Endocrine Disruption - Science topic

Menstrual disturbances in hypothyroidism can occur due to the influence of thyroid hormones on the menstrual cycle. Hypothyroidism, a condition characterized by low levels of thyroid hormones, can disrupt the normal hormonal balance in the body, affecting the menstrual cycle in several ways. Some of the causes of menstrual disturbances in hypothyroidism include:Hormonal imbalance,Anovulation,Alterations in GnRH secretion,Changes in estrogen and progesterone levels,Prolactin levels,Thyroid hormone replacement therapy .menstrual disturbances in hypothyroidism are primarily attributed to the complex interplay between thyroid hormones and other reproductive hormones involved in the regulation of the menstrual cycle.

Hi Peter,

This test method is equivalent to OECD test guideline (TG) 455 (2016):

The original requirement for test methods under REACH goes back to Article 13: No 1907/2006

kind regards

Kerry

Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds arechemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders.

Hormonal imbalances, sexual changes and unusual behaviours are observed in wildlife. Some chemicals are implicated as endocrine disruptors (EDCs). Their dispersal into ecosphere allows them to reach biotopes isolated of emission sources and they accumulate in organisms and they cause alterations in biological functions (reprotoxicity, immunotoxicity, etc.). Beyond the individual, the community equilibrium is endangered with a potential impact on biodiversity. The organohalogen substances are historically concerned. Despite the prohibition of organochlorine pesticides and PCBs, they persist in aquatic and terrestrial habitats. But the “emerging substances” are also dangerous. Numerous examples of endocrine disruption in animal communities are described. The imposex in female of marine gastropods related to tributyltin (TBT) is one of the earliest known events. The feminization of fish in the estuary of the Seine, the hermaphroditism of some amphibians and the strange behaviour of birds, are famous facts. The cumulative effects are of concern to wild populations. These are mix of pollutants or the concomitancy of other global changes, the decline of polar bears or seals from the Baltic Sea proves it. In conclusion, endocrine disruption jeopardizes all natural biological systems and contributes in loss of biological diversity by reducing the number of sensitive species and making them vulnerable, considering the global extinction risk.

Wastewater is a major problem of diffuse pollution. The many endocrine disruptors (including xeno-oestrogens and drugs) that they contain are not treated (or imperfectly) by existing wastewater treatment plants (WWTPs). Some compounds are degraded, but many are not, or only partially; some of these are found downstream in water and sediments, which are still biologically active. Another part is adsorbed on suspended particles, which are often exported with sewage sludge in the fields. The type of treatment and the length of stay are important. Additional treatment of wastewater (ozone or activated charcoal), allows better removal of micropollutants, but often with additional costs. Natural lagooning lengthens the residence time in the treatment environment, and seems more effective; but a possible impact on the birds that frequent them remains to be measured, in order to verify that it is not an ecological trap situation.

Regards

Hello ;

Dear Alex

Thanks for your contribution, Dr Alessandro

Hi Lennart,

I just had an idea. In my previous answer, I said that life history traits and reproductive strategies are so diverse in fish that our current knowledge in endocrine disruption of temperate fish species is too low to extrapolate from laboratory fish species to temperate fish species. I still think so, but research to close the gaps should have some starting points.

Generally, studies involving P. promelas/O. latipes/D. rerio are carried out under constant conditions of temperature and photoperiod. Therefore, during these experiments, gametogenesis is not driven by any external cue and the fish only rely on endogenous regulation of the hormonal system. On the other hand, in temperate fish species, regulation of the hormonal system (at least the reproductive axis) is continuously driven by continuous variations of photoperiod and temperature. Under controlled conditions, most of them do not start gametogenesis or perform badly in the absence of adequate photothermal variations. To some extent, these variations can be seen as endocrine disrupting factors. What if homeostatis of endogenous regulation of the hormonal system was weak against endocrine disruptors, but what if photoperiod and temperature driving effects were much stronger than those of endocrine disruptors, since P and T would continuously re-adjust the endocrine system disruptions?

I'm not a specialist of P. promelas reproduction, but I wonder if its reproductive cycle can be triggered and synchronized by temperature and photoperiod variations. If that were the case, it could be interesting to compare the effect of known endocrine disruptors on P. promelas kept under constant conditions of temperature and photoperiod against P. promelas exposed to adequate variations of temperature and photoperiod throughout gametogenesis and spawning (adequate = those conditions that correctly regulate gametogenesis and spawing). My hypothesis is that photothermal variations could better protect fish against endocrine disruptors.

This research would not solve all the uncertainties such as short vs long gametogenesis or group-synchronous vs asynchronous gamete development. It would neither address species to species extrapolation regarding sex reversal but there may be other ways to tackle this matter as well. This research could be some starting point to see if photothermal variations matter or not. It could start with short-term experiments of a couple months, but could also include longer-term experiments simulating yearly variations of temperature and photoperiod.

