Page 89 - JCTR-11-2

Journal of Clinical and
Translational Research Crude oil pollutants in Southern Nigeria

Iranian heavy crude oil for 5 days displayed significantly T3 is the biologically active form of the thyroid hormone
lower levels of T3 and T4. In contrast, the examination of that binds to nuclear receptors to carry out the functions of
gross and histomorphology in rats exposed to crude oil did the thyroid hormone, facilitating appropriate development
not reveal any evidence of treatment-related changes in the of the brain, liver, and skeletal system. Newborns with a
40
thyroid. Furthermore, long-term exposure to bitumen deficit thyroid hormone may exhibit skeletal abnormalities
31
fumes, specifically from a mixture of 70% air-rectified as a result of insufficient endochondral ossification, a
and 30% vacuum residue bitumen at a concentration of process by which the fetal cartilaginous model of bones
100 mg/m , had only minor effects on the respiratory tract contributes to longitudinal growth and skeletal maturation.
3
and did not exhibit any significant impact on the thyroid In addition, the thyroid hormones control the activity of
gland. Thyroid hormones, notably T3 and T4, are crucial numerous genes that are crucial for the formation of the
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for the fetus’s growth and neurological development. central nervous system in embryos.
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Beginning from week 14 to the end of week 27 of pregnancy,
the fetal hypothalamus-pituitary-thyroid axis activates and The limitation of the study is its inability to quantify
produces an increasing amount of thyroid hormones. 34 crude oil contaminants in the environment, as more than
1,300 different compounds may be produced as a result
The average concentration of T3 in crude oil-exposed of oil and gas search and mining activities. Between
mothers was noticeably lower compared to non-crude oil- 1976 and 1996, the Department of Petroleum Resources
exposed mothers in the present study, which aligned with the reported that close to two million barrels of petroleum
findings of Forhead and Fowden. T3, a hormonally active had been dumped into the area. According to research by
33
compound, is synthesized from T4 and possesses greater the United Nations Development Programme, there were
potency than T4. It affects nearly all physiological processes 6,817 oil spills between 1976 and 2001, resulting in the
within the body. Furthermore, a reduced concentration of spill of three million barrels of oil, more than 70% of which
T3 can lead to a decline in the metabolic rate of body tissues, were not usually recovered. 41
which consequently hampers growth and maturation. The
35
decrease in serum T4 levels observed in individuals exposed The assessment of prenatal exposure to crude oil
to crude oil may be attributed to a shortened T4 degradation pollutants through a single measurement may have its
period. Several chemicals have been identified to reduce limitations; however, measurements taken during the
the serum degradation period of T4 by stimulating liver second and third trimesters are regarded as a reliable
enzymes involved in T4 conjugation. Chemicals found indicator of exposure throughout the latter two trimesters
36
in the environment, such as polychlorinated biphenyls, of gestation. The urinary iodine of the babies was not
bisphenol A, and brominated flame retardants, have been controlled in this study. Urinary iodine concentration
proven to influence hormone metabolism, leading to is regarded as a good marker for recent dietary iodine
alterations in hormone-mediated reactions. 37 status, as more than 90% of dietary iodine is excreted in
the urine. However, a recent study among women of
42
In this study, it was also discovered that the average
level of TSH was notably lower in the umbilical cord blood childbearing age in the study area indicated that a greater
proportion of the women (44.2%) had more than adequate
of newborns whose mothers were exposed to crude oil iodine nutrition, while 6.49% had excessive. The authors
pollution compared to newborns whose mothers were observed that the iodine status of women was adequate, as
not exposed. The average T3 and T4 concentrations in the none of the women was deficient. In addition, thyroid-
43
umbilical cord blood of infants born to mothers exposed
to crude oil pollution were significantly elevated compared binding globulin was not estimated in this study. Thyroid-
to neonates born to non-exposed mothers. The levels of binding globulin is one of the three transport proteins
thyroid hormones in newborns are affected by changes that transport thyroid hormones to the necessary tissues.
in the thyroid function and iodine levels of the mother. It is not known whether crude oil contains dioxin, but a
38
The remarkably lower TSH and increased T3 and T4 levels study has demonstrated that dioxin can originate from
aligned with the findings in deer mice by Movasseghi the regeneration of the catalytic reforming units during
et al. The authors observed that deer mice raised in a petroleum refining to produce gasoline. Dioxin has been
39
reclaimed oil spill site exhibited a notable increase in reported in wastewaters and sludges that are contaminated
follicular cell proliferation and a decrease in colloid levels with chlorinated dibenzo-dioxins and chlorinated
in their thyroid glands compared to control mice. Animals dibenzofurans from petroleum refineries. 44
experiencing higher levels of oxidative stress exhibited a 5. Conclusion
notable increase in thyroid hormone levels. This could
suggest an elevation in metabolic requirements resulting This study found that neonatal health indices, such as
from subclinical toxicity associated with contaminants. recumbent length, head circumference, and PI, were

Volume 11 Issue 2 (2025) 83 doi: 10.36922/jctr.24.00083