Modelling spatial dispersion of contaminants from shipping lanes in the Baltic Sea

Major sources of pollution from shipping to marine environments are antifouling paint residues and discharges of bilge, black, grey and ballast water and scrubber discharge water. The dispersion of copper, zinc, naphthalene, pyrene, and dibromochloromethane have been studied using the Ship Traffic Emission Assessment Model, the General Estuarine Transport Model, and the Eulerian tracer transport model in the Baltic Sea in 2012. Annual loads of the contaminants ranged from 10-2 tons for pyrene to 100 s of tons for copper. The dispersion of the contaminants is determined by the surface kinetic energy and vertical stratification at the location of the discharge. The elevated concentration of the contaminants at the surface persists for about two-days and the contaminants are dispersed over the spatial scale of 10-60 km. The Danish Sounds, the southwestern Baltic Sea and the Gulf of Finland are under the heaviest pressure of shipborne contaminants in the Baltic Sea

Modelling of discharges from baltic sea shipping

This paper describes the new developments of the Ship Traffic Emission Assessment Model (STEAM) which enable the modelling of pollutant discharges to water from ships. These include nutrients from black/grey water discharges as well as from food waste. Further, the modelling of contaminants in ballast, black, grey and scrubber water, bilge discharges, and stern tube oil leaks are also described as well as releases of contaminants from antifouling paints. Each of the discharges is regulated by different sections of the IMO MARPOL convention, and emission patterns of different pollution releases vary significantly. The discharge patterns and total amounts for the year 2012 in the Baltic Sea area are reported and open-loop SOx scrubbing effluent was found to be the second-largest pollutant stream by volume. The scrubber discharges have increased significantly in recent years, and their environmental impacts need to be investigated in detail

Exposure assessments of nanoparticles in aquatic environments – considerations, review and recommendations

Synthetic nanoparticles are new forms of chemical substances. They can be found in severaldifferent forms, such as free particles, surface bound and dissolved in liquid. Nanoparticlescan also exist as free, individual particles or agglomerate consisting of multiple particles. Thisreport discusses the assessment of possible risks of nanoparticles. Chemical risk is usuallyconsidered to consist of two elements: (1) Exposure to the substance, and (2) the substance\u27stoxicity. So far, the risk-related research on nanoparticles has had a strong focus on theparticles \u27 toxic effects. In this report, we would instead focus on how exposure tonanoparticles can be calculated and assessed, with focus on nanoparticles in water. In thereport, we provide an initial background and definitions of nanomaterials and nanoparticles,and describe briefly a standard method of risk assessment of chemicals in the environment.Then we go through important considerations that should be made in the exposure assessmentof nanoparticles. First we discuss three considerations related to the emissions ofnanoparticles, namely the lack of data for annual production of nanoparticles, the importanceof applying a substance flow perspective, and lack of data for so-called emission factors fornanoparticles of various products and materials. Furthermore, we discuss considerations formodeling of nanoparticles behavior in water, mainly by listing a number of key processeswith large influence. These are agglomeration, sedimentation, and dissolution. Related to that,we discuss how natural organic materials, coatings and aging of particles can affect theseprocesses. We note here three particle properties that are important in order to describenanoparticles dispersion in water, in a similar way that the octanol-water partition coefficientand half-life is important to describe the fate of organic chemicals in the environment. Fornanoparticles these are the particle size (a) and the density (ρ). We also identify a number ofmore complex parameters affecting particle behavior in the environment, but not only becauseof the different particle characteristics, but also depending on characteristics related to theenvironment. These are the collision efficiency (α), point of zero charge (pHpzc), Hamakerconstant (A) and a so-called form factor (β) that affect the sedimentation. In addition to thegeneral difficulty to measure or calculate these parameters they also co-vary. Furthermore, wemake a review of 11 currently available exposure models for nanoparticles in aquaticenvironment. We note that the studies differ regarding modeling method, which sources ofemissions that are included, the nanoparticles taken into account, estimated concentrations inthe environment, and whether the results are presented as mass or particle concentration. Onlytwo studies trying to model the nanoparticle exposure based on particle properties in a mannersimilar to standard methods for chemical risk assessment. The other modeling studies areinstead based on data on flows of specific nanomaterials, and not on generic algorithms. Next,we describe a number of challenges that occur when measuring nanoparticles in theenvironment. Finally, we provide the following recommendations to ensure good exposureassessment of nanoparticles in the future:1. Information of flows and stocks of nanoparticles in society need to be collected.2. Emission factors would need to be developed for each product that makes use ofnanoparticles.3. Emissions should be reported both as mass and particle number until it becomesclearer which one is most relevant.4. More research is needed in order to determine which particle properties need to beknown in order to calculate the concentration of nanoparticles in the environment.5. At least the particle size and particle size distribution, as well as the specific particledensity should be reported.6. More research is required to improve the experimental measurements of nanoparticlesto be able to validate exposure models

