Reproductive Toxic Chemicals at Work and Efforts to Protect Workers' Health: A Literature Review

Integration of chemical health risk assessment (CHRA) and indoor air quality (IAQ) assessment: from a Malaysian perspective

In Malaysia, chemical management in workplaces is managed under the Occupational Safety and Health Act 1994. Hence, the introduction of the Occupational Safety and Health (Use and Standards of Exposure of Chemicals Hazardous to Health) Regulations 2000 has strengthened the chemical management level in workplaces, including higher academic institutions. The introduction of chemical health risk assessment through the regulation required management to conduct the assessment at workplaces. Poor levels of Indoor Air Quality (IAQ) in chemical laboratories may also cause discomfort among workers when there is sick building syndrome in laboratories. IAQ is managed through the Industry Code of Practice on Indoor Air Quality 2010. Although both are different in method and approach, both are meant to ensure the workers' safety and comfort. This study is aimed to investigate the need to integrate both chemical health risk assessment and IAQ assessment in laboratories to ensure optimum safety levels among workers.

Determinants of early neonatal mortality: secondary analysis of the 2012 and 2017 Indonesia Demographic and Health Survey

Background

Most neonatal deaths occur during the first week of life (i.e., early neonatal deaths). In this analysis, we aimed to investigate the determinants of early neonatal deaths in a nationally representative sample of births in Indonesia over the five years before each survey.

Methods

Data were obtained from the 2012 and 2017 Indonesia Demographic and Health Survey (IDHS), including information from 58,902 mothers of children aged <5 years of age. The outcome variable was early neonatal death (death of a newborn within the first six days of life). Explanatory variables were categorized into environmental, household, maternal, pregnancy, childbirth, and child characteristics. Multivariate regression methods were employed for analysis.

Results

Increased odds of early neonatal deaths were associated with mothers who lacked formal education or had incomplete primary schooling (adjusted odd ratio [OR] = 2.43, 95% confidence interval [CI]: 1.18-5.01), worked outside the house in agricultural (aOR = 5.94, 95% CI: 3.09-11.45) or non-agricultural field (aOR = 2.98, 95% CI: 1.88-4.72), and were required to make a joint decision about health care with their partner or another household member (aOR = 1.79, 95% CI: 1.12-2.84). Increased odds were also observed in smaller-than-average infants, particularly those who received low-quality antenatal care services (aOR = 9.10, 95% CI: 5.04-16.41) and those whose mothers had delivery complications (aOR = 1.72, 95% CI: 1.10-2.68) or who were delivered by cesarean section (aOR = 1.74, 95% CI: 1.07-2.82). Furthermore, male infants showed higher odds than female infants (aOR = 1.85, 95% CI: 1.23-2.76).

Conclusions

A multifaceted approach is essential for curtailing early neonatal mortality in Indonesia. Enabling workplace policies, promoting women's empowerment, strengthening the health system, and improving the uptake of high-quality antenatal care services are among the critical steps toward preventing early neonatal deaths in Indonesia.

Physical exposures in the work environment during pregnancy - a challenge for risk assessment

Pregnant women have been preforming work-related activities during pregnancy since time immemorial, from the traditional hunter-gatherer or forager society to today’s modern world. But ever since our society has been industrialized, exposure patterns for pregnant women have changed dramatically, and they keep changing. This change is due partly to exposure changes overall in the labor market and partly the changes in the gender balance in different occupations.

To some extent, women have been protected from the most hazardous occupations, since these mainly have been held by men (1). But active strategies within Europe to move towards a gender-balanced work force have increased the number of women seeking employment in hazardous work environments. One example is heavy truck and lorry drivers, who are predicted to be 40% female by 2030 (2). Today, the labor participation rate for women is high, with a total of 67% in Europe and 74–80% in Scandinavian countries (3), leading to a workforce that eventually has as many exposed women as men.

A gender-balanced work force across occupations brings diversity and thus benefits to the work site (4). But it also introduces a challenge, especially in exposed blue-collar occupations. So far, much emphasis has been given to chemical and particles exposure. This is a very important and crucial area for the risk assessment for pregnant workers (5, 6) but not the only hazard present in occupational settings. Too little attention has been paid to physical factors in the work environment during pregnancy in association with health effects, even though physical factors are more prevalent than chemical and particles exposure in occupational settings. The exception is physical load, about which several original articles and reviews have been published (7–9). But physical exposure is a broad concept and also includes exposure to temperature, whole-body vibration, and noise.

Among the physical exposures in occupational settings, physically strenuous work has been the most studied. This area includes work postures, heavy lifting, standing/walking, sedentary work as well as a cardiovascular strain from physical labor. Recent reviews show an overall modest effect for physically strenuous work during pregnancy as well as pregnancy complications and adverse birth outcomes (10). In summary, the evidence so far concludes that pregnant workers should avoid occasional heavy lifting and lifting >10 kg in general (9). Heat in residential settings during pregnancy has been extensively studied (11), and some studies have also focused on occupational settings. An association between heat exposure and heat stress in relation to pregnancy complications as well as birth outcomes has been reported (12). But the evidence is not strong enough to recommend specific temperature levels in occupational settings for pregnant workers.

Only a few studies have investigated noise and whole-body vibration and its effect on pregnant workers. In both areas, reviews have shown inconclusive results (13, 14) and, since then, only a handful studies have been published, including only one large scale cohort study divided into five manuscripts (15–19). The evidence so far suggests that working full-time (8 hours) in weighted average of >80dBA occupational noise and >0.5m/s2 whole-body vibration is associated with an increased risk of pregnancy complications and negative birth outcomes. But since these findings come from one cohort, they need to be confirmed in other high quality cohort studies where levels of exposure can be assessed.

