空氣汚染氟化物對農林植物之影響及其果實累積之研究

Abstract

空氣汚染氟化物主要來自磚窯、陶瓷、煉鋁廠、磷肥工廠及玻璃纖維工廠，在工業製程中經過高溫加熱下會將冰晶石、螢石與含氟礦物等中的氟化物排放至空氣中，進而由植物的氣孔吸收並導致植物受到損害。 本研究主要調查新北鶯歌區的陶瓷工廠及雲林虎尾鎮的玻璃纖維工廠之周圍常見作物與樹木之葉片及果實，在排放口下風處50至200公尺內受氟化物危害之植株，並採集植物樣品後記錄病徵及利用氟選擇性電極檢測植物樣本之氟化物含量。新北鶯歌陶瓷工廠周圍採集植物有青苧麻、羊蹄甲、稜果榕、番石榴及柿子，其病徵皆為葉緣枯萎及褪綠，病部氟含量可達數千ppm；雲林虎尾玻璃纖維工廠周圍採集植物有羊蹄甲、月桃、青剛櫟、春不老、香蕉、聖女番茄、台灣海桐、無患子、木瓜及苦楝，其病徵皆為緣枯及褪綠，病部氟含量可達數百至數千ppm；果實有台灣海桐、苦楝、木瓜、香蕉及聖女番茄，其皆無明顯病徵，但仍有少量氟化物累積於果皮。 將植物葉片細分各部位後利用氟選擇性電極檢測氟含量，結果得知，樣本葉尖及葉緣之氟累積情形皆為最高且兩者無顯著差異，並與葉片健康基部之相差倍率約數倍；果實樣品檢測台灣海桐、苦楝、木瓜、香蕉和玉女番茄等果實之果皮含有較高量的氟化物，但相對於葉片病部倍率皆差幾十倍之多且無明顯病徵產生，果肉及種子的氟含量則少量或趨近於無。 為研究氟化物稀釋液對葉片及果實之危害性，故以4000 ppm氟化氫稀釋液噴施已結果之香蕉、木瓜、番石榴及玉女番茄，噴施後逐日觀察其葉片及果實病徵。兩天後葉片皆有產生緣枯及褪綠之病徵，各噴施植株之葉片病部皆含有約數千ppm之氟含量；果實則僅有番石榴產生褐班，氟化物皆多累積於果皮，氟含量約有數百ppm。番石榴病徵產生推測應是急性發生或番石榴果皮氣孔相較於其他植株之果實氣孔為多所導致，故未來可朝果實氣孔數量及型態之方向進一步探討研究。 為研究氟化物氣體對葉片及果實之危害，故以氟化氫對五彩辣椒、桑椹、金桔、青椒、辣椒、無花果、檸檬、四季豆及胡瓜共9種進行熏氣6小時。隔日後觀察，葉片皆產生緣枯及褪綠等病徵，其中五彩辣椒、桑椹、青椒、辣椒、四季豆及胡瓜熏氣後隔日即全株落葉，其葉片病部氟含量皆有達數千至數萬ppm；果實病徵以金桔及檸檬果皮產生褐班，辣椒果皮皺縮，胡瓜果皮黃化等，其氟含量皆以果皮累積最高，皆有達數百至數千ppm。 為準確鑑定氟汚病徵以減少公害糾紛發生，故在田間調查及試驗植株栽培過程中會比較與氟化物相似的疫病蟲害及生理障礙之病徵，並藉由病理學之診斷以確認疫病蟲害之病因。

Air pollution fluoride is mainly emitted from brick kiln, ceramics, aluminum smelter, phosphate fertilizer factory and glass fiber factory. Through the high temperature heating process, hydrogen fluoride and other fluoride compounds will be released from cryolite, fluorite and fluorine-containing minerals into the air, then absorbed by the stomata of plants and cause injuries on various plants. This study was conducted to investigate the fluoride injury symptoms on leaves and fruits of crops or trees around the glass fiber factory in Huwei, Yunlin County and the tile factory in Yingge, New Taipei County. The plants located in downwind areas 50 to 200 meters from the emission source were diagnosed and collected for fluoride content analysis. The fluoride content of the plant samples was measured using a fluorine selective electrode. Plants showed F-injury symptoms around the tile factory in Yingge including green ramie, orchid tree, angular fruit fig, guava and persimmon. Symptoms on leaves are marginal or tip necrosis and chlorosis. Their fluoride content of the diseased portion can reach several thousands of ppm. Plants showed symptoms around the glass fiber factory in Huwei, including orchid tree, beautiful galangal, ring-cupped oak, ceylon ardisia, banana, tomato, fragrant pittosporum, chinese soap berry, papaya, and china berry. Symptoms on leaves are marginal or tip necrosis and chlorosis. Their fluoride content of the diseased portion can reach several hundreds to thousands of ppm. Fruits of fragrant pittosporum, chinese berry, papaya, banana and tomato were diagnosed without visible symptoms, and only small amount of fluoride accumulated in the peel portion of these fruits. The injured plant leaves collected from field were dissected into various parts and their fluoride contents were determined by the fluorine selective electrode. Results showed that fluoride in majority accumulate in the tip or marginal portions of leaf with no significant difference between them. While there was a several times difference between the diseased and healthy base portion of a leaf. Fruit peels of fragrant pittosporum, chinese berry, papaya, banana and tomato have higher fluoride contents than the pulp portions. However, the contents in diseased leaves were several dozens higher than those in fruit peels and fluoride contents in pulp and seeds is very low or close to none. In order to compare the harmful effects of fluoride on leaves and fruits, field-grown banana, papaya, guava and tomato plants in NTU Experimental Farm were sprayed with 4000 ppm hydrogen fluoride solution. The leaves and fruit symptoms were diagnosed since the day after spraying. After two days, all the leaves of four plants showed symptoms of marginal or tip necrosis and chlorosis. Their leaves contain several thousand ppm of fluoride in the diseased portions. Among the four plants, only the fruits of guava produce the brown spot symptoms, with fluoride accumulated in the peel portion for several hundred ppm. The guava fruit injury is supposed to be caused by high dose treatment together with higher density of the stomata on guava fruit than those of other fruits. They need further studies in the association of the number or density of stomata with fluoride injury sensitivity on fruits. In order to compare the injury of fluoride gas on plant leaves and fruits, nine pot plant species bearing fruits, including colorful pepper, mulberry, kumquat, green pepper, chill, fig-tree, lemon, green bean and cucumber were fumigated for 6 hours with hydrogen fluoride gas produced from a gas generator. After the next day, all of the leaves of nine plants showed severe injury symptoms such as severe tip or marginal necrosis, chlorosis, and leaf drop. Among them, colorful peppers, mulberry, green peppers, chill, green bean and cucumber are all defoliated, and their fluoride content of the leaves reach to thousands to tens thousands of ppm. Only four species of them showed injury symptoms on fruits, including the kumquat and lemon with brown spot, chill with shrunken peel, cucumber with fruit yellowing. The fluoride contents in diseased fruits were higher in the peels, usually hundreds to thousands of ppm. In order to accurately diagnose the fluoride injury in the field and reduce the public dispute over the pollution, the mimic symptoms caused by biological or physiological disorder were also studied and compared in this study with typical F-injury symptoms. Through the plant doctor’s diagnosis, all the factors causing the diseases can be verified and confirmed.