Water samples were collected on a monthly basis at three locations along the north-south axis of the lake at 1 m depth intervals for 1 year. A sedimentation technique was used for microscopic examination of the samples. The monthly mean and seasonal phytoplankton densities were calculated. The original data were square-root transformed, and analysis of variance performed with SPSS version 10.0. The significant treatment effects were determined using Fisher's least significance difference at the 5% probability level. The mean phytoplankton population per millilitre was very high for the entire sampling period. There was a phytoplankton bloom formation in the early rainy season, with the mean total phytoplankton population density for the rainy season (April-October) being significantly higher than that of for the dry season (November-March). A population increase was observed during the late part of the dry season to the early part of the rainy season. During the rainy season, Chlorophyceae (mostly desmids) were most abundant, followed by Cyanobacteria, Bacillariophyceae, Euglenophyceae, Dinophyceae, Cryptophyceae, Chrysophyceae and Xanthophyceae, in decreasing order of abundance. This order changed slightly in the dry season, when there was relative abundance of Bacillariophyceae over Cyanophyceae, and Dinophyceae over Euglenophyceae. The low population of Euglenophyceae indicates that the organic pollution is still low, with the predominance of desmids, indicating an oligotrophic lake condition.

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Agriculture around Nike lake uses fertilizers. Fertilizers are known to cause eutrophication of water bodies and associated algal blooms whose consequences may be deleterious to the environment and man. We investigated ex situ to assess the effect of the nutrients on the algal flora and show the impact of farm land runoffs on aquatic environment. The lake water was analysed for initial nitrogen, phosphorus and potassium; and algal content using standard methods. The fertilizer sources used by the farmers—NPK (20:10:10 and 15:15:15); urea and poultry drops, were used in the study to enrich the lake water in concentrations of 0.2, 0.4, 0.6, 1.0 and 2.0 g/L in three replicates respectively. A control was set up without the fertilizer sources and the set up was left on a laboratory bench and monitored for 36 days. Cyanobacteria (blue green algae), Chlorophyta (green algae) and Bacillariophyta (diatoms) were encountered and their population increased with time and increase in concentration of fertilizers. The following taxa were encountered—Gloeocapsa, Anabaena, Oscillatoria (blue-green algae); Chlorella, Chlamydomonas, Spirogyra, Closterium, Pediastrum, Ankistrodesmus, Selenastrum, Scenedesmus, Staurastrum (green algae); Pinnularia and Navicula (diatoms) some of which are notable bloom forming species

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41In spite of treated wastewater presenting itself as an attractive alternative to scarce quality water 42 in the developing countries, the associated contamination of fresh produce by irrigation waters 43 leading to outbreak of foodborne illnesses is on the rise. Horizontal transfer of integrons play 44 important role in the spread and maintenance of antimicrobial resistance among strains of 45 Escherichia coli. This study assessed the effluents from the University of Nigeria, Nsukka 46 Wastewater Treatment Plant (UNN-WWTP) as well as vegetables irrigated with the effluent, and 47 vegetables sold in selected markets from Nsukka and Enugu cities for the presence of E. coli and 48 determined the prevalence integrons in multidrug-resistant isolates. Isolation of E. coli was done 49 using eosin methylene blue agar and isolates subjected to Gram staining for identification of 50 presumptive colonies. Confirmation of E. coli was achieved by polymerase chain reaction (PCR) 51 technique, targeting beta-glucuronidase (uidA). Resistance to antibiotics was determined using the 52 Bauer-Kirby disk diffusion assay and the Clinical and Laboratory Standard Institute criteria.53Integrons were detected by multiplex PCR using primers specific for class 1 and 2 integrons. A 54 total of 178 E. coli isolates were obtained from WWTP effluent (41), and vegetables from 55 greenhouse (46), farms (55) and market (36). Multi-drug resistance was detected in all the isolates, 56 ranging from five-drug resistance in a single isolate to 16-drug resistance patterns in two different 57 isolates. Of the total isolates, class 1 integrons were abundantly detected in 175 (98.3%) and class 58 2 in 5 (2.8%). All the class 2 integrons were found in isolates that were positive for class 1. The 59 high detection of E. coli in the studied effluent and vegetables pose potential public health hazards 60 heightened by observed multidrug resistance in all the isolates and the high prevalence of class 1 61 integron. It is concluded that the vegetable samples are significant reservoirs for potentially 62 pathogenic E. coli. Therefore, vegetable irrigation farming with unsafe water should be 63 discontinued, while appropriate improvement strategies to ensure compliance should be facilitated 64 without further delay. 65 66 Pathogenic Escherichia coli causes significant morbidity and mortality worldwide [1-3]. Reported 68 risk factors in the developing countries and sub-Saharan African regions include poor hygiene, 69 unsafe water, improper disposal of waste and faeces, and contaminated food, local beverages and 70 vegetables [2, 4, 5]. Vegetables can become contaminated with pathogenic and commensal 71 bacteria from animals and humans, during growth, harvesting, distribution, storage and processing 72 [6]. Although the contamination of fresh produce by irrigation waters has led to outbreak of 73 foodborne illnesses, yet treated wastewater presents itself as an attractive alternative to scarce 74 quality water in the developing countries. 75 E. coli has bee...