Studies have shown that per- and polyfluoroalkyl substances (PFAS) may impact thyroid function in human health. While the consistency between PFAS exposure and thyroid health effects in pregnant women has been validated, the effects on men and non-pregnant women remains inconclusive. To address this, a meta-analysis was carried out in this paper, with 14 eligible studies retrieved from Embase, PubMed, and Web of Science that were published up to 2 June 2024, focusing on the relationship between PFAS exposure and its effect on thyroid hormone levels in the human body. The thyroid function indexes analyzed included thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4). The estimated value (β) and the corresponding confidence interval (95% CI) were extracted from the literature. A heterogeneity test was carried out, and the sensitivity analysis and publication bias of the studies were analyzed using Stata 18.0. The results revealed that in men and non-pregnant women, PFOA was positively correlated with FT3 (β = 0.011, 95% CI = 0.001, 0.02, I² = 13.4). However, no significant associations were found between exposure to other PFAS and thyroid hormones. A subgroup analysis further indicated that the correlations between PFAS exposure and thyroid hormone levels were more significant in adolescents, in both America and Europe.

Microplastics (MPs) removal by coagulation and sand filter was investigated in a secondary wastewater treatment plant effluent matrix. The samples were collected and treated using three typical coagulants, i.e., ferric chloride (FeCl3), polyferric sulfate (PFS) and polyaluminum chloride (PAC). Results showed that all the three tested coagulants can effectively remove MPs with applicable dosages in tertiary treatment (10-50 mg/L). The highest removal rate obtained was 61% with 40 mg/L PFS, and PFS were slightly more efficient than PAC and FeCl3. After sand filtration, about 75.7% of MPs was removed. The combined PFS (40 mg/L) +sand filter process could remove 91% of MPs, 82% of suspended solids (SS) and 85% of total phosphorus (TP). The treatment cost of coagulant was about 0.0594 Yuan/t wastewater. Therefore, it is technologically and economically feasible to use coagulation and sand filter process to remove MPs from wastewater in tertiary treatment process in wastewater treatment plant.