Improving water quality has become an important environmental issue, spurred in part by the Water... more Improving water quality has become an important environmental issue, spurred in part by the Water Framework Directive. However, the relationship of policy change with forest water protection measures is relatively unknown. We analyzed how policy and practice have developed in Sweden using 50 years of historic data from the Krycklan Catchment Study, focusing on riparian buffers. Corresponding to legislation, education and voluntary measures emphasizing stream protection, two step changes occurred; between the 1970s–1980s, buffers increased by 67%, then by 100% between 1990s and 2000s. By 2013, just 50% of the stream length affected by forestry was protected and the application has varied by stream size; small streams lacked a buffer approximately 65% of the time, while 90% of large streams had buffers. The doubling of buffer implementation from the 1990s–2000s corresponded to the adoption of a number of environmental protection policies in the 1990s that all came into effect during t...
The Science of the total environment, Aug 17, 2016
In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeoc... more In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeochemical processes occurring in the riparian zone (RZ). However, RZs are spatially heterogeneous and information about solute chemistry is typically limited. This is problematic when making inferences about stream chemistry. Hypothetically, the strength of links between riparian and stream chemistry is time-scale dependent. Using a ten-year (2003-2012) dataset from a northern Swedish catchment, we evaluated the suitability of RZ data to infer stream dynamics at different time scales. We focus on the role of the RZ versus upslope soils in controlling sulfate (SO4(2)(-)) and dissolved organic carbon (DOC). A priori, declines in acid deposition and redox-mediated SO4(2)(-) pulses control sulfur (S) fluxes and pool dynamics, which in turn affect dissolved organic carbon (DOC). We found that the catchment is currently a net source of S, presumably due to release of the S pool accumulated durin...
Long-range atmospheric transport is a major pathway for delivering persistent organic pollutants ... more Long-range atmospheric transport is a major pathway for delivering persistent organic pollutants to the oceans. Atmospheric deposition and volatilization of chlorinated pesticides and algae-produced bromoanisoles (BAs) were estimated for Bothnian Bay, northern Baltic Sea, based on air and water concentrations measured in 2011-2012. Pesticide fluxes were estimated using monthly air and water temperatures and assuming 4 months ice cover when no exchange occurs. Fluxes were predicted to increase by about 50 % under a 2069-2099 prediction scenario of higher temperatures and no ice. Total atmospheric loadings to Bothnian Bay and its catchment were derived from air-sea gas exchange and "bulk" (precipitation + dry particle) deposition, resulting in net gains of 53 and 46 kg year(-1) for endosulfans and hexachlorocyclohexanes, respectively, and net loss of 10 kg year(-1) for chlordanes. Volatilization of BAs releases bromine to the atmosphere and may limit their residence time in ...
Abstract Measurements of persistent organic pollutants (POP) in air and deposition have been carr... more Abstract Measurements of persistent organic pollutants (POP) in air and deposition have been carried out at sea-based and coastal sites on the Swedish west coast. The aim was to obtain knowledge concerning the input of these contaminants to the Skagerrak via atmospheric transport and deposition. The measurements showed a continuous deposition of POP, here represented by PAH, PCB and HCH, to the sea surface of the Skagerrak and an important episodic input in connection with long-range air transport especially together with precipitation. However, the deposition fluxes may also be affected by local sources. A seasonal variation was observed in the concentrations of the different compounds in both air and deposition. The deposited amounts of the selected compounds were within the same order of magnitude at the coastal and sea-based stations but there were differences in the deposition on the individual sampling occasions. There were minor geographical variations with a somewhat greater deposition of HCH and PAH in the southern part of Skagerrak.
Improving water quality has become an important environmental issue, spurred in part by the Water... more Improving water quality has become an important environmental issue, spurred in part by the Water Framework Directive. However, the relationship of policy change with forest water protection measures is relatively unknown. We analyzed how policy and practice have developed in Sweden using 50 years of historic data from the Krycklan Catchment Study, focusing on riparian buffers. Corresponding to legislation, education and voluntary measures emphasizing stream protection, two step changes occurred; between the 1970s–1980s, buffers increased by 67%, then by 100% between 1990s and 2000s. By 2013, just 50% of the stream length affected by forestry was protected and the application has varied by stream size; small streams lacked a buffer approximately 65% of the time, while 90% of large streams had buffers. The doubling of buffer implementation from the 1990s–2000s corresponded to the adoption of a number of environmental protection policies in the 1990s that all came into effect during t...
The Science of the total environment, Aug 17, 2016
In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeoc... more In boreal forest catchments, solute transfer to streams is controlled by hydrological and biogeochemical processes occurring in the riparian zone (RZ). However, RZs are spatially heterogeneous and information about solute chemistry is typically limited. This is problematic when making inferences about stream chemistry. Hypothetically, the strength of links between riparian and stream chemistry is time-scale dependent. Using a ten-year (2003-2012) dataset from a northern Swedish catchment, we evaluated the suitability of RZ data to infer stream dynamics at different time scales. We focus on the role of the RZ versus upslope soils in controlling sulfate (SO4(2)(-)) and dissolved organic carbon (DOC). A priori, declines in acid deposition and redox-mediated SO4(2)(-) pulses control sulfur (S) fluxes and pool dynamics, which in turn affect dissolved organic carbon (DOC). We found that the catchment is currently a net source of S, presumably due to release of the S pool accumulated durin...
Long-range atmospheric transport is a major pathway for delivering persistent organic pollutants ... more Long-range atmospheric transport is a major pathway for delivering persistent organic pollutants to the oceans. Atmospheric deposition and volatilization of chlorinated pesticides and algae-produced bromoanisoles (BAs) were estimated for Bothnian Bay, northern Baltic Sea, based on air and water concentrations measured in 2011-2012. Pesticide fluxes were estimated using monthly air and water temperatures and assuming 4 months ice cover when no exchange occurs. Fluxes were predicted to increase by about 50 % under a 2069-2099 prediction scenario of higher temperatures and no ice. Total atmospheric loadings to Bothnian Bay and its catchment were derived from air-sea gas exchange and "bulk" (precipitation + dry particle) deposition, resulting in net gains of 53 and 46 kg year(-1) for endosulfans and hexachlorocyclohexanes, respectively, and net loss of 10 kg year(-1) for chlordanes. Volatilization of BAs releases bromine to the atmosphere and may limit their residence time in ...
Abstract Measurements of persistent organic pollutants (POP) in air and deposition have been carr... more Abstract Measurements of persistent organic pollutants (POP) in air and deposition have been carried out at sea-based and coastal sites on the Swedish west coast. The aim was to obtain knowledge concerning the input of these contaminants to the Skagerrak via atmospheric transport and deposition. The measurements showed a continuous deposition of POP, here represented by PAH, PCB and HCH, to the sea surface of the Skagerrak and an important episodic input in connection with long-range air transport especially together with precipitation. However, the deposition fluxes may also be affected by local sources. A seasonal variation was observed in the concentrations of the different compounds in both air and deposition. The deposited amounts of the selected compounds were within the same order of magnitude at the coastal and sea-based stations but there were differences in the deposition on the individual sampling occasions. There were minor geographical variations with a somewhat greater deposition of HCH and PAH in the southern part of Skagerrak.
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Papers by Hjalmar Laudon