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An immense volume of tailings and tailings water is accumulating in tailings ponds located on mine leases in the oil sands area of Alberta, Canada. Oil sands mining companies have proposed to use tailings- and tailings water-amended lakes and wetlands as part of their mine remediation plans. Polycyclic aromatic hydrocarbons (PAHs) are substances of concern in oil sands tailings and tailings water. In this study, we determined concentrations of PAHs in sediments, insect larvae and adult insects collected in or adjacent to three groups of wetlands: experimental wetlands to which tailings or tailings water had been purposely added, oil sands wetlands that were located on the mine leases but which had not been experimentally manipulated and reference wetlands located near the mine leases. Alkylated PAHs dominated the PAH profile in all types of samples in the three categories of wetlands. Median and maximum PAH concentrations, especially alkylated PAH concentrations, tended to be higher in sediments and insect larvae in experimental wetlands than in the other types of wetlands. Such was not the case for adult insects, which contained higher than expected levels of PAHs in the three types of ponds. Overlap in PAH concentrations in larvae among pond types suggests that any increase in PAH levels resulting from the addition of tailings and tailings water to wetlands would be modest. Biota-sediment accumulation factors were higher for alkylated PAHs than for their parent counterparts and were lower in experimental wetlands than in oil sands and reference wetlands. Research is needed to examine factors that affect the bioavailability of PAHs in oil sands tailings- or tailings water-amended wetlands.

BUSAN 30WB® is an alternative to pentachlorophenol as an antisapstain agent in the lumber industry. The active ingredient is 2‐(thiocyanomethylthio)benzothiazole (TCMTB). Because very little information is available in the open literature on the fate of TCMTB in aquatic environments, we wish to report our studies on TCMTB and related benzothiazoles, some of which are potential transformation products of TCMTB. We measured the water solubility and octanol/water partition coefficients of TCMTB, benzothiazole (BT), 2‐mercaptobenzothiazole (MBT), and 2‐(meth‐ylthio)benzothiazole (MTBT). The water solubility of TCMTB at 24°C was 40 mg/L, and the log Kow was 3.12. At pH 8 and 24°C in dilute borax‐phosphate buffer, the half‐life of TCMTB was 750 h; in seawater (pH 7.8‐8.0, 24°C) it was about 740 h. Attempts to measure sediment/water partitioning of TCMTB produced traces of MTBT, presumed to result from biological methylation of MBT released by hydrolysis of TCMTB. MTBT was produced directly from MBT in the presence of sediment. In phosphate buffer, TCMTB readily underwent direct photolysis in sunlight to produce MBT, in about 50% yield, and traces of BT. The photochemistry of MBT, the major photolysis product of TCMTB, was studied in some detail. Sunlight quantum yields of TCMTB and MBT are estimated to be 0.01 and 0.002, respectively. Sunlight photolysis of MBT in phosphate buffer with and without dissolved organic matter and in a natural water led to three products: BT (28‐47%), 2‐hydroxybenzothiazole (HOBT) (4‐5%), and an unidentified product. On the basis of our laboratory and field results, in addition to literature reports on the occurrence of benzothiazoles, we propose a partial pathway for this family of benzothiazoles in aquatic environments. TCMTB and MBT are unlikely to persist or bioaccumulate. Stable end products appear to be BT, MTBT, and 2‐hydroxybenzothiazole.

An exploratory study of urban runoff toxicity was undertaken at 14 urban sites, including two sites receiving runoff from major multi-lane divided highways (>100,000 vehicles·day−1). To assess various types of toxicity, a battery of tests was used including Daphnia magna, Microtox™, sub-mitochondrial particles, and the SOS Chromotest (for genotoxicity). The whole data set comprised almost 70 samples and 350 test results, which were reduced to toxicity point values using a toxicity scale. About two fifths of all data did not show any toxic responses, one fifth indicated severe toxicity, one fifth confirmed toxicity, and one fifth potential toxicity. When comparing urban stormwater toxicity to that of multi-lane divided highway (MLDH) runoff, the main difference was noted for the severe toxicity level; almost 20% of MLDH samples were severely toxic compared to 1% of urban stormwater samples. The MLDH data were obtained at the edge of the pavement, and although attenuation of runoff toxicity during transport can be expected, particularly in grassed swales, additional research is required.

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