Bioassay crustacean

Ecotoxicity assessment of water samples was carried out, in parallel to chemical analysis, using three standardized bioassays based on the micro-crustacean Daphnia magna, the algae Pseudokirchneriella subcapitata, and the bioluminescent bacteria Vibrio fischeri. 

Toxaphene is extremely toxic to freshwater and marine biota. In laboratory tests of 96-h duration, 50% mortality was recorded for the most sensitive species of freshwater and marine teleosts, marine crustaceans, and freshwater insects at nominal water concentrations of less than 10 pg/L of toxaphene, and, in several cases, less than 1 pg/L (Table 27.2). Bioassays of longer duration, based on exposure of aquatic organisms for the entire or most of the life cycle, produced significant adverse effects on growth, survival, and reproduction at toxaphene concentrations between 0.025 and 1.0 pg/L (Table 27.3). Toxaphene was most toxic to freshwater fishes in soft water at elevated temperatures (Saleh 1991). Based on its high toxicity and extensive use, it is not surprising that toxaphene was considered a major cause of nationwide fish kills in 1977 (USEPA 1980b). 

The selection of suitable single species and protocols is not a trivial task and may be dependent on various factors. Some of these include simplicity, low cost, or modest material and equipment demand. However, a higher sensitivity than other species to toxicants may be decisive in this choice in order to serve as warning systems. Table 1 shows the sensitivity in terms of effective concentration (EC50), which is the toxicity endpoint for the organisms (bacteria, crustaceans, algae, and fish) selected for the toxicity bioassays. These toxicity bioassays are usually classified according to the test species involved. 

P. promelas, the midge larva C. riparus, the crustacean D. magna and the water snail L. stagnalis were obtained. When the bioassays were carried out with surface water, the determined NOECs were higher, with this fact a consequence of the suspended matter in the water [127]. 

The use of bioassays in environmental monitoring has not been developed in Chile [191]. In 1998 the Ministry of Agriculture started to set up a bioassay laboratory for evaluation of the presence of toxic substances in water for irrigation and animal consumption. This ministry is now in the process of implementation of EPA standardized crustacean and algal tests with Daphnia and Selenastrum capricomutum, respectively. There is no governmental wastewater bioassay monitoring. 

The first study was designed to assess the suitability of various microscale bioassays and recommend an appropriate testing strategy for sediment toxicity assessment (Cote et al., 1998a,b). The recommended test batteries included seven micro-scale laboratory assays conducted on bacteria (Vibrio fischeri), cnidarians (Hydra attenuata), micro-crustaceans (Thamnocephalus platyurus), and benthic macroinvertebrates (Hyalella azteca and Chironomus riparius), and involved two phases of exposure (pore water and whole sediment). A total of 16 stations were included in the toxicity assessment scheme. 

Three bioassays a) 48h and 96h acute crustacean test (Daphnia pulex) b) 96h acute fish test (Oncorhynchus mykiss and Oncorhynchus nerka) c) residual oxygen fish test (Oncorhynchus mykiss and Oncorhynchus nerka) Municipal solid waste (MSW) leachates originating from a) Landfills b) Laboratory lysimeters (downward) c) Field lysimeters (downward) Unspecified pretreatment... 

Four bioassays a) 5 min acute bacterial test (Vibrio fischeri) b) 11 to 21 d algal test (Pseudokirchneriella subcapitata) c) 48h acute crustacean test (Daphnia magna) d) 96h acute fish test (Pimephales promelas) Municipal and industrial solid waste leachates originating from a sanitary landfill Filtered (glass fiber and 0.45 pm membrane filters for algal test) and unfiltered... 

Two bioassays a) 48h plate incorporation AMES test with Salmonella typhimurium his- (TA 98, 100, 1535, 1537 et 1538) b) 24h acute crustacean test (Daphnia magna) MSW landfill leachates Ashes and slags from MSW incinerator leachates Centrifuged and 0.45 pm filtered only for AMES test... 

Four bioassays a) 120h lettuce germination test (Lactuca sativa) b) 48h acute crustacean test (Ceriodaphnia dubia) c) 96h acute amphipod test (Hyalella azteca) Waters collected from wells dug in an urban landfill, sediments collected in an adjacent river... 

It has been reported that synthesis of cHH is not restricted to the XO in the eyestalks of crustaceans, but is also shown by immunocytochemistry to be localized to the suboesophageal ganglion and thoracic second roots in H. americanus [89], in the POs of C. maenas [90] and is transiently expressed in gut paraneurons of C. maenas where it is involved with water uptake to facilitate ecdysis [91]. Interestingly, the PO-cHH of C. maenas has a free C-terminus, its first 40 amino acid residues are identical to the SG-cHH and, not surprisingly, it displays no functional activity in the cHH bioassay [90]. 

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