Assessing toxicities of industrial effluents and 1,4-dioxane using sulphur-oxidising bacteria in a batch test Anup Gurung 1 , Sang-Hun Kim 2 , Jin Ho Joo 1 , Min Jang 3 & Sang-Eun Oh 1 1 Department of Biological Environment, Kangwon National University (KNU), Chuncheon, Gangwon-do, Republic of Korea; 2 Water Environment Research Department, Watershed Ecology Research Team, National Institute of Environmental Research, Republic of Korea; and 3 Institute of Mine Reclamation Technology Korea, Mine Reclamation Corporation, Coal Center, Jongno-gu, Seoul, Republic of Korea Keywords effluent; environment management; hazardous waste; industry; legislation. Correspondence S.-E. Oh, Department of Biological Environment, Kangwon National University (KNU), 192-1 Hyoja-dong, Chuncheon, Gangwon-do 200-701, Republic of Korea. Email: ohsangeun@kangwon.ac.kr doi:10.1111/j.1747-6593.2011.00280.x Abstract In this study, the qualities of the final effluents from nine different industries (A, B, C, D, E, F, G, H and I) discharging 1,4-dioxane mainly as effluents were assessed using sulphur-oxidising bacteria (SOB) as a test micro-organism in batch mode. Results showed that effluent from industry ‘B’ was the most toxic of all the effluents tested, followed by E, C and A effluents. An EC50 value of 13% was obtained for effluent from B, whereas with E, C and A effluents, the EC50 values of 23%, 25% and 29% were found, respectively. Similarly, batch tests were performed in order to evaluate the potential for 1,4-dioxane to inhibit growth on SOB. The lowest test concentration of 1,4-dioxane (12 mg/L) resulted in 17% of inhibition of SOB, whereas the highest test concentration (3.125 mg/L) resulted in > 75% of the inhibition. An EC50 value of 0.105 mg/L was obtained for 1,4-dioxane. Introduction Discharge of effluents either from wastewater treatment plants or industrial sectors are primary sources of chemi- cals entering aquatic ecosystem (Gómez et al. 2001). Con- sequently, the contamination of soil and water resources (especially groundwater) with persistent organic pollut- ants is becoming an emerging concern (Han et al. 2001). 1,4-dioxane (1,4-D) is one such emerging organic pollut- ant, which is hydrophilic in nature and highly soluble in water (Duncan et al. 2004). 1,4-D is widely used as a solvent in a variety of commercial and industrial appli- cations such as for manufacturing plastics, pesticides, inks, dyes, paints, cosmetics, deodorants, rubber, oils and resins (Son et al. 2006; Otto & Nagaraja 2007; Sei et al. 2010). The contamination of groundwater with 1,4-D has become a major threat to the existence of living organ- isms in the aquatic environment as 1,4-D results in both acute and chronic toxicity (Stickney et al. 2003). 1,4-D is highly mobile which may migrate rapidly in groundwa- ter, ahead of other pollutants, and does not volatilise readily from surface water bodies (Duncan et al. 2004; EPA 2006). It is also classified as a probable human car- cinogen (Beckett & Hua 2000; Stickney et al. 2003). Depending on the extent and duration of exposure to 1,4-D, both humans and animals can experience several adverse health conditions such as irritation of eyes, nose, skin and the respiratory tract, and can even cause lung, liver and kidney damage (Johnstone 1959; Derosa et al. 1996; EPA 2009). Therefore, the rapid and continuous monitoring of industrial effluent is of great importance to ensure that they will not cause adverse effects on the aquatic environment. The assessment of industrial effluents based on the biological effects of their discharge to the aquatic ecosys- tem is a matter of increasing concern (Tonkes et al. 1999; Farre & Barcelo 2003; Kim et al. 2008). In many coun- tries, local governments still rely on physicochemical characteristics of effluents to regulate and manage efflu- ents produced by industrial sectors (Liu et al. 2002; Ra et al. 2007; Jo et al. 2008). Physicochemical parameters are insufficient to characterise effluents and to predict the potential harmful effects of chemicals on the aquatic environment (Sahu et al. 2008). Chemical analysis alone has difficulty assessing complex mixtures of substances in industrial effluents (Eltzov et al. 2009). Hence, the toxic effects of these complex mixtures can only be detected using biological toxicity tests (Chen et al. 1999; Kohler et al. 2006). Biological tests respond to the total effect of chemical activity (Blaise et al. 1988). Hence, bioassays have been used extensively for the assessment of toxic effects of complex mixtures in industrial effluents (Tanaka et al. 2002; Schmitt et al. 2005). Numerous methods have been developed and applied to living organisms such as fish, algae, daphnids, plant cells, animal cells and several bac- Water and Environment Journal. Print ISSN 1747-6585 Water and Environment Journal •• (2011) ••–•• © 2011 The Authors. Water and Environment Journal © 2011 CIWEM. 1