Clean Sweep

REDUCING PESTICIDE EXPOSURE. Pesticides accumulate on surfaces which they contact either directly or indirectly. Protective equipment and apparel must be maintained on a regular basis to prevent the buildup of pesticide residues and increasing the risk of continuing exposure to applicators. Clothing and equipment worn during pesticide applications should be dedicated for those purposes only. If clothing contaminated with chemical is worn during other activities, it increases the likelihood that the pesticides will penetrate to the skin beneath. This is especially true in areas of the body that perspire more heavily.

Clothing worn during pesticide applications should be laundered on a regular basis (preferably daily). In recent years there has been a significant amount of research into the laundering and refurbishment of pesticide-contaminated clothing due to the need for this information on pesticide labels.

When laundering protective clothing it is important to establish a communications system between the pesticide applicator and the launderer. The persons handling the clothing should also protect themselves from pesticides on the clothing. It is important that exposed clothing be separated from other items of family laundry. It is best to use a plastic garbage bag for collecting contaminated clothing, or use a "dedicated" laundry hamper.

Clothing should be washed as soon as possible after each day’s use. Residue removal is less complete as the concentration of pesticide increases. The concentration of pesticide in fabric builds up with successive exposures, and the more concentrated the pesticide, the more difficult it is to remove in laundering. Our research has shown that pesticide residues at the end of five days of repeated contamination were greater in fabrics laundered on the fifth day than in fabrics laundered each of the five days. Additionally, the pesticide residue in the waste water from laundering only on the fifth day was much greater than the waste water from the fabrics laundered daily.

PREWASHING HELPS. Pesticide removal is enhanced when prewash products or presoaking is used. If the presoak cycle on a washer is used, it is best to let the presoak water drain, then refill with fresh water for detergent washing.

Because pesticide residues do transfer from contaminated clothing to "clean" clothing during the washing cycle, it is important to launder pesticide-contaminated clothing separately. One should only wash together garments contaminated with the same pesticide. It is best to use a full tub of water for a limited number of garments to maximize residue removal.

When it comes to wash water, the hotter the better. Cold water washing of pesticide-contaminated clothing should be avoided. Generally washing temperatures of at least 140 degrees Fahrenheit have proven best for removal. However, the rinse temperature is not as important.

During laundering it is best to use a phosphate detergent or a heavy-duty liquid detergent. Heavy duty liquid detergents are particularly effective in removing oily soils and are best in hard water situations. Phosphate powdered detergents are particularly effective in removing particulate soils, but are not as effective in hard water. If hard water is a problem in your area, it is recommended that the amount of detergent used be increased 1.25 to 1.5 times to improve pesticide removal. If you have used a soil/water repellent finish (such as Scotchguard or Zepel), it is also recommended that detergent amounts be increased.

It is best to use a normal 12-minute washing cycle. The mechanical action of agitation increases the dislodgment of particulate material, so it is best to limit the number of garments included in the load. Too many items in the wash tub or too low water volume, or the combination of both decreases agitation and therefore reduces soil removal.

If the washer has a sud-saver feature, it should not be used for pesticide-soiled clothing.

Fabric softeners and bleaches can be used in laundering, but they are not effective in removing significantly more pesticides. Fabric softener does not affect pesticide adsorption or residue removal in laundering but it can make clothing more comfortable to wear. Bleach can be used in laundering, but it must not be used in combination with ammonia, as highly toxic chlorine gas is formed.

Investigations into the use of starch indicate that pesticide residues cling to the starch and are easily removed in the subsequent wash cycle. Starch, particularly at heavy levels, inhibits the pesticide penetration into the fiber, and also makes removal easier. It is important, however, to be realistic when using starch to make sure that the clothing is comfortable to wear.

WHAT ABOUT MULTIPLE WASHINGS? Depending on the extent of contamination, multiple washings are recommended. Clothing worn while using slightly toxic pesticides may be effectively laundered in one to three machine washings. It is strongly recommended that multiple washings be used to remove the excess residues on clothing contaminated with more toxic or more concentrated pesticides.

It is best to discard clothing contaminated with concentrated, highly toxic pesticides, using disposal directions found on the pesticide label. One should not depend on staining, odor, or color differences, or the lack thereof, as indicators of "clean" clothing. When it comes to pesticide-contaminated clothing "if in doubt…throw it out." In one study with a highly toxic pesticide, after 10 washing cycles the fabric was still toxic enough to kill cockroaches within a few minutes of exposure.

After laundering pesticide-contaminated clothing, it is best to swab down the inside of the washer tub and run the washer through a cycle before using it for the rest of the family wash. Only a slight amount of residue is retained, but care must be taken to decontaminate the equipment before it is used again.

When it comes to drying clothing following laundering, line drying is recommended. Many pesticides break down in sunlight and through line drying there is less chance of contaminating another piece of equipment. If proper laundry procedures have been followed, the amount of pesticide residue remaining in clothing should be minimal.

Dry cleaning pesticide-contaminated clothing is not recommended. The dry cleaning process is effective in removing pesticide residues of many products, but the solvents that are used in the process are recycled and could potentially transfer pesticide from one load to the next. The dry cleaning industry is concerned about subsequent contaminations with pesticides, and as a result usually will not accept applicator clothing for cleaning.

Dr. Roger Gold is head of the Endowed Chair of Texas A&M University, College Station, Texas. Additional information about cleaning pesticide-contaminated clothing and other safety-related stories have appeared in past issues of PCT. If you would like to receive complimentary copies of these articles, write: PCT, "Safety Articles," 4012 Bridge Ave., Cleveland, Ohio 44113.

REFERENCES

Bohmont, B.L. - 1983. The New Pesticide User’s Guide. Reston Publishing co. Inc, Reston , Va. 452 pp.

Durham, W.F. and H.R.Wolfe - 1962. Measurement of the exposure of workers to pesticides. Bull. Wld. Health Org. 26:75-91.

Gold, R.E., J.R.C. Leavitt, T. Holcslaw and D. Tupy - 1982. Exposure of urban applicators to carbaryl. Archives of Environ. Contam. And Toxicol. 11:63-67.

Leavitt, J.R.C., R.E. Gold, T. Holcslaw and D. Tupy - 1982. Exposure of professional pesticide applicators to carbaryl. Archives of Environ. Contam. And Toxicol. 11:57-62.

Ottoboni, M.A. - 1984. The Dose Makes the Poison-A plain language guide to toxicology. Vincente Books, Berkeley, Calif. 222 pp.