The improper disposal of antibiotics in water bodies and using contaminated wastewater in irrigation severely damage the environment. Despite efforts to monitor these contaminants, effective detection methods are limited. Here, we design and develop a novel microfluidic electrochemical (EC) sensor for on-site detection of trimethoprim (TMP) using a selenite-enriched lanthanum hydroxide (La(OH)(3):SeOx) working electrode and a polyimide (PI)-filter integrated microfluidic channel (MFC), thus termed a mu TMP-chip. For the first time, we introduced a new two-pronged strategy for enhancing TMP detection: i) incorporating selenite into the La(OH)(3) lattice to improve charge transfer properties and ii) using a laser-processed PI filter in the MFC to trap and isolate complex biomasses. Material characterizations confirmed that incorporating selenite into the La(OH)(3) lattice initiated La-O-Se bond formation and enhanced hybridization between the La 4f and O 2p orbitals. This process created holes in the O 2p valence band and improved the charge transfer properties, thus enhancing both sensitivity and selectivity. EC studies confirmed that when the PI filter is not used in the MFC, the mu TMP-chip experiences a 15-45 % drop in efficiency. The scalable mu TMP-chip offers cost-effective, highly reproducible TMP detection in soil and water.

A traditional grid model for soil sampling may suffer from poor efficiency and low accuracy. With a nonferrous metal processing plant as the study area, a three-dimensional kriging interpolation model was built based on this plant's preliminary investigation data for arsenic (As), and a detailed survey sampling programme was proposed. The sampling density at the pollution interval of the surface soil was estimated by the coefficient of variation method, and the sampling depth was determined by the pollution interval of the vertical prediction results. The results showed that the encrypted soil sampling distribution optimisation method obtains greater pointing accuracy with fewer points. The sampling accuracy was 87.62% after optimising the depth of pointing. Moreover, this approach could save 66.13% of the sampling costs and 56.93% of the testing costs compared to a full deployment programme. This study provides a new and cost-effective method for predicting the extent of contamination exceedance at a site and provides valuable information to guide post-remediation strategies for contaminated sites.

Changes in food availability may act as a major mechanism by which global change impacts populations of birds, especially in seasonal environments at high elevations or latitudes. Systematic sampling of invertebrates, which constitute the diet of many bird species during the breeding season, is however largely missing in mountain ecosystems and is overall very rare for soil-dwelling species or stages. Here, we repeatedly sampled earthworms (Lumbricidae), the staple prey of the Ring Ouzel Turdus torquatus, over a whole breeding season in a study area in the Swiss Alps. Our main goal was to finely characterise spatio-temporal patterns of food availability for this declining bird species, in relation to elevation, habitat type and snowmelt stage. In 24 sampling plots, we extracted two soil cores every week for 6-10 weeks and hand-sorted soil invertebrates separately for two 5-cm soil layers. We then analysed the abundance of earthworms in those two layers in relation to various environmental parameters. We show that within our study area, edaphic and topographical parameters are poor predictors of the mean abundance of earthworms over the breeding season. Ground vegetation cover and soil moisture, however, are suitable predictors for the number of earthworms within the soil profile at each sampling time, i.e., of their availability for Ring Ouzels. Moreover, we provide evidence for a clear seasonal peak in earthworm availability, which was more pronounced in open grasslands compared to forested areas and happened later in the season where snow lingered. This study, by improving our understanding of the factors driving food availability for a mountain bird species, provides insights into how shifts in land-use and climate might lead to altered predator-prey interactions.