Chris Karman - Academia.edu (original) (raw)

Papers by Chris Karman

Research paper thumbnail of Alkylphenols in Produced Water: A First Tier Risk Assessment

Research paper thumbnail of Assessment of the Cumulative Effect of Aktivities in the Maritime Area: Overview of relevant legislation and proposal for a harmonised approach

Research paper thumbnail of Report on 15 causal linkages, with proposals for monitoring: Annex 4 of Framework for GES assessment and prioritization of pressures and activities

Research paper thumbnail of Random Sampling of HOCNFs and Underlying Test Reports

Poultry Science - POULTRY SCI, 2007

Research paper thumbnail of Ecotoxicological risk assessment related to chemicals and pollutants in off-shore oil production

Toxicology Letters, 2000

Offshore oil production results in environmental discharges of drill cuttings and produced water,... more Offshore oil production results in environmental discharges of drill cuttings and produced water, contaminated with residuals of exploration and production (E&P) chemicals and formation chemicals. Ecotoxicological risk assessment has been adopted as a tool in environmental chemical management (i.e. reduction of the use and environmental release of chemicals, use of 'green chemicals' and application of non-chemical alternatives). This paper presents an introduction to the basic principles of ecotoxicological risk assessment of offshore E&P chemicals, as it is elaborated in the internationally harmonised CHARM model. In northwestern Europe, this model is used for the purpose of E&P chemicals, notification and environmental care within the offshore oil industry.

Research paper thumbnail of Offshore olie- en gasactiviteiten en Natura 2000: inventarisatie van mogelijke gevolgen voor de instandhoudingsdoelen van de Noordzee

Research paper thumbnail of Environmental Risk Assessment of Produced Water Discharges on the Dutch Continental Shelf

Global Change Biology - GLOB CHANGE BIOL, 2009

Research paper thumbnail of Rational application of chemicals in response to oil spills may reduce environmental damage

Integrated Environmental Assessment and Management, 2012

Oil spills, for example those due to tanker collisions and groundings or platform accidents, can ... more Oil spills, for example those due to tanker collisions and groundings or platform accidents, can have huge adverse impacts on marine systems. The impact of an oil spill at sea depends on a number of factors, such as spill volume,

Research paper thumbnail of COMPARISON OF TOXICITY OF ZINC FOR SOIL MICROBIAL PROCESSES BETWEEN LABORATORY-CONTAMINED AND POLLUTED FIELD SOILS

Environmental Toxicology and Chemistry, 2003

Soil microbial processes are readily disturbed by added zinc (Zn) in laboratory ecotoxicity tests... more Soil microbial processes are readily disturbed by added zinc (Zn) in laboratory ecotoxicity tests. This study compares Zn toxicity between freshly spiked soils and soils that have been contaminated with Zn in the field. Soils were sampled in three transects (Ͻ80 m) toward galvanized electricity transmission towers (pylons). The soil total Zn concentrations gradually increased in each transect from background values (25-82 mg Zn/kg) to elevated Zn concentrations near the pylon (226-595 mg Zn/kg). Soil samples taken at the furthest distance from the Zn source were spiked with ZnCl 2 to a range of total Zn concentrations similar to those in the transect. Nitrification, respiration, and N-mineralization rates were significantly reduced by added Zn in laboratoryspiked soils and were 9 to 95% (mean 32%) of the control values at largest doses depending on soil type and the microbial process. In contrast, these processes were either unaffected by soil Zn (p Ͼ 0.05) or increased significantly with soil Zn concentrations in the transect soils. These increases could not be explained by soil pH or % soil organic carbon. Leaching soils after spiking significantly lowered the toxic effects of Zn on nitrification or on substrate-induced respiration. The soil solution Zn concentrations of field soils were always smaller than in spiked soils at equivalent total Zn. Highest soil solution Zn concentrations were always lower than the soil-solution EC50s of spiked soils. It is concluded that there is a large discrepancy in microbial responses to elevated Zn between spiked soils (unleached) and field-contaminated soils and there is a need to explain this discrepancy in terms of Zn availability, adaptation processes, and additional soil factors controlling the microbial processes.