An important review on the evidence so far regarding physical exposures during pregnancy and preterm birth is on the way; the method and protocols have already been published (20), but a review is only as good as its included studies, and we need more high-quality original studies in this research area. Overall, more prospective cohort studies with objectively assessed exposures are needed to be able to identify a safe level for occupational physical exposures during pregnancy. So far, the current evidence on physical load is predominantly based on self-reported physical load, and future studies should focus on high quality objective exposure assessment to increase the level of evidence within this part of the research field.

To be able to progress, future studies also need detailed information on absence from work. In many countries, absence from work due to pregnancy benefit, sick leave and parental leave is common during pregnancy. In Sweden, 7 out of 10 women apply for leave of absence benefits at some point during pregnancy [21). In contrast to chemical exposures, that can bioaccumulate, physical exposures predominately affect the working mother during pregnancy. Hence, to correctly assess occupational exposure to physical factors during pregnancy in relation to health effects in the mother and child, absence from work needs to be addressed properly. Associations can otherwise be missed due to misclassification of exposure. This have been shown in a large-scale cohort study from Sweden, where associations only were found in full time workers with low leave of absence during pregnancy [16-18).

Leave of absence data is also needed to assess the potential beneficial effect that leave of absence can have on the pregnant worker. This was shown in Skröder et al 2021, where pregnant women highly exposed to whole-body vibration only had an increased risk of preterm birth if they had few days of leave of absence during pregnancy. With increased levels of leave of absence from work, women highly exposed to whole-body vibration at work had the same risk of delivering preterm as the general working population. In high levels of leave of absence data, women highly exposed to whole-body vibration had a lower risk of preterm birth then the general population with the same level of absence from work, indicating a healthy worker effect [16). Leave of absence during pregnancy can also be seen as an intermediate measure, since early health effects can lead to an increased level of sick leave, parental leave or pregnancy benefit. An association between exposure at the workplace and level of absence from work have been seen in a recent Danish study and in a recent review [22, 23).

High quality environmental epidemiological studies have been of use when assessing the effect of occupational exposure during pregnancy to chemical and particle exposure on pregnancy complications and birth outcomes. But for physical exposures, the exposures and levels differ substantially between environmental and occupational settings and some of the mechanisms. This is true for the mechanism between noise and health, where occupational and residential exposure to noise both are associated with a stress mechanism, but were only the residential exposure contribute to sleep disturbance and related health effects [13). An exposome approach is needed to identify and assess all the potential risk factors for pregnant women [24). In the exposome concept, multiple exposures in a life course perspective are assessed, with a focus on vulnerable stages, such as pregnancy. It is important to adjust for other co-exposures in the work environment, such as chemical and particle exposure, psychosocial exposures, shift work and other physical exposures when assessing the relationship between occupational exposure to one physical factor and the outcome. These exposures are partly correlated with each other [15-19). Few previous studies have been able to adjust for other occupational exposures at work when investigating individual occupational exposures. Very few studies examined the interaction of occupational exposure and how they jointly contribute to the risk of health effects in the mother and child, even though most of these exposures correlate in the work place [25). Some of the existing birth cohort studies can be regarded as hidden treasures for occupational data, with detailed information on occupational environment of the parents that many times have not been used [26). We need to be able to produce valid exposure-response curves and thereby ensure a safe work environment for the pregnant worker and her child. But also, to avoid excluding women from the labor market during pregnancy unnecessary. An unnecessary exclusion from the labor market can hinder female workers career advancement to the next level of their career and lead to lower salaries, and in the end lower pensions compared to men. So, a well-balance discussion based on high quality evidence can provide a safe and non-discriminatory work environment for pregnant women.

Regarding chemical and particle exposure, an equal low level of exposure for both men and women in reproductive ages can reduce reproductive effects successfully. In physical exposures, there is less need to reduce exposure levels for all, unless these are associated with other health outcomes. It is mainly women of reproductive age who need to be protected, preferably early on since at least whole-body vibration is suspected to be associated with miscarriages. A better system to identify and inform pregnant workers already at the time of their prenatal care registration (usually in gestational week 10) is needed. Overall, there remains a significant knowledge gap regarding the effect of physical occupational exposures during pregnancy and health effects among children. More high-quality cohort studies with objectively assessed exposure that have access to leave-of-absence-during-pregnancy data are needed to increase the level of knowledge in this important area so researchers can generate accurate exposure–response functions and provide correct and well-balanced advice to occupational health services, employers, and pregnant workers.

