Major ion concentrations and the inorganic carbon chemistry of the Humber rivers

摘要: Measurements of major ion concentrations in the main rivers draining into Humber estuary show two dominant spatial patterns, related to anthropogenic sources from catchments urban/industrial areas and background weathering rural catchments. Most ions exhibit dilution effects with flow, higher at baseflow compared stormflow conditions. This suggests a predominance point (effluent) and/or groundwater (weathering) ions. An exception is NO3−, which exhibits under conditions certain catchments, suggesting diffuse (catchment) sources, possibly derived agricultural runoff. Inter-ion relationships were used for endmember mixing analysis identify whether or not components exhibiting conservative behaviour within river. The relationship between straight line endmembers, indicative processes. chemical patterns appear be controlled by hydrology existence distinct inter-ion ratios endmembers. In terms inorganic carbon system, HCO3− component dissolved (DIC), CO2 (H2CO30 CO2(aq)) representing approximately 10% CO32− less than 1% DIC. All river waters are oversaturated respect CO2, excess partial pressures dioxide (EpCO2) typically 5 20 times atmospheric pressure. elevated levels EpCO2 water sufficient decouple pH alkalinity. microbial production breakdown organic availability nutrients (particularly NO3−) generally highest urban industrial together Derwent receives high rates do simple both determinands inherently non-conservative behaviour. These results provide important information on base more detailed process studies modelling work. imply that most can modelled using relationships. contrast may require thorough evaluation in-stream system.