As a consequence of World War II, large amounts of munition have been deposited in coastal waters. Deterioration of the mines and bombs is resulting in a release of munition compounds (MCs) like trinitrotoluene to the surrounding marine environment, with potential implications to ecosystems. Analytical methods have thus far been unable to detect these compounds reliably in seawater. We present a highly sensitive method for the analysis of MCs in the marine environment. We combine preconcentration and sample clean up by solid phase extraction with separation and detection by ultra-high performance liquid chromatography - electrospray ionisation - mass spectrometry (UHPLC-ESI-MS) for the detection of MCs dissolved in filtered (< 0.2 µm) seawater. For biota, dried and ground samples were extracted in acetonitrile and analysed after simple dilution. Eleven MCs were detected by UHPLC-ESI-MS with limits of detection between 0.01 and 25 pg. For the first time, we used heavy isotopes of trinitroluene and dinitrobenzene to improve quantification in environmental samples. We detected 7 MCs in waters sampled at a known munition disposal site in the Baltic Sea after a 1000-fold preconcentration and using an injection volume of 25 µL. Trinitrotoluene and dinitrobenzene were the most abundant MCs, occurring at concentrations between 0.1 and 11.8 ng L-1. We observed 10 MCs at concentrations up to 24 µg g-1 dry weight in benthic organisms sampled from the site. The enhanced sensitivity of our method allowed us to detect MCs at concentrations relevant for assessment and management of munitions disposal sites in the marine environment.
Keywords: Environmental analysis; Explosives; Nitroamines; Nitrotoluenes; Organic contaminants; Seawater.
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