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Macroinvertebrates are one of the key components of lake ecosystems and are required to be monitored alongside other biological groups to define ecological status according to European Union legislation. Macroinvertebrate communities are highly variable and complex and respond to a diverse series of environmental conditions. The purpose of this study was to examine the relative importance of environmental variables in explaining macroinvertebrate abundance. A total of 45 sub-alpine lakes were sampled for macroinvertebrates in the shallow sublittoral. Environmental variables were grouped into four types: (1) aquatic physical and chemical parameters, (2) littoral and riparian habitat, (3) lake morphometric parameters and (4) sediment chemical characteristics. Nonparametric multiplicative regression (NPMR) was used to model the abundance of individual macroinvertebrate taxa. Significant models were produced for nine out of the 24 taxa examined. Sediment characteristics were the group most frequently included in models and also the factors to which taxa abundance was the most sensitive. Aquatic physical and chemical variables were the next group most frequently included in models although chlorophyll a was not included in any of the models and total phosphorus in only one. This indicates that many taxa may not show a direct easily interpretable response to eutrophication pressure. Lake morphometric factors were included in several of the models although the sensitivity of macroinvertebrate abundance tended to be lower than for sediment and aquatic physical and chemical factors. Habitat factors were only included in three models although riparian vegetation was found to have a significant influence on the abundance of Ephemera danica indicating that ecotone integrity is likely to play a role in its ecology. Overall, the models tended to be specific for species with limited commonality across taxa. Models produced by NPMR indicate that the response of macroinvertebrates to environmental variables can be successfully described but further research is required focussing in more detail on the response of key taxa to relevant environmental parameters and anthropogenic pressures

Highlights71 water samples from the Danube River and its tributaries were analysed.Most relevant micropollutants were benzotriazoles, pharmaceuticals, organophosphorus compounds, and PFOS/A.PFOS concentrations exceed its environmental quality standard (EQS).Concentrations and loads are similar for the years 2007 and 2013.

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Contact CEH NORA team at noraceh@ceh.ac.ukThe NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Convention and largely restricted in Europe. It continues to be detected in aquatic 18 environments, with only limited studies into the on-going sources. This paper explores PFOS 19 emissions discharged by the general population into a small catchment comprising of two 20 rivers in the UK. A sampling campaign was undertaken to improve our understanding of 21 population-derived PFOS sources from sewage treatment plants (STPs) and in rivers. A 22 corresponding modelling exercise allowed an emission estimate of 13 µg/day/per capita to be 23 derived for the Aire and Calder rivers. PFOS emission was linked to STP discharges, and 24 thereby population density, by using a correlation with the artificial sweetener sucralose, a 25 conservative chemical marker for waste water (R 2 = 0.69). The model was able to accurately 26 estimate the spatial trends of PFOS in the rivers, while predicted concentrations were within a 27 factor of three based on per capita emission values taken from the literature. Measured PFOS 28 concentrations in rivers suggested that emissions from STPs are partially dependent on 29 treatment type, where plants with secondary or tertiary treatment such as activated sludge 30 processes emit less PFOS, possibly due to increased partitioning and retention. With 31 refinements based on the type of treatment at each STP, predictions were further improved. 32 2 The total PFOS mass discharged annually via rivers from the UK has been estimated to be 33 between 215 and 310 kg, based on the per capita emissions range derived in this study. 34 1 Comparing Measured and Modelled PFOS Concentrations in a UK