Water pollution can affect sex characteristics in humans and animals. These pollutants are found in many water sources, such as fountains and oceans. Some common pollutants include endocrine disruptor chemicals (EDCs) found in birth control and Bisphenol A (BPA). These chemicals, which can cause changes in sex characteristics, are becoming more common in water around the world. They harm both people and animals that come into contact with them.

Endocrine disruptor chemicals

Endocrine disruptor chemicals (EDCs) are substances that interfere with sex hormones in the body. These chemicals are called anti-estrogens and anti-androgens because they block or reduce the effects of estrogen and testosterone. When these hormones are not able to function properly, fertility can decrease, and hormone imbalances may cause changes in male characteristics. This issue is not limited to humans; scientists have observed similar effects in fish populations around the world. They believe that chemicals in water supplies are causing more females to develop in male fish. Estrogen can collect in body fat and tissues, and as animals eat one another in the food chain, these chemicals can build up in the bodies of higher-level animals.

EDCs can be found in the environment, whether they occur naturally or are made by humans. While chemicals from birth control pills clearly affect humans, research shows that estrogen given to farm animals is even more common in the United States.

Pollutants and their source of origin

Sex-altering pollutants come from many sources. One growing source is water pollution caused by medicines. Some medicines contain tiny pollutants that copy the chemical structure of hormones in living things. These chemicals are called hormone-disrupting chemicals. They often copy the structure of estrogen and testosterone. These artificial chemicals are found in many common household and industrial products. For example, chemicals like parabens, phthalates, and triclosans are in everyday items such as shampoos, conditioners, soaps, perfumes, makeup, and lotions. These chemicals can enter the body through the skin, be swallowed and passed out in urine, or be washed down the drain and found in water samples. Below are some of the most common hormone-disrupting chemicals found in medicines and personal care products:

• Parabens: Help prevent the growth of yeast, mold, and bacteria in cosmetics. They are found in deodorants, facial scrubs, makeup, lotions, and cleansers. Parabens also copy estrogen and have the same chemical structure.
• Phthalates: Used in cosmetics to make materials more flexible, such as in nail polish and hairspray. They act like estrogen by binding to cell receptors and causing estrogen-like effects in the body.
• Triclosans: Work as germ-killers and are found in toothpaste, cosmetics, and soaps. They behave like estrogen and testosterone, interacting with both types of hormone receptors in complex ways.

In addition to these chemicals, other medicines such as antidepressants, anti-seizure drugs, and birth control pills are often found in water samples. However, medicines are not the biggest cause of gender-altering pollution in water. Scientists at the University of California, San Francisco (UCSF) say other sources also contribute. These include crop fertilizers, dairy cows, and industrial chemicals like BPA. These chemicals are often found in landfills, and runoff from landfills eventually reaches water sources, causing contamination.

Another source of pollutants is the burning of fossil fuels. Chemicals and metals released into the air during this process end up in the ocean, changing ocean chemistry. One example is the Haber-Bosch process, which produces fertilizer and affects the global nitrogen cycle, influencing ocean climate.

Humans also contribute to this issue. The body naturally produces and excretes chemicals that affect hormones. Pregnant women release more of these chemicals through their bodily functions. This shows that gender-altering pollutants are not natural but are caused by man-made chemicals that are released globally.

Circulation of pollutants

Chemicals such as EDCs and artificial estrogens move continuously around the planet through many different ways. Humans are a major cause of the harmful buildup of these chemicals in the environment. Major sources of drinking water, like rivers, lakes, streams, and oceans, are some of the ways these chemicals travel from one place to another. Most exposure to these chemicals by people living in poor conditions in rural areas is connected to their contact with polluted water sources.

The process of EDCs entering water sources starts with a source. Whether it comes from an industrial plant, a pharmaceutical company, or a person, it eventually reaches a larger water source, usually as waste. The Environmental Protection Agency (EPA) has recorded the amount of pharmaceuticals released into the environment from manufacturing plants, but this information is not as common for household waste. Some efforts are being made to reduce this pollution. For example, 80% of pharmacies in Clark County, Washington, have joined programs to help people safely dispose of non-controlled drugs. These efforts are gaining support as pollution becomes more visible, but they are still being expanded on a large scale. The polluted water then goes to different places.

