Automated thin-film microextraction coupled to a flow-through cell: somewhere in between passive and active sampling

Sorption of selected antiparasitics in soils and sediments

BACKGROUND

Veterinary pharmaceuticals can enter the environment when excreted after application and burden terrestrial and aquatic ecosystems. However, knowledge about the basic process of sorption in soils and sediments is limited, complicating regulatory decisions. Therefore, batch equilibrium studies were conducted for the widely used antiparasitics abamectin, doramectin, ivermectin, and moxidectin to add to the assessment of their environmental fate.

RESULTS

We examined 20 soil samples and six sediments from Germany and Morocco. Analysis was based on HPLC-fluorescence detection after derivatization. For soils, this resulted in distribution coefficients K D of 38-642 mL/g for abamectin, doramectin, and ivermectin. Moxidectin displayed K D between 166 and 3123 mL/g. Normalized to soil organic carbon, log K OC coefficients were 3.63, 3.93, 4.12, and 4.74 mL/g, respectively, revealing high affinity to organic matter of soils and sediments. Within sediments, distribution resulted in higher log K OC of 4.03, 4.13, 4.61, and 4.97 mL/g for the four substances. This emphasizes the diverse nature of organic matter in both environmental media. The results also confirm a newly reported log KOW for ivermectin which is higher than longstanding assumptions. Linear sorption models facilitate comparison with other studies and help establish universal distribution coefficients for the environmental risk assessment of veterinary antiparasitics.

CONCLUSIONS

Since environmental exposure affects soils and sediments, future sorption studies should aim to include both matrices to review these essential pharmaceuticals and mitigate environmental risks from their use. The addition of soils and sediments from the African continent (Morocco) touches upon possible broader applications of ivermectin for human use. Especially for ivermectin and moxidectin, strong sorption further indicates high hydrophobicity and provides initial concern for potential aquatic or terrestrial ecotoxicological effects such as bioaccumulation. Our derived K OW estimates also urge to re-assess this important regulatory parameter with contemporary techniques for all four substances.

GRAPHIC ABSTRACT

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s12302-021-00513-y.

In-situ formation of Zn-Al layered double oxides on electrochemically anodized nanoporous aluminum film as sorbent for chlorophenols extraction from water and wastewater followed by determination using HPLC

Herein, we present a simple, cost-effective, and robust strategy for the in-situ preparation of Zn-Al layered double oxides-anodized aluminum thin film via a facile hydrothermal method, followed by calcination treatment of the Zn-Al layered double hydroxide in the air atmosphere. The in-situ prepared Zn-Al layered double oxide-anodized aluminum film was implemented as sorbent for thin film microextraction of four selected chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol), followed by high-performance liquid chromatography-ultraviolet detection. The different variables of the thin film microextraction were screened via Plackett-Burman design and then optimized through Box-Behnken design. Under the optimum condition, the method showed good linear ranges (0.2-200 μg/L) with the coefficient of determinations higher than 0.9938. The calculated limit of detections were between 0.07 and 0.56 μg/L. Relative standard deviations of the method for determination of the analytes at 5 μg/L concentration level (n = 3) were ranged from 3.5 to 3.9% (as interday). The enrichment factors were between 39 and 58. This extraction method was demonstrated to be fast, efficient, and convenient. To study the capability of the developed method for real sample analysis, tap, well, river, and two types of wastewater samples were satisfactorily analyzed.