Ecological effects - trdoer40183

and pH. Bioaccumulation in biological organisms does not tend to occur upon

repeated exposure indicating fairly rapid excretion.

Ecological effects

The toxicity of copper to aquatic life is related primarily to the presence of

the free cupric ion, Cu2+, and possibly some of the hydroxy complexes (USEPA

1984). The Cu2+ forms stable complexes and precipitates with many inorganic

and organic constituents in natural waters. Generally, the concentration of free

ion is low compared to total copper present in the water. Organic and inorganic

copper complexes appear to be less toxic than the free cupric ion. Aquatic

toxicity studies indicate that increasing alkalinity, hardness, and total organic

carbon in natural waters decreases copper toxicity. Three major classes of

compounds contribute to alkalinity in natural waters. These classes include

hydroxide, carbonates and bicarbonates. More copper is complexed as carbonate

species, resulting in a significant reduction of the free Cu2+. A change in ionic

strength of water alters sensitivity of some aquatic species to copper. The copper

ion is significantly more toxic in lower ionic strength waters such as tap water

(USEPA 1984).

Acute toxicity data are available for species in 41 genera of freshwater

animals. At a hardness of 50 mg/L, the genera range in sensitivity from

16.74 ug/L for Pytochocheilus (northern squawfish) to 10,240 ug/L for

Acroneuria (stonefly). The next most sensitive species after Pytchocheilus were

the Cladoceran and amphipod species (USEPA 1984). Data for eight species

indicate that acute toxicity decreases as hardness increases. Additional data for

several species indicate that toxicity also decreases with increases in alkalinity

and total organic carbon.

Chronic values are available for 15 freshwater species and range from

3.873 ug/L for brook trout to 60.36 ug/L for northern pike (USEPA 1984). Fish

and invertebrate species seem to be about equally sensitive to the chronic

toxicity of copper.

The acute sensitivities of saltwater animals to copper range from 5.9 ug/L for

the blue mussel to 600 ug/L for the green crab. Chronic tests in a mysid observed

adverse effects at 77 ug/L but not at 38 ug/L, yielding an acute-chronic ratio of

3.346 (USEPA 1984). Effects were observed in several saltwater algal species

between 5 and 100 ug/L. Oysters can bioaccumulate copper up to 28,000 times

and become bluish-green, apparently without significant mortality. In long-term

exposures, the bay scallop was killed at 5 ug/L.

References

U.S. Environmental Protection Agency. (1984). "Ambient water quality criteria

for Copper," EPA 440/5-84-031, Office of Water Regulations and Standards,

Washington, DC.

D31

Appendix D Toxicological Profiles