INFLUENCE OF WATER QUALITY ON SILVER TOXICITY TO RAINBOW TROUT (ONCORHYNCHUS MYKISS), FATHEAD MINNOWS (PIMEPHALES PROMELAS), AND WATER FLEAS (DAPHNIA MAGNA)

Rainbow trout is a new fish farming object for Uzbekistan, the adaptability of which (first of all, growth) to local conditions should be carefully studied. We analyzed the growth of rainbow trout in the conditions of flowing pools and cages in the foothill zone of Tashkent province of Uzbekistan. From March to October, the water temperature in the Khojikent reservoir varied from 4.9 to 13.1 °C, the amount of dissolved oxygen was 8.4 to 11.5 mg/l, and the pH was 7.40 to 7.67. In the flowing basin, the temperature was 15-18 °C, pH 7.2-7.5, the amount of dissolved oxygen 6.1-11.2 mg/l. The conditions of the foothill zones of Uzbekistan in terms of water quality are favorable for the development of trout breeding. During the season, fish in cages increased from 250 g to 623 g, in pools from 25 g to 390 g on average. The waste was 1.7%. The actual fish productivity of the basin is 39 kg/m3, the cage is 30 kg/m3 and the feed coefficient in the basin is 1.2, in the cages - 1.09.

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Summary of Case Studies Investigating the Causes of Pulp and Paper Mill Effluent Regulatory Toxicity

Water Quality Research Journal ◽

10.2166/wqrj.2004.016 ◽

2004 ◽

Vol 39 (2) ◽

pp. 93-102 ◽

Cited By ~ 7

Author(s):

Tibor Kovacs ◽

Sharon Gibbons ◽

Brian O'Connor ◽

Pierre Martel ◽

Michael Paice ◽

...

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Daphnia Magna ◽

Paper Mill ◽

Pulp And Paper ◽

Pulp And Paper Mill ◽

Pulp And Paper Mills ◽

Paper Mills ◽

Paper Mill Effluent ◽

Rainbow Trout Oncorhynchus Mykiss

Abstract In Canada, effluents from pulp and paper mills are regulated for toxicity. The regulation requires ≥50% survival of rainbow trout (Oncorhynchus mykiss) exposed to full-strength (i.e., 100%) effluent for 96 h in tests that must be conducted monthly. The regulation also calls for ≥50% survival of Daphnia magna exposed to 100% effluent for 48 h in weekly monitoring tests. Every year, about 10 to 25% of the mills exceed the regulatory limit at least once in tests with either rainbow trout or Daphnia magna. Between 1996 and 2003, we investigated 84 such cases from 32 mills. Of the 84 investigations, 49 involved only trout, 29 involved only Daphnia, and six involved both species. We identified the actual cause of toxicity in 70% of the cases and partially or tentatively identified the toxicant(s) in 17% more. In the cases involving only trout, the most frequent causes of toxicity were related to biotreatment performance (e.g., ammonia). In the cases involving only Daphnia, the most frequent cause of toxicity seemed to be related to polymeric formulations. For those cases involving both trout and Daphnia, the cause of toxicity was traced to more than one compound or to excess concentrations of a specific compound resulting from a spill or biotreatment-related problems.

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