There are several problems with human health in some parts of our region due to consumed the fish which contaminated by heavy metal elements.

Please follow the link for Ethiopian case:

https://www.sciencedirect.com/science/article/pii/S0045653513001410

There is a substantial body of research on this general subject area. I am not an expert on the health effects area.

Although not necessarily recent, there has been ties to methyl mercury and wetlands. Ionic deposits of mercury from air pollution or other sources, are sulfate reduced in wetlands to the toxic methyl mercury form, and bioaccumulated by various minute organisms to noticeable to high levels in mosquito fish and carnivorous fish. Most of the coastal or other wetland dominated blackwater streams in my state and vicinity have potential for this, and most of these streams have fish consumption advisories for certain species, especially carnivorous fish. Pregnant women and babies are especially sensitive. To some degree, humans are able to pass minor amount of mercury. The term “Mad Hatter” was given to some early hat makers who used mercury in the processing of hats. Probably some gold minors also developed effects from mercury poisoning, as mercury was used to concentrate the gold. In some local testing of black water streams, we found mercury easier to find in carnivorous fish brains fatty tissues, than in water or sediment. More information is available from US National Mercury Lab. The US EPA has set water standards for drinking water based on various testing and considerations for human health. Review of their references and citations may yield more information to apply to your question. If other heavy metals act similar, consuming carnivorous fish may have the greatest potential for bioaccumulation.

Eskinder Zinabu

Thanks for useful web site

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Thanks all for your good contribution

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Nice discussion.

The small fish is probably to considerate for human consumption, because the predatory fish usually has a link to accumulate of heavy metal contamination in their body.

Thanks Irwan Ramadhan Ritonga ffor your coments

Thanks Hamid Reza Samadifard for your contribution

Heavy metals in fish tissues can be manifold higher than their corresponding waterborne values. Consumption of contaminated fish is an important route of accumulation of heavy metals in the tissues can result in chronic illness and cause potential damage to the population. The most commonly found heavy metals in waste water include copper, nickel, zinc, cobalt and cadmium all of which cause risks for human health and environment. Heavy metal toxicity can lower energy levels and damage the functioning of brain, lungs, kidney, liver and blood composition and other important organs. Long term exposure to high concentrations lead to gradual and progressive physical, muscular and neurological degenerative processes that initiate disease like multiple sclerosis, Parkinson’s, Alzheimer’s and muscular dystrophy. Repeated long term exposure of some metals and their compounds may cause cancer. Please Check out a recent publication at following link:-

https://reader.elsevier.com/reader/sd/pii/S2214750018300519?token=68DEF4BDA4270EA4D098EC3252B03C293FC0815A8A4FDE09D9C73EA244BE83B206E2196BA7EDD6103A0C49CF6BD0053E

Fish that often exposed to highly polluted water, show different disabilities, ranging from biochemical changes in single cells to changes in the whole organism. The toxic effects of heavy metals on fish are multi-directional and manifested by numerous change in the physiological and chemical process of their body system. Accumulation of metals in various organs of fish may cause structural lesions and functional disturbances this appears on the effect on fish production and growth rate. Fish are well known for their major role in the aquatic food-web and they can take up and accumulate high metal concentrations. Therefore besides the health risk of heavy metals in the fish itself, this leads to a risk potential for human consumption of fish accumulating high quantities of heavy metals in their tissues. In most studies of the accumulation of heavy metals in fish species, muscle (the most consumed organ by human being), accumulates the lowest concentration of metals, while, the high concentration of metals was found in the internal organs of the fish.

Please Check out a publication at following link:-

https://www.peertechz.com/articles/AMS-1-104.pdf

https://link.springer.com/article/10.1007/s11356-016-6915-7

Thanks all for your contributions.

Hi Noori Abdul-nabi Nasir

One of the main contaminants that is of concern in fish is the accumulation of mercury, as was mentioned by William F. Hansen.

The reason for this is because microbes that thrive in habitats devoid of oxygen, such as sediments or anoxic waters, can convert inorganic mercury to an organic form that accumulates in fish tissue through bioaccumulation in the food web. While this is more likely to happen in contaminated environments and results in anything from kidney to liver damage to even neurological and motor issues in fish, it can also happen in relatively pristine environments. It is not uncommon to see mercury concentration in fish tissue several orders of magnitude higher than what can be found in the ambient water. Same goes for benthic invertebrates which feed near the sediment where this type of organic mercury is produced.

For a more comprehensive discussion on how microbes can contribute to mercury cycling and toxicity in aquatic environment I invite you to the following literature reviews:

Article Shining light on recent advances in microbial mercury cycling

and

http://www.facetsjournal.com/article/facets-2016-0027/ by Avnee Paranjape, one of Britt D Hall 's research students.

Furthermore, for a more in depth discussion on mercury toxicity in fish please consult this document stemming from the UN's Minamata Convention on Mercury: https://www.unenvironment.org/explore-topics/chemicals-waste/what-we-do/mercury/global-mercury-assessment

A new assessment is available for comments as well and should be coming out soon.

I hope this helps.

Thanks Daniel Gregoire for very useful contribution.

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thanks all for your contribution

Sajda Taha Mahmood

Good contribution

Hi. I think if the water is stagnant, the effect of minerals will be greater, but if the water is running, its effect will be small and there are contaminants where the water is more dangerous or the minerals contain reactive substances that increase their danger to the fish. As we saw the death of fish in Iraq, Behind her death, thank you

Agree with D.R Hussein Saleh Al-Rubaey

The following study examined species-specific bioaccumulation of metals in commercially important fishes and shellfishes, and calculated the potential human health hazards through their consumption:

https://www.nature.com/articles/s41598-022-08471-y

Also, kindly check:

Heavy metals contamination in water, sediments and fish of freshwater

ecosystems in Pakistan

Its effect lies in the proportions of minerals that have moved to it and thus affect human health if it is negative

I agree with Dr. Asst.Prof.Doctor.Hussein Saleh Al-Rubaey when the concentration of those metals is higher than the permissible limit (MRL), it will show its negative effects on health...Unfortunately heavy metals are non-biodegradable elements, so they will accumulate in the tissues of aquatic organisms and have bioaccumulation and biomagnification along the food chain ...I posted a discussion earlier about whether we should stop eating fish because of the mercury, I hope it is useful...My sincere gratitude to all.

https://www.researchgate.net/post/Should-We-Avoid-Fish-Because-of-Mercury

Good contribution from D.R Hussein Saleh Al-Rubaey, Manal Hadi Kanaan and Suhad Mohammed. Regards

I think the Geo-ecological location of the water is very important. Yes many work have done in this area. I have shown in most of my work that the health risk of fish from not high polluted area have very low health risk in short term however in a life there may concern here. see

Thanks for all of you for such useful contribution.

Happy new year and all the best.

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