Acute and Chronic Effects of Water Quality Criteria-Based Metal Mixtures on Three Aquatic Species

Abstract

Acute and chronic toxicity tests were conducted with three aquatic species to determine the effects of metals combined as mixtures at proposed water quality criteria concentrations and at multiples of the LC50 and maximum acceptable toxicant concentration (MATC) obtained from tests on six metals. These studies were the first part of a larger research effort to derive water quality criteria for combined pollutants by the U.S. Environmental Protection Agency.Arsenic, cadmium, chromium, copper, mercury and lead combined at criterion maximum concentrations caused nearly 100% mortality in rainbow trout and daphnids (Cerioduphniu dubiu) during acute exposures. Fathead minnows were not adversely affected at this or two times this concentration, although a mixture of four to eight times the maximum value caused 15 to 60% mortality. Metals combined at the criterion average concentrations significantly reduced production of daphnid young and growth of fathead minnows after 7 and 32 d, respectively. Embryo hatchability and survival of rainbow trout were reduced at four times this criterion but not at the criterion average concentration.Acute tests with metals mixed at multiples of the LC50 indicated that the joint action of the metals was more than additive for fathead minnows and nearly strictly additive for daphnids, based on toxic units calculated from the individual components of the mixture. Chronic tests showed that the joint action was less than additive for fathead minnows but nearly strictly additive for daphnids, indicating that long-term metal interactions may be different in fish than in lower invertebrates. Adverse effects were observed at mixture concentrations of one-half to one-third the MATC for fathead minnows and daphnids, respectively, suggesting that components of mixtures at or below no effect concentrations may contribute significantly to the toxicity of a mixture on a chronic basis. These results point out the need for additional studies to determine the type and degree of interaction of toxicants because single-chemical water quality criteria may not sufficiently protect some species when other toxicants are also present.

Impact assessment of dredging to remove coal fly ash at the Tennessee Valley Authority Kingston Fossil plant using fathead minnow elutriate exposures

“…All measured dissolved concentrations are well below a 48-h NOEC [21] and a 30-d maximum allowable toxicant concentration (MATC) [23] reported for P. promelas. Overall, Cr would not be expected to be of toxicological concern because the measured concentrations in the 100% elutriates were more than 11 times lower than the CCC and 1,000 times lower than a MATC reported in the literature.…”

The toxicity of metal mixtures to the estuarine mysid Neomysis integer (Crustacea: Mysidacea) under changing salinity

“…Note that these sums function as a unit of additive toxicity, except that values greater than 1 are not symmetrical with values less than 1 (Spehar and Fiandt, 1986). For example, in our tests a value of 6 would indicate that there would be no interaction because six toxicants made up the mixture; however, values of 0.5 and 3.0 would be equally more than additive and less than additive, respectively, since they are midway between 0 and 1, and 0 and 6.…”

“…Attempts to model the joint action of chemicals have already been made for the freshwater environment (Altenburger et al, 1990;Drescher and Boedeker, 1995;Spehar and Fiandt, 1986). The toxicity of a mixture of chemicals with a similar mode of action can be predicted by the concentration Á/addition model as proposed by Anderson and Weber (1975).…”

Sensitivity of three unionid glochidia to elevated levels of copper, zinc and lead

“…Interaction of metals may be influenced by the tested species, the combination of metals and water quality (Otitoloju, 2002;Kungolos et al, 2009). Spehar and Fiandt (1986) indicated that the same combination of metals (arsenic, cadmium, chromium, copper, mercury and lead) showed different interactive effects depending on both the species exposed and the endpoint tested. Utgikar et al (2004) reported that the toxic effects of binary mixtures were substantially higher than simple addition of toxicity of the individual metals.…”