近年來,由於工業大量使用,在電鍍業、不?袗?、皮革業、染整業、金屬表面處理業等不乏有鉻的存在,工廠廢水、廢氣甚至於土壤污染間接造成灌溉水污染及人體健康暴露危害。由於鉻具有有價與有害之雙重性質,有必要瞭解其在環境中的分佈,以做為風險管理之基礎;而利用物質流分析方法結合風險評估技術,可以對鉻在經濟系統與環境系統之互動與流向有全盤之掌握,以尋求資源循環與降低風險之契機。 研究結果顯示,鉻從原料、材料至工廠使用或產品共分為12項子項目:不?袗?產品、催化劑、皮革業、表面處理業、鉻染料、鉻木材塗料、合金、抗腐蝕、紡織、能量生產(燃煤及燃油)及實驗室藥品之消耗量及排放量,估計全台鉻排放至空氣約28 tons/year、表面水體23 tons/year、土壤67 tons/year。 政府在訂定灌溉水標準的時候,以不傷害農作物本身及降低產量為目標,其並未考慮人體健康風險評估。而在所使用之CalTOX模式當中,其灌溉水鉻標準0.1mg/L在各縣市所造成之危害商數約在0.3∼0.5之間。 目前在所估計之物質流排放呼吸致癌風險值當中,北部區域為2.32E-7;中部區域9.5E-8;南部區域為6.1E-8,除了北部區域接近傳統之風險安全標準 ,其他地區之風險值尚無危害人體健康之疑慮存在。 在考慮估算之物質流當作環境原有的背景值加上灌溉水0.1mg/L的最大鉻濃度,台南市、高雄市、台中市之HQ已經接近1,若以不影響人體健康之前提下,改善工廠污染量,或訂定嚴格之灌溉水標準都是可行之辦法。
In recent years, chromium and its compounds are widely used in industries. For example, electroplate, stainless steel, leather tanning, textile dyeing process, and surface treatment which discharge wastewater, air pollution, and soil pollution cause irrigation water pollution and, indirectly, human health problem. The understanding of chromium’s distribution in the environment is the basis of risk management measures, since chromium is both useful and hazardous. Using material flow analysis and risk assessment, we can understand the role of chromium played in the interaction of economic system and environmental system, so as to seek resource circulation and reduce the risk. The result shows that chromium is divided into 12 categories ranging from raw materials, materials, the use in factory, and products, including stainless steel products, catalyst, leather industry, surface treatment, dyeing, wood preservatives, alloy, corrosion inhibitor, textile, energy production, and laboratory chemicals. It is estimated that chromium is discharged to air 28 tons/year, to surface water 23 tons/year, and to soil 67 tons/year in Taiwan. The goals of government’s irrigation water quality standards are to protect the crops and to maintain yields. However, the government sets the standards without considering human health risk assessment. In CalTOX multimedia and multimedia pathway model, the 0.1 mg/L chromium of irrigation water standard would cause the hazard quotient to be between 0.3~0.5 in 21 cities. The inhalation carcinogenic risk of material flow is 2.32E-7 in northern area, 9.5E-8 in middle area, 6.1E-8 in southern area. Except for north part approaching to the traditional safe risk value, the risks of the other areas acceptable. Using material flow estimation as environment pollution background values and adding it to 0.1 mg/L chromium of irrigation water standard to calculate hazard quotients, the results of Tainan city, Kaohsiung city, Taichung city are approaching to 1. Under the premise not to influence the human health, it is useful to reduce the polluting amount of the factory, or to consider stricter irrigation water quality standards.