Determination of chlorpyrifos and some toxic heavy metals in vegetable samples from Loei River

Abstract

The research aimed to analyze and compare content of accumulated residue of Chlorpyrifos, Chromium, Lead and Cadmium in five varieties of vegetables in Loei River, Loei Province. Five varieties of vegetables such as Diplazium esculentum, Limnocharis flava  (L.) Buch, Lasia spinosa (L.) Thwaites, Ipomoea aquatica Forsk and Neptunia oleracea Lour.were collected during winter, summer and rainy seasons from Phu Luang, Mueang Loei and Chiang Khan District. The determination of Chlorpyrifos content was carried out as extraction by Sodium chloride, Sodium sulfate anhydrous and Ethyl acetate before analyzed by high performance liquid chromatography (HPLC). The result showed that highest Chlorpyrifos content have found in vegetables in winter and summer season as 0.0416±0.0034 mg/kg. Analysis of heavy metals were carried out by 2 steps including dry ashing at 500°C and acid digestion with nitric acid prior analyzed by flame atomic absorption spectrometry (FAAS). The results showed that cadmium accumulated was the highest content of all metals in Neptunia oleracea Lour in summer season from Phu Luang District (1.8329±0.0079 mg/kg). The second highest metal content was Lead which has found in Ipomoea aquatica Forsk in summer from Mueang Loei District (1.3993±0.0817 mg/kg). Chromium has lowest content in Limnocharis flava Buch in winter from Mueang Loei District (0.4697±0.0441 mg/kg. The content of Chlorpyrifos and heavy metals did not exceed the legal limits set by International Standard Food and Ministry of Republic Health of Thailand except Ipomoea aquatica Forsk in summer from Mueang Loei District have Lead content higher than the legal limits (1 mg/kg for Pb).