Tobrilus gracilis
[ref. ID; 1276]
Test system
Acute toxicity
Strains
Samples were taken near Wageningen, The Netherlands.
Toxicants
Cadmium chloride (CdCl2), Pentachlorophenol.
Test design
LC50-tests were performed in water containing a defined mixture of minerals with concentrations resembling those found in interstitial water of sandy forest soils (K+: 0.1 mmol/L, Na+: 0.2 mmol/L, Ca2+: 0.35 mmol/L, Mg2+: 0.3 mmol/L, NH4+: 0.3 mmol/L, NO3-: 1.7 mmol/L, Cl-: 0.3 mmol/L) (Schouten and Van der Brugge 1989). pH 6.0+/-0.1.
Two replicates of the tests were carried out in multi-dishes (Greiner, 24 compartment plate, no. 662160) with lid and sealed with parafilm to minimize volatilization. Each compartment was filled with 0.9 ml of water containing toxicant. Samples of 0.1 ml of the multi-species suspension, containing 10-50 adult individuals of each species, were taken and suspended in each compartment. Temperature 20+/-0.1 degrees C in dark.
Measurements/observations
Mortality (24, 48, 72 and 96 hr).
Evaluations
LC50 according to the trimmed Spearmann-Karber method (Hamilton et al. 1977).