References 1. Statistikdatabasen - Online database on occupation and demographics.[Internet] Sweden. Statistics Sweden [Cited: 2023 Oct 01 Available from: https://www.statistikdatabasen.scb.se/pxweb/en/ssd/START__AM__AM0208__AM0208E/YREG54/table/tableViewLayout1/ 2. Fler tjejer blir lastbilsförare 40 procent kvinnliga chaufförer om 10 år tror TYA. More girls become truck drivers 40 percent female drivers in 10 years TYA believes [Internet] Landskrona Sveriges trafikbildares riksförbund, [Cited: 2023 Oct 06] Avaliable from: https://www.str.se/mittitrafiken/artikelarkiv/fler-tjejer-blir-lastbilsforare-40-procent-kvinnliga-chaufforer-om-10-ar-tror-tya]. 3. Women’s employment in the EU [Internet]. Brussels. Eurostat.. [Cited: 2023 Sep 18]. Available at: https://ec.europa.eu/eurostat/web/products-eurostat-news/-/EDN-20200306-1 4. Johansson M, Ringblom L. The business case of gender equality in Swedish forestry and mining - restricting or enabling organizational change. Gender Work Org. 2017;24(6):628-642. https://doi.org/10.1111/gwao.12187 5. Rim KT. Reproductive toxic chemicals at work and efforts to protect workers’ health: A literature review. Saf Health Work. 2017;8(2):143-150. https://doi.org/10.1016/j.shaw.2017.04.003 6. Bonde JPE. On endocrine disruption at the workplace - how to get from suggestive to conclusive evidence? Scand J Work Environ Health. 2020;46(4):335-338. https://doi.org/10.5271/sjweh.3897 7. Marbury MC. Relationship of ergonomic stressors to birthweight and gestational age. Scand J Work Environ Health. 1992;18(2):73-83. https://doi.org/10.5271/sjweh.1598 8. Paul JA, van Dijk FJ, Frings-Dresen MH. Work load and musculoskeletal complaints during pregnancy. Scand J Work Environ Health. 1994;20(3):153-9. https://doi.org/10.5271/sjweh.1414 9. Croteau A. Occupational lifting and adverse pregnancy outcome: a systematic review and meta-analysis. Occup Environ Med. 2020;77(7):496-505. https://doi.org/10.1136/oemed-2019-106334 10. Palmer KT, Bonzini M, Bonde JPE. Pregnancy: occupational aspects of management: concise guidance. Clin Med (Lond). 2013;13(1):75-9. https://doi.org/10.7861/clinmedicine.13-1-75 11. Veenema RJ, Hoepner LA, Geer LA. Climate change-related environmental exposures and perinatal and maternal gealth outcomes in the US. Int J Environ Res Public Health, 2023 20(3). https://doi.org/10.3390/ijerph20031662 12. Rekha S, Bhuvana NS, Kanmani S, Vidhya V. A comprehensive review on hot ambient temperature and its impacts on adverse pregnancy outcomes. J Mother Child. 2023;27:10-20. https://doi.org/10.34763/jmotherandchild.20232701.d-22-00051 13. Ristovska G, Laszlo HE, Hansell AL. Reproductive outcomes associated with noise exposure - a systematic review of the literature. Int J Environ Res Pub Health. 2014;11(8):7931-7952. https://doi.org/10.3390/ijerph110807931 14. Seidel H. Selected health risks caused by long-term, whole-body vibration. Am J Ind Med. 1993;23(4):589-604. https://doi.org/10.1002/ajim.4700230407 15. Skröder H, Pettersson H, Albin M, Gustavsson P, Rylander L, Norlén F, et al. Occupational exposure to whole-body vibrations and pregnancy complications: a nationwide cohort study in Sweden. Occup Environ Med. 2020;77(10):691-698. https://doi.org/10.1136/oemed-2020-106519 16. Skröder H, Pettersson H, Norlén F, Gustavsson P, Rylander L, Albin M, et al. Occupational exposure to whole body vibrations and birth outcomes - A nationwide cohort study of Swedish women. Sci Total Environ. 2021;751:141476. https://doi.org/10.1016/j.scitotenv.2020.141476 17. Selander J, Albin M, Rosenhall U, Rylander L, Lewné M, Gustavsson P. Maternal occupational exposure to noise during pregnancy and hearing dysfunction in children: a nationwide prospective cohort study in Sweden. Environ Health Pers. 2016;124(6):855-860. https://doi.org/10.1289/ehp.1509874 18. Selander J, Rylander L, Albin M, Rosenhall U, Lewné M, Gustavsson P. Full-time exposure to occupational noise during pregnancy was associated with reduced birth weight in a nationwide cohort study of Swedish women. Sci Total Environ. 2019;651:1137-1143. https://doi.org/10.1016/j.scitotenv.2018.09.212 19. Lissåker CT, Gustavsson P, Albin M, Ljungman P, Bodin T, Sjöström M. et al. Occupational exposure to noise in relation to pregnancy-related hypertensive disorders and diabetes. Scand J Work Environ Health. 2021;47(1):33-41. https://doi.org/10.5271/sjweh.3913 20. Adane HA, Iles R, Boyle JA, Collie A. Maternal occupational risk factors and preterm birth: Protocol for a systematic review and meta-analysis. PLoS One. 2023;18(7):e0283752. https://doi.org/10.1371/journal.pone.0283752 21. Försäkringskassan. Gravidas socialförsäkringsskydd - Jämlik, ekonomisk trygghet? [Pregnant women`s social security protection - Equal, financial security?] 2022: https://www.forsakringskassan.se/download/18.7fc616c01814e179a9f81c/1662473039324/gravidas-socialforsakringsskydd-socialforsakringsrapport-2022-2.pdf. 22. Hansen ML, Thulstrup AM, Juhl M, Kristensen JK, Ramlau-Hansen CH. Occupational exposures and sick leave during pregnancy: results from a Danish cohort study. Scandinavian Journal of Work Environment & Health. 2015;41(4):397-406. https://doi.org/10.5271/sjweh.3507 23. Henrotin JB, Gulisano F, Sick leave during pregnancy and occupational factors: a systematic review. Occup Med. 2022;72(8):550-558.https://doi.org/10.1093/occmed/kqac090 24. Handakas E, Robinson O, Laine JE. The exposome approach to study children`s health. Curr Op Environ Sci Health. 2023;32. https://doi.org/10.1016/j.coesh.2023.100455 25. Nurminen T, Kurppa K. Occupational noise exposure and course of pregnancy. Scand J Work Environ Health. 1989;15(2):117-124. https://doi.org/10.5271/sjweh.1873 26. Ubalde-Lopez M, Garani-Papadatos T, Scelo G, Casas M, Lissåker C, Peters S, et al. Working life, health and well-being of parents: a joint effort to uncover hidden treasures in European birth cohorts. Scand J Work Environ Health. 2021;47(7):550-560. https://doi.org/10.5271/sjweh.3980

