Icpe 9000

The surface and groundwater samples were filtered by filter papers (Qualitative, circle, 90 mm Ø, Whatman^TM, New Jersey, US) to obtain a 100-mL solution, to which 1 mL of HNO₃ (65%) was added and then heated for 2 h without boiling at 80–90 ℃. The samples were cooled to room temperature and then filtered with 0.2-μm syringe filters [29 ]. The waters were analyzed using a multitype inductively coupled plasma emission spectrometer (ICP-ES) and ICPE-9000 (Shimadzu, Tokyo, Japan).
Five grams of soil were added to 20 mL of HNO₃ (7 mol/L), stirred for 1 h, and then placed in an autoclave at 120 °C for 30 min. The mixture was cooled to room temperature, filtered by filter papers, and diluted by deionized water [30 ]. The samples were filtered again by a 0.2-μm syringe filter and transferred to tubes for analyses by ICPE-9000 (Shimadzu, Tokyo, Japan).
The roots, stems, and leaves of the plant samples were dried and ground into powder. An amount of 0.5 g of each sample was added to 6 mL of concentrated HNO₃ (65%) and 2 mL of concentrated HCl (30%) and stood until the reaction was completed. The mixture was moved to an autoclave for 66 min at 132 °C for digestion [30 ]. The plant samples were analyzed by ICPE-9000 (Shimadzu, Tokyo, Japan).

On weeks 3, 6, 10, 16, 25, and 33 after transplanting, stems, leaves and fruits were sampled, washed with distilled water, and then dried in a ventilated oven at 75°C to constant weight. Nutrient contents in leaves and fruits samples were analyzed. The contents of K, Ca, Mg, and P were assayed after digestion with H₂SO₄-HNO₃-HClO₄ (H₂SO₄:HNO₃:HClO₄ = 1 ml:5 ml:1 ml) by inductively coupled plasma spectrometry (ICPE-9000, Shimazu, Japan; ICP-MS 7900, Agilent Technologies, United States). The N content was assayed after digestion with H₂SO₄-H₂O₂ by continuous flowing analyzer (AA3, Seal, Germany). The S content was assayed after digestion with HNO₃ by inductively coupled plasma spectrometry (ICP-MS 7900, Agilent Technologies, United States) (Zhou et al., 2000 ).