水回收再利用化學性風險評估

The Chemical Risk Assessment For Water Reuse

賴佶甫(Chi-Fu Lai)

指導教授 ： 馬鴻文

國立臺灣大學/工學院/環境工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00546

摘要

水再生利用為新時代水資源經營管理的重要議題，除可促進水資源的循環再利用外，也解決了部分水資源不足的問題，然而水再生利用雖有其利亦有其蔽之處，尤其是對人體健康及環境上的危害，更成為限制水再生利用的重要因素。回收水中影響人體健康的考量因素，主要為致病微生物及有毒化學物質，然而目前大多數的準則均已明確地規定了微生物的濃度標準，但對於化學性的標準卻較為缺乏且不足。
由於作為回收水源的都市污水承受了各種化學品的排放，縱使經過了污水廠的處理後，水中仍含有微量的化學品濃度，其中不乏具有荷爾蒙效應的物質或較具毒性的致癌物。因此本研究透過文獻的回顧，選擇了七種較具危害性的化學物質，並以兩種不同模式來進行化學性的風險評估，期望能對水再生利用可能產生的化學性危害有初步的瞭解。
經由本研究的結果發現，水再生利用於洗澡、農業灌溉用途所產生的非致癌及致癌性風險均超過了安全限值，而主要的暴露途徑來自於皮膚接觸水及攝食農作物的途徑，且主要的危害物質為Bis(2-ethylhexyl)phthalate(DEHP)及N-Nitrosodimethylamine(NDMA)，因此對於此兩項物質需加以管制或去除，以降低化學性的風險危害。
在不確定性的比較上，以Diethyl Phthalate(DEP)與NDMA在農業灌溉用途產生的變異性較洗澡用途來的大，而在洗澡用途，以呼吸空氣途徑的風險變異性最大，在農業灌溉用途，以誤食土壤途徑的風險變異性最大。
另外本研究嘗試以不同區域的參數來計算分區的風險，期望根據此風險結果來推測所需訂定的化學品濃度標準範圍，結果發現在本研究的計算下，各區域的風險差異不大，因此所訂出化學品濃度標準差異不大。

關鍵字

水再生利用 ； 化學風險評估 ； 洗澡 ； 農業灌溉 ； 環境荷爾蒙 ； 鄰苯二甲酸酯類

並列摘要

Water reuse is an important issue in water resource management. It can facilitate efficient management of water resource and reduce degree of water shortage. Although the reuse and recycling of water has many advantages, it also has some disadvantages, specifically concern of impact on public health and the environment. The cause of this damage is the microorganisms and toxic chemicals in the water, as well as the insufficient and ineffective standards and guidelines regarding recycled and reused water.
Municipal sewage contains a variety of chemicals. Even if it has been treated, there are trace chemicals such as environmental hormones and carcinogenic chemicals in it. This research selects seven hazardous chemicals and uses two models to assess the chemical risk of water reuse.
The results show that the primary risk of sewage reuse comes from dermal contact and the intake of food when the contaminated water was used in agricultural irrigation. The non-carcinogenic and carcinogenic risks in reused water are higher than the acceptable levels. Bis(2-ethylhexyl)phthalate (DEHP) and N-Nitrosodimethylamine (NDMA) are the major hazardous chemicals; therefore we must take some measures to reduce risks.
Regarding uncertainty of the estimation, diethyl phthalate (DEP) and NDMA have higher risk variability in agriculture irrigation use than in shower use. In shower use, the pathway of inhalation has the highest variability. In agriculture irrigation use, the pathway of soil intake has the highest variability.
We calculate chemical risks with regional parameters in four areas, and on the basis attempts to set the concentration standards of chemicals. The results show that risks in the four different areas are similar, and therefore we could use the same standards in Taiwan.

並列關鍵字

Water reuse ； Phthalate esters ； Chemical risk assessment ； Environmental hormone ； Agricultural irrigation ； Shower

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