Effects of Platelet-Rich Plasma on the Oxymetholone-Induced Testicular Toxicity

Oxymetholone is one of the anabolic steroids that has widely been used among teenagers and athletes to increase their muscle bulk. It has undesirable effects on male health and fertility. In this study, the therapeutic effects of platelet-rich plasma (PRP) on oxymetholone-induced testicular toxicity were investigated in adult albino rats. During the experiments, 49 adult male albino rats were divided into 4 main groups: Group 0 (donor group) included 10 rats for the donation of PRP, Group I (control group) included 15 rats, Group II included 8 rats that received 10 mg/kg of oxymetholone orally, once daily, for 30 days, and Group III included 16 rats and was subdivided into 2 subgroups (IIIa and IIIb) that received oxymetholone the same as group II and then received PRP once and twice, respectively. Testicular tissues of all examined rats were obtained for processing and histological examination and sperm smears were stained and examined for sperm morphology. Oxymetholone-treated rats revealed wide spaces in between the tubules, vacuolated cytoplasm, and dark pyknotic nuclei of most cells, as well as deposition of homogenous acidophilic material between the tubules. Electron microscopic examination showed vacuolated cytoplasm of most cells, swollen mitochondria, and perinuclear dilatation. Concerning subgroup IIIa (PRP once), there was a partial improvement in the form of decreased vacuolations and regeneration of spermatogenic cells, as well as a reasonable improvement in sperm morphology. Regarding subgroup IIIb (PRP twice), histological sections revealed restoration of the normal testicular structure to a great extent, regeneration of the spermatogenic cells, and most sperms had normal morphology. Thus, it is recommended to use PRP to minimize structural changes in the testis of adult albino rats caused by oxymetholone.

Susceptibility of male reproductive system to bisphenol A, an endocrine disruptor: Updates from epidemiological and experimental evidence

Bisphenol A (BPA) is an omnipresent environmental pollutant. Despite being restrictions in-force for its utilization, it is widely being used in the production of polycarbonate plastics and epoxy resins. Direct, low-dose, and long-term exposure to BPA is expected when they are used in the packaging of food products and are used as containers for food consumption. Occupationally, workers are typically exposed to BPA at higher levels and for longer periods during the manufacturing process. BPA is a known endocrine disruptor chemical (EDC), that causes male infertility, which has a negative impact on human life from emotional, physical, and societal standpoints. To minimize the use of BPA in numerous consumer products, efforts and regulations are being made. Despite legislative limits in numerous nations, BPA is still found in consumer products. This paper examines BPA's overall male reproductive toxicity, including its impact on the hypothalamic-pituitary-testicular (HPT) axis, hormonal homeostasis, testicular steroidogenesis, sperm parameters, reproductive organs, and antioxidant defense system. Furthermore, this paper highlighted the role of non-monotonic dose-response (NMDR) in BPA exposure, which will help to improve the overall understanding of the harmful effects of BPA on the male reproductive system.

Effect of bisphenol F on sexual performance and quality of offspring in Male Wistar rats

This study investigated the effect of BPF on male sexual performance and the quality of the offspring. Eighty (80) Male Wistar rats (n = 10 per group) were randomised into normal saline-treated control and control recovery, BPF varied doses (low, medium, and high), and BPF varied doses recovery (low, medium, and high) groups. The study was terminated after 28 days of BPF oral administration. The animals were sacrificed after 24 h from the last dose, while those in the recovery groups were allowed to recover for another 28 days before being sacrificed. BPF administration was found to impair sexual performance, as shown by a significant decrease in frequencies (mount, intromission, and ejaculation frequencies) and an increase in latencies (mount, intromission, and ejaculation latencies). This was accompanied by a significant decrease in plasma LH, FSH, testosterone, dopamine, acetylcholinesterase, nitric oxide, and penile cyclic guanosine monophosphate (cGMP) level. The level of plasma oestrogen and prolactin were significantly increased following BPF administration. BPF also reduced the sperm count, morphology, viability, and motility. Furthermore, BPF reduced fertility success and index, litter size, litter weight, and offspring survival rate. These toxic effects of BPF were dose-dependent and were not reversed by withdrawal following 28 days of recovery. This study concluded that BPF disrupts sexual competence and offspring quality by suppressing the hypothalamic-pituitary-gonadal axis and mediating oestrogen-induced hyperprolactinemia. These events were associated with reduced fertility index and success, poor semen quality, and reduced offspring survival rate. The observed toxic effects of BPF were dose-dependent and not reversed by cessation of BPF exposure.

