Patrik Fauser

Phthalates, nonylphenols and LAS in an alternately operated wastewater treatment plant—fate modelling based on measured concentrations in wastewater and sludge

The performance of an alternately operated activated sludge wastewater treatment plant (WWTP) has been investigated with respect to six phthalates, nonylphenol (NP) and nonylphenol diethoxylate (NPDE) and linear alkylbenzene sulphonates (LAS). Samples of raw sewage, primary and secondary sludge and treated water were collected during an 8-day period in May 1999 and analysed for dissolved and sorbed substances. To evaluate the system performance with respect to substance removal through biodegradation and sorption to sludge the measured data were applied in a model describing the different bioreactors as one single reactor, corresponding to the concepts of, e.g. SimpleTreat. The most abundant of the investigated phthalates was di-(2-ethylhexyl)-phthalate (DEHP) with a measured mean inlet flow of 240g/day. Two percent of this amount was found in the treated water, 70% was biodegraded and 28% was found in the sludge. For LAS the mean inlet flow was 20,300g/day, of which less than 1% was found in the treated water, 84% was biodegraded and 15% was found in the sludge. The mean inlet flow of NP and NPDE was 44 and 590g/day, of which 4% and 2% was found in the treated water, 80% was biodegraded for both substances, and 16% and 18% was found in the sludge, respectively. The WWTP removal of the investigated substances was thus high compared to other studies of conventional activated sludge WWTPs. The simple model set-up presents a strong tool for predicting substance removal and system sensitivity related to changes in the inlet conditions, such as concentrations and flow. Furthermore, it allows the inclusion of complex alternately operated WWTPs in risk assessment tools such as e.g. SimpleTreat.

Human health risk screening due to consumption of fish contaminated with chemical warfare agents in the Baltic Sea.

Chemical warfare agents (CWAs) have been disposed of in various fashions over the past decades. Significant amounts of CWA, roughly 11,000ton, have been dumped in the Baltic Sea east of the island Bornholm following the disarmament of Germany after World War II. This has caused concerns over potential human and environmental health risks, and resulted in restrictions on fishing in the dumpsite area. The purpose of this paper is to assess the potential indirect human health risks due to consumption of CWA-contaminated fish from the dumpsite area east of Bornholm. Earlier studies suggest that the fish community may be at risk from CWA exposure in the Bornholm basin. Moreover, elevated frequencies of lesions on fish caught in a CWA dumpsite in the Mediterranean Sea have been observed. The fish at the Mediterranean dumpsite had elevated total arsenic (As) concentrations in their tissue, and elevated total As levels were also observed in the sediment. Elevated total sediment As concentrations have also been recorded in CWA dumpsites in the Skagerrak and the Baltic Sea. Triphenylarsine and sulfur mustard gas (Yperite) are the CWAs with the greatest indirect human health risk potential. There are recognized uncertainties concerning Yperites and CWA-derived arsenicals fate and speciation in the environment, as well as their inherent toxicity, warranting caution and further site-specific environmental and human health risk assessments of CWAs dumped in the Bornholm basin.

Sensitivity analysis of calculated exposure concentrations and dissipation of DEHP in a topsoil compartment: The influence of the third phase effect and Dissolved Organic Matter (DOM)

The fate and risk assessment of hydrophobic substances in the terrestrial environment can be associated with large errors. These can be attributed to the partitioning and process coefficients derived in experimental studies and to the model set-up that is designed to calculate the exposure concentrations. In many cases, the concentration of xenobiotics are low in the environment, which gives the aqueous phase the characteristics of a true solution, which are in accordance with the thermodynamic description of dilute solutions. Under these circumstances, the conventional equilibrium coefficients, such as Kd, Henrys Law constant H and the bioconcentration factor, BCF, are independent of the activity coefficient of the partitioning compound in the respective phases. However, for hydrophobic substances, these coefficients are often measured in laboratory experiments, where the nominal concentration levels are above the substance saturation point within the bulk water phase. In the case of the phthalates, the hydrophobic effect induces the formation of microdroplets (third phase) in the bulk water phase, by which the system is characterised as a heterogeneous mixture. Consequently, the linearity between dissolved and sorbed concentration is no longer true. Furthermore, in the terrestrial and aquatic environment, the presence of natural Dissolved Organic Matter (DOM) will have an influence on the fate and effects of hydrophobic substances. Hydrophobic compounds show large affinity for sorption to DOM, and contrary to Fixed Organic Matter (FOM), DOM is mobile and can be transported through the soil pores with the advective flow. It is therefore crucial that dispersed or emulsified phases within the continuous aqueous phase, e.g. DOM and microemulsions of phthalates, are distinguished from true solutions in the experimental measurements of partitioning coefficients, e.g. in order not to underestimate the mobility of sorbed substance. These aspects are treated in this study, where the exposure concentration, vertical transport and microbial degradation of Di-(2-ethylhexyl)-phthalate (DEHP) is modelled in an organic rich topsoil compartment, using experimental partitioning coefficients and degradation rates from the literature. Two model set-ups are derived for the topsoil compartment, i.e. (1) a system with dilute solution of substance and (2) a system with the presence of a third phase of microdroplets. In both models, the presence of DOM is incorporated. The first model shows that the error in the calculated exposure concentration, by using partitioning coefficients derived under unfavourable experimental conditions, compared to realistic conditions, amounts to 1400%. A comparison between the two models shows that when emulsion formation is not incorporated in the model, the calculated flux will be overestimated by a factor of 60.

