Daphnia

Figure 5-31. Search for atrazine and daphnia toxicity in the Cennan Environmeiital Information NetworkGEIN portal (excerpt from search, October 21, 2002) http //wu u. geln.de/incfex en.htm ).

For the sample search on aquatic toxicity of atrazine, 1459 results were found. An excerpt on the daphnia acute aquatic toxicity tests (EC50. LC.50) is prc.scnted in Figure 5-33. 

AH of the propylene glycols are considered to be practically nontoxic to fish on an acute basis (LC q < 100 mg/L) and practically nontoxic to aquatic invertebrates, also on an acute basis. Acute marine toxicology testing (38) on propylene glycol showed that the 96-h LC q for fathead minnows was 54,900 mg/L and the 48-h LC q for Daphnia magna was 34,400 mg/L. A 24-h NOEL of 50,000 mg/L was also observed for fingerling trout. Similar results were observed for guppies and rainbow trout (39). 

The compound is relatively nontoxic. Because many golf courses and recreational grassy areas abut lakes and ponds that are used for fishing, the environmental toxicity data are important. The LC q for trout (96 h) is 80 mg/L for bluegiU. (96 h), 36 mg/L and for Daphnia, 64 mg/L. 

Life cycle in aquatic invertebrates (daphnia/mycid)... 

Aquatic Toxicity. The standard tests to measure the effect of substances on the aquatic environment are designed to deal with those that are reasonably soluble ia water. Unfortunately this is a disadvantage for the primary phthalates because they have a very low water solubiUty (ca 50 p.g/L) and this can lead to erroneous test results. The most common problem is seen ia toxicity tests on daphnia where the poorly water-soluble substance forms a thin film on the water surface within which the daphnia become entrapped and die. These deaths are clearly not due to the toxicity of the substance but due to unsuitable test design. 

Aquatic toxicity is reported in mg/L for Pimepha/espromealas (fathead minnow), 69-h LC q 7650 (17) for Daphnia magna (water flea), 48-h EC q 3310 (18) for Mjriophjllum spicatum (water milfoil), phytotoxicity (EC q for growth) 5962 (19) and for Pana breviceps (frog), no observed effect concentration (NOEC) 400 (20). LC q and EC q are lethal and effect concentrations, respectively, for 50% of the subjects tested. 

Both acute and chronic toxicity testing of the treated effluent on daphnia shrimp and fathead minnows have indicated that the effluent is completely suitable for discharge into receiving waters with no adverse impact (42). 

Unknown until 1950 when E. Haxo isolated it from an edible mushroom Cantharellus cinnabarinus canthaxanthin has since been identified in sea trout, algae, daphnia, salmon, brine shrimp, and several species of flamingo. Crystalline canthaxanthin is prepared synthetically from acetone or P-ionone using procedures similar to those used for -carotene and P-apo-8 -carotenal (55). 

EinaHy, the ecotoxicological studies, designed to assess the impact of the substance on the environment, embrace acute toxicity tests to fish and Daphnia, and a battery of tests for the biodegradabiUty of the substance and its biological oxygen demand characteristics. 

By results of biotesting sewage dumped in a reservoir the payment for toxie dump pays off. More often in toxieologieal experiments as test-objeet ai e used Daphnia. Toxieity of water of eity reservoirs of Astrakhan during the different periods 2004 by use Daphnia magna is investigated. Results of reseai ehes are shown in the table. 

Definition of a degree of toxieity of water with Daphnia magna during 2004... 

The invertebrate phyla are often neglected in ecotoxicological testing protocols. A token invertebrate species such as the copepod Daphnia may be used to evaluate the effects on extremely diverse phyla. This neglects the diversity of biochemical and physiological functions that may render different phyla vulnerable to different classes of compound at different stages of their life cycles. 

Daphnia assay, the brine shrimps are exposed to different concentrations of toxicant, and the toxicity is expressed as the LCjo value. Extracts of cyanobacterial blooms and laboratory cultures, containing microcystins or anatoxin-a, have been found to be toxic towards brine shrimp," and fractionation of such extracts resulted in brine shrimp fatalities only with fractions containing microcystins." " ... 

Acute daphnia toxicity Biodegradability Physico-chemical properties cumulative... 

BASE SET Mutagenicity Toxicity to reproduction Toxicity to algae Acute daphnia and fish toxicity Abiotic and readily biotic degradability Additional physico-chemical properties 1 t/annum or 5 t cumulative... 

Bacteria- Escherichia coli Creen algae-Scenedesmus quadricauda Daphnia magna Protozoa microregma... 

A distinct dependence between LAS alkyl chain length and the chronic or long-term toxicity is also shown (see Table 22) [290,291]. As can be seen, the ecotoxicity of LAS for fishes and daphnia increase significantly with increasing alkyl chain length of the LAS homolog. 

LAS homolog Acute fish toxicity (LC50) [mg/L] Long-time fish toxicity (NOEC) [mg/L] Acute daphnia toxicity (ECS0) (mg/L) Long-time daphnia toxicity (NOEC) (mg/L)... 

Further examinations have been done in the biodegradation ecotoxicity sequence rest (BEST). In this test a realistic diluted effluent of the modified OECD confirmatory test (DIN 38412, part 26) is tested continually on daphnia reproduction over three generations. It can be said that the effluents of an OECD confirmatory plant (feed 10 mg/L LAS), containing nondegraded surfactants and catabolites, have no negative effect on the juvenile and adult daphnia even in the third generation and do not influence their reproduction [296]. 

Daphnia toxicity (Daphnia magnallA h) (OECD 202) ec50 12.5... 

Chronic Daphnia reproduction test (OECD 202) LOECb 3.0... 

Coupled Daphnia multigeneration test (toxicity of effluent ... 

Secondary alkanesulfonate in effluent has no toxic effect on the fish food organism Daphnia magna. 

Alcohol sulfates and alcohol ether sulfates have similar toxicities to daphniae and fish but alcohol ether sulfates can be considered slightly more toxic. Ger-... 

Fish and microorganisms used as nutrients for fish suffer from a low surface tension of water. The lethal level of surfactant solutions was found to correlate with the surface tension of the culture solutions in which fish and microorganisms like daphnia and Cyclops were maintained. Lethality was at 49 mN/m. This effect possibly corresponds to the destruction of the respiratoric epithelia of the gills [196]. Consequently, knowledge about the so-called functional or primary biodegradation is important. 

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