S.V. Kotelevtsev

Toxicity and mutagenicity of waste waters from Baikalsk Pulp and Paper Mill: Evaluation of pollutant contamination in Lake Baikal

Lake Baikal has no agricultural and only little municipal pollution. Instead a potential source of pollution is the Baikalsk Pulp and Paper Mill (BPPM). All waste waters of the mill are mechanically, biologically and chemically purified and there are sedimentation and aeration ponds at the final stage. In this study the efficiency of the waste water purification was detected by testing toxicity and mutagenicity. Waters and sediments were collected along the cellulose bleaching process and waste water treatment. Free and bound polychlorinated phenols, guaiacols, catechols, anisoles and veratroles were analysed. Cytotoxicity of diethylether-extracted waste waters was screened by measuring total protein content in a fish hepatoma cell line (PLHC-1). The mutagenicity of the water, sediment and tissue extracts of selected aquatic species was determined by a modified Ames test. Diethylether fractions of the effluents from BPPM were cytotoxicfor the PLHC-1 cells when concentrated. Biological purification of the waste waters did not affect the cytotoxicity (ED50 ~2.2 and ~2.0 μml−1 before and after). The cytotoxicity was decreased after chemical purification (ED50 ~3.7μml−1) and even more after the aeration pond (ED50 ~4.2 μml−1). Mutagens were found in nearly all water samples released after the pulp chlorination. However, the mutagenic activity was effectively decreased during both biological and chemical treatment of waste waters. Only the tissue extracts of seals and a few roach possessed mutagenic activity. In conclusion, even the modern waste water purification systems do not totally abolish potential toxicity and/or mutagenicity of the effluents.

Genotoxicity in native fish associated with agricultural runoff events

The primary objective of the present study was to test whether agricultural chemical runoff was associated with in-stream genotoxicity in native fish. Using Sacramento sucker (Catostomus occidentalis), we combined field-caging experiments in an agriculturally dominated watershed with controlled laboratory exposures to field-collected water samples, and we coupled genotoxicity biomarker measurements in fish with bacterial mutagenicity analysis of water samples. We selected DNA strand breakage as a genotoxicity biomarker and Ames Salmonella mutagenicity tests as a second, supporting indicator of genotoxicity. Data from experiments conducted during rainfall runoff events following winter application of pesticides in 2000 and 2001 indicated that DNA strand breaks were significantly elevated in fish exposed to San Joaquin River (CA, USA) water (38.8, 28.4, and 53.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively) compared with a nearby reference site (15.4, 8.7, and 12.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively). Time-course measurements in field experiments supported a linkage between induction of DNA strand breakage and the timing of agricultural runoff. San Joaquin River water also caused significant reversion mutation in two Ames Salmonella tester strains. Salmonella mutagenicity corroborated in-stream effects, further strengthening a causal relationship between runoff events and genotoxicity. Potentially responsible agents are discussed in the context of timing of runoff events in the field, concordance between laboratory and field exposures, pesticide application patterns in the drainage, and analytical chemistry data.

Present-Day State of Coral Reefs of Nha Trang Bay (Southern Vietnam) and Possible Reasons for the Disturbance of Habitats of Scleractinian Corals

Our investigations were conducted from 1990 to 2002. Sampling of bottom sediments and biological objects, as well as photo and video shooting, were performed during scuba diving. The state of the environment and coral reef communities was assessed using the chemical–analytical, fluorometric, and luminometric methods, as well as the Ames test and the transect technique. The research results suggest that the spectrum and distribution pattern of persistent congeners of PCDD/Fs (dioxins) in bottom sediments are similar to those of the defoliant “Agent Orange” and that the bottom sediments are toxic and display photo inhibition and a mutagenic effect. The bottom of the bay is heavily silted throughout its depth. Many large dead colonies of corals without mechanical damage were observed everywhere. The total coverage by live corals in all sites investigated does not exceed 30%. Although, without a doubt, many factors contributed much to the disturbance of the bay ecosystems, the actual trigger for the degradation of the coral reefs seems to be the input of dioxin-containing chemicals used as defoliants during the American–Vietnamese war (Vietnam War).

Lake Baikal: biomonitoring of pulp and paper mill waste water

The quality and biological effects of the waste waters released by Baikalsk Pulp and Paper Mill were monitored chemically and biologically. In 1:5 dilution, the treated waste water induced monooxygenase activity in the liver of grayling and bullhead in standardised laboratory conditions. The Ames test was used to monitor mutagenicity of waste waters of the mill and tissue extracts of fish, sponge, mollusc and plankton collected near the mill and of seals collected from the middle part of the lake. Mutagens were found in waste water produced during pulp chlorination before treatment and in a few samples of fully treated waste water during 10 years (1982–1993). Bottom sediments near the mill showed some mutagenicity. Mutagens were not found in tissues of most aquatic animals studied with the exception of zooplankton, roach and seals collected in Lake Baikal close to the discharge outlet of the mill.

