知識中心

In our previous article, we discussed the dangers and sources of lead poisoning; in this issue, we will explore methods for preventing and treating lead poisoning. Surgery is generally not used to remove lead from the body. It is important to avoid and eliminate sources of lead exposure. A balanced diet, adequate nutrition, and ensuring the body has sufficient iron, calcium, vitamin C, and other nutrients can help reduce lead absorption and support the treatment of patients with lead exposure. However, nutrition alone cannot treat lead poisoning. Patients with severe cases may require additional treatment with medications (chelating agents). These medications bind to lead in the body, allowing it to be excreted, primarily through the kidneys in urine. This process can reduce lead levels in the body and improve some symptoms; however, it cannot reliably reverse damage already done to the central nervous system or other organs. Because chelation therapy can have serious side effects and must be tailored to the patient’s condition and blood lead level, a specialist must carefully control the dosage and treatment regimen. Do not allow children to come into contact with lead. In fact, anyone can be at risk of lead poisoning, but children are particularly vulnerable, especially those aged 1–5, who frequently put their hands or objects in their mouths and may ingest non-food substances. Lead poisoning can seriously damage children’s rapidly developing brains and other organs. Other high-risk groups include those who regularly drink water from lead-containing pipes, consume food from lead-lined cans, or use lead-containing cosmetics [...]

When deciding whether to buy bottled water, consumers should consider key factors such as chemicals, contaminants, and price. In February 2008, Reader’s Digest published an article titled “Is Bottled Water Safe?” . The magazine analyzed the reality of the situation and common consumer misconceptions about drinking bottled water. According to the publication’s survey results: More than 25 percent of bottled water comes from public water sources. Although most bottled water is safe, a 1999 report by the “Natural Resources Defense Council” found that one-third of branded bottled water contained contaminants. Between 1990 and 2007, there were approximately 100 bottled water recalls. Only 20% of plastic or glass bottles for bottled water under one liter have an environmental recycling system in place. By Michael Chiu, MWS, CI – Updated and Revised in 2026

Recent news reports have frequently alerted the public to the possibility of pharmaceutical contamination in the water supply. The following facts are provided for the reference of consumers and users: Installing a filtration system at home provides an additional level of water treatment. In terms of water consumption, less than 20 percent of water is used for domestic purposes and human consumption; therefore, using these point-of-use filtration systems may be a cost-effective and environmentally friendly option for treating drinking water. Although water supplied by government treatment plants must meet established safety standards, home filtration systems serve as an additional barrier against certain contaminants and can further treat and purify drinking water in the home. At the time this article was written, specific performance standards for pharmaceutical contaminants in residential drinking water filtration systems may not yet have been established. However, many filtration technologies had already demonstrated effectiveness in removing certain emerging waterborne contaminants. Research conducted by the Colorado School of Mines evaluated nanofiltration and reverse osmosis systems at full-scale water treatment facilities in Arizona and California to remove pharmaceutical contaminants from water. Among purification and filtration systems designed to remove these contaminants—including activated carbon, distillation, ozone disinfection, and advanced oxidation—effectiveness varies depending on the contaminant and treatment conditions, and these technologies do not necessarily achieve similar results. According to research attributed to Utah State University, up to 90 percent of some orally administered medications may pass through the human body without being fully metabolized. These drugs and their metabolites can enter wastewater systems and [...]

Molds are scientifically classified as fungi, a group of organisms that includes microorganisms. Microorganisms are often grouped into categories such as viruses, bacteria, fungi (including molds and yeasts), and algae, although these categories do not represent five equivalent biological groups. Published literature has documented tens of thousands of fungal species, with older estimates placing the number of known fungi between 60,000 and 80,000. Molds play a role in maintaining the Earth's ecosystem by breaking down organic matter and serve specific functions in the production of pharmaceuticals and fermented foods; they are not entirely detrimental to human health. However, the damage molds cause to food, homes, and buildings is not only unsightly and unhygienic but can also lead to allergic reactions, respiratory problems, and, in some cases, infections in humans. Mold growth requires a source of nutrients and moisture, while temperature and other environmental conditions influence how quickly it grows. Many molds thrive in humid environments, but suitable growth temperatures vary by species, and some molds can grow at temperatures below 15°C. Mold spores float in the air and can readily settle on various surfaces. When conditions are favorable, the spores germinate to produce hyphae (filamentous structures), allowing the mold to grow and eventually produce more spores. Impact on Human Health: Humid environments facilitate mold growth on food and household items. Exposure to mold spores, fragments, and other substances produced by certain molds can affect health, particularly by triggering allergies, irritating the respiratory system, or worsening asthma. Mold-related health effects include allergic reactions, irritation, and, [...]

