Trace-level analysis of organic contaminants in drinking waters and groundwaters

Conversations about the Future of Dicamba: The Science Behind Off-Target Movement

Dicamba is an important herbicide for controlling post-emergent resistant weeds in soybean farming. Recently, the scientific community and general public have further examined off-target transport mechanisms (e.g., spray drift, volatilization, and tank contamination) and the visual responses of soybeans to ultralow dicamba concentrations. This paper synthesizes key chemical concepts and environmental processes associated with dicamba formulations, transport mechanisms, drift measurements, and plant responses. This paper proposes additional areas of research and actions to increase our understanding and communicate the science findings, which should provide farmers with more robust tools and practices for sustainable dicamba use.

Multiresidue method for the determination of high production volume plastic additives in river waters

The aim of this study was to develop a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)-based method for the multiresidue analysis of 21 plastic additives in river water. Analysed compounds included phthalates, benzophenone, bisphenol A and long- and short-chain alkylphenols (APs), which are of relevance because most of them are high production volume chemicals largely used in the plastic industry. These compounds can reach river waters due to direct discharge from wastewater treatment plants and leaching from plastic materials and microplastics present in rivers. In a first step, ionisation and acquisition parameters were optimised to obtain high sensitivity and structural information. Then, different solid-phase extraction cartridges and elution conditions were tested using Milli-Q and river water. With the optimised conditions, quality control parameters (recoveries, limits of detection, intra- and inter-day variability and blank contribution) proved that the method was accurate and selective for the trace monitoring of these compounds in river water. For nonylphenol, octylphenol and bis(2-ethylhexyl)phthalate, included in the Water Framework Directive, limits of detection were below environmental quality standard concentrations considering blank contributions. All other compounds were efficiently detected at trace levels, and focus was given to o- and p-substituted and di- and tri-substituted APs, which are first reported in the present study. A pilot survey was finally carried out to determine the occurrence of plastic additives in river waters surrounding the city of Barcelona.

National screening study investigating nine phthalates and one adipate in raw and treated tap water in France

The goal of this study was to determine the potential exposure of much of the French population to nine phthalates and bis (2-ethylhexyl) adipate (DEHA) due to water consumption. The occurrence of these compounds was investigated in raw and treated water from public water systems. Water samples were collected in one sampling campaign equally distributed across 101 French départements (a French administrative unit) from November 2015 to July 2016. In all, 271 raw water samples and 283 treated water samples were collected. A specific sampling protocol was conducted in order to assess phthalate pollution during sampling and analysis, and to produce reliable results. Field blanks were thus collected at the same time as real samples at each sampling point. The contamination detected in field blanks was due to diethyl phthalate (DEP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), and di-2-ethylhexyl phthalate (DEHP), which are common phthalate interferences in blanks. Their concentrations were never ten times higher than the limits of quantification (LOQ). In tap water, the most frequently detected compound was DBP, at a maximum concentration of 1300 ng/L. In raw water, however, DEP was the most frequently detected analyte with concentrations ranging from 255 to 406 ng/L, while DIBP was observed at a maximum concentration of 1650 ng/L. It is worth mentioning that DEHP-the most widely used phthalate-was only detected in one sample of raw water. Phthalates are not concentrated in any particular area of France in either raw or treated water.