Quantitative modelling of Ostracod bioassay: assigning toxicity index to potentially chemical contaminated swimming pools.

One of the primary objectives of any public health programme is to design a protocol that will curtail a population from being predisposed to toxic substances in the environment. Biomarkers help in actualising such an objective by their potential to detect the presence of toxic substances in environmental media such as soil, water and air. The Ostracod Heterocypris incongruens, an already established biomarker for quality evaluation of freshwater, does not quantify toxicity. This work was aimed at modelling Ostracod bioassay as a quantitative whole-water toxicity assay (QWTA) for the determination of potentially chemical contaminated swimming pools. In this modelling approach, a pool water sample was deliberately contaminated with a mixture of Fenton reagent (FR) and Bonny light (BL) crude oil. The mechanism of toxic injury of this mixture is via oxidative stress-mediated superoxide ion and other free radicals. The mortalities and growth factors of the exposed freshly hatched Ostracods to the serial dilutions of the contaminated swimming pool water sample for 6 days were mathematically modelled to toxicity indices (Ti), which were used to construct the toxicity reference curve (TRC). A graph of the "toxic concentrations" of the serially diluted contaminated pool water sample against Ostracod mortality was plotted. The TRC and the linear graph constitute the "Ostracod-linked mathematical model". Against the reference mortality ≤ 20% of the Ostracods, the toxicity index based on the model prediction is ≤ 32.5, and this signifies "no observed toxic effect" for toxicity values below 32.5 units. Using this model, toxicity indices were calculated for 5 randomly selected swimming pools in the study area. The results showed that the outdoor pool SP 5 has a toxic index of 49.0, while outdoor pools SP 2 and SP 3 each has a toxic index of 42.5. The indoor swimming pool (SP 4) and Standard water (control) have zero toxicity, thus suggesting that that the outdoor pools SP 2, SP 3 and SP 5 were possibly contaminated by chemicals from extraneous sources while contamination of SP 1 was very much negligible, hence the "no observed toxic effect".

Risk assessment of the anthropogenic activities (quarrying) and heavy metal profile in mining environment.

The need to generate internal revenue by most individuals and government in Nigeria has led to the establishment of quarries in different parts of Ebonyi state of Nigeria. This study was aimed at determining the risk associated with the heavy metal burden in the state. Soil samples from the quarrying environments designated as MS1, MS2, and MS3 were analyzed for the metal profile using inductively coupled plasma optical emission spectrometry (ICP-OES). The result showed that the mean concentration of metals which is a representation of the whole sites showed a higher concentration of Ca (40.065 ± 1.011 ppm), Mg (12.450 ± 8.815 ppm), K (16.631 ± 14.670 ppm), and Mn (19.539 ± 3.225 ppm) while Na (1.326 ± 0.117 ppm) was low. The heavy metal profile showed Pb (0.120 ± 0.027 ppm), Fe (27.718 ± 1.523 ppm), Zn (2.227 ± 0.570 ppm), Cu (6.267 ± 1.402 ppm), Ni (1.856 ± 0.472 ppm), Mo (1.758 ± 0.258 ppm), Cd (0.023 ± 0.006 ppm), Cr (0.037 ± 0.011 ppm), etc. Hg was found to be below detectable limit while the Cs was not radioactive. The mean values were found to be lower than the permissible limit of each metal. The pollution index (PI) was calculated for the different sites, and the result reveals that MS3 (0.0426) had a higher PI when compared to MS1 (0.0341) and MS2 (0.0317). Therefore, the PI of the sites showed MS3 > MS1 > MS2. These results showed that the environment is still as safe as PI < 1. The geoaccumulation index also showed a safe environment since its values were less than 0 which means that the environment is practically uncontaminated. Other risk determining parameters showed that the three locations were still within a safe level. Although the results of the study have shown a safe environment, it is still necessary to keep close monitoring of the heavy metal profile of the environment, since these metals can bioaccumulate in living tissues with time.

Biotechnological tools for environmental sustainability: prospects and challenges for environments in Nigeria-a standard review.

The environment is a very important component necessary for the existence of both man and other biotic organisms. The degree of sustainability of the physical environment is an index of the survival and well-being of the entire components in it. Additionally, it is not sufficient to try disposing toxic/deleterious substances with any known method. The best method of sustaining the environment is such that returns back all the components (wastes) in a recyclable way so that the waste becomes useful and helps the biotic and abiotic relationship to maintain an aesthetic and healthy equilibrium that characterizes an ideal environment. In this study, the method investigated includes biological method of environmental sustainability which seeks to investigate the various biotechnological tools (biotools) in current use and those undergoing investigations for future use.

Environmental pollution levels of lead and zinc in Ishiagu and Uburu communities of Ebonyi State, Nigeria.

Water and soil samples from the area were therefore analyzed for their lead and zinc content. Computation of pollution statuses of lead and zinc revealed topsoil lead geoaccumulation indices of -0.143 and -0.069 and zinc geoaccumulation indices of 1.168 and 0.713 for Ishiagu and Uburu respectively. The pollution indices were determined to be 0.499 and 0.3564 for soil in Ishiagu and Uburu respectively and also 5.11 and 2.42 for water in Ishiagu and Uburu communities respectively. Water/soil concentration ratio were found to be 0.0018 and 0.0014 for lead in Ishiagu and Uburu respectively. On the other hand, the water/soil concentration ratio for zinc was computed to be 0.001 and 0.0008 for Ishiagu and Uburu respectively. These results seem to suggest that the pollution of the environment by these heavy metals in the areas were as a result of the water being contaminated by lead and zinc not necessarily their concentrations in the soil.