Skin Absorption


As evidence that North Americans are consuming an alarming number of trace toxins in their home water continues to mount, a recent Boston study claims you don't even have to swallow the water to be harmedtaking a bath is worse. Our skin is the primary means by which we absorb toxic chemicals.

Toxic chemicals are readily absorbed by the skin.  Bathing, showering, water from pools and spas are much more dangerous than the contaminates ingested bydrinking the same water. This is a potential problem area that has not been examined by regulatory agencies. The results are startling."

In one of the studies cited, scientists analyzed extremely diluted solutions of three common toxic solvents: toluene, ethyl benzene and styrene. Although only the subjects' hands were exposed, breath and urine measurements showed that rapid absorption of the chemicals had occurred. Based on the skin absorption rates derived in the study, the Boston researchers calculated doses to adults and children swimming or bathing in contaminated water and compared these to doses resulting from ingestion at similarly low levels. Absorption by the skin was almost always greater than ingestion, contributing from 29 to 91 percent of the chemicals later excreted, depending on the individual. The average was 64 percent.

"The skin is really the body's largest organ," explains Bishop. "It is an efficient and complex structure, but it's just not able to stand up to the abuse we give it. Once a chemical gets through the outermost layer, the epidermis, there's nothing more to stop it."

Some areas of the epidermis, it turns out, are more permeable than others. For example, the study found that compared with the hand, the scrotum is like a sponge. Other highly absorbent areas include the scalp, the forehead, the abdomen, the underarm, and any wounded or infected skin.

Bishop's team also concluded that children, women, and the elderly are the most susceptible. A child's skin is immature and sensitive; women usually have a higher ratio of body fat than men, which tends to aid in the accumulation of chemicals; and the elderly often experience a mild breaking down of the skin that reduces it's efficiency as a barrier.

This does not mean, however, that the rest of the population is exempt. All human skin will readily transport toxic chemicals and, under certain conditions, extremely easily. For instance, dermal cells, when hydrated or warm, expand and their absorption capacity increases. And when the chemicals are very dilute, as they are in domestic water supplies, the process is even more efficient. Finally, when some chemicals are combined with other substances commonly found in household water - like chlorine, chloroform, and even soap - a catalytic effect occurs, speeding the absorption even further.

Although Bishop claims that "if the water supply is okay for drinking, it's likely okay for bathing," the challenge is in recognizing what actually is "okay." Municipal authorities and government laboratories frequently cite "acceptable" levels of contamination in drinking water, even for carcinogenic substances such as solvents, pesticides, and chlorinated compounds. What they do not consider are the synergistic and mutenagenic effects of chemicals acting in combination. Nor can they fully dispute that even the smallest traces of powerful toxins might lead to birth defects or cancer. "With a carcinogen," says Bishop, "no one can say there's a safe level. That's a policy, rather than a scientific fact."

In their summary, Bishop and her co-researchers come to the chilling conclusion that our exposure to toxic chemicals in water is underestimated. "The risk has likely only been calculated for ingestion and not for skin absorption. It's highly possible that people are receiving much larger doses than expected."

Tony Leighton in Equinox Magazine.