By Henrylito D. Tacio
IN recent years, researchers from all over the world are finding substantial evidence that those chemicals encountered in people’s everyday routines could be causing subtle but potent health problems other than cancer. While it is now widely accepted that certain diseases may result from exposure to hazardous substances – leukemia, for instance, has been linked to benzene, an ingredient in gasoline – scientists have agreed that chemicals cause systemic damage by disrupting the functions of the endocrine system.
Aside from affecting the nervous system, chemicals also destroy the immune system which defends the body against infectious diseases and cancer. Lowered fertility, abnormal sexual development, eccentric behavior, and lowered resistance to diseases were among the health effects the scientists reported in a conference held at Racine, Wisconsin, in the United States, a couple of years back.
At the said conference, the participants noticed that most regulation of toxic chemicals had been aimed mostly at preventing cancer and overt poisoning in adults, neglecting subtle chemical effects on development, hormone regulation, the immune system, the nervous system, and reproduction.
“Our fascination with cancers has led us to underestimate (chemicals’) other health effects,” decried Dr. Theo Colborn, a zoologist from the Worldwide Fund for Nature who helped organize the conference.
The recent conference is just the beginning. “Society has understood for centuries the dangers posed by many natural and synthetic substances, often through casual observation of diseases that have beset workers in various ‘dirty’ industries,” noted a report released by the Washington-based Worldwatch Institute.
Take the case of asbestos, name of various fibrous materials, chiefly chrysotile and amphibole. It is a valuable industrial material because it is refractory, alkali- and acid-resistant and an electrical insulator. It can be spun to make fireproof fabrics for protective clothing and safety curtains, or molded to make tiles, bricks and automobile brake linings.
Asbestos fibers, once inhaled, become lodged in the lungs – probably for life. Asbestos is called “the silent killer,” since it remains in the lungs for decades before causing disease. These fibers have been conclusively linked to scarring lung tissue and mesothelioma, a rare lung cancer.
Recently, the chemical that caught the attention of researchers is lead, a soft, bluish-grey heavy metal that resists corrosion. It is part of many different manufacturing processes, and is used in batteries, fishing weights, ammunition, solder, ceramic glaze, and in paint applied to bridges and the hulls of ships.
Surprisingly, lead’s health hazards were recognized even in the ancient times. Hippocrates noted cases of leading poisoning among miners in the fourth century B.C. Dioscerides, a Greek physician, reported in the second century B.C. that “lead makes the mind give away.”
But even with such warnings, Worldwatch’s Ann Misch lamented that manufacturers continued to use lead. It was not until the 1970s that the use of lead in gasoline and hospital paint was banned in the United States. Two decades later, government officials estimate that one of every six American children under the age of five has enough lead in his or her blood to be at risk for health aftermaths.
According to Misch’s research, lead can create IQ deficits of up to eight points in children without any outward, recognizable signs of damage. This was the reason why Dr. Louis Sullivan, former US health and human services secretary, called lead poisoning “the number one environmental health hazard” for children.
Another chemical that may prove to have more effects on the human body is dioxin. “Outside the workplace, lead primarily threatens the central nervous system, but dioxin appears capable of interfering with a number of physiological systems,” said Misch, who has been studying the link between health and the environment.
Dioxin is created by the paper industry’s chlorine bleaching, by waste incineration, and as an unintended by-product of the manufacture of a pesticide and a wood preservative. Of the 75 dioxins known to science, the most toxic is the tetrachlorodibenzo-p-dioxin. It is found in Agent Orange, a defoliant used widely during the Vietnam War. More than 90 percent of exposure to dioxin comes from food, particularly meat, dairy products, and fish. It is also found in soils, and traces have even been found in mothers’ breast milk.
Research studies have shown that low-level exposure to dioxin damages the immune system and reproductive functions. Dioxin also causes cancer, particularly breast cancer. The chemical also appears to affect behavior and learning ability, which suggest that it is neurotoxic.
Other industrial chemicals which pose health hazards include antimony, arsenic, cadmium, chromium, and mercury. Experts called these as heavy metals, which are mined from the earth and used in numerous manufacturing processes and countless products.
Antimony, for instance, is used in the manufacturing of foil, batteries, ceramics, safety matches, and textiles. Although fatalities are rare, health reports said that antimony irritates the mucous membranes and tissues.
Arsenic, a chemical element whose compounds are deadly poisons, has caused severe health problems in drinking water in Asia and in South and North America. Yellow arsenic is used as a doping agent in transistors while gray arsenic is used in lasers.
Cadmium is used in plastics to stabilize colors and in plating metals and solders. It is soluble in acid foods like fruit juices and vinegar. Health experts say that ingestion of as little as 10 milligrams of cadmium causes marked symptoms. Severe gastrointestinal inflammation and liver and kidney damage can result.
Chromium is used in steel-making, electroplating, leather tanning and as radiator anti-rust inhibitor. It is also used as mordants in dyeing. Health hazards include irritating and destroying human cells.
Mercury is used in manufacture of thermometers, felt, paints, explosives, lamps, electric apparatus, and batteries. Dimethyl and dimethyl mercury compounds are used in treating seeds. Mercury poisoning can occur by direct intake of mercury, but usually occurs when contaminated organisms, such as fish that have been concentrations of mercury in their bodies, are eaten and accumulate in the body over time. Mercury poisoning can result in acute illness and disabilities such as numbness and garbled speech, or mental retardation.
Most industrial companies dump their heavy metal wastes into bodies of water or into sewage systems, which make their way into natural bodies of water. Shellfish in many parts of the world are contaminated with heavy metals. Several years ago, 121 people were poisoned in Minamata, Japan, after eating fish contaminated with methyl mercury.
Lead, leaking out of disposed-of car batteries into the groundwater, is one reason many landfills have been closed.
Meanwhile, people are now exposed to thousands more chemicals than were their ancestors of a mere 150 years ago. The world’s understanding of how all these substances affect human beings is still elementary. — ###