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Papers by John Munthe

... JOHN MUNTHE1∗, BENNY LYVÉN2, HELENA PARKMAN1,4, YING-HUA LEE1, ÅKE IVERFELDT1, CONNY HARALDSS... more ... JOHN MUNTHE1∗, BENNY LYVÉN2, HELENA PARKMAN1,4, YING-HUA LEE1, ÅKE IVERFELDT1, CONNY HARALDSSON2, MATTI VERTA3 and PETRI PORVARI3 1 IVL ... to the transport of dissolved organic matter (Lee et al., 1994; Johansson and Iverfeldt, 1994; Bishop ...

Science of The Total Environment, 2010

We conducted a whole-lake experiment by manipulating the stratification pattern (thermocline dept... more We conducted a whole-lake experiment by manipulating the stratification pattern (thermocline depth) of a small polyhumic, boreal lake (Halsjärvi) in southern Finland and studying the impacts on lake mercury chemistry. The experimental lake was compared to a nearby reference site (Valkea-Kotinen Lake). During the first phase of the experiment the thermocline of Halsjärvi was lowered in order to simulate the estimated increase in wind speed and in total lake heat content (high-change climate scenario). The rate of methyl mercury (MeHg) production during summer stagnation (May-August) was calculated from water profiles before the treatment , during treatment (2005, 2006) and after treatment . We also calculated fluxes of MeHg from the epilimnion and from the hypolimnion to the sediments using sediment traps. Experimental mixing with a submerged propeller caused a 1.5-2 m deepening of the thermocline and oxycline. Methyl mercury production occurred mostly in the oxygen free layers in both lakes. In the experimental lake there was no net increase in MeHg during the experiment and following year; whereas the reference lake showed net production for all years. We conclude that the new exposed epilimnetic sediments caused by a lowering of the thermocline were a major sink for MeHg in the epilimnion. The results demonstrate that in-lake MeHg production can be manipulated in small lakes with anoxic hypolimnia during summer. The climate change induced changes in small boreal lakes most probably affect methyl mercury production and depend on the lake characteristics and stratification pattern. The results support the hypothesis that possible oxygen related changes caused by climate change are more important than possible temperature changes in small polyhumic lakes with regularly occurring oxygen deficiency in the hypolimnion.

Data on mercury levels in freshwater fish (mainly pike, perch, trout and char), from Norway, Swed... more Data on mercury levels in freshwater fish (mainly pike, perch, trout and char), from Norway, Sweden and Finland have been collected in a common database to assess spatial patterns as well as relationships with environmental factors such as atmospheric mercury deposition. A preliminary evaluation of fish Hg data from >1500 lakes shows that Hg levels referring to a 1-kg pike are highest in low-altitude lakes of the southern regions S. Norway, S+C. Sweden, and C. Finland, where regional medians are 0.5-0.8 mg/kg fw. In these regions, about 50-80 % of the lakes exceed 0.5 mg/kg and about 5-20(40) % of the lakes exceed 1.0 mg/kg. Fish Hg levels in high-altitude lakes are lower than in low-altitude lakes in the corresponding region.

AMBIO: A Journal of the Human Environment, 2009

Materials and …, 2004

1 IVL Swedish Environmental Research Institute, PO Box 47086, SE-402 58 Gothenburg, Sweden. john.... more 1 IVL Swedish Environmental Research Institute, PO Box 47086, SE-402 58 Gothenburg, Sweden. john.munthe@ivl.se 2 Norwegian Institute for Water Research (NIVA), Postboks 173 Kjelsås N-0411, Oslo, Norway 3 Institute of Applied Environmental Research (ITM), ...

