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Increased use of fertilisers and pesticides has raised levels of agricultural pollution in surface and ground waters. Organism using these water sources are at risk of exposure to ammonium nitrate fertiliser. The effects of ammonium nitrate on spawn, larva and adult common frogs was investigated using ammonium nitrate fertiliser in solution and granular form at various stages of frog development. The concentrations used, up to 100mgIL NO-3-N used reflect nitrate concentrations on agricultural land in the United Kingdom in water bodies located within and adjacent to agricultural land at times when common frogs are actively breeding or developing. Nitrate concentrations in frog breeding ponds were high (> 1OOmgIL NO-3-N) during the frog breeding season, especially when water entered from field drains, but significantly lower (<25 mglL) for the remainder of the year. Frogs did not show a selective preference for ponds with low nitrate concentrations. Frog spawn swelled when exposed to ammonium nitrate and its viability was reduced (87% survival in controls; 63% at 80 mgIL NH\NO-3). The 96 hour LCso for frog larvae was 781 mglL (95% confidence intervals of 587 to 942) and the 48 hour ECso was 399 mgIL (95% Cl = 234 to 546). Long term exposure to 100 mgIL NW4NO-3 in a flow through system reduced larval survival from 85% (controls) to 53% after 96 days, with most mortality occurring during the three weeks prior to metamorphosis. Larval growth was affected marginally but with some evidence of enhanced mass in the treated larvae, especially at the lowest nitrate concentration of 25 mWL NH\NO-3. Metamorphosis in this group was earlier than in the other groups; by day 80, 48% of the metamorphs had emerged, by comparison with 38, 34 and 24% for the controls and those exposed to 50 and 100 mgIL NW4NO'3 respectively. Furthermore, the mass of emergent metamorphs in the 25 mgIL treatment group was significantly higher than that of the controls.

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The Western Boreal Forest exhibits complex hydrogeology juxtaposed with rapid resource development. Predicting surface water chemistry to assess the influence of landuse and climate change is needed. The research purpose was to test if a global model (Gibbs), used to assess water chemistry relative to precipitation, geologic and evaporative processes can be applied to mid-continental locations; and test if regional to local scale controls of surface-groundwater interactions can be used to refine predictions where geologic processes dominate water chemistry. The global model applied to many ponds, but failed in dilute and saline ponds. Caution is necessary, as the model assumes chloride-dominated precipitation, and continental to regional scale groundwater systems influence water chemistry, independent of evaporative processes. Bedrock geology influenced ion composition, TDS and pH via mineral dissolution and scale of flow. Surficial geology influenced TDP, TDN, DOC, pH and TDS, and wetland connection influenced TDP, TDN and DOC via flowpath. To assess water chemistry and the influence of landuse and climate change, regional to local controls of surface-groundwater interactions prove valuable over the global assessment of chemistry in heterogeneous and complex landscapes. / Ecology

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Wetland systems have been widely studied and found to have enhanced capacity to transform meaningful amounts of nitrate (NO3-N) from shallow subsurface water before the improved-quality water is delivered to lake, river, and groundwater systems. Wetland are characterized by the abundant presence of electron donors and acceptors (i.e., organic carbon & NO3-N, respectively) as well as anoxic and reducing conditions which are crucial for supporting denitrification processes and the reduction of excessive nitrate levels in the environment. When favorable conditions within the wetland systems are not present, denitrification is often limited to the biofilm-protected bacteria hosted on the sediment surfaces. However, there is still a need to determine if floodplain wetlands are being utilized to their maximum potential in excess nitrate removal.

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