Eva Nilsson

Sediment and water phase toxicity and UV-activation of six chemicals used in military explosives ☆

Abstract Explosives used in ammunition have been dumped in both lakes and oceans before the potential environmental effects of these chemicals were understood. Growing environmental concern in society and in the Swedish military resulted in a project dealing with the aquatic toxicology of explosives. The aim of the present study was to assess the hazard of six explosives by determining the acute sediment and water phase toxicity for two crustaceans (Daphnia magna and Nitocra spinipes). Detoxification during storage was used as an indication of degradability (hydrolysis and biodegradation). The effect of ultraviolet light on the toxicity of these compounds was determined by post-exposure to ultraviolet light and determination of toxicity enhancement. The explosives were picric acid, trinitrotoluene, (2,4-dinitrotoluene), hexahydro-1,3,5-trinitro-1,3,5-trazine, nitroguanidine, and pentyl. The stabilising agent diphenylamine was tested in the same way. For the major explosive, trinitrotoluene, the water-phas...

Toxicity assessment of sequential leachates of tire powder using a battery of toxicity tests and toxicity identification evaluations.

Approximately 460,000 ton of rubber are dispersed annually along the European roads due to tire wear. Tire rubber is known to leach compounds that are toxic to aquatic organisms. However, the potential effects of tire wear material on aquatic organisms at environmental relevant concentrations, and over time have so far not been extensively studied. In this study, rubber from three different tires was abraded and the powder leached in deionised water. The rubber powder was leached six times sequentially. All leachates were tested for toxicity using standardized toxicity tests including green algae (Pseudokirchneriella subcapitata, 72h growth inhibition), crustaceans (Daphnia magna, 24 and 48h immobility and Ceriodaphnia dubia, 48h survival and 9d reproduction and survival), and zebra fish eggs (Danio rerio, 48h lethality). The reproduction of C. dubia was the most sensitive endpoint tested, with an EC50 of 0.013 g L(-1) up to the third leaching of the most toxic tire, which is similar to a predicted concentration in road runoffs. The toxicity of all tires was reduced by the sequential leachings and after the sixth leaching the EC50s were >0.1 g L(-1) for all endpoints. Toxicity identification evaluations indicated that the toxicity was caused by zinc and organic compounds.

Sediment toxicity in the Kattegat and Skagerrak

Sediments were sampled from 62 sites in the Kattegat and Skagerrak, which are located between the Baltic and the North Sea in the Western Atlantic, during autumn 1989 and spring 1990. From each site 5 to 6 samples were taken wit ha box-corer. After mixing to composite samples on board, transport and storage (at 4 °C for 2 to 4 weeks), the samples were tested for toxicity to Daphnia magna and Nitocra spinipes. Immobility in Daphnia after exposure to 16 percent sediment (wet wt) in reconstituted standardized water (ISO, 1982) ranged from 0 to 88 percent after 24 h and from 3 to 95 percent after 48 h. For Nitocra the toxicity, determined as the 96-h LC50 (% wet wt) at 7‰ salinity, ranged from > > 32 percent (nontoxic) to 1.8 percent (most toxic). All exposures were made in duplicates and the effects obtained in the duplicates with the same sediment were correlated to each other. However, sediment toxicity to Daphnia and Nitocra was not. The test with Nitocra, which was made at several concentrations of sediment, was considered to give the most reliable picture of sediment toxicity in the Kattegat and Skagerrak. This ambient toxicity assessment identified three areas with toxic sediment, (1) the Göta älv estuary (outside the city of Göteborg) and its surroundings, (2) the Bay of Laholm in southern Kattegat, which is an area with periodic oxygen depletion and where repeated mussel kills have occurred during the last decade, and (3) an area in the open Skagerrak northwest of Skagen (the tip of the Jutland peninsula). Sediments, which had been stored at 4 °C, were tested again after 6 to 13 mos with the Nitocra test. Stored sediment toxicity was poorly correlated with fresh sediment toxicity. The average detoxification during storage was 5 times, but the range was 3 orders of magnitude, from 17 times more toxic to 73 times less toxic. The reasons for the observed areal and storage differences in sediment toxicity are so far not understood.

