使用洗手策略移除皮膚暴露於塑化劑之研究

近年來塑化劑汙染食品與日用品事件再度警示出塑化劑暴露對人體之健康危害。鄰苯二甲酸二(2-乙基己基)酯(di-(2-ethylhexyl) phthalate, DEHP)是塑化劑中使用最廣泛毒性也最高的分子。每個人每天皆暴露於微量的DEHP中，暴露的途徑包含皮膚接觸、食用、吸入等方式，但其中透過皮膚接觸塑化劑的濃度較難預測，因而其對於人體之健康風險常被忽略。塑化劑可透過皮膚吸收直接進入體內，或經由碰觸食物吃入體內。洗手為簡單的衛生習慣，食用食物前進行洗手之動作可移除皮膚表面塑化劑之濃度並降低食入體內之濃度。目前針對皮膚表面塑化劑之暴露與其移除機制較不了解，並缺乏人體皮膚接觸塑化劑暴露之數據，因此本將可增加塑化劑對於皮膚接觸暴露情況之了解。本研究分析不同洗手策略對皮膚上DEHP之移除效率(dermal removal efficiency)，利用N-of-1研究設計招募一位受試者進行前驅測試，在受試者手上模擬現實生活DEHP濃度暴露，透過洗手介入，了解DEHP之移除效率。介入組利用無塑化劑之洗手乳洗手、非介入組利用清水洗手，結果顯示介入組的表皮DEHP移除效率可達99.40±13.70%(mean±SD)；非介入組僅為5.11±4.85%。確認研究流程後再招募16名(8男8女)受試者透過隨機控制交叉研究設計(randomized controlled crossover)，讓16位受試者分別加入介入組與非介入組，結果發現介入組移除效率為91.42±5.78%; 非介入組為10.64±6.54%。本研究結果顯示使用不含塑化劑成分的肥皂，洗手表皮DEHP的移除效率顯著高於清水洗手。本研究也發現雖然清水洗手移除表皮DEHP的效率低，但若再用肥皂洗手，可將原本殘留在手上無法用清水移除的DEHP成功移除。不同性別的受試者雖然在手的大小上有顯著差異，但其移除效率並無顯著差異。透過標準的洗手步驟洗手，並提升正確洗手觀念，皆可提高洗手移除DEHP的效率。

關鍵字

洗手；皮膚移除效率；塑化劑； DEHP ； N-of-1

並列摘要

Recent incidence on phthalate contamination in food products and daily wares alerted the public about the adverse health impact of phthalate use. Phthalate esters are widely use in daily life; studies had confirmed that long term exposure to phthalate will result in chronic health symptoms. Phthalate esters are classified as toxic chemical substance by the Environmental Protection Administration, Executive Yuan, ROC. Di-(2-ethylhexyl) phthalate (DEHP) is the most commonly found phthalate in our daily life with the highest toxicity. There is a universal exposure to a small concentration of DEHP via dermal contacts, inhalation, and ingestion every day. Strict regulations are imposed on the use of DEHP in daily products, and a Tolerable Daily Intake (TDI) limit is set at 50μg/kg bw/day. However, dermal exposure to DEHP is hard to estimate thus its risk to our health is often neglected. DEHP can be directly absorbed by the skin; DEHP can also be ingested by hand-to-mouth behavior and hand-to-food contacts. Hand washing is a simple way to practice good hygiene. Washing hands before eating can reduce the amount of dermal exposure to phthalate and other chemicals, and thus, reduce the level of exposure in our body. Current knowledge on dermal exposure to DEHP is limited and no published study has been found to investigate the removal efficiency of DEHP on skin. This study aimed to understand the removal efficiency of dermal exposure to DEHP by hand washing with phthalate-free soap. The study employed N-of-1 study design for the pilot study. One subject was recruited to mimic DEHP exposure on hands at a concentration comparable to real life situation, the subject then receive Treatment (hand washing with phthalate-free soap) and Placebo (washing with water only) interventions in order to study the removal efficiency of DEHP on hand surface. The pilot study showed that the Treatment had removal efficiency of 99.40±13.70%；whereas Placebo only had 5.11±4.85%. The study was then expanded to a field study using a randomized controlled crossover study design. A total of 16 subjects with 8 females and 8 males were randomly assigned to the Treatment or Placebo group. After one week washout, crossover was performed and each subject received the other intervention. The result showed that the Treatment intervention had removal efficiency of 91.42±5.78%；Placebo had 10.64±6.54%. Using phthalate-free soap can significantly remove 90% or higher dermal exposure to DEHP on hands, and the efficiency was significantly higher than washing with water alone. The study also found that although water wash had lower removal efficiency, the DEHP left on hands unable to be washed off by water-only can be successfully removed if an additional soap washing step was added. Males and females had significantly different hand sizes; however, no difference in the removal efficiency across genders was observed in the study. This study suggested that using proper hand washing technique and improving understanding and familiarity on hand washing can also increase the removal efficiency on dermal exposure to DEHP.

並列關鍵字

hand washing ； dermal removal efficiency ； phthalate ； DEHP ； N-of-1

參考文獻

1. Li, J.-H., Yu, W.-J., Lai, Y.-H. & Ko, Y.-C. Major food safety episodes in Taiwan: implications for the necessity of international collaboration on safety assessment and management. The Kaohsiung journal of medical sciences 28, S10–6 (2012).

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