Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions

Abstract

The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty‐one acute toxicity tests were conducted, with LC50 values ranging from 85 μg/L for the white sucker Catastomus commersoni during the summer to greater than 7,770 μg/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. Both were adversely affected at the lowest concentrations tested, i.e., 4.1 and 26 μg/L, respectively. The duckweed Lemna minor was the least sensitive, with no apparent effects after exposure for 21 d to concentrations as high as 1,440 μg/L. The greatest variation in toxicity was due to species sensitivity. Within a given season there was as much as a 40‐fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14‐fold. There were also substantial differences in acute‐chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.

Effects of temperature and chemical formulation on the acute toxicity of pentachlorophenol toSimocephalus vetulus(Schoedler, 1858) (Crustacea: Cladocera)

“…Lewis & Horning (1991) found no significant difference in the toxicity of sodium pentachlorophenate (NaPCP) to either Daphnia pulex or Daphnia magna neonates following an increase in temperature from 20 to 26°C. Although Hedtke et al (1986) found S. vetulus adults to be significantly more sensitive to NaPCP at 24°C than at 18°C, this was a seasonal alteration of temperature and other factors such as nutritional status may have contributed to the result. In the present study the toxicity of PCP to S. vetulus was increased at the higher temperature of 22°C.…”

“…Because PCP increases metabolic oxygen demand (Weinbach 1957), its toxicity might be expected to increase with temperature, though tests using Daphnia magna and Daphnia pulex have shown no influence of temperature on PCP toxicity (Lewis & Horning 1991). Hedtke et al (1986) found PCP toxicity to S. vetulus to increase with temperature although this study employed seasonal collection of test organisms requiring temporal separation of comparative tests. The test temperatures chosen for the current study lie within the range of summer temperatures experienced in New Zealand freshwaters.…”

“…Simocephalus vetulus is a littoral or shallow-water cladoceran which is found throughout New Zealand (Chapman & Lewis 1984) and is relatively large and easy to handle compared to many other cladocerans. These factors and the previous use of this species in toxicity tests (Mount & Norberg 1984;Hedtke et al 1986;Hickey 1989) suggest that S. vetulus has potential as a test species in New Zealand.…”

Interacting Effects of pH Acclimation, pH, and Heavy Metals on Acute and Chronic Toxicity to Ceriodaphnia dubia (Cladocera)

“…Morgan (1986) found Ceriodaphnia to be slightly acid tolerant in enclosure experiments conducted in New Jersey pine bogs. Data presented by Hedtke et al (1986) strongly suggested low pH increased toxicity of pentachlorophenol to species of Ceriodaphnia. To date, however, definitive toxicological data have not been reported on pH sensitivity to ceriodaphnids and the role of pH in the acclimation and testing of discharges or single chemicals to C. dubia.…”

Validation of a Four-Day Ceriodaphnia Toxicity Test and Statistical Considerations in Data Analysis

“…The ASTM guideline also describes methods for detecting outlying data values and for transforming responses to obtain homogeneous variance across treatments and suggests that nonparametric methods might be useful with heterogeneous data. Hedtke et al [21] use analysis of variance with Dunnett's method of multiple comparisons for analysis of survival and reproduction data from chronic tests with three species of cladocerans. Spehar and Fiandt [19] use the Spearman-Karber method to estimate the LC50 values for C. dubia survival data from 48-h and 96-h tests.…”