Characteristics of sewage sludge and distribution of heavy metal in plants with amendment of sewage sludge

In order to better understand land application of sewage sludge, the characterization of heavy metals and organic pollutants were investigated in three different sewage sludges in Shanghai City, China. It was found that the total concentrations of Cd in all of sewage sludge and total concentrations of Zn in Jinshan sewage sludge, as well as those ofZn, Cu, and Ni in Taopu sludge are higher than Chinese regulation limit of pollutants for sludge to be used in agriculture. Leachability of rig in all of studied samples and that of Cd in Taopu sewage sludge exceed the limit values of waste solid extraction standard in China legislation. Based on the characteristics for three kinds of sewage sludge, a pot experiment was conducted to investigate the effect of soil amended with Quyang sewage sludge on the accumulation of heavy metalo.by Begonia semperfloreas-hybr; Ophiopogon japonicas （L.F.） Ker-Gaw; Loropetalum chindense-var, rubrum; Dendranthema morifolium; Viola tricolor; A ntirrhinum majas; Buxas radicans Sieb; Viburnum macrocephalum; Osmanthas fragrans Lour; Cinnamomum camphora siebold and Ligustrum lucidum ait. Results showed that 8 species of plant survived in the amended soil, and moreover they flourished as well as those cultivated in the control soil. The heavy metal concentration in plants varied with species, As, Pb, Cd and Cr concentration being the highest in the four herbaceous species studied, particularly in the roots of D. morifolium. These plants, however, did not show accumulator of As, Pb, Cd and Cr. The highest concentration of Ni and Hg was found in the roots ofD. morifolium, followed by the leaves ofB. semperflorens-hybr. Levels of Zn and Cu were much higher in D. morifolium than in the other plant species. D. morifolium accumulated Ni, Hg, Cu and Zn, which may contribute to the decrease of heavy metal contents in the amended soil. Treatment with sewage sludge did not significantly affect the uptake of heavy metals by the L. chindense-var, rubrum, however, it significantly affected the uptake of heavy metals by D. morifolium.

Accumulation and Fractionation of Rare Earth Elements in Soil-Rice Systems

Accumulation and fractionation of rare earth elements （REEs） were studied through applications of exogenous REEs in soils with pot-cultured rice for 2 years. The results show that the biomass of rice consistently decreases at sprouting and maturity stages when the amount of exogenous REEs are over 400 mg· kg^- 1. It illustrates that the endurance of rice to exogenous REE exposure is much weaker than that of wheat. The distribution patterns of REEs in rice of the control are similar to that in the soil, both exhibiting light REE （LREE） enrichment and positive Tb in the roots and the aboveground parts. Applications of exogenous REEs ranging from 400 to 1200 mg· kg^- 1 have significant effects on the distribution patterns of REEs in roots, some effects in stems and leaves, and almost no effects in grains. Accumulation rates of REEs in different organs follow the order of roots 〉 leaves 〉 stems 〉 panicle axes and crusts 〉 grains. The roots take up different REEs at almost the same rates, except for the selective accumulation of Th. In the aboveground parts, the accumulation rates of middle REEs （MREEs） and heavy REEs （HREEs） are higher than those of LREEs, there are significant selective accumulations of Eu and Tb. Accumulation rates of REEs in the roots, stems and leaves increase with the increasing applications of exogenous REEs, but they change slightly in the panicle axes, crusts and grains, demonstrating that it is easier for the roots, stems and leaves to accumulate exogenous REEs. Selective accumulation and fractionation of exoge nous Nd are also observed in rice organs including grains.

Phytoremediation potential of Cyperus rotundus for diesel-contaminated wetland

Oil spills may considerably damage sensitive coastal wetlands. The phytoremediation potential and restoration of a dominant coastal marsh plant, Cyperus rotundus, for diesel pollutant and its phytoremediation effectiveness were investigated in this open-air pot experiment. Cyperus rotundus was transplanted into soil contaminated with diesel at concentrations of 1 000, 5 000, 10 000, 15 000, 20 000 mg/kg. In order to better elucidate the biochemical and physiological responses to diesel pollutants, activity of the antioxidant enzymes peroxidase （POD）, catalase （CAT） and ascorbic acid oxidase （AAO） were determined in the plant tissue after 50 d treatment at the levels mentioned above. The results showed that CAT and AAO of stem and leaf exhibited peak enzyme activities on 15 000 mg/kg soil and 10 000 mg/kg soil respectively, and declined at higher concentrations. Additionally, the increment of biomass and the content of soluble protein, as well as chlorophyll content were affected by diesel. The highest restoration effectiveness appeared at the level of 5 000 mg/kg. Collectively, Cyperus rotundus is a potential plant which can be used for restoring the diesel-contaminated soil.

