The Phytoextraction of Copper from Tropical Soil 21 Years after Amendment with Heavy-Metal Containing Waste

Abstract

Several particular plants are suggested to extract significant parts of heavy metals from soils and accumulate them in their roots and shoots. This research aimed to study the phytoextraction of Cu by several plants from heavy-metal contaminated tropical soils. Soil samples collected from plots treated in 1998 with 0, 15 and 60 Mg industrial waste ha-1 were planted with three different plants, i.e., caisim, water spinach, and lettuce. Plant parts (roots and shoots) and soil samples were harvested after a four-week growth period and analyzed for plant and soil Cu. The results show that the growth of plants was depressed by the increase in the soil Cu (extracted by 1 N HNO3) as affected by waste levels, with water spinach being the most progressive and produced the most significant biomass. The absorption of Cu by caisim and water spinach increased with the soil extracted Cu (linear R2 = 0.71* for caisim and 0.32* for water spinach) and accumulated greater in plant roots than that in shoots. The translocation factor (TF << 1.00) indicates that all plants were good Cu phytostabilizators rather than phytoextractors, with water spinach being the best Cu extractor.

The biochar-improved growth-characteristics of corn (Zea mays L.) in a 22-years old heavy-metal contaminated tropical soil

“…Analysis of variance (Anova) indicates that waste level significantly depressed the plant height and plant biomasses (roots, shoots, and the whole plant) and significantly enhanced the soil concentrations of Cu and Zn (Table 2). Our previous researches also showed that the waste borne Cu and Zn in the soils depressed the growth of several plants including corn plant, water spinach, caisim, lettuce, and napier grass [20][21][22]. The phenomena were also in accordance with various researches previously reported [14][15][16][17].…”

“…Our previous research showed that the growth of corn (Zea mays) [20], water spinach (Ipomoea aquatica), caisim (Brassica chinensis var. Parachinensis) and lettuce (Lactuca sativa) [20][21] were retarded by the presence of Cu and Zn originated from metal-wares industrial waste amended in tropical soils. For examples, [21] reported that the dry weight of caisim decreased by 38.1%, while those of water spinach and lettuce decreased by 52% and 100%, respectively, in soil amended with Cu-containing waste at 60 Mg ha -1 .…”

“…Parachinensis) and lettuce (Lactuca sativa) [20][21] were retarded by the presence of Cu and Zn originated from metal-wares industrial waste amended in tropical soils. For examples, [21] reported that the dry weight of caisim decreased by 38.1%, while those of water spinach and lettuce decreased by 52% and 100%, respectively, in soil amended with Cu-containing waste at 60 Mg ha -1 . Several other soil workers also reported the negative effects of heavy metals on the growth and production of agricultural commodities and grasses like napier grass (Penissetum purpureum) [12,17,[22][23][24] .…”

The Potential Roles of Biochar in Restoring Heavy-Metal-Polluted Tropical Soils and Plant Growth

“…It is possible to employ plants like water spinach in phytoremediation. Biomass analysis showed also that the plant uptake of Cu and Zn of water spinach was much higher than were other two plants [63].…”

“…Heavy metals are detrimental to living things, particularly at high concentrations [2]. As mentioned previously, their negative effects are reported from various sites in [63] shows the negative effect of heavy metal-containing waste on the growth of water spinach, caisim and lettuce in 23 years old heavy metal-containing waste amended tropical soils. Clearly found that the growth of these plants was depressed at high heavy metals and the growth in control soil was the best (Figure 1).…”