The occurrence of emerging pollutants (EPs) is continuously reported worldwide. Nevertheless, only few of these compounds are toxicologically evaluated due to their vast numbers. Reliable analytical methods and toxicity assessment methods are the basis of either the management or the elimination of EPs. In this paper, literature published in 2018 on EPs were reviewed with special regard to their occurrence, detection methods, fate in the environment, and ecological toxicity assessment. Particular focus was placed on practical considerations, novel processes, and new solution strategies.Practitioner points Literature published in 2018 on emerging pollutants were reviewed. This review article is with special regard to the occurrence, detection methods, fate and toxicity assessment of emerging pollutants. Particular focus was placed on practical considerations, novel processes and new solution strategies.

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A novel method using a micro-ion-selective electrode (micro-ISE) technique was developed for in situ lead monitoring at the water-metal interface of a brass-leaded solder galvanic joint in a prepared chlorinated drinking water environment. The developed lead micro-ISE (100 μm tip diameter) showed excellent performance toward soluble lead (Pb) with sensitivity of 22.2 ± 0.5 mV decade and limit of detection (LOD) of 1.22 × 10 M (0.25 mg L). The response time was less than 10 s with a working pH range of 2.0-7.0. Using the lead micro-ISE, lead concentration microprofiles were measured from the bulk to the metal surface (within 50 μm) over time. Combined with two-dimensional (2D) pH mapping, this work clearly demonstrated that Pb ions build-up across the lead anode surface was substantial, nonuniform, and dependent on local surface pH. A large pH gradient (ΔpH = 6.0) developed across the brass and leaded-tin solder joint coupon. Local pH decreases were observed above the leaded solder to a pH as low as 4.0, indicating it was anodic relative to the brass. The low pH above the leaded solder supported elevated lead levels where even small local pH differences of 0.6 units (ΔpH = 0.6) resulted in about four times higher surface lead concentrations (42.9 vs 11.6 mg L) and 5 times higher fluxes (18.5 × 10 vs 3.5 × 10 mg cm s). Continuous surface lead leaching monitoring was also conducted for 16 h.

Galvanic corrosion in drinking water distribution systems, such as conditions following partial lead (Pb) service line replacement, has received recent attention. In order to better understand conditions at galvanic connections that lead to enhanced metal release and provide remedial strategies, the water-metal and anodic-cathodic interfaces at these locations must be better understood. In this paper, a pH microelectrode system was used to create in-situ 2D spatial images of the pH of water across two brass coupons connected by a leaded solder joint at 100 μm above the metal's surface under flowing and stagnation conditions. Water stagnation resulted in significant pH changes across the surfaces compared to flow condition. Under stagnation, the pH above the anode (leaded solder) was 1.5 pH units below the bulk water and as much as 2.5 units below the cathode (brass). These conditions can enhance lead release at the anode, which reflects different anodic-cathodic relationships of coupled metals primarily controlled by water flow. Most importantly, this work has demonstrated the ability to make real pH measurement at the surface of corroding metals using a novel microelectrode approach.

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