Evaluation of Toxicity on Ctenopharyngodon idella Due to Tannery Effluent Remediated by Constructed Wetland Technology

Abstract

Aquatic pollution caused by industrial effluents is an environmental issue, imposing deleterious impacts on the overall environment, specifically, on humans, by disrupting the balance of the ecosystem. Among all the industries, tanneries are considered some of the most polluting due to heavy use of toxic organic and inorganic compounds during leather processing, most of which find their way into rivers, lakes, and streams, thus exerting adverse effects on aquatic life, particularly on fish. Considering the huge concentrations of pollutants present in tannery effluents, toxicity evaluation is of prime importance. Therefore, bioassays are usually employed to assess the acute toxicity of industrial effluents and efficiency of effluent clean-up technologies as they provide a thorough response of test species to the substances present in the tested media. In the present study, the toxic effects of tannery effluent on common grass carp (Ctenopharyngodon idella) were studied for 96 h in laboratory conditions. The effluent was added at different concentrations, before and after treatment by constructed wetlands (CWs). During this period, mortality data was collected to calculate the 96 h-LC50 (lethal concentration inducing 50% mortality) and acute toxicity of C. idella. In addition to this, observations on change in morphological, physiological, and behavioural patterns were also made every 24 h. The present toxicity assay revealed that the raw tannery effluent changed the morphology, physiology, and behavioural response of fish. Moreover, fish exposure to raw/untreated effluent caused high acute toxicity and 100% mortality, due to the presence of high concentrations of salts and chromium (Cr) metal. While treatment of tannery effluent by CWs vegetated with different plants (B. mutica, L. fusca, and T. domingensis) significantly reduced its toxicity and fish mortality as well, and inoculation of salt and Cr-tolerant endophytic bacteria (Enterobacter sp. HU38, Microbacterium arborescens HU33, and Pantoea stewartii ASI11) further reduced (up to 90%) its toxicity level. Hence, the use of CWs for tannery effluent treatment can be recommended to favour public health and promote the overall safety of the environment.

Histopathological analysis of selected organs of Oreochromis niloticus due to sub-lethal industrial effluents exposure

“…Similarly, Nagarajan (30) found that when effluent concentrations increased, muscle tissue began to deteriorate. Many researchers have investigated the effect of various contaminants on the muscles of fish have identified histological abnormalities in the muscles of the analyzed fish (41); (42) and (36).…”

Investigating degradation metabolites and underlying pathway of azo dye “Reactive Black 5” in bioaugmented floating treatment wetlands

“…Fish showed more behavior changes, such as liveliness, sense of balance, opercular motion, swimming velocity, sideways movement, frontward motion with the posterior side up, and motion in a circular fashion with jerks when exposed to untreated waters (C1 and C2) as compared to the treated waters (T1 and T1*) (Table 3). Earlier studies also reported that biological treatments, including phytoremediation, reduced the toxic effects of the pollutants present in the water (Ashraf et al 2020;Shehzadi et al 2014, Tara et al 2019b). Moreover, sh showed more changed behavior in the treated water (T1*) initially having RB5 concentration of 1000 mg L − 1 as compared to the treated water (T1) initially having a concentration of 200 mg L − 1 of RB5.…”

“…Toxicity of untreated and treated waters was tested using Labeo rohita (a freshwater dwelling sh) as reported earlier (Ashraf et al 2020). Treated water (twenty liters) by different treatments (C1, C2, T1, and T1*) were put in each clean glass aquarium (in triplicates), as per the experimental design.…”

“…Behavioral responses, such as liveliness, sense of balance, opercular motion, swimming velocity, sideways movement, frontward motion with the posterior side up, and motion in a circular fashion with jerks, were evaluated through visual observation (Ashraf et al 2020).…”

Bioremediation of Diesel Contaminated Marine Water by Bacteria: A Review and Bibliometric Analysis

“…The use of oil and petroleum derivatives in many industrial sectors generates saline wastewater with high organic contaminants. Some examples of organic contaminants are phenols, aromatic hydrocarbons, nitroaromatics, and azo dyes [14].…”