中文摘要：

采用室内培养实验,首先用0~300μg·L-1砷酸盐[As(Ⅴ)]处理钝顶螺旋藻(Spirulina platensis),分析了螺旋藻对As(Ⅴ)的吸附和吸收特性,并在300μg·L-1 As(Ⅴ)处理下,研究了不同磷浓度(P正、1/10 P正、1/25 P正、1/50 P正)对螺旋藻吸附、吸收和转化As(Ⅴ)的影响。结果表明,在本研究As(Ⅴ)处理范围内,螺旋藻的干重与对照没有显著差异。随着As(Ⅴ)浓度的升高,藻体富集的总砷含量增加,当As(Ⅴ)处理浓度为150~300μg·L-1时砷富集量为1.006~1.569 mg·kg-1,超过了国家保健(功能)食品的砷污染限量1.0 mg·kg-1(GB 16740—1997)。随着培养基中磷浓度的降低,螺旋藻体内吸收的砷含量呈现增多趋势。在正常磷(P正)和1/10 P正条件下,螺旋藻体内的砷均为As(Ⅴ);当磷浓度降低至1/25 P正时,藻细胞中的砷有3.28%为As(Ⅲ);当磷浓度降低为1/50 P正时,螺旋藻吸收的砷增加至1.457 mg·kg-1,其中有9.24%和37.35%分别转化为As(Ⅲ)和二甲基砷(DMA),表明降低培养基中磷浓度促进了螺旋藻体对As(Ⅴ)的吸收、还原和甲基化,但藻细胞中砷的主要形态仍为As(Ⅴ)。在正常磷浓度培养下,藻体富集的砷以藻细胞表面吸附为主,通过磷酸盐缓冲液脱附可去除95%以上螺旋藻富集的砷。

英文摘要：

Arsenic(As)accumulation in Spirulina platensis may reduce the quality of health products produced from this microalga. Phos-phorus(P)may influence the algal uptake and biotransformation of As. Thus it would be possible to reduce the accumulation of As in algae by manipulating P concentrations in growth media. To test this, we first sat up an experiment to examine the As(Ⅴ)adsorption and absorp-tion characteristics of S. platensis under 0~300μg·L-1 As(Ⅴ), and then conducted another experiment to study the effects of normal and low P levels on the As(Ⅴ)uptake, adsorption and biotransformation by S. platensis at 300μg·L-1As(Ⅴ). Algal biomass was not signifi-cantly affected by As(Ⅴ)treatments, compared with the control. However, arsenic accumulation increased with As(Ⅴ)levels in the growth media. At 150~300 μg·L-1 As(Ⅴ), S. platensis contained 1.006 to 1.569 mg·kg-1, which exceeded the national standard(GB 16740-1997)for health(functional)foods(1.0 mg·kg-1). The As absorption was reduced by increasing P concentrations. At P levels of 1/10 normal or higher, P did not change As speciation in S. platensis, whereas only 3.28% of As was transformed to As(Ⅲ)at 1/25 normal P level. When P concentration was lowered to 1/50 of normal P level, As uptake increased significantly to 1.457 mg·kg-1, of which 9.24% and 37.35%were converted to As(Ⅲ)and DMA, respectively. In conclusion, decrease in P supply promoted the uptake, reduction and methyla-tion of As(Ⅴ), though As(Ⅴ)was still the main As species in the microalgae. The majority of As was adsorbed on the surface of algal cells, suggesting that more than 95%of As in the S. platensis could be removed by washing with phosphate buffered saline(PBS)solution.