Lethal Bentazone Intoxication - A Report of Two Cases

Bentazone in water and human urine in Wuhan, central China: exposure assessment

Bentazone is a widely used post-emergence herbicide, while no data was available on its concentrations in tap water from China and in urine among the general population. It was determined in the source (Wuhan section of the Yangtze River watershed), treated, and tap water (n = 20, 20, and 170, respectively) in different seasons (2019) in Wuhan, central China. Also, urine samples (n = 38) collected from healthy adults in Wuhan (September 2020) were analyzed to characterize its urinary concentration. Bentazone was detected in all the source and treated water samples. Its concentrations in the source water in July were higher than those in February (median: 17.9 ng/L vs. 2.86 ng/L) (p < 0.05). It cannot be removed efficiently (27.8-27.9%) by conventional drinking water treatment using NaClO, but it can be efficiently removed by using chlorine dioxide or ozone combined with activated carbon. Bentazone was frequently detected (detection frequency: 96.3%) in 160 tap water samples (underwent conventional treatment) (median: 1.95 ng/L, range: <0.02-47.0 ng/L), while it was not detectable in tap water samples that underwent ozone combined with activated carbon. Seasonal variations were found, with the lowest median concentration (ng/L) in April (0.46) and the highest in July (17.6). In addition, bentazone was frequently (92.1%) detected in human urine samples (median: 0.02 ng/mL; range: < 0.01-0.11 ng/mL). The estimated daily intake of bentazone based on its median concentration in tap water (0.04 ng/kg-body weight [bw]/day) accounted for approximately 8% of that based on the median urinary concentration (0.48 ng/kg-bw/day). This is the first time to characterize its occurrence in drinking water from China and its occurrence in the urine of the general population.

Au@Ag bimetallic nanoparticles deposited on palygorskite in the presence of TiO2 for enhanced photodegradation activity through synergistic effect

Herbicides are hazardous organic pollutants that contribute to the risk of environmental contamination. The aim of this work was to investigate the synergistic effect of silver (Ag) and gold (Au) bimetallic nanoparticles deposited on palygorskite (PAL) in the presence of TiO₂ for photodegradation of bentazone (BTZ) herbicide under UV light. Ag and Au@Ag nanoparticles exhibited an average size below 75 nm and surface charge values less than - 30 mV. UV-Vis spectroscopy indicates the formation of core@shell bimetallic nanoparticles. XRD results showed the interactions between the NPs and the palygorskite structure. SEM images clearly illustrate the presence of small spherical particles distributed in the clay fibers. The control of the size and distribution of the nanoparticles played an important role in the properties of the composites. The degradation of the herbicide BTZ showed that nanoparticles, clay, and only TiO₂ did not produce satisfactory results; however, when Ag-Pal and Au@Ag-Pal were in the presence of the TiO₂, the degradation was efficient. The best photodegradative system was Au@Ag-Pal+TiO₂, which was maintained after the third cycle. The bentazone photodegradation using Au@Ag-PAL+TiO₂ exhibited toxicity against Artemia salina. Therefore, Au@Ag-PAL+TiO₂ photocatalyst showed that the synergy of bimetallic nanoparticles deposited on clay for enhanced photodegradation activity of bentazone herbicide.

Electrochemical determination of bentazone using simple screen-printed carbon electrodes

Bentazone is one of the most problematic pesticides polluting groundwater resources. It is on the list of pesticides that are mandatory to analyze at water work controls. The current pesticide measuring approach includes manual water sampling and time-consuming chromatographical quantification of the bentazone content at centralized laboratories. Here, we report the use of an electrochemical approach for analytical determination of bentazone that takes 10 s. The electrochemical electrodes were manually screen printed, resulting in the low-cost fabrication of the sensors. The current response was linearly proportional to the bentazone concentration with a R² ~ 0.999. We demonstrated a sensitivity of 0.0987 μA/μM and a limit of detection of 0.034 μM, which is below the U.S. Health Advisory level. Furthermore, the sensors have proved to be reusable and stable with a drop of only 2% after 15 times reuse. The sensors have been applied to successfully quantify bentazone spiked in real groundwater and lake water. The sensing method presented here is a step towards on-site application of electrochemical detection of pesticides in water sources.