Monitoring Phthalates in Maternal and Cord Blood: Implications for Prenatal Exposure and Birth Outcomes

Although many phthalates are endocrine-disrupting chemicals that are associated with adverse birth outcomes, the relationship between maternal phthalate exposure and birth outcomes is not yet conclusive. The objective of the present study was to investigate the association between prenatal exposure to phthalates in human maternal and cord blood and birth outcomes of the infants. Sixty-five mother-infant pairs were recruited in Taipei City and New Taipei City, and birth outcomes of the infants were recorded. Twelve phthalate metabolites were measured in maternal and cord blood samples. The mean of mono-ethyl phthalate, mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl) phthalate (MEHP) was relatively higher than that of the other metabolites in both maternal and infant blood. There was a significant difference (p < 0.05) for mono-methyl phthalate (MMP) and MnBP between the maternal blood and cord blood of male infants. Mono-benzyl phthalate (MBzP), MMP, MiBP, and ∑di-2-ethylhexyl phthalate (∑DEHP) in maternal blood were inversely correlated with the anogenital index (AGI) of male infants, with a p value between 0.011 and 0.033. Mono-n-octyl phthalate, MMP, MiBP, MnBP, and MBzP were positively correlated with the AGI of female infants, with a p value between 0.001 and 0.034. Cord blood levels of MnBP, mono-(2-ethyl-5-oxohexyl)-phthalate, MEHP, and ∑DEHP were found to be inversely associated with head circumference in all the infants, adjusted for gestational age. Phthalate monoesters are potentially estrogenic and antiandrogenic chemicals. Longitudinal follow-up of the present study population could help clarify the long-term impact of phthalates on growth and the health effects of background exposure levels. Environ Toxicol Chem 2022;41:715-725. © 2022 SETAC.

The Reproductive Injury and Oxidative Testicular Toxicity Induced by Chlorpyrifos Can Be Restored by Zinc in Male Rats

The current study aimed to evaluate the harmful effect of chlorpyrifos (CPF) on the reproductive functions and fertility in male rats and to assess the protective role of zinc (Zn) in improving the adverse effects of CPF on male fertility. Sixty mature male rats were divided into four groups: Group 1: The control group was orally administered with the corresponding dose of corn oil. Group 2 animals received chlorpyrifos (1 mg/kg, oral). Group 3 rats received oral zinc (25 mg/kg) daily. Group 4 animals received oral zinc treatment (25 mg/kg). CPF caused a significant decrease in the body and reproductive organs' weights, sperm count, sperm motility percent, serum testosterone, FSH, and LH. The CPF-treated group showed a significant increase in dead sperm percent and sperm abnormalities. CPF induced a significant internucleosomal DNA fragmentation and marked histological alterations in the testes of treated male rats. Conversely, co-treatment with Zn improved the reproductive organs weights, sperm characteristics, internucleosomal DNA fragmentation, and histological alterations of the testes. In conclusion, CPF triggered significant detrimental effects on male reproductive organs and functions and the co-treatment with zinc partly alleviate the injurious effects of CPF on male fertility.

The Association Between Long Working Hours and Infertility

Background

This study aimed to investigate whether working long hours was related to infertility among female Korean workers, while taking age into consideration.

Methods

We used data from the 2018 National Survey on Fertility and Family Health and Welfare in Korea that is a cross-sectional, nationally representative, and population-based survey. Infertility was defined as women who were not pregnant after regular unprotected intercourse for a year. Working long hours was classified as ≥52 hours, and subgroups as per age were classified on the basis of being younger or older than 40 years of age. Differences in infertility risk between the long working hour group and none were estimated in crude and fully adjusted logistic regression models with age-group stratification.

Results

Of 5,909 Korean female workers, the crude and adjusted odds ratios (95% confidence intervals) of infertility for working long hours were 1.295 (0.948–1.737) and 1.303 (0.921–1.809), respectively. In the subgroup of patients below 40 years of age, the crude and adjusted odds ratios (95% confidence interval) were 1.957 (1.216–3.039) and 1.921 (1.144–3.120), whereas those aged 40 years or older had 0.994 (0.647–1.471) and 0.939 (0.560–1.501), respectively. The weighted prevalence of infertility increased as weekly working hours increased only for the younger than 40-year subgroup.

Conclusions

Infertility is associated with working long hours, especially in young-aged workers. Thus, the working schedule must be structured to better suit young female workers.

Glyphaeaside C- enriched extract of Glyphaea brevis restored the antioxidant and reproductive integrity of 1,4-Dinitrobenzene-intoxicated rats

This study assessed the fertility potential of methanol leaf extract of Glyphaea brevis (MGB) in rats exposed to 1,4-Dinitrobenzene (DNB), an environmental reprotoxicant. Male Wistar rats were orally exposed to 50 mg/kg DNB and administered 750 mg/kg MGB, 1500 mg/kg MGB or 300 mg/kg vitamin E for 21 days after 48 h of DNB exposure. Determination of serum reproductive hormone levels by enzyme-linked immunosorbent assays, evaluation of hematologic profile, computer-assisted sperm analyses (CASA) of sperm kinematics and morphology, assessment of testicular and spermatozoan antioxidant systems, and histopathological evaluation of reproductive tissues were performed. HPLC-DAD analysis identify Glyphaeaside C as the major component of the extract. In rats toxified with 50 mg/kg DNB, testicular and epididymal weights, serum levels of luteinizing hormone, testosterone and follicle-stimulating hormone, and packed cell volume, haemoglobin concentration, and white blood cell counts were decreased. There was altered sperm kinematics which reflected in increased sperm abnormalities. Treatment with the Glyphaeaside C -enriched MGB counteracted all DNB-induced changes and corrected DNB-induced aberrations in kinematic endpoints. Also, testicular and epididymal antioxidant systems were disrupted and there was damage to tissue histoarchitecture. Furthermore, our molecular docking study revealed that Glyphaeaside-C exhibited high binding affinities to the binding pocket of some free radical generating enzymes. Conclusively, the results indicated that Glyphaeaside C-enriched extract of Glyphaea brevis leaf enhanced the quality of semen and improved the functional capabilities of spermatozoa following exposure of rats to DNB which could translate to enhanced fertility.

