以物質流方法探討臺灣含汞物質的管理

Abstract

汞是毒性化學物質，卻廣泛運用在電池、恆溫器、溫度計、燈管、血壓計、陀螺儀……等各種產品。臺灣不產汞，原料全仰賴進口，根據財政部關稅總局進口量，資料顯示2000至2009年汞與氯化汞平均進口量約6.3公噸，使用量高。再者，目前廢棄物項目僅有廢照明光源，回收為原料汞，其餘皆是將污染物濃縮成廢棄物，後續再採取隔絕或隔離的方式儲存在土壤圈，事實上，污染物依然存在。因此，為瞭解臺灣含汞物質種類、特徵、流布、管理效果等，本研究首先簡介汞的物理、化學與毒理特性，再回顧日本水俁病與國內外汞污染事件及法令管制現況，強調管理的重要性。其次，為分析臺灣含汞物質的流動過程，包含原料、半成品/產品製造、使用、廢棄物處理與回收等階段，使用物質流方法，定出「量」的資訊，建立基準線後，再判定管理效果；換句話說，就是以物質流方法探討臺灣含汞物質的管理。除此之外，為了進一步找出最有管理方式，設計推演「情境」，希望作為決策方案參考依據。 研究結果顯示2006—2009年34種195項含汞物質總汞量為155.548公噸；總輸入量（總進口量）為229.830公噸，具經濟價值（可回收）佔76%；不具經濟價值（難回收）佔24%；總輸出量（總出口量）為95.742公噸，具經濟價值佔94%；不具經濟價值佔6%；國內開採量為0.760公噸（其中升級回收量佔0.359公噸，開採量佔0.402公噸），具經濟價值佔47%，不具經濟價值佔53%；存量為57.577公噸，整體廢棄物掌握率逐年遞減，整體升級回收率全部未達1％；國內排放量為76.913公噸，排放至空氣佔49%；排放至水體佔2%；排放至土壤佔49%。 輸出入汞量皆是半成品/產品階段最高。輸出入淨值汞量前十大項目分別為電池、原油、煤、汞、溫度計、恆溫器、鐵、血壓計、石灰、鋁。不具經濟價值方面，總輸入量以原料階段汞量高於半成品/產品階段，代表項目是煤及原油；總輸出量以半成品/產品階段汞量比原料階段高，主要代表項目為水泥、顏料、石油。 國內排放量，原物料階段部分，釋放於空氣主要項目分別為原油、煤、鐵；釋放於水體主要項目是鋁；釋放於土壤主要項目為銅和金。半成品/產品階段部分，釋放於空氣主要項目分別為水泥、石油、牙齒汞齊；釋放於水體主要項目是牙齒汞齊、電池、燈，牙齒汞齊與燈；釋放於土壤含汞項目為電池和燈。使用階段部分，釋放於空氣主要項目為水泥、顏料、燈；釋放於水體主要項目是牙齒汞齊、顏料；釋放於土壤則無主要含汞項目。廢棄物處理與回收部分，不論釋放於空氣、水體與土壤主要項目皆是廢乾電池、廢汞及其化合物、污泥，又以廢乾電池排放到土壤量最高。 推演情境結果，只有禁止輸出入與國內製造產品情境，才能將降低總汞量，倘若要提升整體升級回收量，需組合增列回收項目、改變拋棄習慣與提升廢棄物回收與處理設備三項情境。十七個推演情境，整體升級回收率皆低於30%，其中第十七個情境結果顯示，即使禁用原料汞與半成品/產品階段所有具經濟價值（可回收）的含汞產品，仍有汞量存在。 整體來說，含汞物質種類複雜，而且具有人類圈代謝典型特徵，輸入量大於輸出量與存量。主要含汞項目由2006年的電池轉為2009年恆溫器，顯示禁或限用法令規範具有顯著成效，但整體廢棄物掌握率下降，應再禁用其他含汞產品。 具體而言，提高整體升級回收率所面臨的技術瓶頸高，線性流難變為循環流；因此，建議不具經濟價值含汞物質管理方式應朝管末處理，具經濟價值產品應採取全面禁用，舊有的含汞產品則是集中掩埋隔離，毋須再升級回收。與此相應，本研究所定義的整體廢棄物掌握率與整體升級回收率兩項指標，是可以作為管理的參考依據。