One possibility is that the water is sent to a waste management facility to be cleaned and reused. However, experts have found that sewage treatment does not completely remove these chemicals from drinking water. Any water that is poured down a shower, toilet, or sink usually carries some EDCs. These drains connect to pipes that lead to a wastewater management plant. A typical wastewater treatment plant uses a multi-step process to clean water, but because EDC particles are very small, the process is not always fully effective. For example, Boulder, Colorado’s Wastewater Management receives water through pipes that lead to large holding pools at the facility. The treatment process usually lasts between 12 and 24 hours and includes three main steps. First, physical treatments remove solid and organic materials from wastewater. Then, microbiological treatments use bacteria to break down carbon and nitrogen compounds in the sewage. Finally, the water is cleaned with ultraviolet light to kill remaining germs. The treated water is then sent back into local creeks, streams, and freshwater sources. This basic wastewater treatment plan works well for larger contaminants but is not effective at removing tiny EDCs. As a result, EDC micro-pollution is creating harmful chemical mixtures in freshwater environments.

In response, the water industry has said there is no proof of health risks from exposure to these chemicals. However, the Food and Drug Administration (FDA) states that many contaminants survive wastewater treatment and natural breakdown, and can still be found in the environment. Therefore, the polluted water is reused in communities, exposing more people and releasing more chemicals along the way.

Another way these chemicals move is through the water cycle. The water cycle describes how water moves around Earth. It goes through several steps where water changes form until it returns to Earth to be used again. In the water cycle, both organic and inorganic pollutants are naturally broken down or filtered out, reducing their danger. This is also true for small amounts of chemicals in water. However, when very large amounts of chemicals, organic or inorganic, are present in water as it moves through the atmosphere, harmful effects can occur in areas where the water falls as rain. This rainwater then re-enters the ongoing movement of water pollution.

Another path for water to circulate is by flowing directly into the ocean. Pollutants are common in coastal and open-ocean waters as contaminated water moves from specific sources to the sea. These pollutants spread worldwide due to ocean currents and the movement of marine life. This explains how chemicals again reach humans. Marine life in polluted areas lives in and drinks contaminated water daily. When this wildlife is caught and eaten, it has absorbed a high level of harmful chemicals or EDCs compared to normal ocean levels. These chemicals are then passed to humans who eat the seafood, building up in their bodies over time and causing health issues related to sex and reproduction.

Effects of pollutants on sex

These chemicals can influence the sex of humans due to long-term exposure. Pollutants in water have been studied, and the results show how they affect hormones in both males and females. Research on animals has found similar effects in humans. Scientists who studied endocrine-disrupting chemicals (EDCs) in women’s blood discovered that these chemicals act like human hormones and can change how the sex of unborn children is determined. Some scientists believe this hormonal change may have caused fewer males compared to females. Other effects include fewer or weaker sperm and problems with the male reproductive system.

When looking at how EDCs affect sperm, these chemicals cause a chemical to be released too early, which sperm need to reach an egg. Studies explain why this happens. In terms of problems with the male reproductive system, EDCs can begin affecting males as early as birth. During the development of the testes, a type of cell called Sertoli cells changes. If a male is exposed to EDCs like estrogen during this time, fewer Sertoli cells are created. This leads to less sperm production and a less effective reproductive system. EDCs are also linked to early puberty, infertility, and birth defects. These effects have been found in humans and in aquatic life, as these animals are often exposed to EDCs. Fish populations have been greatly affected by EDCs in their environments.

A study from 2008 in Japan looked at how EDCs from personal care products affected a local river. The chemical triclosan was found to harm the growth of algae, protozoa, crustaceans, bacteria, and amphibians. Surveys of freshwater, estuarine, and marine ecosystems show that EDCs harm fish. Chemicals that mimic estrogen and androgen (male hormones) disrupt fish hormones, which are important for reproduction and growth. When EDCs build up in water, they confuse the hormone vitellogenin, which is vital for fish reproduction. A review by the U.S. Environmental Protection Agency found that when fish were exposed to estrogen and androgen mimickers, their reproduction was harmed. This included fewer eggs, fewer males, lower sperm production, less sexual behavior in males, and more physical problems in fish.

Solutions

To help remove small amounts of pollutants from water leaving waste treatment plants, studies by Westerhoff et al. and Schafer et al. examined which water filtration systems are most effective at removing EDCs. They found that Powdered Activated Carbon (PAC), membrane filtration (including nonfiltration and biofiltration), and reverse osmosis are the most effective methods for removing EDCs.

• Powdered Activated Carbon (PAC): PAC is made from materials like wood, coal, and coconuts that have a lot of carbon. These materials are treated to create many tiny pores, which increase the surface area. PAC is added in large amounts during the early stages of water treatment. The carbon absorbs toxins because it has a strong attraction to certain molecules.
• Membrane filtration: Membrane filtration uses membranes made from organic and inorganic materials to separate molecules based on their size and other properties.
• Reverse osmosis: Reverse osmosis works like membrane filtration but uses pressure to push water through a special membrane. This process forces water to move from areas with more contamination to areas with less. The membrane only lets water pass through, leaving contaminants and toxins behind.