Research paper thumbnail of Consequences of stressor-induced changes in species assemblage for biodiversity indicators

Environmental Toxicology and Chemistry, 2010

Protection of biodiversity is a major objective in environmental management. However, standard pr... more Protection of biodiversity is a major objective in environmental management. However, standard protocols for ecological risk assessments use endpoints that are not directly related to biodiversity. In the present study, the changes in five biodiversity indicators, namely, the Hill, Shannon-Wiener, Simpson's diversity index, AZTI's Marine Benthic Index (AMBI), and Benthic Quality Index (BQI), are calculated in case species experience direct chemical effects. This is done for an uncontaminated situation as well as for situations in which the effect concentration of a certain fraction of species (x%) is exceeded, that is, at the hazardous concentration (HCx) of the species sensitivity distribution (SSD) of the considered community. Results indicate that the response of the biodiversity indicators to concentrations spanning the complete concentration range of the SSD is variable. This response depends mainly on the type of indicator, the species assemblage, and the ratio of the slope of the concentration effect curves of the species and the slope of the SSD. At the HC5, a commonly used threshold in environmental risk assessment, biodiversity indicators, are affected at a marginal level (change is less than 5% in 99.6% of the simulated cases). Based on the results, the HC5 level is likely to be a protective threshold for changes in biodiversity in terms of richness and heterogeneity in the vast majority of the simulated cases (99.6%) for chemicals for which direct effects are dominant.

Research paper thumbnail of The Variation in Slope of Concentration–Effect Relationships

Ecotoxicology and Environmental Safety, 2001

Implementing the variation within populations in ecological modeling of risk and e4ects of toxica... more Implementing the variation within populations in ecological modeling of risk and e4ects of toxicants could contribute to a more sophisticated way of modeling. To give insight into the magnitude and spread in sensitivity within test populations the variation in sensitivity of individuals expressed as the slope of a concentration}e4ect curve (Sm) within more than 300 test populations from toxicity tests with 36 species and 116 substances is analyzed. The overall average variation from this study is 0.65 (Sm) and corresponds to an EC 50 /EC 5 ratio of 2.9. The mode of action is often suggested as an explanation for the di4erent slopes of concentration+e4ect curves. For metals, indeed, signi5cant di4erent median slope values are observed compared with organic substances. However, within the group of organic substances no distinction between the slope values of narcotic substances and substances with a speci5c mode of action could be made. Between species groups, signi5cant di4erences in the amount of variation could be demonstrated. The median slopes for all toxicants within the data set of 96-h tests speci5ed for 5shes and mollusks are signi5cantly steeper (median slopes of 0.38 and 0.37, respectively) than those for algae and crustaceans (1.2 and 0.72, respectively). Experimental factors that might explain these di4erences are discussed. The results from this study provide insight into the variation within a test population and can be used to estimate sensitivity parameters for risk and e4ect modeling.

Research paper thumbnail of Ecotoxicological Risk of Produced Water Discharged From Oil Production Platforms in the Statfjord and Gullfaks Field

Research paper thumbnail of Alkylphenols in Produced Water: A First Tier Risk Assessment

Research paper thumbnail of Assessment of the Cumulative Effect of Aktivities in the Maritime Area: Overview of relevant legislation and proposal for a harmonised approach

Research paper thumbnail of Report on 15 causal linkages, with proposals for monitoring: Annex 4 of Framework for GES assessment and prioritization of pressures and activities

Research paper thumbnail of Random Sampling of HOCNFs and Underlying Test Reports

Poultry Science - POULTRY SCI, 2007

Research paper thumbnail of Ecotoxicological risk assessment related to chemicals and pollutants in off-shore oil production

Toxicology Letters, 2000

Offshore oil production results in environmental discharges of drill cuttings and produced water,... more Offshore oil production results in environmental discharges of drill cuttings and produced water, contaminated with residuals of exploration and production (E&P) chemicals and formation chemicals. Ecotoxicological risk assessment has been adopted as a tool in environmental chemical management (i.e. reduction of the use and environmental release of chemicals, use of 'green chemicals' and application of non-chemical alternatives). This paper presents an introduction to the basic principles of ecotoxicological risk assessment of offshore E&P chemicals, as it is elaborated in the internationally harmonised CHARM model. In northwestern Europe, this model is used for the purpose of E&P chemicals, notification and environmental care within the offshore oil industry.

Research paper thumbnail of Offshore olie- en gasactiviteiten en Natura 2000: inventarisatie van mogelijke gevolgen voor de instandhoudingsdoelen van de Noordzee

Research paper thumbnail of Environmental Risk Assessment of Produced Water Discharges on the Dutch Continental Shelf

Global Change Biology - GLOB CHANGE BIOL, 2009

Research paper thumbnail of Rational application of chemicals in response to oil spills may reduce environmental damage

Integrated Environmental Assessment and Management, 2012

Oil spills, for example those due to tanker collisions and groundings or platform accidents, can ... more Oil spills, for example those due to tanker collisions and groundings or platform accidents, can have huge adverse impacts on marine systems. The impact of an oil spill at sea depends on a number of factors, such as spill volume,

Research paper thumbnail of COMPARISON OF TOXICITY OF ZINC FOR SOIL MICROBIAL PROCESSES BETWEEN LABORATORY-CONTAMINED AND POLLUTED FIELD SOILS