Exposure assessments of nanoparticles in aquatic environments – considerations, review and recommendations

Synthetic nanoparticles are new forms of chemical substances. They can be found in severaldifferent forms, such as free particles, surface bound and dissolved in liquid. Nanoparticlescan also exist as free, individual particles or agglomerate consisting of multiple particles. Thisreport discusses the assessment of possible risks of nanoparticles. Chemical risk is usuallyconsidered to consist of two elements: (1) Exposure to the substance, and (2) the substance\u27stoxicity. So far, the risk-related research on nanoparticles has had a strong focus on theparticles \u27 toxic effects. In this report, we would instead focus on how exposure tonanoparticles can be calculated and assessed, with focus on nanoparticles in water. In thereport, we provide an initial background and definitions of nanomaterials and nanoparticles,and describe briefly a standard method of risk assessment of chemicals in the environment.Then we go through important considerations that should be made in the exposure assessmentof nanoparticles. First we discuss three considerations related to the emissions ofnanoparticles, namely the lack of data for annual production of nanoparticles, the importanceof applying a substance flow perspective, and lack of data for so-called emission factors fornanoparticles of various products and materials. Furthermore, we discuss considerations formodeling of nanoparticles behavior in water, mainly by listing a number of key processeswith large influence. These are agglomeration, sedimentation, and dissolution. Related to that,we discuss how natural organic materials, coatings and aging of particles can affect theseprocesses. We note here three particle properties that are important in order to describenanoparticles dispersion in water, in a similar way that the octanol-water partition coefficientand half-life is important to describe the fate of organic chemicals in the environment. Fornanoparticles these are the particle size (a) and the density (ρ). We also identify a number ofmore complex parameters affecting particle behavior in the environment, but not only becauseof the different particle characteristics, but also depending on characteristics related to theenvironment. These are the collision efficiency (α), point of zero charge (pHpzc), Hamakerconstant (A) and a so-called form factor (β) that affect the sedimentation. In addition to thegeneral difficulty to measure or calculate these parameters they also co-vary. Furthermore, wemake a review of 11 currently available exposure models for nanoparticles in aquaticenvironment. We note that the studies differ regarding modeling method, which sources ofemissions that are included, the nanoparticles taken into account, estimated concentrations inthe environment, and whether the results are presented as mass or particle concentration. Onlytwo studies trying to model the nanoparticle exposure based on particle properties in a mannersimilar to standard methods for chemical risk assessment. The other modeling studies areinstead based on data on flows of specific nanomaterials, and not on generic algorithms. Next,we describe a number of challenges that occur when measuring nanoparticles in theenvironment. Finally, we provide the following recommendations to ensure good exposureassessment of nanoparticles in the future:1. Information of flows and stocks of nanoparticles in society need to be collected.2. Emission factors would need to be developed for each product that makes use ofnanoparticles.3. Emissions should be reported both as mass and particle number until it becomesclearer which one is most relevant.4. More research is needed in order to determine which particle properties need to beknown in order to calculate the concentration of nanoparticles in the environment.5. At least the particle size and particle size distribution, as well as the specific particledensity should be reported.6. More research is required to improve the experimental measurements of nanoparticlesto be able to validate exposure models

MODELLING ENVIRONMENTAL FATE OF TiO2 NANOPARTICLES IN WATER – IMPLICATIONS FOR EMPIRICAL VALIDATION STUDIES

The potential environmental effects of nanoparticles (NPs) require interdisciplinary research to assess the risks. One part of a risk assessment concerns exposure, which builds on knowledge of the environmental fate. In this particular case the fate of TiO2 NPs in the water compartment was modelled by applying a second order kinetic rate equation and the DLVO theory. Assumptions were made regarding water parameters such as pH, salt concentration and temperature, as well as regarding particle properties such as Hamaker constant, primary particle size and point of zero charge. The effect of sedimentation was taken into account, but as one would expect the influence of sedimentation on such small particles is very small. The model was implemented in MATLAB\uae. Results indicate the importance of agglomeration as an important fate mechanism, and that pH andpoint of zero charge are important parameters with regards to agglomeration. Other parameters such as the Hamaker constant, salt concentration and temperature were shown not to have a significant effect, which is in goodcorrelation with empirical studies. Also, we would like to see our model validated by empirical studies. Important implications then are to include a continuous inflowof NPs in the experimental setup and to work at environmentally relevant water properties. For example is the effect of natural organic matter (NOM) on theagglomeration not modelled, despite that its significance has been pointed out in many studies. This is due to a weak link between mathematical expressions andempirical data for this particular part of the model. It is of importance that this linkage is strengthened both by theoretical and empirical studies on NOM aimingat producing mathematical expressions, and empirical data, that can assist fate modelling of NPs