Wastewater and seawater monitoring in Antarctica: Passive sampling as a powerful strategy to evaluate emerging pollution

The Ross Sea, among the least human-impacted marine environments worldwide, recently became the first marine protected area in Antarctica. To assess the impact of the Italian research station Mario Zucchelli (MZS) on the surrounding waters, passive sampling - as well as spot sampling for comparison - took place in the effluent of the wastewater treatment plant (WWTP) and the receiving surface marine waters. Polar Organic Chemical Integrative Samplers (POCIS) were deployed for six consecutive 2-week periods from November to February in a reservoir collecting the wastewater effluent. Passive samplers were also deployed at shallow depth offshore from the wastewater effluent outlet from MZS for two separate 3-week periods (November 2021 and January 2022). Grab water samples were collected alongside each POCIS deployment, for comparison with passive sampling results. POCIS, used for the first time in Antarctica, demonstrated to be advantageous to estimate time-averaged concentrations in waters and the results were comparable to those obtained by repeated spot samplings. Among the 23 studied ECs - including drugs, UV-filters, perfluorinated substances, caffeine - 15 were detected in both grab and passive sampling in the WWTP effluent and followed similar concentration profiles in both types of sampling. High concentrations of caffeine, naproxen and ketoprofen in the dozens of μg L-1 were detected. Other compounds, including drugs and several UV filters, were detected down to sub- μg L-1 concentrations. In marine waters close to the effluent output, only traces of a drug (4.8 ng L-1) and two UV filters (up to 0.04 μg L-1) were quantified.

Solvent-Free Determination of Selected Polycyclic Aromatic Hydrocarbons in Plant Material Used for Food Supplements Preparation: Optimization of a Solid Phase Microextraction Method

The exploitation of waste and by-products in various applications is becoming a cornerstone of the circular economy. A range of biomasses can be employed to produce food supplements. An example is a particular extract obtained from plant buds (rich in bioactive molecules), which can be easily retrieved from cities' pruning. In order to safely use this material, its possible contamination by organic pollutants needs to be estimated. A green and simple method to detect priority polycyclic aromatic hydrocarbons (PAHs) in bud samples by head space solid phase microextraction coupled to GC-MS was developed. This strategy, optimized through experimental design and response surface methodology, requires a minimal sample pre-treatment and negligible solvent consumption. The final method was found to be accurate and sensitive for PAHs with mass up to 228 Da. For these analytes, satisfactory figures of merit were achieved, with detection limits in the range 1-4 ng g-1, good inter-day precision (relative standard deviation in the range 4-11%), and satisfactory accuracy (88-105%), along with specificity guaranteed by the selected ion monitoring detection. The method was applied to bud samples coming from differently polluted areas, thus helping in estimating the safety of their use for the production of food supplements.

A Review on Polyethersulfone Membranes in Polar Organic Chemical Integrative Samplers: Preparation, Characterization and Innovation

The membranes in polar organic chemical integrative samplers (POCIS) enclose the receiving sorbent and protect it from coming into direct contact with the environmental matrix. They have a crucial role in extending the kinetic regime of contaminant uptake, by slowing down their diffusion between the water phase and the receiving phase. The drive to improve passive sampling requires membranes with better design and enhanced performances. In this review, the preparation of standard polyethersulfone (PES) membranes for POCIS is presented, as well as methods to evaluate their composition, morphology, structure, and performance. Generally, only supplier-related morphological and structural data are provided, such as membrane type, thickness, surface area, and pore diameter. The issues related to the use of PES membranes in POCIS applications are exposed. Finally, alternative membranes to PES in POCIS are also discussed, although no better membrane has yet been developed. This review highlights the urge for more membrane characterization details and a better comprehension of the mechanisms which underlay their behavior and performance, to improve membrane selection and optimize passive sampler development.

An optimized processing method for polar organic chemical integrative samplers deployed in seawater: Toward a maximization of the analysis accuracy for trace emerging contaminants

Passive sampling of emerging contaminants (ECs) in seawater represents a challenge in environmental monitoring. A specific protocol for Polar Organic Chemical Integrative Sampler (POCIS) processing may be necessary when dealing with marine applications, due to the peculiarity of the considered matrix. Herein, both the instrumental LC-MS/MS analysis and the sampler processing for the determination of 22 ECs in seawater were carefully optimized. The study entailed a test simulating POCIS sorbent exposure to seawater as well as the processing of replicated field POCIS with different elution solvents. The final method involved washing the sorbent with water, to eliminate most salts, and a two-step elution, by using methanol and a small volume of a dichloromethane-isopropanol mixture. With this protocol, recoveries between 58 and 137% (average 106%) were obtained for most analytes, including non-steroidal anti-inflammatory drugs, UV-filters, perfluorinated substances and caffeine. Still, the protocol was not suitable for very hydrophilic compounds (recovery under 20% for artificial sweeteners and the pharmaceutical salbutamol), which also showed remarkable ion suppression (matrix effects in the range 4-46%). For all other chemicals, the matrix effects were in the range 67-103% (average 86%), indicating satisfactory accuracy. Also, the overall method showed high sensitivity (detection limits in the range 0.04-9 ng g^-1 of POCIS sorbent) and excellent specificity, thanks to the monitoring of two "precursor ion-product ion" MS transitions for identity confirmation. The method was applied to samplers deployed in the Ligurian coast (Italy), detecting caffeine, bisphenol A, ketoprofen and two UV-filters as the most concentrated in the POCIS sorbent.