Phytoremediation ability of Panicum maximum and Salicornia europaea irrigated with treated wastewater for salt elements in the soil

Abstract

Soil salinity is one of the major problems that threaten the soils in Jordan, which led to a decrease in the percentage of arable land in Jordan. The phytoremediation process is concerned with the restoration of contaminated soils using tolerant plants, such as halophyte plants. In this context, the potential short term phytoremediation ability of Panicum Mombasa and Salicornia Europaea was evaluated and measured. A field experiment was conducted over two consecutive years to study the ability of these previous two crops for the phytoremediation of saline soils induced by treated wastewater irrigation. Both crops with bare soil as a control were irrigated together from the effluent of the Ramtha Wastewater Treatment Plant at the same time. Soil electrical conductivity was identified as the main parameter for measuring the plant’s ability for salt absorption. The results for both seasons show a higher accumulation of salts in bare soil significantly as expected since no plants were present to absorb these salts and no leaching requirements were added with irrigation water. The absorption rate for each crop was measured at the 1st season for comparison. It measured for each crop depending on the length of the growing season. Salicornia’s absorption rate was greater than Panicum, and it reached 36 ppm/day for salicornia, whereas it reached 33 ppm/day for panicum. In the 2nd season, both crops are planted and harvested together. Salt absorbed percentage from the soil under Salicornia was greater than Panicum and it reached 73 % as compared to bare soil. However, in the soils under Panicum, the amount of salts absorbed reached 37 % as compared to bare soil. Plant analysis for both crops shows higher salt ions accumulation in Salicornia tissues than Panicum, and this explains the higher absorption rate for Salicornia than Panicum. Microbiological analysis for Panicum shows some contamination, whereas no contamination occurs in Salicornia. This is explained by the high salinity environment in Salicornia which is not favorable for e-coil, total, and fecal coliform to grow. Obtained Results from this research state that both crops have the ability for phytoremediation, with greater ability for Salicornia.