Approximately 40% of Canadians have access to community-fluoridated water through their municipal water supply systems. Scientific research has shown that fluoride helps prevent tooth decay, particularly in children. However, fluoride has not been unequivocally established as an essential element for humans, and excessive intake can be harmful. Some countries add fluoride to drinking water in areas with low fluoride levels to prevent tooth decay, while others oppose this practice. Generally, fluoride in the human body comes from drinking water, food, and other sources. Most of the fluoride in an adult’s body is stored in hard tissues such as bones and teeth. In its natural state, fluoride is present in soil, seawater, surface water, and groundwater. Fluorine primarily occurs in nature in compound form, mainly in minerals such as fluorite, fluoroapatite, and cryolite, which are important raw materials used in aluminum smelting, phosphate fertilizer production, steel manufacturing, and the production of fluorinated chemicals. However, fluoride-containing wastewater, exhaust gases, and solid waste discharged during some industrial processes can cause environmental pollution; the combustion of coal can also release fluoride-containing emissions. Excessive fluoride exposure can harm plants, and leaves can absorb fluoride from the air. The absorbed fluoride can accumulate at leaf tips and margins, where sufficiently high concentrations may cause tissue damage and necrosis. High concentrations of certain fluoride compounds can cause skin burns, dermatitis, and respiratory tract irritation or injury, depending on the compound and route of exposure. Excessive long-term fluoride intake can cause dental and skeletal fluorosis. Dental fluorosis can cause changes in tooth [...]

Carbon monoxide is a chemical compound. It has very low solubility in water but is highly soluble in ammonia solution. Its explosive limits in air range from 12.5% to 74%. Carbon monoxide is a product of the incomplete combustion of carbon-containing substances. It can also be used as a fuel; coal and water can produce water gas (a mixture of carbon monoxide and hydrogen) at high temperatures. Since carbon monoxide has an affinity for hemoglobin in the body that is 200–300 times greater than that of oxygen, and carbon monoxide hemoglobin dissociates 3,600 times more slowly than oxygenated hemoglobin, carbon monoxide exposure can cause harm to the human body, depending on the concentration and duration of exposure. A concentration of 35 ppm is a recommended occupational exposure limit averaged over a work shift, rather than a universal threshold for poisoning. Exposure to carbon monoxide can result in carbon monoxide poisoning or gas poisoning. Because carbon monoxide has the property of turning blood a very bright red, some meat merchants treat fresh meat with carbon monoxide to prevent it from oxidizing and discoloring; this treatment can help meat retain its red appearance for an extended period under suitable packaging and storage conditions. However, the specific claim that raw meat can be stored at 10°C for 28 days while still appearing freshly slaughtered requires further verification. This practice has drawn controversy. Consumer advocates have raised concerns that even if this treatment is harmless, it may mask the fact that the meat is no longer fresh, leaving [...]

Carbon dioxide is a common compound found in the air; its molecule consists of one carbon atom and two oxygen atoms. At standard atmospheric pressure, it is a colorless, odorless, non-oxidizing, and non-flammable gas. Carbon dioxide is soluble in water, and a small portion of it reacts with water to form carbonic acid. Carbon dioxide is typically produced by the combustion of organic compounds, cellular respiration, and microbial fermentation. Plants absorb carbon dioxide in the presence of sunlight and use it in their chloroplasts for photosynthesis, producing carbohydrates and oxygen. This oxygen is then used by other organisms for respiration; these processes are part of the carbon cycle. Carbon dioxide is one of the greenhouse gases; it absorbs infrared radiation emitted by Earth's surface, slowing the loss of heat to space. When the concentration of carbon dioxide in the atmosphere increases, it strengthens the greenhouse effect, causing the Earth's average temperature to rise. This process contributes to global warming. The solid form of carbon dioxide is dry ice. At atmospheric pressure, dry ice sublimates directly into a gas. Carbon dioxide can exist as a liquid only under sufficient pressure; its triple point, where solid, liquid, and gas coexist, occurs at approximately 5.1 times atmospheric pressure and −56.6°C. Carbon dioxide can be injected into beverages to create bubbles, enhancing the drinking experience; examples include soda and beer. Liquid carbon dioxide and dry ice can both be used for rapid food freezing. Liquid carbon dioxide absorbs heat as it expands and vaporizes, while dry ice absorbs [...]

