Research On Phytoremediation For Heavy Metals Contaminated Sediment

In recent years, a large number of untreated or treated nonattainment of industrial wastewater and domestic sewage coerced heavy metal contaminants into the water, and enriched in the mud. When the external environment changes, heavy metals in sediment accumulation may be re-released into the overlying water, resulting in the overlying water quality exceeded. Phytoremediation low cost, does not destroy the original structure of the sediment, does not cause secondary pollution its become sediment heavy metal pollution control technology has broad prospects for development, and attracted widespread attention.This selection of Nymphaea L、Typha orientalis Presl、Eichhornia crassipes、 Alternanthera Philoxeroides(Mart.)Griseb、Nymphaea L、Potamogeton crispus L-Hydrilla verticillata、Myriophyllum verticillatum L, Ceratophyllum demersum L、 Nephrolepiscordifolia(L.)Presl-Acorus tatarinowii、 Cyperus alternifolius L. ssp. flabelliformis (Rottb.) Kukenth.were a total of fifteen plants preferred test, by changes in the body of the plant growth cycle complete heavy metal content, preferably the effect of Pb enrichment plants better:Alternanthera Philoxeroides(Mart.)Griseb, Eichhornia crassipes, Cyperus alternifolius L. ssp. flabelliformis (Rottb.) Kukenth、Ceratophyllum demersum L,Its BCF values were:2.93、6.27、3.73、13.77; for Mn enrichment better results plants :Nymphaea L、 Typha orientalis Presl、Canna indica L、Eichhornia crassipes、Hydrilla verticillata、 Potamogeton crispus L、Digitaria sanguinalis (L.) Scop,Its BCF values were:2.58、4.33、1.91、 1.32、3.72、3.76、2.23; effect of Cr-rich plants better:Nymphaea L, Hydrilla verticillata, Myriophyllum verticillatum L,Its BCF values were:2.45、2.42、1.47;better for Zn enrichment effect Plants:Myriophyllum verticillatum L、Acorus tatarinowii、Typha orientalis Presl、Canna indica L、 Cyperus alternifolius L. ssp. flabelliformis (Rottb.) Kukenth、Ceratophyllum demersum L,Its BCF values were:6.03、2.47、4.99、3.79、6.40、4.50.better for Zn enrichment effect Plants:Potamogeton crispus L、Hydrilla verticillata.lts BCF values were:1.65、1.61.Tessier extraction method using a five-step analysis of heavy metals in sediments around the plant growth patterns, the results show that Ceratopliyllum demersum L, Eichhornia crassipes,Potamogelon crispus L,Nymphaea L,flabelliformis (Rottb.) Kukenth,Alternanthera Philoxeroides(Mart.)Griseb, Cyperus alternifolius L. Ssp., iris fixed effect of Cr;Nymphaea L, Cyperus alternifolius L. Ssp., iris for fixed Mn effects;Ceratophyllum demersum L, Potamogeton crispus L, Myriophyllum verticillatum L, As a fixed effect. These plants can change the form of heavy metals in sediment, heavy metals activity and bioavailability of reduced planting these plants will reduce the dangers of heavy metal pollution. Nymphaea L, Ceratophyllum demersum L, Nymphaea L, Cyperus alternifolius L. Ssp., iris no influence on the morphology of Pb; Myriophyllum verticillatum L has no effect on Cr morphology; Digitaria sanguinalis (L.) Scop no effect on Mn morphology; Typha orientalis Presl As no effect on morphology. These plants bioavailability of heavy metals had no effect, consider planting only to its enrichment of heavy metals. Planting other plants to improve the bioavailability of heavy metals will increase the ecological risk of heavy metals, so it should be considered when elected Hyperaccumulators ecological risks that may exist.Decompose release of heavy metals by plant research, found that heavy metals will be released along with the decomposition process of plants to water, heavy with the decomposition process of the plant will be released into the water, hornwort, P.crispus decomposition fastest and most rapid release, such as the release of Pb in the first 50d reaches the maximum were 52.91mg/kg,32.82mg/kg. So for these two large lakes or rivers aquatic plants, its large number of deaths in the decomposition of the season, there will be major changes in water quality.