Elemental distribution and uptake by watercress (Nasturtium aquaticum) as a function of water quality

Watercress (Nasturtium aquaticum), is an edible plant commonly found in Southern Africa, which grows both in terrestrial and aquatic environments. The elemental concentrations in the plant and surrounding water (growth solution) were investigated to determine the plants nutritional value and to establish impact of water quality on elemental uptake by the plant. The concentrations in the leaves, roots and water were analyzed at eight different sites along the east coast of KwaZulu-Natal, South Africa (30.0000° S, 25.0000° E). Elemental concentrations in the leaves/roots (μg g−1, dry mass) and water exchangeable/total (μg L−1) at Verulam (situated in the northern part of KwaZulu-Natal) were: As (1.2/7.5 and 0.053/0.09), Ca (18272/26091 and 0.336/7.15), Cd (0.9/0.8 and 0.004/0.01), Co (37.2/34 and 0/0), Cr (7/35 and 0.003/0.03), Cu (3/19 and 0.016/0.16), Fe (528/4308 and 0.375/0.6), Mg (3444/1141 and 6.4/7), Mn (110/667 and 0/0), Ni (20/63 and 0/0.01), Pb (16/17 and 0.01/0.02), Se (28/11 and 0.003/0.01) and Zn (102/116 and 0.099/0.36). Elemental uptake was controlled by the plant but water quality did have an impact on uptake. Concentrations of metals in the leaves were in decreasing order of Ca > Mg > Fe > Mn > Zn > Cu > Cr > Ni > Pb > Se > Cd > As > Co. The watercress plant was found to be a rich source of essential elements especially Fe and Cr and contained low concentrations of the toxic metals investigated thereby making it safe for human consumption.

[1]  J. Dwyer,et al.  Table 17. Dietary Reference Intakes (DRIs): Tolerable Upper Intake Levels (UL a ) for Vitamins (130)Food and Nutrition Board, Institute of Medicine, National Academies , 2015 .

[2]  S. B. Jonnalagadda,et al.  Elemental composition and nutritional value of the edible fruits of Harpephyllum caffrum and impact of soil quality on their chemical characteristics , 2013, Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes.

[3]  S. B. Jonnalagadda,et al.  Elemental composition and fatty acid profile of the edible fruits of Amatungula (Carissa macrocarpa) and impact of soil quality on chemical characteristics. , 2012, Analytica chimica acta.

[4]  W. Fragoso,et al.  Determination of the Mineral Composition of Watercress and Data Evaluation Using Multivariate Analysis , 2011 .

[5]  A. Begum,et al.  Bioaccumulation of trace metals by aquatic plants. , 2010 .

[6]  D. Mozaffarian,et al.  Omega-6 Fatty Acids and Risk for Cardiovascular Disease: A Science Advisory From the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention , 2009, Circulation.

[7]  A. Aksoy,et al.  Bioaccumulation, Detection and Analyses of Heavy Metal Pollution in Sultan Marsh and Its Environment , 2005 .

[8]  M. Rashed,et al.  Assessment of essential and toxic elements in some kinds of vegetables. , 2003, Ecotoxicology and environmental safety.

[9]  M. Bhan,et al.  Management of the severely malnourished child: perspective from developing countries , 2003, BMJ : British Medical Journal.

[10]  Alam Khan,et al.  Role of Diet, Nutrients, Spices and Natural Products in Diabetes Mellitus , 2003 .

[11]  W. Lund,et al.  Multi-element Speciation of Tea Infusion Using Cation-exchange Separation and Size-exclusion Chromatography in Combination with Inductively Coupled Plasma Mass Spectrometry , 1997 .

[12]  D. Crisp.  Input and output of minerals for a small watercress bed fed by chalk water. , 1970 .

[13]  O. Ransome-kuti,et al.  Improvement of impaired carbohydrate metabolism by chromium 3 in manourished infants. , 1968, The American journal of clinical nutrition.

[14]  R. Levine,et al.  Effects of oral chromium supplementation on the glucose tolerance of elderly human subjects. , 1968, Metabolism: clinical and experimental.