Isolation and Identification of Colletotrichum sp.from Strawberry and Screening of Effective Fungicides

[Objective] The paper was to isolate Colletotrichum sp.from strawberry and to screen effective fungicides.[Method] The indoor toxicity of 7 fungicides to Colletotrichum sp.was measured by growth rate method.The potted control effect of 3 fungicides on Colletotrichum sp.was evaluated.[Result] Fludioxonil exhibited the highest indoor toxicity to Colletotrichum sp.,with the EC50 value of 0.117 mg/L,and the EC50 value of prochloraz and difenoconazole were 0.141 and 0.357 mg/L,respectively.The pot experiment showed that the potted control effect of 20% fludioxonil2 000 times dilution on Colletotrichum sp.was the highest of 92.86%.450 g/L prochloraz EW 4 500 times dilution and 250 g/L difenoconazole EC2 500 times dilution also received high control effects against Colletotrichum sp.,which were 91.68% and 89.29%,respectively.[Conclusion] Fludioxonil,prochloraz and difenoconazole could be used for the control of strawberry anthracnose.

Experimental study on the uptake and effects of arsenic originated from poultry litter on the growth of Brassica napus in greenhouse pot cultivation and health risk assessment

Organoarsenics are widely used as growth promoters in poultry industry,resulting in arsenic(As)accumulation in poultry litter.A greenhouse pot study was implemented to investigate the fate of arsenic originated from poultry litter and their effects on the growth of Brassica napus(oilseed rape),and assess their potential health risks.Five poultry litter application rates(0,5%,10%,20%and 40%)were used,dividing into two groups:one for soil incubation(SI)and the other for plant cultivation(PC).Experimental results indicated that the total arsenic for composted poultry litter was(10.94±0.23)mg/kg,As(V)and As(III)decreased while methylated arsenic increased after 21 d in SI and PC treatments.Seed germination rates were negatively correlated with monomethylarsenic acid(MMA,R2=0.63,p<0.05).The length and biomass of roots and shoots were significantly inhibited by poultry litter,but plant length of 5%treatments was slightly stimulated.Within an average weekly intake of 0.5 kg Brassica napuss,the risk quotient(RQ)values induced from roots nearly all surpassed the acceptable limit(1),were two orders magnitude higher than shoots.According to the potential risk to order,child exhibited the highest risk,adolescent ranked secondly,and adult exhibited the lowest risk.Hence,people should better avoid intake Brassica napus roots to reduce arsenic potential risk.

Exotic tree seedlings are much more competitive than natives but show underyielding when growing together

Aims Invasive species continue to be a worldwide threat to ecosystems mainly as a cause for biodiversity loss.Forest ecosystems,for example,are subject to a change in species composition due to the invasion of exotic species.specifying the attributes that cause the strong competitiveness of several exotic species may improve the ability to understand and effectively manage plant invasions in the future.In this study the following hypotheses were tested:(1)biomass production of below-and aboveground plant compo-nents of the exotic tree species is higher than that of the natives,resulting in a higher competitiveness of the exotics;(2)the exclu-sion of root competition has a positive effect on the biomass pro-duction of the inferior native species;and(3)mixtures of native and exotic species yield a higher biomass production than the respective monocultures.Methods a pot experiment,containing about 2000 tree seedlings,was established.We investigated the biomass productivity and growth reactions of two native(Quercus robur l.,Carpinus betulus l.)and two exotic tree species(Prunus serotina Ehrh.,Robinia pseudoacacia l.)in different intra-and interspecific,competitive situations with and without the influence of root competition.Important Findingsthe biomass production of both exotic species was significantly higher and led to a strong competitive advantage,resulting in a biomass decrease of the less competitive native species.the high belowground biomass of both exotic species had a negative effect on the biomass production.the competitive pressure of exotic tree seedlings on the native ones was largely driven by root competition.Furthermore,mixtures of native and exotic tree species had a higher productivity than their growth in monocultures would have predicted.Competition was lower for exotic species in mixtures with the less productive native species compared to the competition in monocultures or in mixture with the other highly productive exotic species.accordingly,both highly competitive exotic species produced less biomass in mixture with each other compared to monocultures.Despite the significantly higher biomass of P.serotina in all mixtures and in monoculture,R.pseudoacacia seemed to be the dominating species.Due to its strong root competition,R.pseudoacacia significantly reduced the biomass production of P.serotina.