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NGUYÔN §×NH Tø , NGUYÔN Vò THANH ViÖn Sinh th¸i vµ Tµi nguyªn sinh vËtTrong nhiÒu n¨m trë l¹i ®©y do sö dông nhiÒu c¸c lo¹i thuèc b ¶o vÖ thùc vËt trong n«ng nghiÖp, ph¸t triÓn c«ng nghiÖp, vËn chuyÓn hµng h ¶i còng nh− viÖc ®« thÞ hãa t¨ng nhanh ® g©y « nhiÔm nhiÒu nguån n−íc do phÕ th ¶i kh«ng qua xö lý ®ae ra s«ng, theo s«ng ra biÓn g©y « nhiÔm nhiÒu vïng réng lín. Ngoµi viÖc g©y « nhiÔm m«i tr−êng, nguån n−íc, qu¸ tr×nh l¾ng ®äng, tÝch tô phÕ th ¶i trong ®ã cã nhiÒu kim lo¹i nAEng trong líp trÇm tÝch cã thÓ g©y ra qu¸ tr×nh tÝch tô sinh häc th«ng qua chuçi sinh th¸i tù nhiªn ®èi víi nhiÒu lo¹i ®éng vËt ®¸y, trong ®ã cã t«m, cua, c¸, trai, èc... lµ nh÷ng nguån thùc phÈm quan träng cho céng ®ång.Khu sinh quyÓn CÇn Giê, tp Hå ChÝ Minh n»m ë l−u vùc 2 s«ng lín lµ s«ng §ång Nai vµ s«ng Sµi Gßn. §©y lµ n¬i héi tô cña nhiÒu ho¹t ®éng c«ng n«ng nghiÖp, giao th«ng, ®« thÞ tõ th−îng nguån ®Õn cöa biÓn nªn ch¾c ch¾n còng kh«ng tr¸nh khái t¸c ®éng ®ã. Cïng víi nh÷ng nghiªn cøu sinh th¸i häc nhãm ®éng vËt ®¸y trong ®ã cã tuyÕn trïng [2-5] th× nghiªn cøu vÒ t×nh tr¹ng « nhiÔm kim lo¹i nAEng trong líp bïn ®¸y ®Õn hÖ sinh vËt ®¸y còng b−íc ®Çu ®−îc tiÕn hµnh. Qua kÕt qu ¶ nghiªn cøu, cã thÓ ®¸nh gi¸ ¶nh h−ëng cña kim lo¹i nAEng ®Õn qu¸ tr×nh tÝch tô sinh häc cña sinh vËt ®¸y trong cïng hÖ sinh th¸i. Ph©n tÝch kim lo¹i nAEngTÊt c ¶ c¸c kim lo¹i nAEng trong bïn ®¸y, bao gåm Cr, Zn, Cu, Cd, Pb (trõ Hg, As), dÇu mì vµ thuèc trõ s©u gèc clo h÷u c¬ ®−îc ®Þnh l−îng trªn m¸y ph©n tÝch quang phae ph¸t x¹ plasma. Ph−¬ng ph¸p xö lý mÉu ®−îc ¸p dông lµ AOAC 990.08.MÉu lÊy vÒ ®−îc ph¬i kh« trong kh«ng khÝ, sau ®ã mÉu ®−îc gi vµ r©y víi kÝch th−íc lç 0,25 cm sau ®ã sÏ tuú theo ®èi t−îng ph©n tÝch sÏ cã c¸ch xö lý kh¸c nhau.Ph©n tÝch ®Þnh tÝnh c¸c kim lo¹i nAEng, dÇu mì vµ thuèc trõ s©u gèc clo: Sau khi mÉu ®Êt mïn ®−îc xö lý b»ng hçn hîp HCL vµ HNO 3 trong 1 giê trªn bÕp ®iÖn, ®Ó nguéi sÊy kh« vµ xö lý thªm mét lÇn n÷a víi axÝt HNO 3 , sau ®ã mÉu ®−îc läc, chuyÓn vÒ d¹ng dung dÞch, sau ®ã mÉu ®−îc ®o trªn thiÕt bÞ ph©n tÝch quang phae ph¸t x¹ plasma (Inductively coupled plasma atomic emmission spectrometric -ICP).Ph−¬ng ph¸p Varian AA-72 cho Hg, AOAC-990.08 cho As. MÉu sau khi ® ®−îc xö lý sÏ ®o trªn m¸y hÊp thô nguyªn tö kh«ng ngän löa cïng víi bé Hydrua ®èi víi Hg vµ ®o As trªn AAS víi bé Hydrua cña As.

Ethephon not only has the effect in the stimulation of defoliation, but also makes fruits ripen quickly and evenly. Ethephon pushes hard the process of fruit ripening from 1-2 days instead of 4-6 days as before. However, the residues of Ethephon in the fruits will cause health problems such as damage to the liver, kidneys. The method used to determine Ethephon residues is high pressure liquid Chromatography Mass Spectrometry (LC-MS/MS). The limit of detection (LOD) Etherphon is 0.92 mg /kg and Limit of quantitation is LOQ = 2.7mg/Kg. The linear range curve is from 0.96ppm to 96ppm with R 2 = 0.999 repeatability. The study subjects are green bananas soaked in Ethephon solution with concentrations: 4.8%, 9.6%, and 24%. Soaking time was from 1 day, 2 days, 3 days, and 4 days. Results obtained after 4 days of experiments showed that Ethephon content in banana increased proportionally with the concentration of Ethephon in the solution. The highest increase was on day 1, measured at 90.5 ppm at soaked concentration 24%, and 42.2 ppm at 9.6% and finally is 21.9ppm at soaked concentration of Ethephon 4.8%. Till the second, third, and fourth day, Ethephon content in banana started to decrease. Ethephon content in bananas of the fourth day is 20ppm at soaked concentration 24%, 9.6ppm at soaked concentration 9.6% and 3.3 ppm at soaked concentration 4.8% of Ethephon solution tank. However, after 4 days, bananas soaked in Ethephon solution had blackened and become inedible in comparison with bananas soaked in the Etherphon solution only within 1 or 2 days, the banana still remained beautiful and edible.

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