Dietary risk assessment of fluoride, lead, chromium, and cadmium through consumption of Tieguanyin tea and white tea

Contamination Status and Ecological Security Thresholds of Fluoride in Farmland around a Phosphorus Chemical Plant in a Karst Area of Southwestern China

The phosphorus chemical plant (PCP) production process leads to the substantial discharge of fluoride into the surrounding environment. However, there is limited research data regarding the pollution levels and ecological safety thresholds of farmland fluoride around PCPs in karst areas. This study evaluates the local contamination status and health risks by determining the fluoride content in farmland and vegetables in vicinity of a PCP in a karst area of Southwestern China. Farmland ecological security threshold was derived based on the species sensitivity distribution (SSD) model. Results showed that the fluoride contents in the soil ranged from 529.36 to 1496.02 mg kg^-1, with the median value of 823.93 mg kg^-1, which was higher than the national background value in China (478 mg kg^-1) by 172.37%. Fluoride contents in vegetables ranged from 0.01 to 25.21 mg kg^-1, with the median value of 1.29 mg kg^-1, which was higher than the limits of contaminants in food (1 mg kg^-1) by 129.00%, and 53.85% of vegetable samples were contaminated. Leafy vegetables showed a higher tendency of fluoride enrichment compared to non-leafy vegetables. Despite there being no significant health risk to the residents via the intake of vegetables overall, there may be potential health risks from the intake of sweet potato leaves. Based on the SSD model, the ecological safety thresholds of fluoride in local farmland was classified into the suitable for planting category (≤174.13 mg kg^-1), safe plant utilization category (174.13-4005.42 mg kg^-1), and strict control of planting category (≥4005.42 mg kg^-1). These findings will provide valuable insights to facilitate the safe cultivation of local agricultural products and optimize the utilization of soil resources.

Prediction and Health Risk Assessment of Copper, Lead, Cadmium, Chromium, and Nickel in Tieguanyin Tea: A Case Study from Fujian, China

Heavy metal is widespread in food and the environment due to multiple origins, raising concerns over their persistent potential health risks. Contamination of multiple heavy metals in tea leaves is frequently reported. However, the dietary exposure risk that heavy metals in Tieguanyin tea (a famous type of oolong tea,) pose to different subpopulations has not been explored. In this study, contaminations of five heavy metals (Cu, Pb, Cr, Cd, and Ni) of concern in Tieguanyin tea were monitored, then the related health risk was assessed for six different subpopulations based on tea brewing experiments and a previous consumption survey. Results show that the mean levels found were as follows: 8.18 mg/kg (Cu), 0.84 mg/kg (Pb), 0.51 mg/kg (Cr), 0.04 mg/kg (Cd), and 1.90 mg/kg (Ni), respectively, and their transfer rates during tea brewing varied within 10.2–70.4%. All estimated daily intakes of individual targeted elements via Tieguanying tea consumption were far below their corresponding tolerable limits. The adjusted hazard index value ranged from 1.1 × 10−2 to 1.7 × 10−2, indicating that exposure to these five elements via drinking Tieguanyin tea would not pose significant non-cancer risks for six subpopulations under the current consumption habit. In addition, the carcinogenic risks associated with heavy metals (Pb, Cd, and Cr) were acceptable because no total cancer risk values exceeded the 10−4 threshold. However, in order to improve consumer protection, we still suggest that considerable attention should be paid to Pb, Ni, and Cd because of their high concentration in infusion, high extraction rate, and major carcinogenic risk contribution, respectively.

Assessment of renal and hepatic dysfunction by co-exposure to toxic metals (Cd, Pb) and fluoride in people living nearby an industrial zone

Togo's phosphate processing plant at Kpeme discharges waste, containing Cd, Pb, and fluoride, into the sea and on the soil. Heavy metals toxicity on kidneys and the liver has been studied. However, fluoride toxicity on these organs remains to be investigated. The present study deals with the variation in renal and hepatic functioning parameters due to fluoride, Cd and Pb. Totally, 350 volunteers were recruited from five different localities around this phosphate processing plant for sample collection. Cd and Pb contents in blood samples were determined by spectrophotometry and fluoride by the titanium chloride method. Biochemical parameters were measured using Biolab kits. The pollutant contents were elevated in polluted areas where ASAT, ALAT, creatinine, and urea increased, and total protein decreased. Correlation and multivariate tests showed that fluoride is related to the various pathologies mentioned. PCA revealed that phosphate processing in Togo is a source of renal and hepatic toxicity.