Lake sediment chronologies of ten lakes in northeastern Germany (Arendsee [AS], Carwitzer See [CR], Feldberger Haussee [FH], Breiter Luzin [BL], Schmaler Luzin [SL], Oberuckersee [OR], Scharmützelsee [PL], Stechlinsee [ST], Tiefwarensee [TF], Großer Wummsee [WM]) were created to reconstruct anthropogenic activity over the past 100 years starting from 2015 as the most present date. Collection of samples took place between 2015-07-10 and 2015-09-04 for all but one lake which was re-sampled in December 2016 (ST). Cores of lake sediments were collected using a gravity corer (90 mm diameter; UWITEC, Mondsee, Austria). Minimum length of the cores was 1 m. Cores were sliced immediately at the shore of each lake into 5 mm (lakes FH and BL) or 10 mm samples (all other lakes). Sliced cores were stored at 4 °C until arrival at the IGB laboratory at Lake Stechlin. There, they were weighed and then frozen at -20 °C for storage until further processing. Loss of ignition was determined using an electric muffle furnace (SNOL 8,2/1100, Utena, Lithuania). Dating of each sliced core horizon was performed by direct gamma assay of isotopes 210Pb and 137Cs of a freeze-dried subsample (1 g). Depending on the lake, a time span starting with the sampling year (i.e. 2015/2016) and reaching back to at least the 1950s and at most to pre-1900s was covered. Concentrations of elements (aluminium, arsenic, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, molybdenum, sodium, nickel, phosphorus, lead, sulphur, zinc) were determined with microwave-assisted aqua-regia (MAE-AR) extraction in conjunction with inductively coupled plasma-optical emission spectrometry (ICP-OES). Concentrations of organic pesticides DDX (2,4'- and 4,4'- congeners of each dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethane [DDD] and dichlorodiphenyldichloroethylene [DDE]), hexachlorobenzene (HCB), HCHs (α-, β-, γ-, δ-hexachlorocyclohexane [HCH]) and trifluralin were extracted applying miniaturized solid-liquid extraction (MISOLEX; Simon et al. 2021, doi:10.1007/s11368-021-03080-0). Extracts were measured with solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS).