Mutagenicity of bleached and unbleached effluents from Baikalsk pulp and paper mill at Lake Baikal, Russia

The mutagenicity of bleached pulp mill effluents was compared to the mutagenicity of unbleached waste waters. Mutagenicity was assessed with the Ames test, using metabolic activation systems isolated from the liver of rats and fish. Liver extracts from fish caught in polluted areas, and from fish experimentally exposed to waste water, were also investigated. Pulp mill effluents taken after chlorination showed mutagenic activity. The activity diminished during the waste water treatment. Tissue extracts from fish exposed to various concentrations of treated bleached and unbleached pulp mill effluents showed only slight mutagenic activity in a few samples. In the case of bleached pulp mill effluents monooxygenase activities were elevated in those samples where slight mutagenicity was observed. In the case of unbleached effluents no such correlation was found.

Accumulation of Mutagenic Xenobiotics in Fresh Water (Lake Baikal) and Marine (Hornoya Island) Ecosystems

Extracts from tissues of a wide range of aquatic organisms (plants, plankton, decapods, molluscs, fish, Baikal seals, and fish-eating birds and their eggs) from Lake Baikal and from the Selenga River estuary and tissue extracts of birds breeding on Hornoya Island (northern Norway) were assayed for mutagenicity using the Ames Salmonella/microsome test. The activities of cytochrome P-450 and the enzymes of phase II of detoxification were also studied in the liver of fish and birds. Evidence was found for the accumulation of mutagens in the food chain. The relationship of bioaccumulation to the levels of enzyme activities possessing both detoxification and activation functions is discussed in the cases of fish and birds. The accumulation of mutagens was found to depend on the activity and the level of induction of the enzymes providing the detoxification and metabolic activation in the livers of fish and birds.

Biochemical and Genotoxicological Monitoring of Ecosystems with Special Reference to Lake Baikal and Northern Black Sea

The test-systems for biological indication and biological monitoring of carcinogenic and mutagenic compounds in water ecosystems are demonstrated the increasing content of mutagenic compounds in the tissues of the fresh water and marine animal. We use the Ames test for assay of tissue extracts from the water animals. The mutagen content in tissue of fish and other water animals was found in different region of Caspian and Black Sea, Rybinsk Reservoir and Baikal Lake.

Monooxygenase activities in the liver of fish living in Lake Baikal and after treatment with waste waters from the Baikalsk Pulp and Paper Mill

The biological effects of the waste waters released by Baikalsk Pulp and Paper Mill were studied in fish collected from Lake Baikal. Fish were also exposed in laboratory conditions to known inducers of hepatic monooxygenase activities. We did not find any differences in monooxygenase activities of grayling and sculpins caught near the pulp and paper mill compared to control fish caught in the middle part of Lake Baikal. The results showed that the waste water treatment in the mill is effective. Usually the treated waste water enters the lake diluted up to 5% concentration. However, only at 20% concentration did the treated waste water induce hepatic monooxygenase activities in the fish studied in laboratory conditions.

Accumulation of Mutagenic Xenobiotics in Water Ecosystems with Special Reference to Lake Baikal

Mutagenic substances are amongst the most dangerous compounds of the antropogenic pollution. Their action may be delayed and later manifested in the subsequent generations of animals (including fish) and people. Recent sharp increases in the number of tumours in fish in most cases can be attributed to the pollution of aquatic ecosystems with mutagenic and carcinogenic xenobiotics (MCX), with a smaller number of malformations caused by viral diseases. Chemical methods of detection are not sensitive enough to monitor MCX which can cause biological effects at extremely low concentrations in tissues of animals. The advantages of biological testing are high sensitivity and possibility to identify compounds which acquire mutagenic and carcinogenic properties after metabolic activation, for instance with cytochrome P-450. We assayed tissue extracts of aquatic organisms (aquatic plants, decapoda, molluscs, fish, Baikal seals, fish-eating birds and their eggs) from Lake Baikal and the Selenga River estuary as well as fresh and waste water samples usingSalmonella/microsomeAmes test. Presence of MCX was followed in the main food chain in Lake Baikal which consists of a primary zooplankton producerEpishura baikalensis(90%) and amphipods, endemic sculpins (the main species of Baikal oilfish) and Baikal seal. We did not find mutagenic activity in the fish tissues. However some extracts from seal fat and muscles demonstrated genotoxic activity. Frame shift mutations were caused by mutagenic samples from seal fat (Salmonella typhimurumstrain TA 98).

Health Environment of Altai Territory and Monooxygenase and Conjugating Activities in Placentae of Newborn

Intensification of the industry and agriculture in Russia, despite a number of measures on the environmental protection, is accompanied by the exhausts in the air, in water and ground ecosystems of constantly increasing amount of xenobiotics, which possess the ability not only to accumulate in animals and human tissues but causing development of pathological processes of various etiology. Another important factor that initiates different pathological states, is accumulation of radionuclides in the environment, increasing to a great extent after the Chernobyl tragedy. Long-time consequences of minor dosages of the ionized radiation with the chronic character of this influence on the molecular level at present are not thoroughly studied. However, it is known, that the genetic apparatus is the first to suffer, irreversible disturbances in the system of haemogenesis, in the membrane structures of the cells of the blood take place. For the last time in connection with appearance of new data about the character of the radioactive pollution caused by some accidents at the plants of the military industrial complex and consequences after the nuclear arms testing, there occurred the question concerning the associated action of radionuclides and environmental pollution by xenobiotics, that reveal the mutagenous, carcinogenic and teratogenic action.