Fluorine (F) and Cadmium (Cd) have given rise to public concern regarding their adverse impacts on the environment and human beings. Yet, the toxic interplay between F and Cd on the intestine is still vague. Aiming to investigate the role of F on Cd-damaged intestine, a total of five groups of 30 SD rats were picked at random to be gavaged for 90 days: Control group (Ultra-pure water), Cd (Cd 1 mg/kg), Cd+LF (Cd 1 mg/kg+F 15 mg/kg), Cd+MF (Cd 1 mg/kg+F 45 mg/kg), and Cd+HF (Cd 1 mg/kg+F 75 mg/kg). It demonstrated that Cd enriched in the intestine and disordered intestinal barrier of rats. Interestingly, two side effects of F were observed resisting to the Cd toxicity. The Cd levels in colon contents were attenuated by 45.45 %, 28.11 %, and 19.54 % by F supplement, respectively. In the Cd+LF group, SOD, GSH-Px, and CAT activities elevated by 0.93, 1.76, and 1.78 times, respectively, and the MDA content reduced 0.67 times; the expressions of NQO1, SOD2, and GSH-Px mRNA markedly enhanced, as well as the Keap1 mRNA significantly decreased. Nevertheless, all indexes above in the Cd+HF group showed the opposite trends. Furthermore, LPS levels decreased by 45.93 % for the Cd+LF group and increased by 12.70 % in that the Cd+HF group. The ZO-1 expression in the Cd+LF group increased, whereas the Cd+HF group's expressions of Claudin-1, Occludin, and ZO-1 were all diminished by 35.46 %, 27.23 %, and 16.32 %, respectively. Moreover, the levels of TNF-α, IL-1β and TLR-4 decreased and IL-10 level promoted, while all showed opposite trends in the Cd+HF group. Collectively, it indicated there is a twofold interplay between F and Cd on intestinal damage and mainly depends on F dosages.

Due to high geological background and intensive mining activities, soils are prone to heavy metals (HMs) accumulation and ecological fragility in Guizhou Province, China. A total of 740 topsoil samples were therefore collected, and aimed to determine the concentrations of As, Cd, Cr, Hg, and Pb, estimate the ecological pollution, and evaluate the carcinogenic and non-carcinogenic health risks to humans. Results showed As (1.08%) and Cd (24.46%) in soil exceeded standards. The Igeo showed that Cr (1.49%) and Hg (31.62%) in soil were at light pollution levels; single factor pollution index (PI) showed that Cd (21.35%) in soil was mildly polluted; risk index (RI) as at a low risk level. Notably, both deterministic and Monte Carlo analyses revealed unacceptable carcinogenic risks for As and Cr in children, with traditional methods potentially underestimating As risks. Moreover, Target-Organ Toxicity Dose (TTD) revealed soil HMs as a higher risk to hematological health, with notable health risks posed by Pb in children. It is noted that spatial distribution analysis suggested that the southwestern region of Guizhou Province should be prioritized for health risk management and control. By integrating the uniqueness of geological environments, multi-dimensional health risk assessments, and spatial distributions, the present study provides a scientific basis for assessing HMs pollution risks and soil health risks in the karst regions.