Comparison of mice' sperm parameters exposed to some hazardous physical agents

The present study was aimed to compare the effects of exposure to noise, vibration, lighting, and microwave on male mice' sperm parameters. The mice were randomly assigned to five groups of eight, which comprised of the unexposed group and exposure groups including the lighting (1000 lux), noise (100 dB(A)), vibration (acceleration of 1.2 m/s2) and microwave (power density of 5 watts). The exposure groups were subjected to the four agents for 8 hours a day, 5 days a week during a 2-week period. Semen analysis were done according to World Health Organization guidelines. The highest significant mean difference in sperm count (-1.35×106/mL) had being observed between the microwave group and the control one (P=0.001). The highest difference in immotile percent (25.88 %) had being observed between the noise group and the control one (P=0.001). The highest difference in normal morphology (-27.06 %) observed between the lighting exposure group and the control group (P=0.001). The four agents can cause changes in different sperm parameters, however for definite conclusion; more laboratory and field studies are required. In total, exposure to microwave has had the greatest effect on sperm count and exposure to light has had the greatest effect on normal morphology and non-progressive motility. Moreover, exposure to noise has had the greatest effect on progressive motility and immotile percent, respectively.

Immunoassay-based approaches for development of screening of chlorpyrifos

Chlorpyrifos (CPF) is an extensively used organophosphate pesticide for crop protection. However, there are concerns of it contaminating the environment and human health with estimated three lakh deaths annually. Detection of CPF in blood samples holds significance to avoid severe health outcomes due to continuous exposure. The most common techniques for CPF detection are Gas chromatography (GC) and high-performance liquid chromatography (HPLC). However, these techniques might not be feasible at the community healthcare level due to high-cost instrumentation, time-consuming sample preparation protocol and skilled analysts. Therefore, rapid, effective and economical methods such as immunoassay would be imperative for CPF detection in biological samples. The vital step in immunoassay development is the design of a potent immunogen from non-immunogenic molecules. The molecular modelling protocol could assist in redesigning known CPF linkers and inserting them at different substitutable positions of CPF to get distinctive CPF derivatives. Molecular docking and binding free energy analysis can be used to identify the CPF derivatives having a better binding affinity with carrier protein compared to CPF. The top-ranked CPF derivatives based on docking score and binding energy could be ideal for synthesis and immunogen development. The present review will comprehend technological trends in immunoassay kits for detecting chlorpyrifos from biological samples.

Eggshell membranes coated chitosan decorated with metal nanoparticles for the catalytic reduction of organic contaminates

This study focusses on the effect of chitosan coating with eggshell membranes for the reduction of different organic pollutants. Chickens eggs were collected from the local market and utilized to extract the enrich eggshell membranes (ESM). The chicken eggshell membranes are abundant waste material which is inexpensive and illustrates remarkable physiognomies for many possible applications. Fresh fibers/strips coated by chitosan (CS) were prepared by mixing the eggshell membranes with CS solution (2 wt%/v) in different proportions i.e., 10 %, 30 %, 50 %, 60 %, 70 %, 80 %, and 90 %. These strips were then templated with copper and iron metal nanoparticles by putting them in their metal ions aqueous solution to adsorb the metals ions and were then reduced to zero-valent metal nanoparticles (MNPS) by using NaBH₄ aqueous solution. These prepared materials (MNPS@ESM-CS) were characterized by using XRD, XPS, FE-SEM, and EDS to confirm the successful preparation of MNPs over the surface of ESM coated with CS. Afterwards, these prepared materials were investigated as a catalyst for the reduction of different organic pollutants, such as 4-nitroaniline (4-NA), 4-nitrophenol (4-NP) and methylene blue (MB) dye. The catalytic efficiency of ESM was enhanced 5.7-fold by adding only 20 % CS solution. It was observed that Cu@ESM-CS-80 % took 7 min for reduction of 4-NA, 6 min for 4-NP, and 7 min for MB dye. The reusability of the catalytic strip was also investigated for four cycles and found efficient and can be easily recovered by simply pulling it from the reaction mixture.

Organopesticides and fertility: where does the link lead to?

Organopesticides (OPs) are a group of various synthetic chemicals prevalently used in agriculture and homestead plantations. OPs were originally developed to remove insects, weeds, and other pests from agricultural fields for improving crop yields. Modern pesticides including organochlorine pesticides, organophosphorus pesticides, and amido-formyl ester are closely related to our lives. Many people are exposed to various OPs during farming practice. OPs can cause adverse effects and provoke serious impacts on normal reproductive functions of humans, resulting in loss of fertility. The effects of OPs in the reproductive system include association with fluctuation in the levels of sex hormones, delayed menstrual cycle, ovarian dysfunction, alteration in ovary weight, changes of follicle growth, altered oocyte feasibility, and changed the quality of spermatogenesis. Current literature clearly states that exposure to various OPs can impair the fertility of women and cause a high risk of reproductive potential. However, investigations on OPs exposure to woman fertility remain scarce. This review highlights effects of exposure to OPs on the fertility of occupational women and mechanisms of action involved in such effects on the reproductive function of women along with their related impacts.

