Experimental assessment of potentially toxic metals and nutrient content at various morphological parts of two economic plants grown on spent engine oil (SEO) treated soils.

Metals interact with nutrients in plants grown on spent engine oil (SEO) soils; thus, relationship of metals and nutrients in several morphological parts of economical plants cultivated on SEO soils using a 3 × 4 factorial and a totally randomized design is documented. The polluted-vegetated soils were SEO treated at 0, 2, 4, 8% v/w and planted T. paniculatum and T. fruticosum separately. Before treatment, SEO tested positive for Cd, Zn, Pb, Cr, Cu, Fe and Ni, while at treatment, non-vegetated soils accumulated Pb, Cu, Zn, Ni, Fe. The T. paniculatum on SEO had more Cd among plants. ANOVA indicated significant (P < 0.05) relationship between metals, SEO and treated soils. A Post hoc indicated Fe and Pb levels differed significantly across SEO vegetated soils, while PCA suggests treated plant roots and leaves accumulated more of the toxic metals. These plants parts should not be consumed from SEO-polluted areas.

Prevalence of integrons in multidrug-resistant Escherichia coli isolates from waters and vegetables in Nsukka and Enugu, Southeast Nigeria.

Irrigation of fresh produce with poorly treated wastewater or contaminated freshwater sources can lead to produce contamination and foodborne illnesses, as well as the dissemination of antimicrobial resistance determinants. In this study, we assessed the presence of integrons in multidrug-resistant Escherichia coli isolated from the University of Nigeria, Nsukka Wastewater Treatment Plant effluent, tap water, vegetables from irrigated gardens and vegetables sold in selected markets from Nsukka and Enugu cities. E. coli was isolated following standard laboratory procedure and confirmed through beta-glucuronidase (uidA)-targeted polymerase chain reaction (PCR). The antibiotic resistance of the isolates was determined using Bauer-Kirby disk diffusion assay, and multiplex PCR was used to determine the presence of class 1 and 2 integrons. Our result revealed a total of 188 E. coli isolates from WWTP effluent (n = 41), tap water (n = 10) and vegetables from greenhouse (n = 46), farms (n = 55) and market (n = 36). Multidrug resistance was detected in all the isolates, ranging from three-drug resistance in a single isolate to 7-drug resistance patterns in two different isolates. Of the total isolates, class 1 integrons were abundantly detected in 175 (93.1%) and class 2 in 5 (2.7%). All the class 2 integrons were found in isolates that were positive for class 1. The abundance of multidrug-resistant E. coli harbouring class 1 integrons in the effluent and vegetable samples is a potential public health risk. Therefore, the appropriate measures for the safe use of poorly treated wastewater for vegetable farm irrigation are required to be put in place to reduce the microbial load of the discharged effluent. Also, education of farmers and the community on the dangers of wastewater effluent-grown plants and proper methods for cleaning harvested vegetable is recommended.