Conceptual framework for a Danish human biomonitoring program

The aim of this paper is to present the conceptual framework for a Danish human biomonitoring (HBM) program. The EU and national science-policy interface, that is fundamental for a realization of the national and European environment and human health strategies, is discussed, including the need for a structured and integrated environmental and human health surveillance program at national level. In Denmark, the initiative to implement such activities has been taken. The proposed framework of the Danish monitoring program constitutes four scientific expert groups, i.e. i. Prioritization of the strategy for the monitoring program, ii. Collection of human samples, iii. Analysis and data management and iv. Dissemination of results produced within the program. This paper presents the overall framework for data requirements and information flow in the integrated environment and health surveillance program. The added value of an HBM program, and in this respect the objectives of national and European HBM programs supporting environmental health integrated policy-decisions and human health targeted policies, are discussed.In Denmark environmental monitoring has been prioritized by extensive surveillance systems of pollution in oceans, lakes and soil as well as ground and drinking water. Human biomonitoring has only taken place in research programs and few incidences of e.g. lead contamination. However an arctic program for HBM has been in force for decades and from the preparations of the EU-pilot project on HBM increasing political interest in a Danish program has developed.

Weight-of-evidence environmental risk assessment of dumped chemical weapons after WWII along the Nord-Stream gas pipeline in the Bornholm Deep

In connection with installation of two natural gas pipelines through the Baltic Sea between Russia and Germany, there has been concern regarding potential re-suspension of historically dumped chemical warfare agents (CWA) in a nearby dump site and the potential environmental risks associated. 192 sediment and 11 porewater samples were analyzed for CWA residues, both parent and metabolites in 2008 and 2010 along the pipeline corridor next to the dump site. Macrozoobenthos and background variables were also collected and compared to the observed CWA levels and predicted potential risks. Detection frequencies and levels of intact CWA found were low, whereas CWA metabolites were more frequently found. Re-suspension of CWA residue-containing sediment from installation of the pipelines contributes marginally to the overall background CWA residue exposure and risk along the pipeline route. The multivariate weight-of-evidence analysis showed that physical and background parameters of the sediment were of higher importance for the biota than observed CWA levels.

Review of environmental exposure concentrations of chemical warfare agent residues and associated the fish community risk following the construction and completion of the Nord Stream gas pipeline between Russia and Germany

This paper compiles all the measured chemical warfare agent (CWA) concentrations found in relation to the Nord Stream pipeline work in Danish waters for the past 5 years. Sediment and biota sampling were performed along the pipeline route in four campaigns, prior to (in 2008 and 2010), during (in 2011) and after (in 2012) the construction work. No parent CWAs were detected in the sediments. Patchy residues of CWA degradation products of Adamsite, Clark I, phenyldichloroarsine, trichloroarsine and Lewisite II, were detected in a total of 29 of the 391 sediment samples collected and analyzed the past 5 years. The cumulative fish community risk quotient for the different locations, calculated as a sum of background and added risk, ranged between 0 and 0.017 suggesting a negligible acute CWA risk toward the fish community. The added risk from sediment disturbance in relation to construction of the pipelines represents less than 2% of the total risk in the areas with the highest calculated risk. The analyses of benthic infauna corroborate the finding of CWA related low risk across the years. There was no significant difference in CWA risk before (2008) and after the pipeline construction (2012).