Environmental Toxicology and Chemistry, 2003

Soil microbial processes are readily disturbed by added zinc (Zn) in laboratory ecotoxicity tests... more Soil microbial processes are readily disturbed by added zinc (Zn) in laboratory ecotoxicity tests. This study compares Zn toxicity between freshly spiked soils and soils that have been contaminated with Zn in the field. Soils were sampled in three transects (Ͻ80 m) toward galvanized electricity transmission towers (pylons). The soil total Zn concentrations gradually increased in each transect from background values (25-82 mg Zn/kg) to elevated Zn concentrations near the pylon (226-595 mg Zn/kg). Soil samples taken at the furthest distance from the Zn source were spiked with ZnCl 2 to a range of total Zn concentrations similar to those in the transect. Nitrification, respiration, and N-mineralization rates were significantly reduced by added Zn in laboratoryspiked soils and were 9 to 95% (mean 32%) of the control values at largest doses depending on soil type and the microbial process. In contrast, these processes were either unaffected by soil Zn (p Ͼ 0.05) or increased significantly with soil Zn concentrations in the transect soils. These increases could not be explained by soil pH or % soil organic carbon. Leaching soils after spiking significantly lowered the toxic effects of Zn on nitrification or on substrate-induced respiration. The soil solution Zn concentrations of field soils were always smaller than in spiked soils at equivalent total Zn. Highest soil solution Zn concentrations were always lower than the soil-solution EC50s of spiked soils. It is concluded that there is a large discrepancy in microbial responses to elevated Zn between spiked soils (unleached) and field-contaminated soils and there is a need to explain this discrepancy in terms of Zn availability, adaptation processes, and additional soil factors controlling the microbial processes.

Research paper thumbnail of Consequences of stressor-induced changes in species assemblage for biodiversity indicators

Environmental Toxicology and Chemistry, 2010

Protection of biodiversity is a major objective in environmental management. However, standard pr... more Protection of biodiversity is a major objective in environmental management. However, standard protocols for ecological risk assessments use endpoints that are not directly related to biodiversity. In the present study, the changes in five biodiversity indicators, namely, the Hill, Shannon-Wiener, Simpson's diversity index, AZTI's Marine Benthic Index (AMBI), and Benthic Quality Index (BQI), are calculated in case species experience direct chemical effects. This is done for an uncontaminated situation as well as for situations in which the effect concentration of a certain fraction of species (x%) is exceeded, that is, at the hazardous concentration (HCx) of the species sensitivity distribution (SSD) of the considered community. Results indicate that the response of the biodiversity indicators to concentrations spanning the complete concentration range of the SSD is variable. This response depends mainly on the type of indicator, the species assemblage, and the ratio of the slope of the concentration effect curves of the species and the slope of the SSD. At the HC5, a commonly used threshold in environmental risk assessment, biodiversity indicators, are affected at a marginal level (change is less than 5% in 99.6% of the simulated cases). Based on the results, the HC5 level is likely to be a protective threshold for changes in biodiversity in terms of richness and heterogeneity in the vast majority of the simulated cases (99.6%) for chemicals for which direct effects are dominant.

Research paper thumbnail of The Variation in Slope of Concentration–Effect Relationships

Ecotoxicology and Environmental Safety, 2001

Implementing the variation within populations in ecological modeling of risk and e4ects of toxica... more Implementing the variation within populations in ecological modeling of risk and e4ects of toxicants could contribute to a more sophisticated way of modeling. To give insight into the magnitude and spread in sensitivity within test populations the variation in sensitivity of individuals expressed as the slope of a concentration}e4ect curve (Sm) within more than 300 test populations from toxicity tests with 36 species and 116 substances is analyzed. The overall average variation from this study is 0.65 (Sm) and corresponds to an EC 50 /EC 5 ratio of 2.9. The mode of action is often suggested as an explanation for the di4erent slopes of concentration+e4ect curves. For metals, indeed, signi5cant di4erent median slope values are observed compared with organic substances. However, within the group of organic substances no distinction between the slope values of narcotic substances and substances with a speci5c mode of action could be made. Between species groups, signi5cant di4erences in the amount of variation could be demonstrated. The median slopes for all toxicants within the data set of 96-h tests speci5ed for 5shes and mollusks are signi5cantly steeper (median slopes of 0.38 and 0.37, respectively) than those for algae and crustaceans (1.2 and 0.72, respectively). Experimental factors that might explain these di4erences are discussed. The results from this study provide insight into the variation within a test population and can be used to estimate sensitivity parameters for risk and e4ect modeling.

Research paper thumbnail of Ecotoxicological Risk of Produced Water Discharged From Oil Production Platforms in the Statfjord and Gullfaks Field