Bentzen, Thomas Ruby

Larsen, Torben

Rasmussen, Michael R.

The paper discusses the long term mass balance of pollutants in highway ponds. The accumulations of five polycyclic aromatic hydrocarbons (PAHs) and six heavy metals have been measured in eight Danish detention ponds, which receive runoff from highways only. For each pollutant the accumulation has been compared to the long-term influx, estimated from short-term measurements of concentrations in highway runoff. The results show that a large proportion of the incoming heavy metals in short-term runoff events has accumulated in the ponds. This is not the case for the toxic organic compounds. The results also show that the accumulation rates for the heavy metals depend significantly on the relative pond area (pond area divided by catchment area). The conclusion is that the mass balances of heavy metals and PAHs in highway ponds can be estimated with acceptable accuracy from a combination of short-term and long-term measurements.The paper discusses the long term mass balance of pollutants in highway ponds. The accumulations of five polycyclic aromatic hydrocarbons (PAHs) and six heavy metals have been measured in eight Danish detention ponds, which receive runoff from highways only. For each pollutant the accumulation has been compared to the long-term influx, estimated from short-term measurements of concentrations in highway runoff. The results show that a large proportion of the incoming heavy metals in short-term runoff events has accumulated in the ponds. This is not the case for the toxic organic compounds. The results also show that the accumulation rates for the heavy metals depend significantly on the relative pond area (pond area divided by catchment area). The conclusion is that the mass balances of heavy metals and PAHs in highway ponds can be estimated with acceptable accuracy from a combination of short-term and long-term measurements

