Field testing phytoremediation of organic and inorganic pollutants of sewage drain by bacteria assisted water hyacinth.

The study was carried out to identify the potential of phytoremediation within a flowing drain through Eichhornia crassipes in combination with two bacillus species to treat the inorganic and polycyclic aromatic hydrocarbons (PAHs) from industrial effluent at Kala Shah Kaku (KSK), Lahore, Pakistan. Results showed that the highest metals removal efficiency was found in Cr, Pb, Ni, and Cu as 72.4, 83.3, 82.35, and 63.63%, respectively. However, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) removal efficiencies were also considerably higher (66.66 and 66.67%). The BOD, COD, sulfates, phosphate, and total dissolved solids (TDS) showed a higher reduction rate as 1442.7, 1967.3, 1148.2, 7225.4, and 911.5 g m-2 d-1, respectively. Chlorophyll a + b and carotenoid contents were decreased from 7.92 to 5.78 mg kg-1, 3.03 to 3.01 mg kg-1, respectively and total nitrogen was increased from 22 to 27 mg kg-1 in E. crassipes. Bio-concentration factor was higher for all metals and the maximum was found in Cr (<1). The reduction efficiency of Æ©PAHs was found up to 60% with different rings structure. The use of Bacillus safensis strain showed the higher percentage reduction for BOD, nitrates, sulfates, and phosphates. The Study provide practical reference for bacterial assisted phytoremediation of urban drain.

Critical risk analysis of metals toxicity in wastewater irrigated soil and crops: a study of a semi-arid developing region.

Toxic elemental exposure through consumption of contaminated crops is becoming a serious concern for human health. Present study is based on the environment and health risk assessment of wastewater irrigated soil and crops in a semi-arid region Faisalabad, Pakistan. The concentrations of potentially toxic elements (Cu, Cr, Mn, Fe, Pb, Zn, Ni) were analysed by atomic absorption spectrometer in five different crops (Corn, rice, wheat, sugarcane and millet), while, their topsoil's and multi targeted risks analysis were assessed. Results showed, the mean values of Pb and Zn were higher in crop than Food and Agriculture Organization guidelines for food additives and contaminants. A strong positive correlation was found among wastewater and crop's toxic metals (r2 values in Cu, Zn, Pb, Ni and Cr were 0.913, 0.804, 0.752, 0.694, 0.587 respectively). Whereas, a strong correlation was also found among soil and wastewater lead (r2 = 0.639). The calculations of Nemerow Integrated Pollution Index (NIPI) showed the soil samples maximum pollution limit (NIPI > 3) and Potential Ecological Risk Index (PERI) was found to be higher than maximum limit (PERI > 600) for all samples. While, for non-carcinogenic risk, Hazard Index (HI) values in adult were near threshold (HI > 1) for all crop samples. In children, the HI values for Corn, Rice and Wheat were above threshold limit and for Sugarcane and Millet, these were near to threshold. Cancer risk values for Cr found higher than safe limit (1 × 10-6) in adult and children for crop samples. Crop irrigation by wastewater irrigation is a prominent alternative option for water scarce countries, however prior testing and treatment of such wastewater streams must be employed to minimize the adverse impacts on human health and environment.