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The chemical 6PPD-quinone is highly toxic to some fish species of the Oncorhynchus and Salvelinus genera and is the oxidation product of the common car tire additive 6PPD. We present a new sample preparation method that involves liquid-liquid extraction of water samples followed by silica-based solid phase extraction prior to LC–MS/MS analysis. The new sample preparation method showed good analyte recovery from spiked water samples (78%–91%) and a low ion suppression effect, surpassing previously published methods. This new method was successfully validated, achieving a limit of quantification of 5 ng/L and estimated expanded measurement uncertainty of 18.6%. In a proof-of-concept study, the method was applied to several water samples from various sources in Southern Norway. These were runoff samples from tunnel washing, from a tunnel runoff treatment plant and downstream of the plant drain. In addition, two water samples from puddles were included: one was run-off from an artificial soccer turf field and one from a puddle on a country road. The results of the analyses revealed that the concentration of 6PPD-quinone was above the LC50 reported for coho salmon (Oncorhynchus kisutch) in all samples except the samples from and downstream of the treatment plant. The highest measured concentration was 258 ng/L, which is the 2.7-fold of the reported LC50 in coho salmon (95 ng/L). Our initial data emphasize the need for more comprehensive environmental monitoring of 6PPD-quinone as well as toxicological studies in aquatic organisms. car tire, liquid chromatography, mass spectrometry, runoff water, artificial turf pitch, 6PPDQ, 6PPD-quinone

Roach (Rutilus rutilus) is indigenous to south-eastern Norway and alien to the rest of the country. In Trondheim municipality, in the middle part of Norway, roach was introduced into the Ila watercourse in 1881. Roach has a great potential to alter the ecosystem when introduced to new locations. The potential negative impact on potable water source quality and the prospect of permanently eradicating an alien species resulted in rotenone treatment of six lakes in Trondheim municipality. The rotenone concentration in the lakes was surveyed by water sampling until it could no longer be detected. A lethal concentration of rotenone at all test points was measured in all lakes during the survey period. Fourteen days after treatment, a near homogenous concentration was reached. The concentration reduction was similar in the lakes and relatively quicker during the first weeks after treatment. It was also consistent between depths except for the surface, where the concentration degraded more quickly. Rotenone degradation is a key factor when planning eradication efforts, and reports on this varies considerably between different locations. Despite application of rotenone in different depth strata, it took several days to reach homogenous concentration and several months and a fall turnover for the rotenone to break down and dilute below the detection limit in the lakes described.

Signal crayfish, as an invasive alien species in Europe, have caused impacts on aquatic communities and losses of native crayfish. Eradication of recently established populations may be possible in small ponds (<2.5 ha) and short lengths of small watercourses using a nonselective biocide. Between 2004 and 2012, a total of 13 sites in the U.K. were assessed for suitability. Six were treated with natural pyrethrum and crayfish were successfully eradicated from three. In Norway, five sites were assessed and two sites were treated with a synthetic pyrethroid, cypermethrin, both successfully. In Sweden, three sites were treated with another synthetic pyrethroid, deltamethrin, all successfully. Defining the likely extent of population was critical in determining the feasibility of treatment, as well as the ability to treat the whole population effectively. Important constraints on projects included site size, habitat complexity, environmental risks, cooperation of landowners and funding availability. Successful projects were manageably small, had good project leadership, had cooperation from stakeholders, had access to resources and were carried out within one to three years. Factors influencing success included treating beyond the likely maximum geographical extent of the population and taking care to dose the treated area thoroughly (open water, plus the banks, margins, inflows and outflows). Recommendations are given on assessing the feasibility of biocide treatments and project-planning. crayfish; alien species; biological invasion; control; biocide; eradication; signal crayfish Pacifastacus leniusculus; natural pyrethrum; synthetic pyrethroid; toxicity

