Test Types
Related In-house Publications
Quality Assurance

Related In-house Publications

Variability in the Quality of Standard Diets for the Support of Amphipod, Hyalella azteca, During 28-Day Sediment Tests
F.G. Doherty. In Prep.

Growth of the freshwater amphipod, Hyalella azteca, was monitored in standard 28-day duration tests over a multi-year period. Variability in the growth of control organisms held in sediment drawn from a single source prompted an assessment of the yeast-Cerophyl-Trout Chow (YCT) used as food during the testing period. Various formulations of YCT were assessed in which other commonly available fish feeds were used as replacements for the Trout Chow component. Results demonstrate a significant effect on dry weights of amphipods at the end of the test due to the YCT formulation utilized.

Francis G. Doherty1, Joseph P. Kreitinger2 and Edward F. Neuhauser3

1 AquaTox Research, Inc.,
1201 East Fayette Street, Syracuse, NY 13210
2 The RETEC Group,
1001 West Seneca Street, Suite 204, Ithaca, NY 14850
3 Niagara Mohawk,
300 Erie Boulevard West, Syracuse, NY 13202


A modified design for assessing the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) from sediments by the freshwater oligochaete, Lumbriculus variegatus, was developed and assessed. The design entailed the addition of 50 adult worms to 100 ml of either control, reference or test sediment overlain with approximately 150 ml of diluted stream water in 300 ml beakers using four replicate beakers per sediment treatment. Approximately 100 ml of overlying water was manually renewed daily. Surviving worms were harvested after 14 days by passing sediment through stacked stainless steel sieves. Routine chemical parameters of overlying water were assessed on select days. Biological data collected during the test included initial and final worm wet weights and total numbers of worms recovered. Sediments were analyzed for concentrations of PAHs, total organic carbon (TOC), and silt, sand and clay composition.

Sediment PAH concentrations ranged from negligible to greater than 1,100 mg/kg.Sediment TOC levels ranged from <1 to >10%. There were no worms recovered from several of the samples with elevated PAH concentrations however there were also several samples with elevated PAH concentrations for which there were no mortalities observed. Worms retrieved from a majority of all samples exhibited significant losses in wet weight.Losses and gains in wet weight were directly related to TOC content of the sediments. Worms held in sediments with TOC levels of <4.83% lost from 0.7 to 35.3% of their initial wet weight. Worms held in sediment with a TOC content of >6.2% gained from 13.7 to 34.1% of their initial wet weight except for worms from a single sample in this range that lost weight. Numbers of worms recovered from these samples was inversely related to weight data. Numbers of worms recovered from samples with a TOC content of <4.29% either did not change or increased from initial stocking levels. Numbers of worms recovered from samples with a TOC content of >4.83% did not change from initial stocking levels. These data indicate that L. variegatus potentially employs alternating reproductive strategies that are dependent on the availability of an adequate nutritional source via the TOC content of the sediment in which they are being held. Consequently, the use of an increase in the number of worms present in a test sample to suggest a sample is not contaminated is suspect.