Assessing pollution and UV-enhanced toxicity in Torsviken, Sweden, a shallow bay exposed to contaminated dredged harbor sediment and hazardous waste leachate

Abstract Torsviken is a small bay close to the city of Gothenburg, Sweden. Part of the bay has been used for disposal of dredged harbor sediment since the 1970s. Other potential sources of contamination are a deposit site and treatment facility for hazardous waste. The area has been classified as ecologically sensitive and is of great ornithological interest. Birds are abundant and several rare species have been observed. In this study, pollution was assessed by analyzing concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls and heavy metals and by measuring toxicity of sediment samples to Daphnia magna, Nitocra spinipes, Chironomus riparius and Hyalella azteca. The combined exposure to several contaminants and solar light can enhance toxic effects, and since Torsviken is a shallow bay (maximum depth 2 m), organisms surviving the bioassays were exposed to simulated ultraviolet (UV) light of site-relevant intensity for 2 h to detect potential UV-enhanced toxicity. Torsviken is subdi...

Combining sediment quality criteria and sediment bioassays with photoactivation for assessing sediment quality along the Swedish West Coast

Abstract Sediments from 48 sites along the Swedish West Coast were sampled for determination of priority pollutants (metals, polycyclic aromatic hydrocarbons and chlorinated hydrocarbons). Toxicity to two crustaceans (Daphnia magna and Nitocra spinipes) were also determined within 2 weeks and after 12 months of storage at 4°C. Since, according to earlier studies, polycyclic aromatic hydrocarbons may exhibit photoinduced toxicity, all test vessels (including exposed test organisms) were subjected to ultraviolet irradiation after immobility/lethality was recorded. Thereafter, the vessels were recorded again for immobility/lethality and the data were compared with phototoxicity data of analyzed substances, in order to estimate the bioavailability of phototoxic hydrocarbons in these sediments. Immobility of Daphnia exposed to 16% sediment (wet weight) ranged from 0 to 80% both before and after photo treatment. Nitocra 96-h LC50s (% wet weight of sediment) ranged from 1.9 to > 32% before, and from 1.0 to > 32%...

The contribution of cobalt and manganese to the acute and chronic toxicity of sediments from Lake Molnbyggen and adjacent lakes around Leksand, Sweden

A number of studies of pollutants and their effects on the fish fauna of Lake Molnbyggen outside Leksand, Sweden have been focused on leachate from the municipal landfill (Lindbodarna), which is located above the lake. The aim of the present study was to test the toxicity of sediment from Molnbyggen and some adjacent lakes, in order to see if this could explain the causes of the effects on the fish. The sampling sites were selected in co-operation with the project group at the Swedish Environmental Protection Agency to make the results more easily comparable with those from other studies on the fish fauna in the area. Both acute and chronic tests were made with the crustacean Ceriodaphnia dubia, and the sediment samples were equilibrated with standard reference water prior to exposure. The exposures were made under standard conditions in the laboratory to make them more readily comparable between the sampling locations and with previous studies. The effects on survival and reproduction were monitored during 8 days. After that a series of Toxicity Identification Evaluation manipulations of the tested waters were made in order to identify the cause(s) of the toxicity. The results from the Toxicity Identification Evaluation tests pointed towards heavy metals as the cause of toxicity, and the analytical results of heavy metals in the water phase showed that the concentrations of six metals (Cd, Co, Mn, Ni, Pb and Zn) were significantly correlated with toxicity. The concentrations of these metals were also correlated with each other making it hard to separate cause and effect among the metals. However, the concentrations of Cd, Ni, Pb and Zn were below the expected effect concentrations, but the measured concentrations of Co and Mn were high enough to be probable causes of the observed experimental toxicity. There was no indication that lipophilic compounds should have caused these effects. Therefore, the result of this study was rather surprising, showing that heavy metals like cobalt and/or manganese which are not generally considered as environmentally problematic may be of environmental concern. Potential effects of cobalt and manganese could be mediated through the olfactory system, because both these metals have been observed to affect this system in fish. However, the link between such effects and those observed on reproduction in Lake Molnbyggen is vague.