Fish Contamination: Are you Eating your Fish in Right Way?

feature image - fish contamination

Fish is the cold-blooded vertebrate that possesses gills and fins and resides in the water. From a nutritious point of view, the fish contains protein, less fat and is an excellent source of omega-3 fatty acids.

These constituents play a crucial role in our health development, such as brain development, reducing blood pressure, and even cancer. It is the source of energy and boosts up the immunity power once consumed with a healthy diet.

In the present context, fish contamination has been considered a crucial issue throughout the globe. Even the developed countries are facing fish contamination issues day by day.

Despite carrying several activities to halt the contamination of fish, many countries have failed to initiate a step since the legislation’s well-planned approach. Proper implementation and funding matter a lot in targeting such initiation.

Fish contamination

Be careful while eating fish. Copyright: Consumer Reports

In general, while we talk about fish contamination, we understand the consumption of the fish that absorb Polychlorinated Biphenyl (PCBs), DDT (Dichloro Diphenyl TrichloroEthane) dioxins, and chlorinated pesticides.

The fish contaminates water with methylmercury. A fisherman uses various techniques and chemicals to kill the fish in a large amount.

There is the practice of using the trap net having a high voltage of current. Once the chemicals are ingested into the fish’s body, they are contaminated with several substances.

Finally, when we consume the same fish contaminated with chemicals, we do suffer from the contamination. The current generation is going through urbanization and industrialization.

Due to the unmanaged and haphazard industrialization without the pre-treatment, the industries and many factories are discharging the chemicals.

The chemicals, once they enter into the various water bodies, do settle as sediments. Once the fish consumes them, it affects the fish species and impacts human health once the human consumes the fish species.

Mostly, the mercury contaminates the fish in the water arising from the household and the industrial waste. Once the mercury-associated products end up in the landfill sites, the incinerators get filtered into various water bodies and the ground upon leaching the mercury.

Regarding the food chain and the food web of the aquatic ecosystem, mercury does not end up with the organism’s death.

It does accumulate as the species reach the food chain in the upper level by the process called bioaccumulation, which means the accumulation of mercury in the organisms for a long time. The bottom-dwelling fish suffers from mercury contamination.

Once we deal with the basics of fish contamination, it is crucial to know concerning bioaccumulation and biomagnification. Biomagnification refers to transferring chemicals from one trophic level to another within a food web. 

Additionally, bioaccumulation is associated with the substances that enter the food web of an ecosystem. It is believed that fish that reach the top of the food chain possess methyl mercury 1 to 10 million times greater than the fish in the surrounding water, which seems scary data.

Based on the type and the amount of the contaminants, the exposure of the pollutants can be long-term and short-term. Various fish contaminants have been identified, including methyl mercury, arsenic, hexavalent chromium, dioxins, and Polychlorinated Biphenyls (PCBs).

Some pollutants which are found in the fish have a negative influence on the environment. For instance: the contaminants transport long distances through the air and the water medium. They cannot be broken down easily.

Thus, the fish contaminants are persistent in the environment for an extended period. Moreover, since the PCBs are lipophilic, i.e., fat-loving, they are more likely to stay in the body of several fish species.

Incident of Minamata Bay regarding the fish contamination

Once the organic mercury accumulated in the fish had been a public health issue, for instance, in Minamata Bay of Japan, most adults were hospitalized, and some died.

After the medical investigation, the primary cause revealed was they had consumed the fish products from the Bay of the Pacific. 

After the fish consumption contaminated with the organic methyl mercury, caused 600 deaths, and 3000 sick people were hospitalized.

The medical investigation further illustrated that the vapors of mercury metals are very toxic. Once it gets ingested into the human body, we cannot pass it from the digestive system. Thus, it can be persistent in our body for a prolonged time.

This incident reveals that the fish consumed by the people were highly contaminated with methylmercury which had created severe impacts on human health.

The abundance of mercury was from the industrial effluents of the factory that produce the acetic acid introduced to the river, increasing the concentration of the methylmercury. Upon the sedimentation, it entered into the fish.

Once the people consumed the fish contaminated with methylmercury, all were reported with symptoms and signs related to the severe toxicity.

It caused brain damage, paralysis, and delirium. Since it was a significant health issue, the disease identification remained unknown for an extended period. After many years, they identified the disease of methyl mercury contamination in the fish products. 

Effects of the fish contamination on our health

Even Birds are not safe. Copyright: ABC Action News

We can visualize several risks to the fish contamination and the fish that we consume. Numerous research has insisted that it takes five or more five years for childbearing women to get rid of the chemicals such as Polychlorinated Biphenyl (PCBs) and approximately 6 to 12 months to reduce the effects of the mercury.