Pregnancy disorders in female workers at the industrial area of Sidoarjo, Indonesia

Background: The number of female workers in Indonesia has increased and female workers have been discovered to be very vulnerable to several hazards and health problems in the workplace environment linked to their menstrual cycle and pregnancy. Therefore, this study was conducted to analyze risk factors associated with pregnancy disorders in female workers. Design and Methods: The research was conducted through the use of a cross-sectional design with 307 female workers using simple random sampling. Furthermore, a descriptive analysis was conducted to describe the conditions of the respondents during pregnancy to childbirth process. Results: The results showed 45% of respondents had pregnancy disorders, 16% had miscarriages, and despite the fact most of the prenatal care processes was assisted by doctors or midwives, 2.6% of the respondents consulted Traditional Birth Attendants, who were also recorded and was found to account for 2.9% of the deliveries. Moreover, the risk factors associated with pregnancy disorders include vibrations (P=0.004), irritants (P=0.002) and repetitive works (P=0.009). Conclusions: It is recommended that companies should provide maternal and child health protection and control for any risk associated with female workers.

Environmental contaminants and male infertility: Effects and mechanisms

The escalating prevalence of male infertility and decreasing trend in sperm quality have been correlated with rapid industrialisation and the associated discharge of an excess of synthetic substances into the environment. Humans are inevitably exposed to these ubiquitously distributed environmental contaminants, which possess the ability to intervene with the growth and function of male reproductive organs. Several epidemiological reports have correlated the blood and seminal levels of environmental contaminants with poor sperm quality. Numerous in vivo and in vitro studies have been conducted to investigate the effect of various environmental contaminants on spermatogenesis, steroidogenesis, Sertoli cells, blood-testis barrier, epididymis and sperm functions. The reported reprotoxic effects include alterations in the spermatogenic cycle, increased germ cell apoptosis, inhibition of steroidogenesis, decreased Leydig cell viability, impairment of Sertoli cell structure and function, altered expression of steroid receptors, increased permeability of blood-testis barrier, induction of peroxidative and epigenetic alterations in spermatozoa resulting in poor sperm quality and function. In light of recent scientific reports, this review discusses the effects of environmental contaminants on the male reproductive function and the possible mechanisms of action.

Some of the Factors Involved in Male Infertility: A Prospective Review

Infertility is defined as the inability of couples to have a baby after one year of regular unprotected intercourse, affecting 10 to 15% of couples. According to the latest WHO statistics, approximately 50-80 million people worldwide sufer from infertility, and male factors are responsible for approximately 20-30% of all infertility cases. The diagnosis of infertility in men is mainly based on semen analysis. The main parameters of semen include: concentration, appearance and motility of sperm. Causes of infertility in men include a variety of things including hormonal disorders, physical problems, lifestyle problems, psychological issues, sex problems, chromosomal abnormalities and single-gene defects. Despite numerous efforts by researchers to identify the underlying causes of male infertility, about 70% of cases remain unknown. These statistics show a lack of understanding of the mechanisms involved in male infertility. This article focuses on the histology of testicular tissue samples, the male reproductive structure, factors affecting male infertility, strategies available to find genes involved in infertility, existing therapeutic methods for male infertility, and sperm recovery in infertile men.

Reproductive toxic agents in work environments and related cases in Korea

There has been a growing concern and subsequent interest surrounding numerous reproductive toxic agents found in various working and non-working environments. Meanwhile, there have been many efforts in medical fields such as toxicology and epidemiology applying experimental studies to elucidate reproductive toxic agents' characterization and health effects. However, there remains insufficient research data and inadequate evidence in humans. Adverse reproductive outcomes vary from transient, moderate health effects to severely detrimental consequences, such as permanent infertility or childhood cancer of one's offspring. Furthermore, upon exposure to toxic agents, the latent period before reproductive health effects are observed is relatively short compared to other occupational diseases (e.g., occupational cancer); instant action is required once exposure to reproductive toxic agents is detected. Therefore, it is very important for workers and healthcare professionals to know about the reproductive toxic agents they are likely to be exposed to. In this review, we discuss the general epidemiology of reproductive health in Korea, and the information regarding these reproductive toxic agents.

Characterization, antioxidant, antimycobacterial, antimicrobial effcts of Moroccan rosemary essential oil, and its synergistic antimicrobial potential with carvacrol

Thanks to their promising properties, essential oils (EOs) have strong potential to remedy several problems such as microorganisms acquired resistance to antimicrobial agents and chemical antioxidants toxicity. Firstly, this work was conducted to determine chemical composition, antioxydant activity, then antibacterial, antifungal, antimycobacterial properties of Rosmarinus officinalis EO. Secondly, EOs combined antimicrobial effect with carvacrol was assessed. Chemical EO analysis was performed using Gas chromatography/mass spectrometer. 1,1-diphenyl-2-picrylhydrazyl test was used to evaluate in vitro antioxidant rosemary oil effect. The antimicrobial activity against seven bacteria, two fungi, and two mycobacterial strains was screened using the broth microdilution method. Thereafter, the checkerboard essay was used to evaluate the antibacterial effect of this EO and Carvacrol. Chemical EO analysis revealed 1,8-cineole (33.88%), camphor (14.66%), and α-pinene (12.76%) as main constituents. The obtained IC50 value (2.77 mg/mL) showed rosemary EO's radical scavenging power. Moreover, all tested microorganisms showed an important sensitivity to this EO (MIC values: 0.007%–1% (v/v)). Furthermore, results highlighted synergistic and partial synergistic interaction for tested products. The studied EO has both antimicrobial and antioxidant potentials. Combined application showed a remarkable synergistic antibacterial potentiation that can be used as an alternative in pharmaceutical and food processing sectors.

