School of Environment, Nanjing Normal University, Nanjing, 210023, China.
Environ Monit Assess. 2024 Sep 30;196(10):991. doi: 10.1007/s10661-024-13167-z.
Excess nutrients such as phosphate (PO entering surface waters promote eutrophication, and phosphorous (P) removal is important to clear the water. Phytoremediation efforts have been used to improve water quality by varieties of P removal plants, such as water spinach (Ipomoea aquatica Forsk). Water spinach can reduce both internal and external resources of phosphorus from waterbody. The ion of lanthanum (La), one rare earth element (REE), is an immobilization substance for aqueous phosphate and also a fertilizer for plants. Therefore, lanthanum nitrate La (NO) was used further to improve the phytoextraction of P from the polluted water. This study investigated the effects of La on the aqueous P removal by two genotypes of water spinach, green stem large leaves (GSLL) and green stem willow leaves (GSWL). The low concentration La (NO) helped the plant to remove more phosphorous from eutrophic water, but La at high concentration lowered the removal of P. Under La (NO) treatments, the optimum concentration for maximum P removal in GSLL is 3 mg/L, and for GSWL, it is 10 mg/L and P removal rates were enhanced to 95% and 96%, respectively. When the concentration of La (NO) is 100 mg/L, the removal percentage of P was only 10% for both genotypes. The very high concentration of La will impose toxicity and even cause the death of the water spinach and produce secondary pollution; for example, under some specific circumstances, the bond between lanthanum and nitrates dissociates into lanthanum ions (La⁺) and nitrate ions (NO₃⁻). If the concentration is high, then it accumulates in the aquatic water organisms and plants and causes toxicity in their bodies. If humans eat up these plants and fish, it causes toxic effects in humans. The La (NO) positively affects different parameters of plants. La (NO) increases the growth, pigments, enzyme activity, and malondialdehyde (MDA) of plants which were also discussed in this study. The biological mechanism should be responsible for the enhanced aqueous phosphorus removal by water spinach using lanthanum nitrate.
过量的营养物质，如磷酸盐（PO）进入地表水中会促进富营养化，因此去除磷对于净化水质非常重要。人们已经利用各种具有除磷功能的植物，如空心菜（Ipomoea aquatica Forsk）来改善水质。空心菜可以减少水体中内外源磷的含量。镧（La）是一种稀土元素（REE），它可以固定水中的磷酸盐，同时也是植物的肥料。因此，本研究进一步使用硝酸镧（La（NO₃））来提高从受污染水中的植物提取磷的效率。本研究调查了镧对两种空心菜基因型（绿茎大叶型（GSLL）和绿茎柳叶型（GSWL））从富营养化水中去除磷的影响。低浓度的 La（NO₃）有助于植物从富营养水中去除更多的磷，但高浓度的 La 降低了磷的去除率。在 La（NO₃）处理下，GSLL 去除磷的最佳浓度为 3mg/L，GSWL 为 10mg/L，去除率分别提高到 95%和 96%。当 La（NO₃）浓度为 100mg/L 时，两种基因型的磷去除率仅为 10%。镧的极高浓度会产生毒性，甚至导致空心菜死亡，并产生二次污染；例如，在某些特定情况下，镧与硝酸盐之间的键会分解成镧离子（La⁺）和硝酸盐离子（NO₃⁻）。如果浓度过高，它会在水生水生物和植物中积累，并在它们的体内产生毒性。如果人类食用这些植物和鱼类，会对人体造成毒性影响。La（NO₃）对植物的不同参数有积极影响。La（NO₃）增加了植物的生长、色素、酶活性和丙二醛（MDA），本研究也对此进行了讨论。这种生物机制应该是利用硝酸镧提高空心菜去除水中磷的效率的原因。
