Chemical Composition of Industrial Effluents and Their Effect on the Survival of Fish and Eutrophication of Lake Hawassa, Southern Ethiopia

Abstract

Growing trends in industrialization in Ethiopia have raised concerns about pollution of water bodies particularly of lakes. This study was therefore conducted to 1) characterize the chemical contents of major industrial effluents (namely textile ceramic and soft drink factories) that reached Lake Hawassa and 2) investigate the effects of the above mentioned factory effluents on survival of larvae fish and growth of algae. Effluent samples were collected from the outlet lagoons of each factory in December, 2009. Then, effluent samples were analyzed for total N, NO3-N, NH4-N, S 2− , − 2 4 SO , − 3 4 PO , COD, total dissolved solids (TDS) and heavy metals at the federal Environmental Protection Agency (EPA) Laboratory, Addis Ababa. The experiments on the impact of effluents on survival of fish larvae and growth of algae were conducted using six concrete paved ponds (with different concentration of effluent). The results of chemical analysis showed that textile effluent had high COD (nearly 3 times higher), TDS (19 times higher) as well as − 3 4 PO (39 times higher) than the maximum permissible limits (MPL) set by Environmental Protection Authority (EPA). Among heavy metals, Zn and Fe of textile effluent were much higher (41 and 1.5 times higher, respectively) than the MPL set by EPA. Ceramic effluent also contained high concentration of − 3 4 PO (24.5 times), S 2− , − 2 4 SO (2 times) and Zn (14 times) exceeding the limit of EPA. Regarding soft drink factory, high values of COD, − 3 4 PO and Zn were found in the effluent than the limit specified * Corresponding author. B. Berehanu et al. 793by EPA. The biological treatment lagoons of the respective source were not effective since the effluents were taken from the last treatment lagoon (outlet lagoon) and some of the measured parameters were higher than MPL. Results of the pond experiment showed that 5%, 10% and 20% concentration levels of the HTF effluent killed significantly high proportion of the fry (65%, 86.8% and 88.7%, respectively). In contrast, fry mortality in ceramic and soft drink effluent treatments, even at 10 and 20% concentration levels, stayed nearly below 10%, which were not far off from the mortality of the control groups. Algal biomass in the treated ponds varied with the type of effluent treatment and concentration level. Compared with the first day, chlorophyll "a" concentration measured on the 7 th day had increased by 51%, 48%, 74%, 27% and 31% at 0%, 1%, 5%, 10% and 20% concentrations, respectively of textile effluent. The 5% treatment level of textile effluent caused the highest rate of algal growth above the growth rate observed in the control pond, but further increased in concentration to 10% and 20% resulted in a lower growth of algae than in the control pond. Therefore, textile effluent may boost up algae growth at lower concentrations (~5%) but at higher concentration levels its toxic effect may become inhibitory. Regarding the effluent of soft drink factory, algal growth progressively diminished with increasing concentration of the...

Water quality problems, related challenges and their impacts on Ethiopian fishery

“…The evidence is, the effects of textile factory effluents (5, 10 and 20% concentration levels) on the survival of tilapia fish fry killed high proportions of fish (65, 86.8 and 88.7%, respectively) compared to 16.1% mortality at 1% concentration level of the textile effluent. However, this is not quite different from that of the mortality rate in the control pond containing lake water of 9.4% (Berehanu et al, 2015). Besides, the consumption of the African big barb Labeobarbus intermedius whose catch is mainly from the rift valley lakes like Lake Hawassa and Lake Koka has declined.…”

“…The effluents from the textile factories contain high amount of organic and inorganic chemicals and are attributed to high Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Dissolved Solids (TDS), pH, Total Suspended Solids (TSS) values, and low dissolved oxygen (DO) values as well as the color change of the given water body as reported by Abrehet et al (2015). These make the textile industries one of the main sources of water pollution problems (Berehanu et al, 2015). For instance, a study made in Blue Nile River with respect to water quality parameters showed that the mean value of dissolved oxygen (DO) ranged from 3.7 mg/L at the site of waste water outlet of the Bahir Dar textile factory (Abrhet et al, 2015).…”

“…In other words, the water quality parameters such as salinity and turbidity reveal increasing trends due to anthropogenic activities within the catchments and having drastic effect on fish production (Utaile and Sulaiman, 2016). Various studies have been conducted on human activities and their impacts in Ethiopian water bodies (Yohannes et al, 2013;Worako, 2015;Berehanu et al, 2015) such as Lake Hawassa (Utaile and Sulaiman, 2016), Lake Chamo, (Desta et al, 2015;Desta et al, 2017), Lake Ziway (Goshu and Aynalem, 2017;Gebremedhin et al, 2018), Lake Tana, (Abrehet et al, 2015), Blue Nile River (Minuta and Jini, 2017), and Walleme River Southern Ethiopia (Figure 1). Good water quality plays an important role in wild fishes and aquaculture development in the country (Utaile and Sulaiman, 2016).…”

Evaluation of the current water quality of Lake Hawassa, Ethiopia

“…However, in the present study the concentration of these metals exceeded WHO limit for drinking purpose. These might be due to the accumulation of these metals into the lake through effluent discharge from ceramic, textile and leather tanning industries located along the streams that fed into Tikurwuha River (Berehanu et al, 2015).…”

Wastewater Management Techniques: A Review of Advancement on the Appropriate Wastewater Treatment Principles for Sustainability

“…BOD) which can serve as "food" for microorganisms in the receiving body (Al-Mohammed et al, 2013;Ikhajiagbe et al, 2014;Rop et al, 2014). Microorganisms combine this matter with oxygen from the water to yield the energy they need to thrive and multiply; unfortunately, this oxygen is also needed by fish and other organisms in the river (Berehanu et al, 2015). Heavy organic pollution can lead to "dead zones" where no fish can be found; sudden releases of heavy organic loads that can cause sudden fishkills (Cuvin-Aralar et al, 2001;Stephanie et al, 2013).…”