An assessment of the physicochemical properties and toxicity potential of carwash effluents from professional carwash outlets in Gauteng Province, South Africa

Abstract

The assessment of the quality of carwash effluents has received scant attention as a potential source of public and environmental health hazard in South Africa as demonstrated by the lack of literature in this subject. The physicochemical quality and potential ramifications of carwash effluents on receiving waterbodies were investigated in this study. Grab effluent samples were collected from six carwash outlets in Gauteng Province of South Africa and analysed for selected physicochemical qualities including biological oxygen demand (BOD), oil and grease, total petroleum hydrocarbons-gasoline range organics (TPH-GRO), pH, dissolved oxygen (DO), total solids (TS) and total dissolved solids (TDS), electrical conductivity (EC), nutrients (nitrates, nitrites and phosphates), anionic surfactants and heavy metals (zinc [Zn], copper [Cu], lead [Pb] and chromium [Cr]). Further, the toxicity potential of the effluent samples was assessed using organisms from four trophic levels ranging from Selenastrum capricornutum (primary producer), Daphnia magna (primary consumer), Poecilia reticulata (secondary-tertiary consumer) and Vibrio fischeri (decomposer). High pollutant levels were observed in all effluents with BOD ranging from 27±2.1 to 650±4.9 mg/l, TDS from 362±8.5 to 686±8.5 mg/l, GRO-TPH from 0.01±0.0 to 7.6±0.2 mg/l, DO from 0.0 to 0.1 mg/l, Zn from 0.79±0.08 to 20±2.12 mg/l, Cu from 0.77±0.03 to 13±0.71 mg/l and oil and grease from 12±2.8 to 43±2.1 mg/l. Ammonium concentrations ranged from 0.4±0.1 to 75±6.4 mg/l; turbidity from 109±0.7 to 4000±29.7 mg/l, anionic surfactants from 1.4±0.1 to 5.8±0.3 mg/l and TPH from < 0.01 to 7.6 mg/l. Toxicity assessment assays resulted in 100% mortality for fish and Daphnia after 96 and 24 h respectively and significant bioluminescence and growth reduction in Vibrio fischeri and algae after 15 min and 72 h respectively. Most of the measured physicochemical parameters were in concentrations above the Environmental Management Agency (EPA) stipulated guidelines. Additionally, the effluents demonstrated acute toxicity against all four test species.

Potential biotechnological capabilities of cultivable mycobiota from carwash effluents

“…However, to our knowledge, this is the first study to not only report on the existence of fungi in carwash effluents but to also characterize such fungi and profile their secondary metabolites. Since carwash effluents are characterized by high concentrations of heavy metals, polycyclic aromatic hydrocarbons, and detergents (Tekere et al, 2016), it follows that the presence of fungi in such environments underlines their potential as agents of biore- T A B L E 2 Hydrocarbon utilization and enzyme production profiles of the fungal isolates industry, detergent industry, cosmetic industry, biodiesel production as well as in organic chemistry (Andualema & Gessesse, 2012). Because of their broad applications in enzyme technology, research aimed at discovering microbial producers of lipases and other enzymes from previously unexplored environments should be encouraged.…”

“…However, to our knowledge, this is the first study to not only report on the existence of fungi in carwash effluents but to also characterize such fungi and profile their secondary metabolites. Since carwash effluents are characterized by high concentrations of heavy metals, polycyclic aromatic hydrocarbons, and detergents (Tekere et al., ), it follows that the presence of fungi in such environments underlines their potential as agents of bioremediation of environments polluted by any of these pollutants. The excellent potential of fungi to immobilize toxic metals by a number of means among them the formation of insoluble metal oxalates, biosorption and/or chelation onto melanin‐like polymers has previously been reported (D'Annibale, Rosetto, Leonardi, Federici, & Petruccioli, ).…”

“…Carwash facilities produce and discharge effluents that are characterized by high levels of polycyclic aromatic hydrocarbons (PAHs), heavy metals, high biochemical oxygen demand (BOD) and chemical oxygen demand (COD), and detergents. These effluents have demonstrated toxicity against bacteria ( Vibrio fischeri ), daphnia ( D. magna ), algae ( Selenastrum capricornutum ) and fish ( Poecilia reticulata ) (Tekere, Sibanda, & Maphangwa, ). Onsite carwash effluent holding tanks therefore constitute stressed environments which, analogous to natural extreme environments, could be sources of novel mycobiota or mycobiota with potential for production of novel, biotechnologically relevant molecules.…”

Investigating Industrial Effluent Impact on Municipal Wastewater Treatment Plant in Vaal, South Africa

“…Generally, carwash effluent (Industry 4 ) contains a number of contaminants such as sand/dust, salt, oils, grease, organic matter and metal ions that may also influence the resultant wastewater pH, TDS, EC, salinity and heavy metal composition [30,31]. Similar to our finding, other studies have reported that significantly higher EC, TDS and salinity occur during months of low precipitation (such as winter in South Africa), as increased evaporation leads to a more concentrated effluent [32][33][34].…”

Industrial Effluents Harbor a Unique Diversity of Fungal Community Structures as Revealed by High-throughput Sequencing Analysis

“…Industrial effluents are characterized by a complex and variable composition of organic and inorganic pollutants including strong acids, metallic ions, and polyaromatic hydrocarbons (PAHs) [1,2], representing a major source of surface and underground water pollution in many countries [3]. Also, these pollutants have the potential to exert selective pressure on microbial communities found therein.…”