Termiticides are widely used to protect wooden houses from termites. Dieldrin, chlordane, heptachlor, and chlorpyrifos, which are effective termiticides, have been banned because of their high toxicity. Neonicotinoids, pyrethroids, phenyl pyrazoles, and triazoles have been used as alternatives to termiticides in indoor environments. However, despite numerous studies showing that farm-applied pesticides contaminate house dust, the health risks to humans from indoor termiticides remain unclear. We collected house dust and indoor air samples from 37 and 7 houses, respectively, to investigate the indoor termiticide contamination levels. The minimum margin of exposure to fipronil was 173, indicating that fipronil posed the highest risk among the targeted 28 compounds in indoor environment. The mean concentrations of alternative termiticides in house dust and air samples ranged from 1,126 ng g(- 1) (cyproconazole) to 5,356 ng g(- 1) (MGK-264) in thirty-seven houses and 0.08 ng m(- 3) (acetamiprid) to 34 ng m(- 3) (MGK-264) in seven houses, respectively. These results are comparable to the pesticide concentrations in houses close to farms where pesticides were applied, and are higher than atmospheric pesticide concentrations in oceans. Therefore, houses sprayed with termiticides may be as contaminated as agricultural environments where farmers apply substantial quantities of pesticides. The main route of exposure was air inhalation for fipronil, and both air inhalation and house dust ingestion for triazoles and potentiators. Establishment of regulations and development of decontamination methods are needed for indoor contamination of termiticides. Floor cleaning may be effective to remove termiticides that are ingested mainly through the house dust pathway.

Long-term exposure to Cd through contaminated food can lead to multiple adverse health effects on humans. Although previous studies have covered global food Cd concentrations and dietary Cd exposures across different populations, there are increasing concerns regarding the adequacy of current food Cd safety standards to protect populations from adverse health effects. Moreover, incorporation of Cd relative bioavailability (Cd-RBA) in foods improves the accuracy of health risk assessment. However, factors influencing food Cd-RBA have not been systematically discussed, thereby hindering its application in risk assessment. This review aims to provide an overview of Cd contents in foods, discuss concerns regarding international food Cd concentration standards, explore factors influencing food Cd bioavailability, and highlight the opportunities and challenges in refining differences between dietary Cd intakes and body burdens. Our findings suggest that current safety standards may be insufficient to protect human health, as they primarily focus on kidney damage as the protective endpoint and fail to account for global and regional variations in food consumption patterns and temporal changes in dietary habits over time. Factors such as crop cultivars and food compositions greatly influence food Cd-RBA. To improve the accuracy of Cd health risk assessment, future studies should incorporate food Cd-RBA, sociodemographic characteristics, nutritional status, and incidental Cd exposure. This review highlights new insights into food Cd safety standards and Cd bioavailability, identifies critical knowledge gaps, and offers recommendations for refining health risk assessments. This information is essential to inform future bioavailability investigations, health risk assessment, and safety standard development.

Rare earth elements (REEs) are increasingly recognized as significant environmental pollutants due to their environmental persistence, bioaccumulation, and chronic toxicity. This study assessed REEs pollution in soil, water, and vegetables in an ion-adsorption rare earth mining area in Ganzhou, and evaluated the associated health risks to the local population. Results indicated that the REEs content in soil ranged from 168.58 to 1915.68 mg/kg, with an average of 546.71 mg/kg, substantially surpassing the background level for Jiangxi Province (243.4 mg/kg) and the national average (197.3 mg/kg). Vegetables displayed an average REEs content of 23.17 mg/kg in fresh weight, far exceeding the hygiene standard of 0.7 mg/kg. Water samples contained REEs at a concentration of 4.09 mu g/L. The estimated daily intake (EDI) of REEs from vegetables exceeded the threshold for subclinical damage, posing potential health risks, particularly for children and adolescents. Further analysis of the adjusted average daily intake (ADI) and non-carcinogenic risk suggested that while most vegetable consumption remains within safe threshold, the intake of REEs from high-risk vegetables such as pakchoi should be limited. Overall, carcinogenic risks associated with lifetime cancer risk (LCR) model for REEs exposure through vegetables and water were found to be low in this area.

