Australian Journal of Basic and Applied Sciences

May 2022


Using statistical analyses as a key for accurate metal phytoremediation assessment: a case study

Akpétou, K. L., Brou A. D., Sylla, T., Bahi, A. A., Dongui, B. K

ABSTRACT: Phytoremediation projects are frequently assessed upon the measured metal concentrations basis with regard to standards. Since these standards. Therefore, any to these references .Whereas data generated from samples must necessarily be statistically interpretated with regard to standards like the permissible limits. This study aimed to assess statistical significance of measured metal concentrations in four urbain plants analysis contribution to estimating metal phytoremediation capabilities from seewage of an invasive and characteristic flora in Daloa, Côte d’Ivoire. To do that, a tropical climatic dry season sampling of wastewater, sediments, and four plants (Oenothera biennis L., Eichhornia crassipes (Mart) Solms, Alternanthera philoxeroides (Mart.) Griseb, and Phalaris arundinacea L.) was conducted from december 2017 to february 2018. Samples were microwave assisted acid digested according to Huang and Schulte (1985) for multi-element analysis by ICP-MS. Data normality was Shapiro-Wilk’s checked for means comparison under t-student test. That test was used to check the significance of the measured plant metal contents with regard to the permissible limits of FAO/WHO (1996). Results obtained revealed that P. arundinacea, E. crassipes and A. philoxeroides globally bioaccumulated Cd, As, Cu, Cr, Zn, Hg, Ni, Pb and Mn ; with a restricted bioaccumulation activity toward As, Hg, Pb and Zn for O. biennis from the study metals. These metal concentrations were found to be below the permissible limits in absolute values. Hyperaccumulation was observed only in E. crassipes for Hg and Zn ; A. philoxeroides for Hg ; and P. arundinacea for As and Hg. However, t-student tests showed that the overwhelming measured plant metal contents were above the permissible limits. For instance, the O. biennis measured As content was 0.060 mg/Kg. That absolute value of As concentration is lower than 0.43 mg/Kg, the FAO/WHO (1996) permissible limit for that metal. A t-student test of means comparison displayed a p-value = 0.0058 (0.58%). It means that the null hypothesis (μ0) pointing out that O. biennis As content lower than the permissible limit must be rejected at 0.58% risk of error. This finding outlines an eventual misappreciation of those plant heavy metals phytoremediation capabilities wether the measured concentrations were only considerated. Therefore, that invasive macroflora can be used as a biotechnological tool for wastewater treatment in Daloa, and everywhere else where it can be found around the drainage systems.

[ FULL TEXT PDF 1-7 ] DOI: 10.22587/ajbas.2022.16.5.1