Occupational exposure to potentially toxic elements alters gene expression profiles in formal and informal Brazilian workers.

Chemical elements, such as toxic metals, have previously demonstrated their ability to alter gene expression in humans and other species. In this study, microarray analysis was used to compare the gene expression profiles of different occupational exposure populations: a) informal workers who perform soldering of jewelry inside their houses (n = 22) in São Paulo (SP) State; and b) formal workers from a steel company (n = 10) in Rio de Janeiro (RJ) state, Brazil. Control participants were recruited from the same neighborhoods without occupational chemical exposure (n = 19 in SP and n = 8 in RJ). A total of 68 blood samples were collected and RNA was extracted and hybridized using an Agilent microarray platform. Data pre-processing, statistical and pathway analysis were performed using GeneSpring software. Different expression was detected by fold-change analysis resulting in 16 up- and 33 down-regulated genes in informal workers compared to the control group. Pathway analysis revealed genes enriched in MAPK, Toll-like receptor, and NF-kappa B signaling pathways, involved in inflammatory and immune responses. In formal workers, 20 up- and 50 down-regulated genes were found related to antimicrobial peptides, defensins, neutrophil degranulation, Fc-gamma receptor-dependent phagocytosis, and pathways associated with atherosclerosis development, which is one of the main factors involved in the progression of cardiovascular diseases. The gene IFI27 was the only one commonly differentially expressed between informal and formal workers and is known to be associated with various types of cancer. In conclusion, differences in gene expression related to occupational exposure are mainly associated with inflammation and immune response. Previous research has identified a link between inflammation and immune responses and the development of chronic diseases, suggesting that prolonged occupational exposures to potentially toxic elements in Brazilian metal workers could lead to negative health outcomes. Further analysis should be carried out to investigate its direct effects and to validate causal associations.

Human Biomonitoring Data in Health Risk Assessments Published in Peer-Reviewed Journals between 2016 and 2021: Confronting Reality after a Preliminary Review.

Human biomonitoring (HBM) is a rapidly developing field that is emphasized as an important approach for the assessment of health risks. However, its value for health risk assessment (HRA) remains to be clarified. We performed a review of publications concerned with applications of HBM in the assessment of health risks. The selection of publications for this review was limited by the search engines used (only PubMed and Scopus) and a timeframe of the last five years. The review focused on the clarity of 10 HRA elements, which influence the quality of HRA. We show that the usage of HBM data in HRA is limited and unclear. Primarily, the key HRA elements are not consistently applied or followed when using HBM in such assessments, and secondly, there are inconsistencies regarding the understanding of fundamental risk analysis principles and good practices in risk analysis. Our recommendations are as follows: (i) potential usage of HBM data in HRA should not be non-critically overestimated but rather limited and aligned to a specific value for exposure assessment or for the interpretation of health damage; (ii) improvements to HRA approaches, using HBM information or not, are needed and should strictly follow theoretical foundations of risk analysis.

A Multi-Life Stage Comparison of Silver Nanoparticle Toxicity on the Early Development of Three Canadian Fish Species.

Information on the effects of silver nanoparticles (AgNPs) in fish has mostly been generated from standard laboratory species and short-term toxicity tests. However, there is significant uncertainty regarding AgNP toxicity to native species of concern in North America, particularly in northern freshwater ecosystems. We assessed the chronic toxicity of AgNPs in early life stages of three North American fish species: rainbow trout (Oncorhynchus mykiss), lake trout (Salvelinus namaycush), and northern pike (Esox lucius). Newly fertilized embryos were exposed to nominal aqueous concentrations of 0.1, 0.3, 1.0, 3.0, 10.0, or 30.0 nM AgNPs for 126 (rainbow trout), 210 (lake trout), and 25 (northern pike) days. Endpoints included cumulative developmental time (°C × day or degree-days to 50% life-stage transition), mortality, fork length, embryonic malformations, cumulative survival, and histopathology of gill and liver in larvae/alevins. The results showed life stage-specific differences in responses, with endpoints during the embryonic stage occurring more often and at lower concentrations compared to larval/alevin and juvenile stages. Sensitivities among species were highly dependent on the endpoints measured, although developmental time appeared to be the most consistent endpoint across species. At embryonic and larval/alevin stages, northern pike was the most sensitive species (lowest observable effect concentration of 0.1 nM using developmental time). Rainbow trout displayed similar responses to lake trout across multiple endpoints and therefore seems to be an adequate surrogate for trout species in ecotoxicology studies. Moreover, while mortality during individual life stages was not generally affected, the cumulative mortality across life stages was significantly affected, which highlights the importance of chronic, multi-life-stage studies. Environ Toxicol Chem 2021;40:3337-3350. © 2021 SETAC.