Substituted p-phenylenediamines (PPDs), a class of antioxidants, have been widely used to extend the lifespan of rubber products, such as tires and pipes. During use, PPDs will generate their quinone derivatives (PPD-Qs). In recent years, PPDs and PPD-Qs have been detected in the global environment. Among them, N-(1,3-dimethylbutyl)-N '-phenyl-p-phenylenediamine quinone (6PPD-Q), the oxidation product of N-(1,3-dimethylbutyl)-N'phenyl-p-phenylenediamine (6PPD), has been identified as highly toxic to coho salmon, with the lethal concentration of 50 % (LC50) being 95 ng/L, highlighting it as an emerging pollutant of great concern. This review summarizes the physicochemical properties, global environmental distribution, bioaccessibility, potential toxicity, human exposure risk, and green measures of PPDs and PPD-Qs. These chemicals exhibit lipophilicity, bioaccumulation potential, and poor aqueous stability. They have been found in water, air, dust, soil, and sediment worldwide, indicating their significance as emerging pollutants. Notably, current studies have identified electronic waste (e-waste), such as discarded wires and cables, as a non-negligible source of PPDs and PPDQs, in addition to tire wear. PPDs and PPD-Qs exhibit strong bioaccumulation in aquatic organisms and mammals, with a tendency for biomagnification within the food web, posing health threats to humans. Available toxicity data indicate that PPDs and PPD-Qs have negative effects on aquatic organisms, mammals, and invertebrates. Acute exposure leads to death and acute damage, and long-term exposure can cause a series of adverse effects, including growth and development toxicity, reproductive toxicity, neurotoxicity, intestinal toxicity, and multi-organ damage. This paper discusses current research gaps and offers recommendations to understand better the occurrence, behavior, toxicity, and environmental exposure risks of PPDs and PPD-Qs.

Per- and polyfluoroalkyl substances (PFAS) possess distinct properties, such as hydrophobicity, oleophobicity, and thermal and chemical stability, resulting in their wide application in various industrial processes, including electroplating, fire protection, and textile, paper, and leather production. However, due to their propensity for high bioaccumulation, long-distance transport, resistance to degradation, and potential adverse effects on animal and human health, certain PFAS, including legacy perfluorooctanoic acid (PFOA), were listed in Annex A of the Stockholm Convention in 2019, leading to a global ban on their production and usage. Consequently, per- and poly-fluoropolyether carboxylic acids (PFECA), containing ether oxygen bonds in their structure, have emerged as processing-additive substitutes for PFOA in different industries. Recently, with the increasing concern, more and more PFECA have been identified and detected in various environmental matrix and human samples. Epidemiological research and toxicity experiments have also found that some PFECA have health hazards comparable to or even stronger than PFOA. In the present study, we focus on the classification, environmental impacts, and toxic hazards associated with PFECA and summarize recent research regarding non-targeted identification, environmental behavior and fate, biological/human exposure levels, toxic effects, and related molecular mechanisms. The overall aim of this review is to provide a valuable reference for environmental pollution research and biological risk assessment of PFAS alternatives, thereby supporting the regulation and reduction of PFAS alternatives in China. In terms of PFECA recognition, with the rapid development of non-targeted and targeted screening techniques, researchers have identified a series of PFECA with feature structure in various environmental matrix, such as unsaturated PFECA, chlorinated PFECA and homologues of hexafluoropropylene oxide trimer acid (HFPO-TA). However, non-targeted and targeted screening research is still in its infancy, with only 11 reports identifying dozens of PFECA, more and more novel PFECA will definitely be recognized in the future. In terms of quantitative detection, PFECA has been detected in various environmental matrix (including surface water, soil, atmosphere), organisms (including plants, fish and frogs) and even human samples (serum, urine and milk). Among them, there are many reports on water bodies and population samples. Among the existing reports, the PFECA levels in water and human samples accounts for a relatively large proportion. It is worth noting that the detection rate of HFPO-TA homologues in the serum of residents living around fluoride factories exceeds 90%, and the concentration of HFPO-TA ranking the fourth among all the detected PFAS. In terms of the toxic effects, it has been confirmed through several animal exposure experiments that PFECA, such as HFPO-TA, hexafluoropropylene oxide tetramer acids (HFPO-TeA) and perfluoro (3,5,7,9-tetraoxadecanoic) acid (PFO4DA), can cause liver damage, decreased sex hormone levels, metabolic disorders, and developmental abnormalities by interfering with PPAR pathways and metabolic pathways. In addition to in vivo experiments, we also noticed that researchers have carried out in-depth in vitro and in sillico studies on the interaction between PFECA and nuclear receptors or transporters in order to provide a possible explanation for the bioaccumulation and toxic effects of PFECA. Our paper also discusses the challenges, potential risks, and future research directions concerning the application of PFECA. For example, in the development and application of green alternatives, several problems, including unclear information on their structure, physical and chemical properties, and immature quantitative analysis methods, should be addressed to reduce the potential environmental and health hazards caused by the new PFECA at the source. At the same time, developing efficient degradation methods in contaminant treatment is also one of the future research directions. It is also worth paying more attention to combine regulatory, scientific research, and market aspects to provide guarantees for the rational use of novel PFECA.