Environmental Science & Technology, 2003

We observed significant increases in the runoff output of total mercury (TotHg) and methyl mercur... more We observed significant increases in the runoff output of total mercury (TotHg) and methyl mercury (MeHg) from a small spruce forest catchment (0.071 km 2 ) after clearcutting and soil treatment. Here we show that forest regeneration practices may act as an important additional source of TotHg and MeHg to forest lakes. TotHg and MeHg in runoff from two small forested catchments were monitored during the period 1994 to 2001. In the autumn of 1997, one of the catchments was clear-cut. Soil preparation (mounding) was carried out in the autumn of 1998 and replanting in the summer of 1999. During the 3 years after the silvicultural treatment, medians of monthly flowweighted TotHg and MeHg concentrations (12.02 ng L -1 and 0.35 ng L -1 , respectively) and output loads (0.80-0.97 g km -2 a -1 and 0.011-0.036 g km -2 a -1 , respectively) increased significantly compared to the 3 years calibration period (8.13 ng L -1 and 0.15 ng l -1 ; 2.0-5.3 g km -2 a -1 and 0.11-0.16 g km -2 a -1 , respectively). These results indicate that clear-cutting and/or soil treatment significantly increases the mobility of TotHg and MeHg accumulated in forest soil and may thus be an important factor for the total input of Hg to boreal freshwater ecosystems.

Http Dx Doi Org 10 1579 0044 7447 38 7 373, Nov 1, 2009

The Science of the total environment, Jan 15, 2015

Environmental quality monitoring of water resources is challenged with providing the basis for sa... more Environmental quality monitoring of water resources is challenged with providing the basis for safeguarding the environment against adverse biological effects of anthropogenic chemical contamination from diffuse and point sources. While current regulatory efforts focus on monitoring and assessing a few legacy chemicals, many more anthropogenic chemicals can be detected simultaneously in our aquatic resources. However, exposure to chemical mixtures does not necessarily translate into adverse biological effects nor clearly shows whether mitigation measures are needed. Thus, the question which mixtures are present and which have associated combined effects becomes central for defining adequate monitoring and assessment strategies. Here we describe the vision of the international, EU-funded project SOLUTIONS, where three routes are explored to link the occurrence of chemical mixtures at specific sites to the assessment of adverse biological combination effects. First of all, multi-resid...

... JOHN MUNTHE1∗, BENNY LYVÉN2, HELENA PARKMAN1,4, YING-HUA LEE1, ÅKE IVERFELDT1, CONNY HARALDSS... more ... JOHN MUNTHE1∗, BENNY LYVÉN2, HELENA PARKMAN1,4, YING-HUA LEE1, ÅKE IVERFELDT1, CONNY HARALDSSON2, MATTI VERTA3 and PETRI PORVARI3 1 IVL ... to the transport of dissolved organic matter (Lee et al., 1994; Johansson and Iverfeldt, 1994; Bishop ...

Science of The Total Environment, 2010

We conducted a whole-lake experiment by manipulating the stratification pattern (thermocline dept... more We conducted a whole-lake experiment by manipulating the stratification pattern (thermocline depth) of a small polyhumic, boreal lake (Halsjärvi) in southern Finland and studying the impacts on lake mercury chemistry. The experimental lake was compared to a nearby reference site (Valkea-Kotinen Lake). During the first phase of the experiment the thermocline of Halsjärvi was lowered in order to simulate the estimated increase in wind speed and in total lake heat content (high-change climate scenario). The rate of methyl mercury (MeHg) production during summer stagnation (May-August) was calculated from water profiles before the treatment , during treatment (2005, 2006) and after treatment . We also calculated fluxes of MeHg from the epilimnion and from the hypolimnion to the sediments using sediment traps. Experimental mixing with a submerged propeller caused a 1.5-2 m deepening of the thermocline and oxycline. Methyl mercury production occurred mostly in the oxygen free layers in both lakes. In the experimental lake there was no net increase in MeHg during the experiment and following year; whereas the reference lake showed net production for all years. We conclude that the new exposed epilimnetic sediments caused by a lowering of the thermocline were a major sink for MeHg in the epilimnion. The results demonstrate that in-lake MeHg production can be manipulated in small lakes with anoxic hypolimnia during summer. The climate change induced changes in small boreal lakes most probably affect methyl mercury production and depend on the lake characteristics and stratification pattern. The results support the hypothesis that possible oxygen related changes caused by climate change are more important than possible temperature changes in small polyhumic lakes with regularly occurring oxygen deficiency in the hypolimnion.

