabilities of Canadian-based laboratories to perform the method. Five laboratories participated in an initial round robin study and analyzed NIST 2710a, NIST 2711a, BGS119, and Enviromat SS-2. Intra- and inter-laboratory variability were generally acceptable with percentage relative standard deviations (RSD) of less than 20%. The mean total As and Pb concentrations obtained for BGS119 (332 and 936 mg/kg, respectively) and the mean IVBA values (As = 14.3% and Pb = 78.1%) suggested it may be a suitable and acceptable SRM, whereas the concentration of As in Enviromat SS-2 as received (3.2 mg/kg) was deemed too low. Ten soil samples from sites with varying land use were analyzed in a follow-up round robin study using the modified IVBA method that included BGS119 as SRM. The concentrations of As and Pb in the IVBA extracts reported by the participating laboratories were comparable. The mean As IVBA values for the field-collected samples ranged from 0.1% to 56.4%; for Pb, they ranged from 7.0% to 121%. The lowest IVBA values were measured in mine site samples; the highest values were associated with smelter-affected soils. The low IVBA values correlated with high iron content. Intra- and interlaboratory reproducibility were acceptable (RSD < 30%). Based on the findings of the study, laboratories can use the modified method to provide reproducible and comparable As and Pb IVBA data. The use of BGS119 as an alternative SRM to assess contaminated sites in the province of British Columbia for regulatory purposes is recommended, as it is representative of As and Pb concentrations in contaminated soils in British Columbia. Integr Environ Assess Manag 2024;00:1-10. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
RESUMO
In vitro bioassays are widely used to detect and quantify endocrine disrupting chemicals (EDCs) in the influents and effluents of municipal wastewater treatment plants (WWTP). These assays have sometimes led to false positive or negative results, partly due to the low EDC concentrations in the samples. The objectives of the present study were: (a) to compare the estrogen screen (E-Screen) and the yeast estrogen screen (YES) bioassays using the 17beta-estradiol (E2) or its equivalence and (b) to investigate if a combination of the E-Screen and YES assays can be used to improve the accuracy of EDC detection and quantification. The E-Screen bioassay was conducted with the MCF-7 (BOS) human breast cancer cell line while the YES bioassay employed two different types of recombinant yeast. The influent and effluent samples collected from the five WWTPs operated by the Greater Vancouver Regional District (GVRD) were analyzed by both the E-Screen and the YES bioassays. Since the results of the E-Screen and YES bioassays varied by up to 4-fold on the same split sample of a nominal E2 concentration, the mean value of the E-screen and YES bioassays was used to represent the EDC activity of a given WWTP sample. Results of these studies showed that the E2 equivalent concentration in each WWTP sample was consistently higher than 1 ng/L, a concentration that may potentially cause endocrine disruption in different aquatic species. The composition of selected EDCs in a subset of effluent samples was examined using a gas chromatograph-high resolution mass spectrometer (GC-HRMS). EDC composition in 10 WWTP samples correlated with the mean endocrine disrupting activities of the E-Screen and YES bioassays. Results also indicated that secondary treatment plants are comparable to the primary treatment plants in removing EDCs from the final effluents.