Analisis Kadar Logam Kadmium (Cd) pada Kubis Putih (Brassica Oleracea L.) Menggunakan Metode Destruksi Basah Secara Spektroskopi Serapan Atom (SSA)

Abstract

Farmers in Namorambe District, Deli Serdang Regency, are still heavily dependent on the intensive use of inorganic fertilizers in their cultivation practices, including for white cabbage (Brassica oleracea L.). Excessive application of inorganic fertilizers can increase the risk of heavy metal accumulation, particularly cadmium (Cd), in plants. Cadmium is a toxic heavy metal that can accumulate in the human body and cause serious health problems when consumed over a long period of time. This study was conducted to determine the concentration of Cd in white cabbage cultivated in Namorambe District and to analyze the effect of different oxidizing agents in the closed wet digestion method on the accuracy of Cd analysis. The cabbage samples were first homogenized and then digested using two types of oxidizing solutions: pure HNO₃ and a mixture of HNO₃:HClO₄ at a ratio of 4:1. The Cd content was analyzed using Atomic Absorption Spectrophotometry (AAS). The results showed that the Cd concentration in white cabbage reached 0.2761 mg/kg using HNO₃ as the solvent and increased to 0.3619 mg/kg when using the HNO₃:HClO₄ (4:1) mixture. These values exceeded the maximum permissible Cd contamination limit set by SNI 7387:2009, which is 0.2 mg/kg. The HNO₃:HClO₄ (4:1) mixture produced a more effective digestion process, as indicated by the higher Cd concentration compared to digestion using HNO₃ alone. These findings indicate that white cabbage cultivated in the Namorambe area contains Cd levels exceeding the safe consumption limit. Therefore, strict monitoring of inorganic fertilizer use and regular evaluation of agricultural product quality in the region are urgently needed.