Mercury is a poisonous chemical substance, but has been widely used in battery, thermostat, thermometer, fluorescent tube, sphygmomanometer, gyroscope, and other products. Taiwan does not produce mercury; thus, all of the raw materials rely on import. According to the import statistics of the Directorate General of Customs, Ministry of Finance, the average imports of mercury and mercuric chloride from 2000 to 2009 were 6.3 metric ton (MT), which is very high. In addition, the current recycling item for mercury only includes the Waste fluorescent lamps, while other pollutants were compressed into waste and stored in the pedosphere through isolation or insulation. In fact, the pollutants still exist. In order to know the categories, characteristics, spread and management effects of mercury-contained substances in Taiwan, this study first introduced the physical, chemical and poisonous characteristics of mercury. It then reviewed the Minamata Disease in Japan, the domestic and foreign mercury pollution cases, and related and regulations, in order to emphasize the importance of waste mercury management. This study also analyzed the flow of the mercury-contained substances in Taiwan, including raw materials, fabrication and manufacture, use, waste management and recycling process, Substance flow analysis was conducted to determine the amount, establish the base line, and evaluate the management effect. In other words, substance flow analysis was used to discuss the management of mercury-contained substances in Taiwan. In addition, to find the most effective management method, derivative scenarios were designed as the reference for decision schemes. According to the research results, from 2006 to 2009, the total mercury content of 34 kinds and 195 mercury-contained substances was 155.548MT. The input (imports) was 229.830MT;those with economic value (recyclable) accounted for 76%, and those with non-economic value (non-recyclable) accounted for 24%. The output (exports) was 95.742 MT; those with economic value accounted for 94%, and those with non-economic value accounted for 6%. Domestic extraction was 0.760MT (where, the total amount of upcycling was 0.359MT and the extraction amount was 0.402MT); those with economic value accounted for 47%, and those with non-economic value accounted for 53%. The stock was 57.577MT, the waste management rate decreased year by year and all of the upcycling rates failed to achieve 1%. The domestic processed output was 76.913MT; those outputted to atmosphere accounted for 49%,and those to the water body and the soil accounted for 2%, and 49%,respectively. The input and output were both the highest in the semi-finished product/product phase. The top ten items with largest input and output net mercury amounts were battery, crude oil, coal, mercury, thermometer, thermostat, iron, medical blood pressure gauges, lime and aluminum. As for those with non-economic value, the input in production phase was higher than that in semi-finished/finished products phase, where, the representative items were coal and crude oil. The output in semi-finished/finished products phase was higher than that in production phase, where, the representative items were cement, pigment and petroleum. As for the processed output in Taiwan, in the raw material phase, the main items outputted to the atmosphere were crude oil, coal and iron; that outputted to water body was aluminum and those outputted to soil were copper and gold. In the semi-finished/finished products phase, the main items outputted to the atmosphere were cement, petroleum and teeth amalgam; those outputted to water body were teeth amalgam, battery, lamp, teeth amalgam and lamp; those outputted to soil were battery and lamp. In the use phase, the main items outputted to the atmosphere were cement, pigment and lamp; those outputted to water body were teeth amalgam and pigment; those outputted to soil did not include main mercury-contained items. In the waste management and recycling phase, the main items outputted to atmosphere, water body and soil were all waste dry battery, waste mercury and its chemical compound and sewage sludge, where, the amount of waste dry battery outputted to the soil was the highest. According to the derivative scenarios, only through prohibiting input and output as well as semi-finished/finished products in Taiwan could the total amount of mercury be reduced. If the total amount of upcycling was to be increased, the three scenarios, i.e. recycling items increasing, abandoning habit change and waste recycling and treatment equipment improvement, should be combined. The upcycling rates of 17 derivative scenarios were all lower than 30%, where, indicated by the 17th scenario results, even though the mercury-contained products with economic value (recyclable) in production and semi-finished/finished products semi-finished/finished products phases were prohibited, mercury amount still existed. On the whole, the mercury-contained materials had complex categories and the typical characteristics of anthroposphere, and their input was larger than output and stock. The main mercury-contained items changed from battery in 2006 to thermostat in 2009, indicating that the prohibition or restriction laws and regulations had significant effect. However, the waste management rate decreased, thus, the other mercury-contained products should be prohibited. The improvement of upcycling rate faced high technical bottleneck and linear flow was hard to be changed into circular flow. Thus, it was strongly recommended that the mercury-containing substances without economic value should be tightened emission standards, while, those with economic value should be prohibited. The existing mercury-contained products should be centralized, buried and insulated, without upcycling. Correspondingly, the two indicators defined in this research, i.e. waste management rate and upcycling rate, could serve a reference for management.