Fish biomonitoring in an industrial environment: The Toxicity Early Warning System (TEWS).

摘要

Industrial, agricultural and municipal effluent discharge into receiving waters continues to be a significant environmental problem. Currently, industrial effluent quality is assessed using chemical assays or by evaluating physical parameters, which have multiple limitations. To overcome these limitations, aquatic biomonitoring systems (ABS), which use behavioural responses of living organisms, have been introduced. The Toxicity Early Warning System (TEWS) is a flow-through aquatic biomonitoring system developed by our research group at Lakehead University, which utilizes the behavioural parameters (ventilatory depth, ventilatory rate, body movement and cough rate) of rainbow trout fingerlings as an indicator of potential toxicity. In this thesis, the TEWS is implemented at AbitibiBowater Thunder Bay (ABTB), an industrial pulp and paper company, which has intermittently shown indicators of toxicity in cooling water tests during the Spring season. Prior to implementing the TEWS at ABTB to monitor the Kraft Clean Water Outfall (KCWO), it was necessary to improve the sensitivity and reliability of the system under laboratory conditions. TEWS laboratory results showed that 96-h LC50 levels of zinc sulphate (ZnSO 4) and leachates from a municipal waste landfill were detected in 2h by changes in rainbow trout behavioural parameters. The TEWS proved to be effective in detecting Spring toxicity events two consecutive years (2008 and 2009) in a row at the KCWO. Toxicity events were complemented with physical, chemical, biological and theoretical modeling methods, which helped link potential contaminants to the observed toxicity. Aluminum found during 2009 toxicity event (994 mug/L) was well above aquatic guidelines (100 mug/L) and LC 50 values (310 mug/L), modeled as reactive Al (186 mug/L) and linked to fish mortality via high gill-Al concentrations (217 mug/L).