Since most contaminants exist for a prolonged period in the atmosphere and human lives, it doesn’t seem easy to get rid of such pollutants from the body parts.

It has been found that the fetus and the newborn baby who possess mercury in their body have difficulty learning.

Due to the susceptibility of the high chance of the mercury effects to the children, it may entirely affect the central nervous system along with the cardiovascular system.

Moreover, polychlorinated biphenyl can alter the human liver and the blood. Pregnant women feel difficulty in pre-pregnancy and the post-pregnancy phases.

Harmful Contaminations in Fish

1. Polychlorinated Biphenyl

It is revealed that the PCB level may increase from 2000 to 1000000 times greater than the original level in the surrounding water.

Once the fish is contaminated with PCB and when we consume it, it may slow the immune system, thyroid, and kidney problems, increasing the chance of cancer. Since it bioaccumulates in the body for the long term, the impacts caused by it remain for a prolonged period. 

Consuming fish having volatile organic compounds may increase the chance of cancer in human lives and animals. Therefore, we should check the persistent contaminants within the body parts, and we must follow the medical suggestions in time.

2. Chlordane

Unforeseen effects have been visualized regarding the fish contamination. The contaminants of the fish have already devastated the ecosystem, thereby persisting for the long term in the environment.

The chlordane accumulated in the fish human remains in the food supply for a prolonged time. Because in the past, they primarily used it in agriculture. 

Long-term persistence in the environment may cause digestive and nervous system disorders, infants’ behavioral disorders before birth and during nursing time, cancer, and many more. The contaminants such as toxaphene, Aldrin, and dieldrin can have detrimental effects on our health.

3. Dieldrin and Aldrin

Dieldrin is one of the pesticides used heavily in the agricultural field. Consuming the fish containing dieldrin and Aldrin increases the rate of mortality in the infants, lowering the reproductive capacity in the human and causing defects in the birth with effect in the kidney working system and may even lead to cancer in the coming days. Dioxin has been recorded in the surface water, lakes, and soils.  

4. Dioxins

The significant health effects caused by the dioxin accumulated in fish and the same fish consumption cause severe skin disease with the presence of acne-like lesions, thereby resulting in skin discoloration, excessive body hair, and weakening of our body’s immune system.

Moreover, the effects of dioxins in human health entail disruption of the endocrine system and increasing the chance of cancer.

5. Mercury

Mercury level - Fish contamination
Fishes species and their mercury level (source)

The mercury and the associated compounds are considered the top 10 chemicals by the World Health Organization, which have serious public health concerns.

Regarding the mercury, the health impacts are determined by several factors such as the dose, type of the mercury, duration of the mercury exposure, route of the direction which entails ingestion, inhalation and the dermal contact, developmental stage of the person being exposed, and many more.

These may affect neurological development, fine motor, spatial skills, and languages among the children. Regarding mercury contamination, kidney problems have been identified with the issue of increasing protein in the urine to kidney failure. The gastrointestinal tract may be affected highly.

Despite the Minamata convention in 2013, it has been observed that there is no control in releasing mercury in the atmosphere even today. The political instability and the lack of implementation of the set regulations seem on the frontline.

The convention had aligned to stop the mercury level into the water bodies and the less consumption and use of the mercury-related products. Even the World Health Organization has warned on the level of methylmercury in human lives.

The fish contaminants are considered as the indicator of the presence of toxic and harmful chemicals in the water. We can understand that the areas containing high fish contamination reflect the current or past discharge of the industrial effluents from many factories and industries.

Apart from these, mercury flows to the water through atmospheric deposition, including volcanic eruption or the incineration of hazardous wastes. It gets persistent in the atmosphere, either in aquatic bodies or others, through leaking or any means.


Fish contamination is not a minor issue. Once it is persistent in the environment through passing several mediums, it can negatively influence the whole ecosystem.

Among the various contaminants of the fish, methylmercury and Polychlorinated Biphenyl are the most serious, which have created detrimental effects on human lives.

The bioaccumulation and biomagnification process makes us realize how the fish contaminants have been persistent in our bodies for a prolonged time.

Due to the discharge of the industrial effluents from the factories and industries, the river bodies face the massive issue of acidification.

Since the fish resides in the aquatic ecosystem, such activities can undoubtedly hamper aquatic life. Therefore, to critically halt the severe contamination, the industries should discharge the effluents after the proper treatment, ensuring safe marine bodies.

Thus, it looks pretty imperative that there should be strict implementation of the industrial effluents and the flow of chemicals discharged in the river bodies.

So that aquatic lives are secured, and upon consumption of the fish, it is sure that people get less consumption of the methyl mercy and other harmful contaminants that persist in the aquatic lives such as fish.