Ecological effects - trdoer40175

Ecological effects

Aquatic and terrestrial organisms bioaccumulate cadmium. Cadmium

bioconcentrates in freshwater and marine animals to concentrations hundreds to

thousands times higher than the cadmium concentrations in the water.

Levels of cadmium in plant tissue which are considered to be phytotoxic

range from 5 to 700 ppm (Chaney 1982), 5 to 30 ppm (Kabata-Pendias and

Pendias 1984) and 8 to 15 ppm (Davis, Beckett, and Wollan 1978). It was

established that a maximum dietary cadmium concentration chronically tolerated

by livestock of 0.5 ppm (based upon cadmium residues in animal products used

in human foods).

Aquatic and terrestrial organisms bioaccumulate cadmium. Cadmium

bioconcentrates in freshwater and marine animals to concentrations hundreds to

thousands times higher than the cadmium concentration in the water.

Of the 44 freshwater genera for which genus mean acute toxicity values are

available (USEPA 1984), the most sensitive genus, Salmo, trout is 3,400 times

more sensitive than the most resistant genus, Carassius goldfish. Of the

freshwater species, rainbow and brown trout appear to be extremely sensitive to

cadmium when acutely exposed to concentrations ranging from 1 ug/l to 4 ug/l.

The freshwater final acute value of 3.589 ug/l at hardness of 50 mg/l is used to

protect against Salmo gairdneri, rainbow trout. However, brown trout is more

sensitive than rainbow trout based on an EC50 of 1.63 ug/l from a static test.

Chronic mean values derived from acute toxicity values representing 44 genus

were used to calculate a final freshwater chronic value of 0.6582 ug/l at hardness

of 50 mg/l. The genus mean chronic values for Moina and Daphnia, both

cladocerans are below the final freshwater chronic value.

Growth reduction is a major factor toxic effect observed with freshwater

aquatic plants and reported values are in the range of concentrations causing

chronic effects on aquatic animals. In addition, the lowest toxicity values for

freshwater fish and invertebrates species are lower than the lowest values for

aquatic plants.

The acute toxicity of cadmium generally increases as salinity increases. The

acute values for saltwater invertebrates species range from 41.29 ug/l to

135,000 ug/l for an oligochaete worm. Saltwater mollusks have species mean

acute values from 227.9 ug/l for the Pacific oyster to 19,170 ug/l for the mud

snail. Saltwater fish species were generally more resistant to cadmium than

freshwater fish species with acute values ranging from 779.8 ug/l for the Atlantic

silverside to 50,570 ug/l for the mummichog. Of the 33 saltwater genera for

which acute values are available, the most sensitive, mysidoposis is 2,000 times

more sensitive than the most resistant, Monopylephorus, oligoclaete worms. The

saltwater final acute value is 85.09 ug/l and is slightly above the species mean

acute value of 78 ug/l for the American Lobster. For the two saltwater species

(mysids) for which both chronic and acute toxicity ratios exist, a final saltwater

chronic value of 9.345 ug/l was obtained.

D23

Appendix D Toxicological Profiles