Monte Carlo (Tier 2) uncertainty analysis of Danish Greenhouse gas emission inventory

The methodology and results of Monte Carlo (Tier 2) uncertainty analysis of the Danish Greenhouse Gas (GHG) inventory for base year 1990 and most recent year 2008 are presented. The analysis covers 100% of the total net Danish GHG emissions and removals, excluding LULUCF. Methodological procedures such as random sampling of uncertain parameters and parameter correlation between years are explained. Uncertainties in activity data and emission factors are given for all sectors, Input data are assumed to have log-normal probability distributions, represented by median values and 95% confidence interval uncertainties. The total uncertainty levels for GHG emissions, expressed as 95% confidence intervals, are 4.1 and 5.3% for Tier 1 and Tier 2, respectively. Uncertainties in the trend are 2.4 and 6.9% for Tier 1 and Tier 2, respectively. The most influential sources from the Tier 2 analysis to the total uncertainty are CH4 from solid waste disposal on land (4.4%), N2O from leaching (3.0%), N2O from synthetic fertilizer (2.0%), and N2O and CH4 from manure management, each with 1.6%. Tier 1 and Tier 2 uncertainties in levels and trends are comparable to seven European countries that have performed a Tier 2 uncertainty analysis.

Acute toxicity of sea-dumped chemical munitions: luminating the environmental toxicity of legacy compounds*

Abstract As a result of the disarmament of Germany after the Second World War, 65,000 tons of chemical munitions were dumped in the Baltic Sea. Approximately 13,000 tons containing chemical warfare agents (CWAs) of which 11,000 tons were dumped in the Bornholm Basin east of Bornholm. This paper addresses the ecotoxicity of compounds actually present in the Bornholm dumpsite by obtaining novel acute ecotoxicity data. EC50 values were successfully obtained for 12 CWAs from acute tests using Allivibrio fischeri (Microtox™). The three most toxic compounds were α-chloroacetophenone, 2-chlorovinylarsonic acid and 1,2,5-trithiepane having EC50 values of 11.20, 31.20 and 1170 μg L−1, respectively. A. fischeri demonstrated hormesis when exposed to triphenylarsine and triphenylarsine oxide at concentrations of 100 and 50 mg L−1, respectively. Four different mixtures were assessed including compounds which were dissolvable; a mixture of sulphur mustard degradation products, a mixture of the three most toxic sulphur mustard compounds, a mixture of organoarsenical degradation products and a mixture of all compounds. The mixtures deviate by a factor of 1.5–2.5 from the prediction of the concentration addition model and hence, the mixtures demonstrate no sign of synergism or antagonism. The compounds presented in this study are mainly CWA.

Using multiple regression in estimating (semi) VOC emissions and concentrations at the European scale.

This paper proposes a simple method for estimating emissions and predicted environmental concentrations (PECs) in water and air for organic chemicals that are used in household products and industrial processes. The method has been tested on existing data for 63 organic high–production volume chemicals available in the European Chemicals Bureau risk assessment reports (RARs). The method suggests a simple linear relationship between Henry’s Law constant, octanol–water coefficient, use and production volumes, and emissions and PECs on a regional scale in the European Union. Emissions and PECs are a result of a complex interaction between chemical properties, production and use patterns and geographical characteristics. A linear relationship cannot capture these complexities; however, it may be applied at a cost–efficient screening level for suggesting critical chemicals that are candidates for an in–depth risk assessment. Uncertainty measures are not available for the RAR data; however, uncertainties for the applied regression models are given in the paper. Evaluation of the methods reveals that between 79% and 93% of all emission and PEC estimates are within one order of magnitude of the reported RAR values. Bearing in mind that the domain of the method comprises organic industrial high–production volume chemicals, four chemicals, prioritized in the Water Framework Directive and the Stockholm Convention on Persistent Organic Pollutants, were used to test the method for estimated emissions and PECs, with corresponding uncertainty intervals, in air and water at regional EU level.

Model description of an alternately operated wastewater treatment plant––evaluation of the applicability of SimpleTreat

Alternately operated wastewater treatment plants (WWTPs) are fundamentally different compared to conventional activated sludge WWTPs with respect to flow patterns and aeration in the biological reactors. Several model applications exist for conventional WWTPs, e.g. SimpleTreat, and in this study the effect of substituting a complex discontinuous operation, involving alternating degradation and flow conditions between two reactors, with one single bioreactor with continuos flow (SimpleTreat) has been investigated by setting up two models representing the respective operation schemes. The discontinuous operation induces fluctuations in the outlet concentrations that are not modelled with the single bioreactor model, however, the fluctuations and the associated uncertainties were found to be insignificant compared to the influence of the input parameter uncertainties on the model results. An empirical relationship between an aggregate pseudo-1st order degradation rate for the single bioreactor model and realistic aerobic and anoxic 1st order degradation rates, respectively, has been established. When using this aggregate degradation rate in the single bioreactor model an outlet concentration can be calculated that deviates no more than 2% from the mean outlet concentration from the alternating operation model. For substances with aerobic half-lives longer than approximately 2 h, which is valid for many chemical substances, the aggregate 1st order degradation rate can be set equal to the aerobic 1st order degradation rate.