A modified quick, easy, cheap, effective, rugged and safe–ultra-performance liquid chromatography–tandem mass spectrometry method was developed and validated for the analysis of pyraclostrobin residue in rice plants, hulls, soil, and paddy water. Pyraclostrobin residue dynamics and final residues were studied in supervised field trials under Good Agricultural Practice conditions in rice, plants, hulls, soil, and paddy water. The levels of detection of all chemicals in five types of matrices were in the ranges of 2 × 10⁻⁷ to 1 × 10⁻⁵ mg/kg with recoveries in the ranges of 74.1–107.4%. The dissipation experiments showed that the half-lives (T_1/2) of pyraclostrobin in the plants, soil, and paddy water were 6.3–13.9, 5.0–34.7, and 6.9–11.6 days, respectively. At pre-harvest intervals (PHIs) of 14, 21, and 28 days, pyraclostrobin residue levels were <0.01–0.19 mg/kg in rice. The residue levels at 35-d PHI were all below 0.1 mg/kg (maximum residue limit of the USA), and all the health risk quotient values calculated were below 0.027. The environment risk of pyraclostrobin in soil and paddy water was also monitored throughout the rice-growing period, and the results showed that the risk level was between low and medium in the soil and high in the paddy water.

Bisphenol A (BPA), a common bisphenol molecule, is well known in the environment as an endocrine disruptor. Furthermore, BPs (BPA, BPS, BPF, and BPAF) have been shown in recent years to be neurotoxic to zebrafish. Tetramethyl bisphenol F (TMBPF) has recently been introduced as a substitute for bisphenol A (BPA) in various industries, including plastics and food contact coatings. However, a growing number of studies have demonstrated that the toxicity of some BPA substitutes is similar to or even stronger than BPA, posing potential harm to human health and the environment. In this study, we used zebrafish larvae as a model to investigate the neurodevelopmental effects of TMBPF at different concentrations (0, 0.25, 0.5, 1, 2, 4 and 8 mg/L). Our results showed that exposure to TMBPF at concentrations higher than 4 mg/L for 72 h post-fertilization (hpf) resulted in zebrafish mortality, whereas exposure to 2 mg/L for 144 hpf caused deformities. Furthermore, TMBPF exposure inhibited the development of the central nervous system, motor nerves, and dopamine neurons in zebrafish. Real-time polymerase chain reaction (PCR) analysis revealed that TMBPF exposure significantly down-regulated the expression of oxidative stress-related genes (Cu/Zn-SOD, Mn-SOD, and CAT) and neurodevelopmental genes (mbp, gafp, and syn2a), while up-regulated the expression of dopamine-related genes (th1, th2, and dat). Notably, treatment with the antioxidant N-acetylcysteine (NAC) alleviated TMBPF-induced toxicity. NAC can regulate the expression of genes related to oxidative stress, neurodevelopment and dopamine development, and make the nerve development of zebrafish normal. Overall, our research suggested that TMBPF may disrupt the development of the early central nervous system and dopamine neurons, leading to abnormal motor behavior in zebrafish larvae. These results highlight the potential risks associated with the use of TMBPF in various industries and the importance to evaluate its potential risks to human health and the environment.

The removal, and its mechanism, of arsenate from aqueous solutions was investigated using Yunnan red soil. A series of adsorption experiments was designed to disclose the effect of key factors (soil types, soil/solution rates, initial arsenate concentrations, and shaking speeds) on the adsorption capacity of Yunnan red soil for arsenate. The soil/solution ratio was optimized as 0.05 g/100 mL to balance the adsorption capacity and removal efficiency. The optimal shaking speed (225 rpm) not only ensured enough contact frequency between the Yunnan red soil and the arsenate, but also reduced the mass transfer resistance. The results from applying an orthogonal array method showed that the most significant factor affecting arsenate removal efficiency was soil type, followed by the soil/solution ratio, contact time, and shaking speed. The IR spectra of the precipitates further confirmed that the metal arsenide was settled by the Yunnan red soil, indicating that the arsenate ion existed on the red soil surface in the form of protonated bidentate surface complexation of –FeO₂As(O)(OH)⁻ and FeO₂As(O)²⁻. These results indicate that Yunnan red soil is promising for the removal of arsenate from aqueous solutions; it may thus be suitable as a new adsorbent for arsenate removal during water treatment.