Lw. Hall et Rd. Anderson, THE INFLUENCE OF SALINITY ON THE TOXICITY OF VARIOUS CLASSES OF CHEMICALS TO AQUATIC BIOTA, Critical reviews in toxicology, 25(4), 1995, pp. 281-346
The objective of this study was to review all available aquatic toxici
ty literature regarding the effects of salinity on the toxicity of var
ious classes of inorganic and organic chemicals. Toxicity data for stu
dies in which toxicity was assessed at various salinities were organiz
ed by chemical classes and trophic groups. Seventy percent of the stud
ies were conducted with either crustaceans or fish. The other 30% were
with mollusks, annelids, zooplankton, bacteria, phytoplankton, or fun
gi. Results from 173 data entries showed that negative correlations (t
oxicity increasing with decreasing salinity) were reported most freque
ntly (55%), followed by no correlations (27%) and positive correlation
s (18%). The toxicity of most metals such as cadmium, chromium, copper
, mercury, nickel, and zinc was reported to increase with decreasing s
alinity. This finding is likely related to the greater bioavailability
of the free metal ion (toxic form) at lower salinity conditions. Ther
e was generally no consistent trend for the toxicity of most organic c
hemicals with salinity. The one exception to this was reported with or
ganophosphate insecticides, the toxicity of which appeared to increase
with increasing salinity. Physiological characteristics of the variou
s test species were important in determining the toxicity of the vario
us classes of chemicals at a range of salinities. Results from various
studies showed that euryhaline species were more resistant to toxic c
onditions at isosmotic salinities due to minimization of osmotic stres
s. Specific examples showed that fish were more resistant to toxic che
micals at middle salinities when compared with either lower or higher
extremes. Life history and ecology of test species were important fact
ors to consider when interpreting salinity/contaminant interaction dat
a.