Risk analysis for groundwater intakes based on the example of neonicotinoids.

Neonicotinoids are a class of broad-spectrum insecticides that are dominant in the world market. They are widely distributed in the environment. Understanding the sources, distribution, and fate of these contaminants is critical to mitigating their effects and maintaining the health of aquatic ecosystems. Contamination of surface and groundwater by neonicotinoids has become a widespread problem worldwide, requiring comprehensive action to accurately determine the mechanisms behind the migration of these pesticides, their properties, and their adverse effects on the environment. A new approach to risk analysis for groundwater intake contamination with emerging contaminants was proposed. It was conducted on the example of four neonicotinoids (acetamiprid, clothianidin, thiamethoxam, and imidacloprid) in relation to groundwater accessed by a hypothetical groundwater intake, based on data obtained in laboratory tests using a dynamic method (column experiments). The results of the risk analysis conducted have shown that in this case study the use of acetamiprid and thiamethoxam for agricultural purposes poses an acceptable risk, and does not pose a risk to the quality of groundwater extracted from the intake for food purposes. Consequently, it does not pose a risk to the health and life of humans and other organisms depending on that water. The opposite situation is observed for clothianidin and imidacloprid, which pose a higher risk of groundwater contamination. For higher maximum concentration of neonicotinoids used in the risk analysis, the concentration of clothianidin and imidacloprid in the groundwater intake significantly (from several to several hundred thousand times) exceeds the maximum permissible levels for drinking water (<0.1 µg/L). This risk exists even if the insecticides containing these pesticides are used according to the information sheet provided by the manufacturer (lower maximum concentration), which results in exceeding the maximum permissible levels for drinking water from several to several hundred times.

Formation of 3-Aminophenols from Cyclohexane-1,3-diones.

meta-Aminophenols are formed by the action of DBU on 3-amino-2-chlorocyclohex-2-en-1-ones at room temperature in MeCN. The chloro compounds are generated by treating 3-aminocyclohex-2-en-1-ones with the easily prepared halogenating agent BnNMe3·ICl2 in MeOH-CH2Cl2. The amino group must carry two substituents, either two aryl, one aryl and one alkyl, or two alkyl groups; 3-aminocyclohex-2-en-1-ones of this type are readily made from cyclohex-2-en-1-one and a primary or secondary amine.

Fate of selected neonicotinoid insecticides in soil-water systems: Current state of the art and knowledge gaps.

The occurrence of emerging contaminants, such as: personal care products, medicines, pharmaceuticals, pesticides, and their transformation products in the environment is of concern for human health and aquatic ecosystems due to their high persistence, toxicity and potential to bioaccumulation. Among pesticides, the main attention and thus our focus is on neonicotinoids: acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam, which are widely used classes of insecticides in agriculture. Determining the associated risk to humans and ecosystems from neonicotinoid insecticides requires detailed understanding of their fate and transport in the environment which is complex and includes diverse pathways and processes depending on environmental compartments in which they occur. This paper critically reviews the current state of the art about processes, parameters and phenomena influencing the fate of neonicotinoid insecticides in soil-water systems (i.e. soil and groundwater), and reveals existing knowledge gaps. Sorption, biodegradation, chemical transformations of neonicotinoid insecticides in the soil and leaching to the groundwater, as well as groundwater/surface water interactions are highlighted, as they determine their further migration from sources, through soils to groundwater systems and then to other environmental compartments posing ecological and human risks. A number of key knowledge gaps in fate of neonicotinoid insecticides in soil-water systems are identified, that concern mostly processes and pathways occurring in the groundwater, and require further research to assess the associated risk to humans and ecosystems.

LC-MS/MS method validation for determination of selected neonicotinoids in groundwater for the purpose of a column experiment.

The work was carried out to develop and validate a method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous detection and quantification of five neonicotinoid insecticides: acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam in groundwater samples for the purpose of a further column experiment. This experiment will be used to analyze breakthrough curves of neonicotinoids under a saturated water flow to set transport parameters, where the reliability of the results of chemical analysis plays an important role. The validation was performed in a concentration range from 0.09 µg L-1 to 100 µg L-1 using an Infinity 1290 (Agilent, USA) chromatograph coupled with a QTrap 5500 mass spectrometer (Sciex, Canada). The calibration curves were obtained on the basis of the results of six standard solution analyses. Linearity was not lower than 0.998. The limit of detection was set at the lowest concentration which can be determined with an acceptable accuracy and precision. All pesticides had recoveries in the range 85-109% with relative standard deviation values less than 8.1%. The estimated measurement uncertainty did not exceed 30%, so the LC-MS/MS method fits for the intended purpose.