Carcinogens are agents, including certain chemicals, radiation, and infectious organisms, that can cause cancer. They may damage DNA, cause genetic mutations, or disrupt normal cellular processes, such as cell signaling and the regulation of cell growth. These changes can lead to uncontrolled cell proliferation and tumor development. Although many causes of cancer are known, not every case has a single identifiable cause. Exposure to carcinogens can increase the risk of developing cancer, depending on factors such as the type of agent, the level and duration of exposure, and individual susceptibility. Carcinogens include asbestos, benzene, certain nitrosamines, benzo[a]pyrene, formaldehyde, and some forms of chromium and other metals. Other chemicals, including acrylamide and malachite green, have different levels of evidence regarding their potential to cause cancer. Not every hazardous chemical is a proven human carcinogen; classifications depend on scientific evidence, and some substances are considered probably or possibly carcinogenic rather than definitively carcinogenic to humans. In addition, some cancers are caused by infectious agents, including certain viruses, bacteria, and parasites. Infections were estimated to account for approximately 10% of new cancer cases worldwide in 2022. Important cancer-associated viruses include human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), and Epstein–Barr virus (EBV), also known as human herpesvirus 4. Tobacco remains the leading preventable cause of cancer worldwide, while cancer-causing infections are another major preventable risk factor. Viruses can contribute to cancer through several mechanisms, including producing proteins that interfere with normal cell regulation, causing chronic inflammation, suppressing immune function, or altering the host cell's [...]

The formal term for acid rain is “acid deposition,” which can be divided into two main categories: “wet deposition” and “dry deposition.” Wet deposition refers to acidic substances that reach the ground through precipitation, such as rain, snow, fog, or hail. Dry deposition refers to acidic gases and particles that settle onto the ground, vegetation, and other surfaces when precipitation is absent. Chemically, water with a pH of 7.0 is defined as neutral; values below 7.0 are acidic. The atmosphere naturally contains carbon dioxide, which dissolves in rainwater and forms weak carbonic acid, giving natural rainwater a pH of approximately 5.6. Other natural sources, including volcanic emissions and nitrogen oxides produced by lightning, can also contribute to atmospheric acidity. However, acid rain is primarily associated with sulfur dioxide and nitrogen oxides released by human activities, especially fossil fuel combustion. Acid rain generally refers to precipitation that is more acidic than normal rainwater, typically with a pH below 5.6. The precise threshold used may vary by region and monitoring program; there is no universal official definition requiring a pH of 5.0 or lower. Environmental agencies monitor precipitation acidity to assess the effects of atmospheric pollution. The main human health risks associated with acid rain come from the pollutants that cause it. Sulfur dioxide and nitrogen oxides can react in the atmosphere to form fine particles that irritate the respiratory system and worsen conditions such as asthma. These pollutants and related particles can also contribute to cardiovascular and other respiratory problems. An indirect environmental impact of [...]

Antioxidants are substances that inhibit oxidation reactions. In living organisms, oxidation processes can produce highly reactive free radicals and other reactive molecules. These substances can react with and damage other molecules: in some cases, the body uses free radicals to help defend against disease; in other cases, these reactions may damage cells within the body. Antioxidants can help neutralize free radicals by reacting with them, limiting their potential to damage other important molecules. The following vitamins have antioxidant properties: Vitamin A and carotenoids: Carotenoids, which give many green, yellow, and orange plants their color, help protect plants from oxidative damage caused by light. Some carotenoids, such as beta-carotene, can be converted into vitamin A in the human body. Sources of provitamin A carotenoids include carrots, pumpkins, sweet potatoes, tomatoes, kale, and apricots. Vitamin A itself is also found in foods such as eggs, dairy products, fish, and liver. Vitamin C is a water-soluble antioxidant in the body. Important sources include citrus fruits, peppers, green leafy vegetables, and tomatoes. Vitamin E is fat-soluble and helps protect cell membranes and other lipids from oxidation. Its main sources include wheat germ, nuts, seeds, vegetable oils, and green leafy vegetables. Arsenic is sometimes mistakenly associated with antioxidant activity because the body's defenses against toxic substances include antioxidant processes. However, arsenic, particularly in inorganic forms, can cause oxidative stress, damage cells, and increase the risk of certain cancers. The body's protective responses do not make arsenic beneficial, and it is not an essential nutrient. Arsenic can occur in foods [...]