Data on mercury levels in freshwater fish (mainly pike, perch, trout and char), from Norway, Swed... more Data on mercury levels in freshwater fish (mainly pike, perch, trout and char), from Norway, Sweden and Finland have been collected in a common database to assess spatial patterns as well as relationships with environmental factors such as atmospheric mercury deposition. A preliminary evaluation of fish Hg data from >1500 lakes shows that Hg levels referring to a 1-kg pike are highest in low-altitude lakes of the southern regions S. Norway, S+C. Sweden, and C. Finland, where regional medians are 0.5-0.8 mg/kg fw. In these regions, about 50-80 % of the lakes exceed 0.5 mg/kg and about 5-20(40) % of the lakes exceed 1.0 mg/kg. Fish Hg levels in high-altitude lakes are lower than in low-altitude lakes in the corresponding region.

AMBIO: A Journal of the Human Environment, 2009

Materials and …, 2004

1 IVL Swedish Environmental Research Institute, PO Box 47086, SE-402 58 Gothenburg, Sweden. john.... more 1 IVL Swedish Environmental Research Institute, PO Box 47086, SE-402 58 Gothenburg, Sweden. john.munthe@ivl.se 2 Norwegian Institute for Water Research (NIVA), Postboks 173 Kjelsås N-0411, Oslo, Norway 3 Institute of Applied Environmental Research (ITM), ...

Environmental Science & Technology, 2003

We observed significant increases in the runoff output of total mercury (TotHg) and methyl mercur... more We observed significant increases in the runoff output of total mercury (TotHg) and methyl mercury (MeHg) from a small spruce forest catchment (0.071 km 2 ) after clearcutting and soil treatment. Here we show that forest regeneration practices may act as an important additional source of TotHg and MeHg to forest lakes. TotHg and MeHg in runoff from two small forested catchments were monitored during the period 1994 to 2001. In the autumn of 1997, one of the catchments was clear-cut. Soil preparation (mounding) was carried out in the autumn of 1998 and replanting in the summer of 1999. During the 3 years after the silvicultural treatment, medians of monthly flowweighted TotHg and MeHg concentrations (12.02 ng L -1 and 0.35 ng L -1 , respectively) and output loads (0.80-0.97 g km -2 a -1 and 0.011-0.036 g km -2 a -1 , respectively) increased significantly compared to the 3 years calibration period (8.13 ng L -1 and 0.15 ng l -1 ; 2.0-5.3 g km -2 a -1 and 0.11-0.16 g km -2 a -1 , respectively). These results indicate that clear-cutting and/or soil treatment significantly increases the mobility of TotHg and MeHg accumulated in forest soil and may thus be an important factor for the total input of Hg to boreal freshwater ecosystems.

Http Dx Doi Org 10 1579 0044 7447 38 7 373, Nov 1, 2009

The Science of the total environment, Jan 15, 2015

Environmental quality monitoring of water resources is challenged with providing the basis for sa... more Environmental quality monitoring of water resources is challenged with providing the basis for safeguarding the environment against adverse biological effects of anthropogenic chemical contamination from diffuse and point sources. While current regulatory efforts focus on monitoring and assessing a few legacy chemicals, many more anthropogenic chemicals can be detected simultaneously in our aquatic resources. However, exposure to chemical mixtures does not necessarily translate into adverse biological effects nor clearly shows whether mitigation measures are needed. Thus, the question which mixtures are present and which have associated combined effects becomes central for defining adequate monitoring and assessment strategies. Here we describe the vision of the international, EU-funded project SOLUTIONS, where three routes are explored to link the occurrence of chemical mixtures at specific sites to the assessment of adverse biological combination effects. First of all, multi-resid...