    Aalborg UniversitetRelationship Between Accumulation and Influx of Pollutants in Highway PondsBentzen, Thomas Ruby; Larsen, Torben; Rasmussen, Michael RobdrupPublication date:2006Document VersionPublisher's PDF, also known as Version of recordLink to publication from Aalborg UniversityCitation for published version (APA):Bentzen, T. R., Larsen, T., & Rasmussen, M. R. (2006). Relationship Between Accumulation and Influx ofPollutants in Highway Ponds. Aalborg Universitetsforlag.General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: April 30, 2017Relationship between accumulation and influx of pollutants in highway ponds T. R. Bentzen*, T. Larsen and M. R. Rasmussen Department of Civil Engineering, Aalborg University, Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark.   * Corresponding author, e-mail:  i5trb@civil.aau.dk, Phone number: +45 96358080, Fax number: +45 98142555  Abstract The paper discusses the long term mass balance of pollutants in highway ponds. The accumulations of five polycyclic aromatic hydrocarbons (PAHs) and six heavy metals have been measured in eight Danish detention ponds, which receive runoff from highways only. For each pollutant the accumulation has been compared to the long-term influx, estimated from short-term measurements of concentrations in highway runoff. The results show that a large proportion of the incoming heavy metals in short-term runoff events has accumulated in the ponds. This is not the case for the toxic organic compounds. The results also show that the accumulation rates for the heavy metals depend significantly on the relative pond area (pond area divided by catchment area). The conclusion is that the mass balances of heavy metals and PAHs in highway ponds can be estimated with acceptable accuracy from a combination of short-term and long-term measurements.  Keywords Heavy metals, mass balance, PAH, runoff, sediment, xenobiotics 1. Introduction Most ponds have been designed for peak flow control; however, studies have shown that they also have high capacity for removing suspended solids, including heavy metals and organic compounds (Van Buren, Watt & Marsalek, 1997; Petterson, German & Svensson, 1999; Comings, Booth & Horner, 2000). The removal efficiency for particulate pollutants is highly dependent on both pond geometry and hydraulic retention time.  In most studies the efficiency of pollutant removal is calculated from an event-based mass balance, where flow and inlet and outlet concentrations have been measured.  The mass balance equation is:  Accumulation = Influx - Degradation - Outflux  where Accumulation and Degradation are the masses of accumulated and degraded material, respectively, and Influx and Outflux are the masses (the fluxes integrated over time) of the incoming and outgoing pollutant, respectively.  In short-term (event-based) studies only Influx and Outflux can be measured. Long-term studies allow estimation of Accumulation only and rough estimation of Influx.   This study is based on the measurements of the masses of three hydrocarbon fractions, five PAHs and six heavy metals accumulated in the bed sediment in eight wet highway detention ponds. The loads (Influxes) of the  pollutants to each pond have been estimated from generalized values of concentrations based on measurements from a number of locations. The advantage of dealing with accumulated masses in the ponds instead of concentrations in the runoff is that many years are taken into account and time variations of the pollutant loads are averaged out.   The pollutants considered here were selected due to their frequent occurrence in highway runoff and their toxicological effects on the environment and human beings (Makepeace, Smith & Stanley, 1995).   The objective of the present study is to quantify the relationship between the mass of accumulated pollutant and the total load on a long-term basis. This relationship can be used to estimate the long-term mass balance from short-term events. The work is a preliminary study of an ongoing detailed description and modelling of the removal of pollutants in highway ponds. 2. Methods The eight ponds (Table 1) investigated in this study were selected using the following criteria:  - The pond only receives water from highway runoff.  - The drainage system is a closed pipe system without open ditches.  - The highway has curbs and gullies.  - The eight highway catchments cover a wide range of areas.    2.1. Accumulation Each pond was divided into ten areas of equal size and one sample was taken  from each of the ten areas (Figure 1). The samples were taken with a 56-mm diameter cylinder pushed vertically down to the bottom of the sediment (1 to 20 cm). The ten samples were mixed to form compound samples, one for each pond. The compound samples were analysed and two measures calculated: 1) Mass of accumulated pollutant (Accumulation), based on the mass of dry sediment and the concentration of the pollutant 2) Annual accumulation rate per hectare catchment area, based on the age of the pond and the catchment area  2.2. Influx Then mass of incoming pollutant (Influx) was determined from generalized values of concentration (literature values) in highway runoff multiplied by the runoff:  The concentrations (Table 2) were  averages of concentrations of 24 runoff samples from two highway locations in Denmark, where all runoff water was collected each month over one year and analysed for pollutants (POLMIT, 2002) and 60 event mean concentrations (EMC) from highway runoff in the UK (Crabtree, Moy & Whitehead, 2005).   