Illicit drugs constitute a class of emerging contaminants that has been drawing significant concern due to its potent pharmacological and biological activities. In this study, an in situ passive sampling approach that uses diffusive gradients in thin films (DGT) was successfully tested for measuring ketamine (KET), methamphetamine (METH), and amphetamine (AMP) in water. The diffusion coefficients of KET, METH, and AMP in diffusive gel were (8.13 ± 0.12) × 10, (8.55 ± 0.14) × 10, and (7.72 ± 0.18) × 10 cm s at 22 °C, respectively. The capacities of an XAD binding gel for KET, METH, and AMP were 92, 57, and 45 μg per binding gel disc, which were suitable for long-term environmental monitoring. The DGT measurement of these drugs was not influenced by the pH (4 to 9) and the ionic strength (0.001 M - 0.1 M) and unaffected by the water flow, demonstrating the effectiveness of the XAD-based DGT for the in situ monitoring of illicit drugs. DGT samplers were deployed in a WWTP influent and natural rivers in Beijing, China. The ng L levels of the drugs were high in the wastewater influent and low in river waters, with an insignificant fluctuation during the seven-day monitoring. The DGT-measured concentrations were comparable to the average concentrations determined by SPE method, which suggested that the average data measured by DGT could be substituted for high-frequency grab sampling. This study has demonstrated systematically for the first time that DGT is effective and accurate for monitoring illicit drugs in wastewater and surface waters, and provides a powerful tool to investigating the presence, transport, and environmental behaviors of these drugs in the aquatic ecosystem.

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Inactivating antibiotic resistant bacteria (ARB) and removing antibiotic resistance genes (ARGs) are very important to prevent their spread into the environment. Previous efforts have been taken to eliminate ARB and ARGs from aqueous solution and sludges, however, few satisfying results have been obtained. This study investigated whether photocatalysis by TiO was able to reduce the two ARGs, mecA and ampC, within the host ARB, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. The addition of HO and matrix effect on the removal of ARB and ARGs were also studied. TiO thin films showed great effect on both ARB inactivation and ARGs removal. Approximately 4.5-5.0 and 5.5-5.8 log ARB reductions were achieved by TiO under 6 and 12mJ/cm UV fluence dose, respectively. For ARGs, 5.8 log mecA reduction and 4.7 log ampC reduction were achieved under 120mJ/cm UV fluence dose in the presence of TiO. Increasing dosage of HO enhanced the removal efficiencies of ARB and ARGs. The results also demonstrated that photocatalysis by TiO was capable of removing both intracellular and extracellular forms of ARGs. This study provided a potential alternative method for the removal of ARB and ARGs from aqueous solution.

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The occurrence and distribution of five drugs of abuse and their metabolites, namely, methamphetamine (METH), amphetamine (AMP), ketamine (KET), ephedrine (EPH), and hydroxylimine (HY), were investigated in the surface water in urban rivers in Beijing, China. A total of 117 surface water samples were collected from the seven rivers in the Beijing urban areas during four different seasons. Laboratory analyses revealed that EPH and METH were the most predominant drugs, with detection frequency ranging from 94% to 100% and from 65% to 100%, respectively. High levels of METH and KET were observed in the center part of the urban areas, which was likely associated with the drug abuse and the entertainment activities. Seasonal variation of the drug occurrence showed that the highest concentration of drugs of abuse was found during winter, which was likely due to the high consumption, low temperature, and low water flows during the cold weather. By contrast, the concentration and detection frequency of AMP and HY were relatively low. Risk assessment by the risk quotient method indicated that the five drugs of abuse and their metabolites were not likely to exert biological effects on the aquatic ecosystems at current levels in the surface water. However, the potential adverse effect of drugs of abuse and their metabolites on ecosystem functioning and human health should not be neglected.