Measuring and Reducing Chemical Spills by Students: A Randomized Controlled Trial of Providing Feedback

The ability to handle chemicals safely is a key aspect of the learning development of students studying chemistry; however, there have been no previously reported investigations of the quantity of chemicals spilled by students during lab experiments. Therefore, the first part of this article reports the assessment of the volume of chemicals spilled by year 1 undergraduate chemistry students (n = 64) at a U.K. university during an existing chemical analysis practical designed to develop volumetric handling skills. The experiment was carried out on paper liners, allowing the areas of students' spills to be visible and quantified using calibrated spill volumes of liquid to determine the resultant spill area. The volume spilled by the student group was ca. 1.2% of that handled; however, the amount spilled by individual students ranged widely, from ca. 0.02% to ca. 10% of the volume handled. A feedback tool has been developed to allow laboratory demonstrators to rapidly quantify chemical spillage by individual students. This tool also provides the demonstrators with a framework to communicate the potential safety significance of the volume of chemical a student has spilled. A randomized controlled trial (RCT) was carried out to examine the effect of providing feedback to students on their chemical spillage during a subsequent experiment. From a cohort of 185 year 1 undergraduate students, 150 consented to be randomized (81%), and data was collected for 144 students (96% of those randomized). A Hodges-Lehmann estimator for the median change in volume spilled during the second experiment due to providing feedback on spillage during first experiment was a 50% decrease in volume spilled (95% confidence range: 0 to 80% decrease, Mann-Whitney U test p = 0.05). The RCT was a waiting list trial, with all student receiving feedback either during or after the RCT, with blinded assessment by the demonstrators assessing volume spilled for the RCT.

Optimization of Biosorption Conditions for Surfactant Induced Decolorization by Anaerobic Sludge Granules

The sorption of Remazol Black B (RBB) by dried anaerobic sludge granules (ASG) was examined in this study. The biosorption process was monitored based on the statistical optimization data of the batch reactor studies. In the factorial tests, 36 different tests were established by considering the variables such as temperature (25°C, 50°C), pH (1, 3, 5), dye concentration (100, 150, 200 mg/L) and cationic surfactant concentration (0, 0.5 mM). Also, it was intended to investigate the effect of cationic surfactant dodecyl trimethylammonium bromide (DTAB) on decolorization of the anionic dye RBB by ASG. The sorption isotherms and kinetics were determined for RBB removal. The biosorption of RBB was fitted with Langmuir isotherm and pseudo-second-order kinetic models. The oppositely charged dye and surfactant molecules interacted electrostatically. These electrostatic interactions improved the dye biosorption properties of ASG. Our results indicate that a surfactant can be used as an inducer in the treatment of dye-contaminated water. This is the first paper combining factorial experiment design and surfactant-accelerated decolorization to achieve more effective biosorption conditions.

Mercury at environmental relevant levels affects spermatozoa function and fertility capacity in bovine sperm

Over the last several years human sperm quality was found to be significantly reduced and the role environmental contaminants play in this phenomenon remain to be determined. Mercury (Hg) is one of the most widespread contaminants; however the correlation between metal exposure and adverse consequences on human and animals fertility are not completely established. The aim of this study was to determine the effects of direct exposure to inorganic Hg on male gametes using spermatozoa (bovine sperm) which characteristically resemble human sperm. Sperm were divided and incubated for 0.5, 1 or 2 h at low levels of Hg: i) Control: without exposure; ii) Hg8 nM: mercury chloride (HgCl₂) at 8 nM and iii) Hg8 μM: HgCl₂ at 8 μM. Sperm kinetics, morphology, sperm membrane integrity, and in vitro fertilization were assessed. In addition the levels of reactive oxygen species (ROS), lipid peroxidation and total antioxidant capacity were measured. Hg exposure for 2 h impaired sperm morphology and membrane integrity as well as kinetic parameters including curvilinear velocity and straight-line velocity, which are needed for fertilization as evidenced by the reduced fertilization rate in 8 μM Hg-treated gametes. Hg enhanced oxidative stress in male sperm as reflected by elevated levels of ROS and lipid peroxidation and decreased antioxidant capacity. Data demonstrated that low levels of Hg when incubated with spermatozoa are sufficient to increase oxidative stress, adversely affect sperm quality parameters, subsequently impairing sperm fertility capacity.

Squalene is a potential endocrine modulator in rat: A proof-of-principle study with 3-methylcholanthrene-induced toxicity

Oestrus urine was proved as a potential endocrine modulator in alleviating the toxicity induced by 3-methylcholanthrene (3-MC) in male rats. We, in this study, aimed to prove the attributing potential of toxicity alleviation to squalene, an oestrus-specific pheromone in rats. A single dose of 3-methylcholanthrene (25 mg/kg BW, i.p.) was administered to male Wistar rats with concurrent exposure to squalene sprayed in bedding material (Group III). Group II rats did receive 3-MC treatment but did not expose to squalene. Group I rats were intact control neither administered 3-MC nor sprayed with squalene. In consequence of 3-MC toxicity, liver and testes weights were increased and the components of blood cells (RBC and WBC count, Hb level) and testosterone concentration were significantly reduced in Group II rats. Moreover, sperm count was reduced and antioxidants (testes and epididymis) were significantly altered. Exposure to squalene in Group III rats comparatively normalised all the variable components towards baseline and reorganised the histological architecture of reproductive tissues that were exacerbated with 3-MC toxicity. This study ultimately proved squalene as a potent molecule in alleviating the toxicity induced by 3-methylcholanthrene.