The runoff was determined as the local annual rainfall (Table 1) subtracted by an initial loss of 0.6 mm per rain event (average annual value) corresponding to 140 mm/year (Bentzen, Larsen, Thorndal & Rasmussen, 2005).   2.3. Degradation and Outflux  It is not possible to differentiate between Degradation and Outflux, in principle. However, heavy metals do not degrade due to their state of elements; hence, for heavy metals Outflux can be calculated as the difference between Influx and Accumulation.   The PAHs are biodegradable either as carbon/energy sources or in co-metabolic processes. The half-life period for the PAHs varies between 6 and 12 years (Environmental Protection Agency, 1996). Determination of in situ annual degradation rates are subject to further investigations and values cannot be given here. Thus, for PAHs it is not possible to distinguish between Outflux and Degradation. 3. Results The average annual increase in sediment was 1.0 cm/year for ponds with an age of 6 years and 0.6 cm/year for ponds with an age of 11 years – properly due to consolidation. The mean concentrations in the sediments (Table 3) are within the range of what can be found in the literature, e.g. German & Svensson (2005), Durand, Ruban, Amblès, Clozel & Achard (2003) and Marsalek & Marsalek (1997). The annual accumulation rate in each pond and a catchment area weighted mean accumulation rate for each of the 15 pollutants are presented in Table 4. Note that the calculated accumulation rates are based on ponds that receive runoff from highways only.   Calculated values of the annual accumulation relative to the annual influx (Figure 2) are similar to (but slightly lower than) values from efficiency studies based on inlet and effluent concentrations for the metals (Comings et al., 2000; Crabtree et al.,2005; Petterson et al., 1999; Statens Vegvesen, 2005). Figure 1 shows values higher than 1 for especially chromium and nickel in some of the ponds. These values are, of course, unrealistic and reflect the high uncertainty related to the estimated loads from runoff. Still, the high values indicate high retention. With a moderate part (5 % – 40 %) of the metal influxes being dissolved - the high relative accumulations for some of the metals indicate that outflux and resuspension of sediments have an insignificant role for the pollutant transport out of the ponds. For the organic compounds the relative accumulations are generally much lower (approx. 50%) than the values from the efficiency studies. This is probably due to degradation within the pond sediments.   The results show that the accumulation rate for heavy metals significantly depends on the relative pond area (pond area divided by catchment area) (Figure 3). Similar relationships are found by Petterson et al. (1999). The curves in this study do not have the same ‘flattening-out’ tendency at a relative pond area of 250 m2/ha as in Petterson et al. (1999). The relationship between annual accumulation rate and relative pond area for the PAHs (Figure 3) is not as clear as for the metals, probably due to various degradation conditions.  4. Conclusions The investigation shows that:  - The bulk of the incoming heavy metals accumulate - Only parts of the organic compounds accumulate - The outflux and the resuspension are of minor importance - The accumulation increases with increasing relative pond area (pond area divided by catchment area)  - A mass balance approach for the long-term removal of pollutants can be coupled to the short term mass balances of the individual runoff event Acknowledgement The Danish Road Directorate is acknowledged for financial support, supply of data and practical help.  References Bentzen, T.R., Larsen, T., Thorndal, S. & Rasmussen, M. R. (2005). Removal of heavy metals and PAH in highway detention ponds. 10th International Conference on Urban Drainage, Copenhagen, Denmark, 21-26 August 2005.  Comings, K.J., Booth, D.B. & Horner, R.R. (2000). Stormwater pollutant removal by two wet ponds in Bellevue, Washington. Department of Civil and Environmental Engineering, University of Washington, Seattle.  Crabtree, B., Moy, F. & Whitehead, M. (2005). Pollutants in highway runoff. 10th International Conference on Urban Drainage, Copenhagen, Denmark, 21-26 August 2005.  Durand, C, Ruban, V., Amblès, A., Clozel, B., & Achard, L. (2003). Characterisation of road sediments near Bordeaux with emphasis on phosphorus. Journal of Environmental Monitoring, 5(3), 463-467  Environmental Protection Agency (in Danish: Miljøstyrelsen) (1996). Chemical substance behaviour in soil and groundwater No. 20. (in Danish: Projekt om jord og grundvand nr. 20, 1996: Kemiske stoffers opførsel i jord og grundvand)  German, J. & Svensson, G. (2005). Stormwater pond sediment and water - characterisation and assessment. Urban Water Journal, 2(1), 39-50.  Makepeace, D.K., Smith, D.W.  & Stanley, S.J. (1995). Urban stormwater quality: summary of contaminant data. Critical Reviews in Environmental Science and Technology, 25(2), 93-139.  