Assessing behavioural and physiological responses of three aquatic invertebrates to tributyltin and atrazine in a multi-species, early warning biomonitoring technology

Recent global events and anthropogenic changes to the natural environment have raised concerns about the quality of drinking water consumed by the public throughout the world. Traditional chemical testing is slow and is not performed for all possible contaminants, necessitating the development of innovative new technology to detect and mitigate threats to human health. The development of a multi-species, early-warning biomonitoring technology, based on behavioural and physiological changes in aquatic organisms, greatly furthers this goal. In this study, changes in movement behaviour and respiration rates were examined in three aquatic species, Daphnia magna, Hyalella azteca and Lumbriculus variegates, exposed to varying concentrations of TBT and atrazine, using digital video analysis and direct oxygen measurement. Different parameters of movement were examined and evaluated for inclusion in a multi-species, early-warning biomonitoring technology and the utility of incorporating these parameters into a model to determine classes and concentrations of various contaminants is discussed. An evaluation of whether or not direct measurement of oxygen consumption rates is feasible and useful for inclusion in a multi-species, early-warning biomonitoring technology is also discussed.

Assessing behavioural and physiological responses of three aquatic invertebrates to tributyltin and atrazine in a multi-species, early warning biomonitoring technology

Recent global events and anthropogenic changes to the natural environment have raised concerns about the quality of drinking water consumed by the public throughout the world. Traditional chemical testing is slow and is not performed for all possible contaminants, necessitating the development of innovative new technology to detect and mitigate threats to human health. The development of a multi-species, early-warning biomonitoring technology, based on behavioural and physiological changes in aquatic organisms, greatly furthers this goal. In this study, changes in movement behaviour and respiration rates were examined in three aquatic species, Daphnia magna, Hyalella azteca and Lumbriculus variegates, exposed to varying concentrations of TBT and atrazine, using digital video analysis and direct oxygen measurement. Different parameters of movement were examined and evaluated for inclusion in a multi-species, early-warning biomonitoring technology and the utility of incorporating these parameters into a model to determine classes and concentrations of various contaminants is discussed. An evaluation of whether or not direct measurement of oxygen consumption rates is feasible and useful for inclusion in a multi-species, early-warning biomonitoring technology is also discussed.

Optical Oxygen Sensors With Improved Lifetime Incorporating Titania Beads and Polydimethylsiloxane Coatings

The use of optical sensors for oxygen measurement is becoming more important because of their capability for low-cost and direct measurement, but as yet, little has been reported about their long-term performance. Phosphorescent sensors based on platinum octaethylporphyrin (PtOEP) embedded in polymer matrices tend to degrade with time. To reduce the rate of degradation, sensor films were fabricated and then coated with a layer of polydimethylsiloxane (PDMS) and tested in a six-month study. The PDMS-coated sensors showed an average degradation rate of ~0.073 %/day, compared to ~0.18 %/day for uncoated sensors. Titania beads were also incorporated into the films to increase light scattering and improve the response; these beads compensated to some degree for the absorption due to the PDMS films. The films with titania beads improved the response significantly (about 40%) compared to the films without titania beads. Incorporation of titania beads also moderately improved the aging characteristics.