Premise: The dilution water used in the toxicity tests may be natural seawater, hypersaline brine (100 ) prepared from natural seawater, or artificial seawater prepared from commercial sea salts, such as FORTY FATHOMSa or HW MARINEMIXa, if recommended in the method.

Hypothesis: The dilution water in the toxicity tests has to be freshwater from the lake.
Relation: contradiction