Standard Acute Toxicity Tests Research Articles

Detection of aroclor, DDT, malathion and HCB using semipermeable membranes as concentration method

Semipermeable membrane devices (SPMDs) containing 1 g of triolein were used to extract pp'-DDT (DDT), hexachlorobenzene (HCB), malathion and aroclor 1254 from aqueous samples. Recoveries higher than 95% were analytically confirmed for DDT and HCB using GC-MS after an extraction with n-hexane or methylene chloride. Different approaches were made to combine this concentration method with biological detection systems using toxicity tests on Daphnia magna. Direct assays, introducing the exposed membrane into the exposure flask, gave negative results due to the adhesion of the animals to the membrane. Similar negative results were observed when triolein aliquots were directly mixed with the water in the exposure chamber. Finally, the capability of dimetylsulfoxide as solvent (DMSO) was assayed. DMSO was chosen because of its compatibility with ecotoxicity assessments. Membranes were dialysed twice with DMSO. The toxicity of dimethylsulfoxide extracts to Daphnia magna was assessed by the standard acute toxicity test modified for low volume assays. HCB containing extracts were slightly toxic, while no toxicity was observed for DDT, malathion and aroclor 1254. Chemical analysis confirmed a very low recovery, less than 10%; aroclor was not quantified. Data show that although DMSO is a very good solvent for toxicity studies, it can not be used to extract lipophilic pollutants from triolein devices. Nevertheless, the capability of these devices to concentrate hydrophobic pollutants has been confirmed, and new efforts to combine this concentration method with toxicological detection systems are required. The possibilities of these methods are discussed.

A comparison of standard acute toxicity tests with rapid‐screening toxicity tests

AbstractThis study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer(Branchionus calyciflorus);brine shrimp(Artemia salina);lettuce(Lactuca sativa);and two microbial tests(Photobacterium phosphoreum–Microtoxr̀ test, and a mixture of bacterial species–the Polytoxr̀ test). Standard acute toxicity test species included water fleas(Daphnia magnaandCeriodaphnia dubia), green algae(Selenastrum capricornutum), fathead minnows(Pimephales promelas), and mysid shrimp(Mysidopsis bahia).Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC50/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex “real‐world” environmental samples is recommended.

A COMPARISON OF STANDARD ACUTE TOXICITY TESTS WITH RAPID-SCREENING TOXICITY TESTS

This study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer (Branchionus calyciflorus); brine shrimp (Artemia salina); lettuce (Lactuca sativa); and two microbial tests (Photobacterium phosphoreum–Microtoxr̀ test, and a mixture of bacterial species–the Polytoxr̀ test). Standard acute toxicity test species included water fleas (Daphnia magna and Ceriodaphnia dubia), green algae (Selenastrum capricornutum), fathead minnows (Pimephales promelas), and mysid shrimp (Mysidopsis bahia). Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC50/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex “real-world” environmental samples is recommended.

Acute, distribution, and subchronic toxicological studies of succinate tartrates

The estimated single-dose oral toxicity (50% lethality) of succinate tartrates (ST) was 2–3 g/kg in rats. ST produced minimal to moderate dermal irritation but no evidence of systemic toxicity in a standard acute percutaneous toxicity test in rabbits. ST was n not an eye irritant in a standard rabbit low-volume eye irritation test. ST was not genotoxin in a series of six genotoxicity tests. A 14-day oral gavage study in rats at a dose range of 0.05–1.0 g ST/kg/day produced only gastric irritation. The no-observed-effect level (NOEL) for gastric irritation was 0.1 g/kg for males and 0.05 g/kg for females. A 28-day percutaneous toxicity study in rabbits produced minimal to moderate dermal irritation and no adverse systemic effects at a high dose of 450 mg ST/kg/day. Single-dose absorption, distribution, and elimination (ADE) studies in male rats showed that 10–15% of an oral dose and 1–3% of a dermal dose were absorbed. Approximately 98% of the orally administered ST was eliminated as 14C in urine, feces, or expired CO 2 after 72 hr. Approximately 80% of the dermally absorbed 14C dose was eliminated in urine, feces, or expired CO 2 after 72 hr. In conclusion, no adverse effects were noted in acute toxicity, genotoxicity, or subchronic toxicity studies conducted with ST.

Effects of Residues of the Polychlorinated Biphenyl Aroclor 1254 on the Sensitivity of Rainbow Trout to Selected Environmental Contaminants

Rainbow Trout were exposed to two concentrations of the polychlorinated biphenyl, Arachlor 1254: 0.1- and 0.01 ..mu..g/l. Gas-liquid chromatography of the homogenized whole trout revealed average amounts of 0.46 ..mu..g/g at low-level exposure and 3.40 ..mu..g/g at high-level exposure. Sublots of each group were then exposed to the following contaminants in standardized acute toxicity tests: nitrate, nitrite, cyanide, chlorine, mercury, and chromium. The toxicity of cyanide was increased significantly by both concentrations of Arachlor 1254; the toxicity of chromium was increased only by the high concentration. The toxicities of nitrate nitrogen, nitrite nitrogen, chlorine, and mercury were unaffected by previous exposure to either concentration of the polychlorinated biphenyl.