Development of a continuous-flow renewal system for sediment toxicity testing

✍ Scribed by V. Dan Wall; Jack London; Jim E. Warren; Ron Gossett; Michael D. Wenholz; Stephen J. Klaine

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 107 KB
• Volume: 17
• Category: Article
• ISSN: 0730-7268
• DOI: 10.1002/etc.5620170624

✦ Synopsis

Development of a flow-through system for sediment toxicity testing has been difficult in part because of problems associated with the precision, and subsequent expense, necessary to create a pump that accurately delivers small amounts of overlying water. This article describes a novel continuous flow-through apparatus designed to quantitatively and continuously deliver small amounts of overlying water to individual test chambers. This system uses a series of motor-driven pistons, similar to bicycle pumps, to accurately (ϳ5% variability) deliver small amounts of overlying water (Ͻ0.1 ml/min) to individual beakers. The system can deliver more than 3.5 L of replacement fluid in a 24-h period from a single outlet hose. Different solutions can be simultaneously delivered to selected beakers, allowing researchers to study effects of water quality parameters on sediment toxicity. Materials for the system are affordable, but construction requires technical assistance. Detailed schematics to aid in construction of this system are available on the Internet at http://www.clemson.edu/entox or from the corresponding author. Water quality and the growth and survival of Chironomus riparius in clean sediments were tested under conditions of continuously and intermittently renewed overlying water. Both methods of renewal maintained acceptable average dissolved oxygen levels (Ͼ70% of saturation), but an average daily range of 0.685 and 1.67 mg/L dissolved oxygen in continuous and intermittent renewal systems, respectively, was observed. No differences were observed in midge survival between continuous and intermittent renewal, but there was a 33% decrease in growth (dry weight) of C. riparius in test chambers subjected to intermittent renewal.