Dioxins and Their Harmful Effects on Human Health

Introduction

Dioxins are chemical compounds that act as persistent organic pollutants (POP). They are released into the atmosphere due to industrial processes and the burning of by-products released from factories. After being released into the atmosphere, they enter the food chain and will remain in the environment and reach living tissues. Dioxins will accumulate in the fat cells of animals and induce toxic effects. Human exposure to dioxin is mainly through contaminated food, fish, meat, and dairy products. Studies have shown that dioxins can induce toxic effects in the human body. They are associated with developmental defects, immune system damage, reproductive defects, hormonal imbalance, and cancer.

What Are Dioxins?

Dioxins are heavily toxic chemicals that belong to the group of environmental pollutants known as persistent organic pollutants (POPs). Dioxin molecules show different toxicity based on the position and number of chlorine atoms present. Dioxins consist of a group of chlorinated chemicals with a similar structure. Chlorinated chemical compounds with similar structures and properties to dioxins are named dioxin-like compounds. They exhibit toxic effects comparable to dioxins. It includes the following compounds:

• Polychlorinated biphenyls (PCBs).

• Polychlorinated dibenzofurans (PCDFs).

• Polychlorinated dibenzo-p-dioxins (PCDDs).

• Polybrominated analogs.

What Are the Sources of Dioxins?

Dioxins are released into the atmosphere through multiple processes. They can travel through air and water and reach aquatic environments and human cells. The sources of dioxin include the following processes:

• Combustion processes like waste incineration (municipal or commercial).

• Burning of fuels, wood, oil, or coal.

• Backyard burning of contaminated waste materials.

• Natural processes like forest fire and volcanic activity.

• Bleaching techniques like chlorine bleaching of pulp and paper.

• Industrial waste from the production of pesticides and herbicides.

• Improper handling and recycling of electronic waste (E-waste).

• Small amounts of dioxins are released from cigarette smoke.

How Are Humans Exposed to Dioxins?

After reaching the atmosphere through multiple sources, dioxins will combine with other chemicals and settle in air, water, and soil. Dioxins enter the food chain through small living organisms present in the soil and water. Higher animals will have higher concentrations of dioxin in their body due to bioaccumulation. Humans are exposed to dioxin through various sources. They are:

• Accidental occupational exposure in industrial workers.

• Drinking contaminated water containing industrial wastes.

• Consuming fish living in a contaminated environment.

• Breathing dioxin-containing polluted air.

• Consuming fat-rich foods like meat, large ocean fish, and cheese.

• Dermal contact from contaminated soil and water.

What Are the Environmental Impacts of Dioxin?

Dioxin and dioxin-like compounds released into the atmosphere will stay in the environment for a long time. A dioxin molecule may take more than ten years to reduce its toxicity to half its original levels. After reaching aquatic life, dioxins will accumulate in the living cells of the smallest organisms in the water. Dioxins are highly lipophilic. They tend to accumulate in fat-like environments. As a result, they accumulate in the lipid cells of living organisms (bioaccumulation). Later on, these small organisms will be consumed by other higher ones in the food chain and resulting in the biomagnification of dioxins. Due to biomagnification and bioaccumulation, the amount of dioxin in higher organisms will be higher than in small ones. Thus they are most likely to produce toxic health effects due to dioxins.

What Are the Harmful Effects of Dioxin on Human Health?

The toxic effects of dioxin on human cells are mediated through the inappropriate activation of receptors involved in normal physiological actions. Dioxin will bind with the AH (aryl hydrocarbon) receptor present in the body. The AH receptors are involved in normal physiological functions and tissue development. In some conditions, activation of AH receptors will result in the production of toxic reactive metabolites. These reactive metabolites are responsible for the carcinogenic and mutagenic effects of dioxins. Toxic effects associated with dioxins are dose-dependent. The most important toxic effects of dioxin exposure in humans are developmental defects and cancer.

Harmful health effects due to dioxin exposure include the following:

• Increased incidence of malignancies.

• Decreased fertility in males and females.

• Congenital disabilities and developmental defects in newborns.

• Low levels of testosterone and reduced sperm count in males.

• High chances of abortions in females.

• Learning disabilities and poor mental development in children.

• Skin rashes and irritations after dermal contact.

• Endometriosis.

• Liver damage.

• Lung diseases.

• Immune system defects.

• Chloracne (severe acne).

• The patchy, darkened appearance of skin.

• Increased incidence of type 2 diabetes.

• Altered thyroid hormone levels.

• Gastrointestinal irritations.

• Ischemic heart diseases.

• Pancreatitis (inflammation of the pancreas).

• Eye irritations and resultant swelling of eyelids.

How to Reduce Dioxin Exposure?

Toxic environmental and health effects of dioxin can be prevented by reducing the amount of dioxin and dioxin-like chemicals released into the atmosphere. It can be established by monitoring the waste disposal methods followed in the industries. Proper handling and disposal of industrial waste must be done to avoid environmental pollution. Contaminated wastes must be properly incinerated at very high temperatures. Human exposure to dioxin through food can be reduced by avoiding high-fat-containing fish and meat. Care must be taken to avoid contaminated food in pregnant women, children, and young girls to reduce developmental defects and other complications. Dietary exposure to dioxins can be minimized by shifting to a low-fat version of dairy products, meats, and poultry.

Conclusion

Dioxins are highly toxic chemicals that reach the atmosphere through various industrial processes and rarely through some natural sources. After reaching the environment, they readily settle in air, water, and soil. They reach living cells through contaminated air, water, and soil and accumulate in the fat cells. Dioxins can induce toxic health effects such as neurodevelopmental defects, weakened immune system, hormonal imbalance, reproductive defects, and increased cancer incidence. Proper handling and disposal of industrial waste materials must be done to reduce dioxin release into the environment. The majority of human exposure can be prevented by avoiding the consumption of fat-rich fish, meat, and dairy products that may contain dioxin.