Marsalek, J. & Marsalek, P. M. (1997) Characteristics of sediments from a stormwater management pond. Water Science and Technology, 36(8-9), 117–122.  Petterson, T.J.R., German, J. & Svensson, G. (1999). Pollutant removal efficiency in two stormwater ponds in Sweden. Proceedings of the 8th International Conference on Urban Storm Drainage. Sydney, Australia, 30 August – 3 September.  POLMIT (2002). Pollution from roads and vehicles and dispersal to the local environment. Final Report. Project co-coordinator: Transport Research Laboratory (TRL), UK.   Norwegian Road Directorate (In Norwegian: Statens Vegvesen) (2005). Monitoring of runoff from Highway E6, Skullerudkrydset, Oslo 2003-2004 (Original in Norwegian: Overvåkning av rensebasseng for overvann fra E6 Skullerudkrysset i Oslo, 2003-2004).   Van Buren, M.A., Watt, W.E. & Marsalek, J. (1997). Removal of selected urban stormwater constituents by an on-stream pond. Journal of Environmental Planning and Management, 40, 5-18  Table 1. Site descriptions. Pond/Station number  306.7 302.9 205.4 195.9 Nearby town  Hjallerup Vodskov Randers S Hadsten N Pond area [m2] 1500 2299 2300 3480 Catchment area [ha] 1.7 2.7 3.7 6.0 Opening year for traffic 1999 1999 1994 1994 Annual day traffic in 2004 15400 14800 32100 30200 Annual precipitation [mm] 820 820 690 690 Table 1. continued.  Site description. Pond/Station number  187.5 95.3 95.1 92.4 Nearby town  Grundfoer Fredericia  Fredericia  Fredericia  Pond area [m2] 2300 200 380 600 Catchment area [ha] 4.1 0.8 2.2 1.6 Opening year for traffic 1994 1994 1994 1994 Annual day traffic in 2004 33800 24100 24100 24100 Annual precipitation [mm] 690 770 770 770  Table 2. Applied average runoff concentrations in [µg/l].  Pollutant Concentration Pollutant Concentration Σ C6-C35 1623 Lead (Pb) 20.0 Flouranthene 0.19 Cadmium (Cd) 0.4 Benzo(b+j+k)flouranthene 0.19 Copper (Cu) 50.2 Benzo(a)pyrene 0.10 Chromium (Cr) 5.4 Dibenzo(a,h)anthracene 0.08 Nickel (Ni) 5.3 Indeno(1,2,3-cd)pyrene 0.07 Zinc (Zn) 156.7 Σ PAH 0.63    Table 3. Concentrations [mg/kg DM] in the sediments in eight ponds. Pollutant                Pond no. 306.7 302.9 205.4 195.9 187.5 95.3 95.1 92.4 Mean C6H6 - C10 13 9 13 11 26 13 19 12 14 C10-C25 215 140 290 155 460 250 505 390 301 C25-C35 902 655 1220 625 2175 1195 2375 1655 1350 THC 1140 805 1530 790 2640 1460 2895 2075 1667 Flouranthene 0.14 0.07 0.32 0.11 0.36 0.21 0.47 0.89 0.32 Benzo(b+j+k)flouranthene 0.23 0.12 0.43 0.14 0.53 0.23 0.61 1.06 0.42 Benzo(a)pyrene 0.06 0.04 0.12 0.04 0.14 0.07 0.19 0.28 0.12 Dibenzo(a,h)antracene 0.01 0.01 0.04 0.01 0.05 0.02 0.05 0.10 0.04 Indeno(1.2.3-cd)pyrene 0.09 0.05 0.17 0.06 0.14 0.09 0.25 0.36 0.15 ΣPAH 0.53 0.28 1.07 0.35 1.21 0.62 1.56 2.68 1.04 Lead (Pb) 20 10 37 22 68 22 51 47 35 Cadmium (Cd) 0.5 0.3 0.5 0.6 0.9 0.4 0.7 0.8 0.6 Copper (Cu) 54 27 125 66 220 81 165 160 112 Chromium (Cr) 24 12 37 22 46 20 43 45 31 Nickel (Ni) 21 10 22 18 33 18 31 35 23 Zinc (Zn) 240 115 420 325 1045 710 1150 715 590 Dry matter fraction 27 % 31 % 38 % 31 % 18 % 29 % 19 % 24 % 27 % Organic content  (Loss of ignition) 11 % 6 % 9 % 19 % 16 % 9 % 14 % 15 % 12 %  Table 4. Annual accumulation rates per hectare of impervious catchment  [ hayrg ⋅ ]. The mean value (Mean) is weighted by catchment area. Pollutant               Pond no. 306.7 302.9 205.4 195.9 187.5 95.3 95.1 92.4 Mean C6H6-C10 43 45 22 25 22 11 6 11 24 C10-C25 723 683 507 346 402 216 172 372 430 C25-C35 3033 3195 2131 1396 1900 1035 809 1579 1881 THC 3835 3927 2673 1765 2307 1264 986 1980 2337 Fluoranthene 0.47 0.35 0.56 0.24 0.31 0.18 0.16 0.84 0.37 Benzo(b+j+k)fluoranthene 0.77 0.57 0.74 0.32 0.46 0.20 0.21 1.01 0.51 Benzo(a)pyrene 0.21 0.17 0.21 0.08 0.12 0.06 0.06 0.27 0.14 Dibenzo(a,h)antrachene 0.03 0.05 0.06 0.02 0.04 0.02 0.02 0.09 0.04 Indeno(1.2.3-cd)pyrene 0.29 0.25 0.29 0.14 0.12 0.08 0.08 0.34 0.19 ΣPAH 1.77 1.38 1.86 0.79 1.06 0.54 0.53 2.56 1.24 Lead (Pb) 67 51 65 49 59 19 17 45 51 Cadmium (Cd) 1.8 1.5 0.8 1.3 0.8 0.3 0.2 0.7 1.0 Copper (Cu) 182 129 218 146 192 70 56 153 156 Chromium (Cr) 79 59 64 48 40 17 14 43 48 Nickel (Ni) 69 50 38 40 29 16 10 33 37 Zinc (Zn) 807 561 734 726 913 615 392 682 709  Figure 1. Sampling method.   0.00.20.40.60.81.01.21.41.61.82.02.22.4FluorantheneBenzo(b+j+k)flourantheneBenzo(a)pyreneDibenzo(a,h)anthraceneIndeno(1,2,3-cd)pyreneLead (Pb)Cadmium (Cd)Copper (Cu)Chromium (Cr)Nickel (Ni)Zinc (Zn)Relative accumulation [-]     Hjallerup - St.306.7 Vodskov - St. 302.9Randers S - St. 205.4 Hadsten N - St. 195.9Grundfoer - St. 187.5 Fredericia W - St. 95.3Fredericia W - St. 95.1 Fredericia W - St. 92.4 Figure 2. Relative accumulation (annual accumulation / annual influx).   0.11101001000100 300 500 700 900Relative pond area [m2 pond / ha impervious catchment]Annual accumulation rate [g/(yr*ha]   Lead (Pb) Cadmium (Cd)Copper (Cu) Chromium (Cr)Nickel (Ni) Zinc (Zn)0.010.1110100 300 500 700 900Relative pond area [m2 pond / ha impervious catchment]Annual accumulation rate [g/(yr*ha]   Fluoranthene Benzo(b+j+k)fluoranthene Benzo(a)pyreneDibenzo(a,h)antrachene Indeno(1.2.3-cd)pyrene Sum PAH Figure 3. Annual accumulation rate as function of relative pond area. 

Relationship Between Accumulation and Influx of Pollutants in Highway Ponds

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Relationship Between Accumulation and Influx of Pollutants in Highway Ponds

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