Response of Primary Producers (Chlorella and Dunaniella Spp) To Soot Deposits on Water Bodies.

Abstract

Soot (black carbon) is essentially the by-products of incomplete combustion of carbon and substances that contains carbon.  Soot is a fine powdery mass of carbon and is regarded as an impure carbon derived from incomplete combustion of substances that contain carbon like hydrocarbon especially the polyaromatic hydrocarbons and air pollution is a growing cause of morbidity and mortality globally. Nigeria is confronted with rising air pollution concerns due to activities of extractives, industrialization and high population growth rate. Soot, as one of the major air pollutants has been an issue of concern for some years due to the harms it poses on the environment and public health. Therefore, this experimental study was carried out to compare the effect of soot on two microalgae species, Chlorella vulgaris and Dunaliella salina. The Toxicity test was carried using different concentrations of the soot on the isolates. The result of this study brings to light the danger of higher concentration of soot in the environment as the microalgae which serves as biomarker were inhibited by the pollutant, soot. The effect of soot on growth of Chlorella vulgaris in relation to the time of the study showed a maximum growth of chlorella after 28 days occurred in the Control sample with no soot application This was distantly followed by the sample with 0.1 % soot inoculation. This trend was observed in the samples inoculated with 0.2 % and 0.4 % soot. In the sample inoculated with 0.8 %, growth was observed from Day 0 to Day 14 after which the growth remained constant through Day 28. However, in the sample inoculated with 1.0 % soot, decline in growth was observed after the day to day 28 of the study. The effect of soot on growth of Dunaliella saliina over the time of study recorded a steady growth rate from Day 0 to Day 28 of the control sample which had no soot application. This  growth pattern was observed in all other samples except that with 1.0 % where  a slow growth  rate was observed from day 0 to day 21 which was followed by a decline growth of Dunaliella Selina observed on day 28.  The adverse effect of the soot on the Isolates (Chlorella and Dunaliella) as revealed by this study serves as an alert to the potential danger of soot to human and the environment at large. The higher inhalation of soot by human over a long period of time can result in serious health challenges. Therefore, there is a critical need to investigate identified sources of soot and mitigate possible impact. Public health campaigns should be launched for adequate risk communication on the adverse effects of soot, with attention given to gender-sensitive messages. Relevant authorities should develop stringent policies to prevent soot pollution and improve access to appropriate services to address the health effects.