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Environmental Aspects
Published in T. H. Christensen, R. Cossu, R. Stegmann, Landfilling of Waste: Biogas, 2020
T. H. Christensen, R. Cossu, R. Stegmann
Teratogenicity is the ability of a particular chemical substance, micro-organism or ionizing radiation to cause non-inherited malformation of embryos, especially mammalian. Teratogenic agents affect the prenatal life of humans so that there is a permanent (irreversible) disruption of embryonic development in the uterus or a permanent (irreversible) impairment of postnatal development of the child. Theoretically, substances can injuriously intervene in all reproductive phases. Reproduction toxicology deals with the effects of compounds on sperm and ova, conception and implantation, organogenesis and fetal maturity. It is not yet exactly known how embryonic malformations occur. It is assumed that the teratogenic effects are the result of chromosome aberrations, impairment of mitosis and inhibition or interference with nucleic acid synthesis and repair.
Categorization of Chemical Substances
Published in T.S.S. Dikshith, and Safety, 2016
Reproductive and developmental toxins: Many chemical substances cause adverse health effects to the reproductive and developmental cycles of animals and humans. They inflict adverse effects on various aspects of reproduction, such as fertility, gestation, lactation, and the growth and development of the embryo or fetus. These effects include lethality (death of the fertilized egg, the embryo), malformations or terata (the chemical substances are also called teratogens), retarded growth, and postnatal functional deficiencies. When a pregnant worker is exposed to a toxic chemical substance, generally the fetus is also exposed because the placenta is an extremely poor barrier. Reproductive toxins can affect both men and women. Toxic chemical substances like dibromochloropropane cause sterility in male workers.
Toxicology of CERCLA Hazardous Substances
Published in Barry L. Johnson, Impact of Hazardous Waste on Human Health, 2020
Teratogens are substances that cause malformations and other effects in the fetus. The fertilized egg, produced by fertilization of an ovum by a single sperm, first enters the embryonic period, or 14 weeks in which different body organs are formed at different times and rates. Next comes the fetal period, which ends at birth. Many substances are know to produce teratogenicity. For example, the drug thalidomide, taken by pregnant women in the 1960s, caused devastating congenital malformations, including missing or malformed limbs in infants. Hazardous waste concerns are raised by epidemiologic studies in Chapter 5 that associate parental proximity to some kinds of CERCLA sites with particular birth defects and lower birth weight of infants.
Investigation of the embryo-toxicity of the antiviral drug “Ribavirin” in Wistar rats during different gestation periods
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Mohamed Magdy, Abd El Wahab El Ghareeb, Taha M. A. Eldebss, Heba Ali Abd El Rahman
One of several speculative processes proposed as potential treatments for fetal toxicity is the activation of biochemical or metabolic alterations (with negative effects on the fetus) in the mother’s system. For example, the development of oxidative stress in the embryonic system is a critical mechanism of teratogenic agent-induced fetal toxicity [37] . Oxidative stress can induce cell death, intermediate oxidative stress induces apoptosis, and more severe stress induces necrosis [38,39]. However, Wells et al. [40] found that just 5% of the maternal level of most antioxidant enzymes is present in the embryo. This result may be linked to findings showing that low levels of antioxidant enzyme activity increase as development progresses and that the fetus might not be able to adapt well to oxidative disturbances early in organogenesis, leading to teratogenicity [41].
Toxicological effects of hydroxychloroquine sulfate and chloroquine diphosphate substances on the early-life stages of fish in the COVID-19 pandemic context
Published in Journal of Environmental Science and Health, Part A, 2023
Isabella Ferreira Silva, Keiza Priscila Enes, Gustavo Machado Rocha, Fernando Pilla Varotti, Leandro Augusto Barbosa, Ralph Gruppi Thomé, Hélio Batista dos Santos
Newly hatched zebrafish larvae exposed to HCQ were the same length as those in the control group (Fig. 3e). On the other hand, zebrafish larvae exposed to all CQ treatments showed a significant decrease in total length compared to the control group (Fig. 3f). Spinal cord defects, tail curvature, and short body were frequently observed in the groups treated with HCQ and CQ (Fig. 3h). The abnormal spinal cord and tail are teratogenic effects frequently reported in fish embryo acute toxicity assays after exposure to medicines as nimesulide, ibuprofen, ketoprofen, naproxen, and HCQ.[9,20,30,32,39] Although these malformations might not lead to death, they can cause an erratic swimming, which facilitates predation, contributing to an ecological imbalance in nature. The spinal cord defects can be associated with a deficiency or imbalance of phosphorus and calcium,[48] and are probably associated with cardiovascular dysfunction in embryos/larvae after exposure to xenobiotics, preventing the absorption of nutrients for organogenesis.
Concentrations, seasonal trends, sources, health risk and subchronic toxicity to the respiratory and immune system of PAHs in PM2.5 in Xi'an
Published in Journal of Environmental Science and Health, Part A, 2023
Xiang-ni Wang, Hui-juan Wang, Yan Ma, Jin-ren Liu, Yue Hao, Cai-qin Ma, Na Liu, Yi-xin Cui, Xing-min Shi, Fu-liang Gong, Xi-li Wu
PAHs are widespread environmental pollutants formed by incomplete combustion of coal, tobacco or other organic matter.[7] PAHs directly or indirectly affect the quality of the atmospheric environment, climate change and human health. Studies have confirmed that PAHs are carcinogenic, teratogenic and mutagenic substances, involved in the metabolism of living organisms and human bodies, and have strong toxicity.[8] The United States Environmental Protection Agency (USEPA) announced 16 priority PAHs.[9] Regarding the content and hazard of PAHs in atmospheric particles, scholars at home and abroad have done a large number of studies. Many cities in China have carried out researches on the pollution characteristics and sources of PAHs, and domestic researches on PAHs in atmospheric particulate matter focus on the distribution and sources,[10–12] while researches on the relationship between PAHs in atmospheric particulate matter and organism health are scarce.