Wildlife populations have been affected by endocrine disruption, with negative effects on growth. Reproductive and physiological effects of environmental contaminants in fish eating birds of has also been reported. For details consulthttps://www.tandfonline.com & Critical Reviews in toxicology. Vol 48, No. 3

To complete previous answers, you might be interested to know that the EU agencies ECHA and EFSA are going to published on next 7th of June a scientific guidance to enable endocrine disruptors to be identified. 

Following this, the methodology to assess the risk and then to define limit values might be developed but you must be aware that identified ED are considered as Substances of Very High Concern (SVHC) in the EU meaning that they should be finally substituted and banned of the market.

Follow this link

Greeting

Aquatic plants like lemna (duckweed), typha etc. are known to remove toxic substances from wastewater and can also be used for emerging contaminants. However, further research is needed

Thankyou for the review

For rat and mouse,

The LD50 for METH with intraperitoneal (ip) administration is 55 and 57 mg/kg, in rat and mouse, respectively (Davis et al., 1987; Yamamoto, 1963). But temperature is very important eg. at 29oC 80% of rats were died with 9 mg/kg i.p. administration  just 4-5 degree above ambient temp.

For human, 

A lethal dose of methamphetamine varies depending on characteristics of the drug and the user. In fact, each person has a different sensitivity to a specific amount of methamphetamine due to personal tolerance to meth. Therefore, toxic levels are different for each individual. Meth overdose may also be complicated by other drugs the user may have taken. Diseases that the person may have developed also play a role due to the current health condition of the body.

Oral administration = ~ 150mg a day

Injection (iv)= ~100mg or higher

Smoking and snorting methamphetamine = ~50 mg or higher

This glyphosate monograph with many good references may be of interest

Best regards!

thank you !

In Poseidon, which ended more than a decade ago, it was indeed investigated how much Membrane Biological Reactor (MBR) could improve biodegradation. The generally theory behind this is that it has been observed that the ability to degrade organic micropollutants in conventional activated sludge (CAS) increases with higher sludge retention time (average age of biomass) and MBR can operate with higher sludge age than is practically possible in CAS. Additionally sludge flocs in in MBR are smaller than flocs in CAS, which gives a kinetic advantage for MBR.

Sadly, the conclusion is that biodegradation rates for organic micropollutants only improve slightly in MBR compared to CAS. As MBR use significantly more energy for aeration than conventional activated sludge (CAS) it is not a great advantage.

In my comment above I wrote about Moving Bed Biofilm Reactors (MBBR) in which activated sludge is replaced with suspended biofilm. MBBR has more or less the same energy consumption for aeration as CAS. In biofilms the sludge age is extremely high in the lower layers of the biofilm while it is short in the surface, thus there is a continiium of different sludge ages in the same tank that allows more different microorganisms to co-exist. Additionally biofilms in wastewater treatment have a greater redox stratification than is seen in CAs flocs. Altogether this appears to give a greater ability to degrade organic chemicals than is found in CAS.

 Hola Adriana,

There is not many researchers working on aquatic toxicology and endocrine disruption in Latin America that i personally can recommend to contact: Pedro Carrriquiriborde, Gustavo Somoza y Fabiola Lonostro in Argentina; Paulina Bahamonde, Felipe Tucca, Rodrigo Orrego, Ricardo Barra and myself in Chile.

Good luck with your research, Gustavo

Hi, Nico!

I work in the field of ecotoxicology and I am also interested in the effects of pesticides, including DDT. However, I work with fish. Check the following papers, they might help -

Best of luck!

Dear Aziza, I knew the publication of Novillo et el. (2005). It was cited in the review of Weltje and Höss (2007). Novillo et al. investigated changes in gene expression. I was looking for changes in offspring numbers. Nonetheless thank you for your reply and best regards.

You can use ELISA as a quantitative method, or Western Blot using an anti-Vtg antibody and densitometric analysis as a semiquantification.

McKenzie paper (link above)

Exposure to endocrine disrupting chemicals, specifically Bisphenol-A, is common. ► Bisphenol-A produces several effects on various immune cell types. ► Bisphenol-A affects immunity through a variety of intracellular receptors

Rogers J.A., Metz L., V., Yong

W. 2013. Review: Endocrine disrupting chemicals and immune responses: A focus on bisphenol-A and its potential mechanisms. Molecular Immunology, 53 (4): 421 - 430.

Julie

I thank for your contribution in discussion.

Of course, I fully agree with the opinion about the complexity of toxicity effects in the case of the interaction of different pollutants, and about the need to take into account as many physicochemical factors determining toxic effects, as it is possible. Because of this, I have collected and read the literature on these issues.

The only thing I really miss, it is practical advice from the people who know from personal experience these issues. In particular, I would be grateful for any suggestions of compounds (preferably specific compounds or preparations - mentioned by name), which show a particularly strong effect of changing the toxic functions in the mixture with alkylphenol ethoxylates.

I worked with catfishes, but examples from any species will suffice. The fishes are old enough to differentiate between males and females.