Microorganisms such as E. coli, Legionella, or Salmonella, which can be transmitted through contaminated drinking water. They cause gastrointestinal diseases, infections, and can trigger life-threatening complications in individuals with weakened immune systems.

The smallest plastic particles under 5 mm, which are increasingly detected in tap and bottled water. They are suspected of disrupting the endocrine system, triggering inflammatory reactions, and can act as carriers for other pollutants.

Nitrogen compound that primarily enters groundwater through agricultural fertilization and manure. In the body, nitrate can be converted to nitrite, impairing oxygen uptake in the blood (particularly dangerous for infants); the nitrosamines formed from this are considered potentially carcinogenic.

It is occasionally added to the water supply for caries prevention but also occurs naturally. Increased intake can lead to dental and skeletal fluorosis and impair the nervous system and thyroid function.

Industrially manufactured "forever chemical" from the PFAS group, which is hardly degradable in the environment. PFOA is associated with an increased risk of cancer, liver damage, thyroid diseases, and immune system impairments.

Also a PFAS and a persistent pollutant found in industrial and consumer products. Linked to hormonal imbalances, liver damage, immune system damage, and potentially carcinogenic effects.

Heavy metal that enters drinking water primarily through old lead pipes and solder joints. Even small amounts can damage the nervous system, impair cognitive development in children, and affect blood formation and kidneys.

Highly toxic heavy metal that enters the environment through industry, mining, and combustion processes. Even in small quantities, it can damage the nervous system, kidneys, and brain—especially critical for unborn children and infants.

Often found in groundwater and tap water, usually from natural sources or corroding pipes. In elevated concentrations, it causes changes in taste and discoloration and can burden the liver and heart with chronic overconsumption.

It occurs naturally in groundwater, but is problematic in higher concentrations. Long-term intake is associated with neurological impairments, especially in children, as well as learning and behavioral disorders.

Heavy metal that enters drinking water via fixtures, pipes, and industrial discharges. It is one of the most common contact allergens and is suspected of being carcinogenic and damaging to the kidneys and lungs.

Highly toxic form of chromium, which primarily enters water through industrial processes. It is considered a proven carcinogen and can also damage the liver, kidneys, and gastrointestinal tract.

Residues of natural and synthetic hormones (e.g., from contraceptives) enter the water cycle via wastewater. Even in trace amounts, they can affect the endocrine system, disrupt reproduction, and are associated with hormone-dependent diseases.

Active pharmaceutical ingredients (antibiotics, painkillers, psychotropic drugs, etc.) reach drinking water through excretions and improper disposal. The long-term effects of low doses have hardly been researched; the promotion of antibiotic resistance is considered a confirmed risk.

Metalloid that enters groundwater geogenically or through industry and mining. Chronic exposure is proven to be carcinogenic (especially skin, lungs, bladder) and can cause skin, nerve, and cardiovascular diseases.

It is primarily released into drinking water from copper pipes. In higher concentrations, it can cause gastrointestinal problems; in infants and people with metabolic diseases (e.g. Wilson's disease), liver damage can occur.

Chemical disinfectant to reduce the risk of waterborne diseases. However, disinfection by-products (DBPs) can be formed during the disinfection process, which are associated with cancer, reproductive disorders, and damage to the liver, kidneys, and central nervous system.