The invasive alien ectoparasite Gyrodactylus salaris is one of the greatest threats to wild Atlantic salmon (Salmo salar) in Norway. Since its introduction in the 1970s the Norwegian Environmental Authorities have applied a piscicide based eradication strategy, using rotenone to eradicate the host species, Atlantic salmon and the parasite. After refining the methods and techniques following several unsuccessful treatments, the program has become a success and a total eradication of G. salaris from Norway now seems possible. This paper describes the methods and techniques used in this program during a large eradication operation conducted in the Rauma infection zone in central Norway using different land based peristaltic and boat mounted pumps in combination with continuous drip stations and gardening cans. The eradication was performed in 2013 and 2014 and involved six infected rivers. The largest river, the river Rauma has an anadromous section of 42 kilometers and consists of both rugged fast flowing areas and slow flowing parts characterized by laminar water currents. The piscicide, CFT-Legumine®, containing 3.3% active rotenone was applied at a dose of 1 mg/l using a range of application methods aiming to achieve concentrations of 0.033 mg/l rotenone. To ensure target concentrations were met, rotenone concentrations were monitored using liquid chromatography with UV detection in all treated river in an on-site lab on a daily basis. Target concentration was reached in all treated rivers and while investigations are ongoing, to date they indicate eradication has been effective.

Pink salmon is an invasive fish species to the North Atlantic Ocean and Barents Sea regions, spreading from intentional releases in north-west Russia. We assess the removal methods used in 94 Norwegian rivers in 2023. In total, 250 000 adult pink salmon were caught when returning from the ocean feeding migration and removed before they were able to spawn. Successful removals show that it is possible to construct bank-to-bank traps to prevent pink salmon from entering even relatively large rivers – despite thousands and even tens of thousands of pink salmon approaching single rivers within a few weeks. Pink salmon by far outnumbered native salmonids, with 11 times more than Atlantic salmon, 35 times more than sea trout, and 13 times more than Arctic char entering the rivers based on trap catches. Traps were used in 50 rivers: resistance board weirs in six rivers, picket weirs in 16 rivers, and wire mesh traps in 28 rivers. Resistance board weirs and picket weirs were easier to keep clean and operate and ensured better fish welfare than wire mesh traps. Timing of river entry of pink salmon and native salmonids overlapped. Native salmonids were sorted out and released alive upstream of the traps. Immediate mortality of native salmonids caught in all three type traps was low (0.1–0.5% of captured fish). Northern Norway is the gateway for spread of pink salmon into the North Atlantic, and future distribution of pink salmon depends on the success of measures in this area. Experiences gained can be used to further develop a comprehensive strategy for removal of pink salmon to improve construction and operation of effective traps with complete coverage in rivers both in Norway and internationally. Improved trap design is also valuable when using large weirs in rivers for other monitoring and management purposes.

A fast, accurate and simple method using liquid chromatography (LC) with UV detection was used for the on-site determination of the piscicide rotenonein water during fish control treatments. Sample volumes of 10 to 40 µL were loaded onto a Waters XBridge™ C18 2.5 µm 3.0 x100 mm analytical column usinga mobile phase of water–acetonitrile (45:55) at a flow-rate of 0.5 mL/min. The method was evaluated using river and estuarine water spiked with rotenone(0.1–330 µg/L) and various preservation methods. The within-assay precision measured as relative standard deviation (RSD, n = 12) was 5.5 to 6.5% andthe between assay precision (RSD, n = 4) was 6.5 to 7.5%. The limit of quantification was 1 µg/L, below normal piscicidal treatment rates (5 to 200 µg/L)and regulatory limits (< 2 µg/L) generally considered safe. The analysis time was 6 min/sample allowing for real-time adjustment of rotenone dosages duringfish control treatments. The relatively small size (75×60×50 cm) of the LC system made it ideal for transportation and installation in remote treatment areas;it can be operated out of a small trailer in the field with electricity. Our studies indicate that the preservation of water samples with equal quantitiesof acetonitrile stabilizes rotenone indefinitely (> 170 days) if kept cool (4 °C) and in the dark. Although increased salinity decreased the recoveryof rotenone, sample filtration with Spin-X filter membranes negated the effect.