Assessment of chemical contaminants in fresh and packaged tender coconut (Cocos nucifera) water

Pesticide residues and heavy metals were analysed in both fresh tender coconut water (FTCW) (n = 161) and packaged tender coconut water (PTCW) (n = 126) samples collected from three southern states of India [Andhra Pradesh (AP), Kerala (KL), and Tamil Nadu (TN)]. A method validated in the laboratory using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for pesticide residues, while heavy metals were analysed using a validated method of inductively coupled plasma-optical emission spectrometry (ICP-OES). Significant differences in heavy metal concentrations were assessed using analysis of variance (ANOVA) and post hoc test (between different varieties collected 'within' and 'among' states). FTCW samples [n = 9 (6%)] collected from TN showed Monocrotophos and Malathion residues in the range of 1.0 µg L-1 to 51.6 µg L-1 and 0.5 µg L-1 to 0.6 µg L-1, respectively, while they were detected in n = 5 (4%) of the PTCW samples at a range of 0.90 µg L-1 and 0.82 µg L-1 to 1.56 µg L-1. Heavy metals such as cadmium (Cd), chromium (Cr), lead (Pb), and stannum (Sn) were detected in different varieties collected from all three states. Some of the PTCW samples also contained traces of Cd, Cr, cobalt (Co), and Pb. Arsenic (As) was found in one sample from KL, while none of the samples was contaminated with mercury (Hg). The present study accentuates the need for fixing standards for the pesticide residues in coconut water.