Investigation of road runoff inputs from the A42 into the River Mease, UK: winter 2013/14 Final: April 2014 A Taylor, WH Blake*, S Comber, R Goddard, A Fisher, HG Smith, L Gaspar, J Darmovzalova Catchment and River Science Research Group (CaRiS), School of Geography, Earth and Environmental Sciences, Plymouth University, PL4 8AA (*contact: [email protected] ) With Victoria Levett (project manager) and David Fraser (project director) APEM Ltd, Centre for Innovation & Enterprise, Oxford University Begbroke Science Park, Begbroke Hill, Woodstock Road, Begbroke, Oxfordshire, OX5 1PF (APEM Project 412766) This project is part of the IPENS programme (LIFE11NAT/UK/000384IPENS) which is financially supported by LIFE, a financial instrument of the European Community 1 Contents pg 1. Introduction 3 1.1 Project Brief 1.2 Road runoff problems: review of literature 1.3 Aims and objectives 2. Methods and approach 12 2.1. Site selection 2.2. Field monitoring 2.3 Water quality sampling and analysis for metals 2.4 Sediment quality sampling and fingerprinting 3. Results and discussion 15 3.1. Hydrographs from Mease channel above and below and at the A42 culvert input 3.2. Total and dissolved metals during sampled storm periods 3.3. Road dust and impacts on river sediment quality 4. Conclusions and recommendations 29 4.1 Key messages 4.2 Recommendations 4.3 Limitations and further work This project is part of the IPENS programme (LIFE11NAT/UK/000384IPENS) which is financially supported by LIFE, a financial instrument of the European Community’ “The Improvement Programme for England’s Natura 2000 Sites (IPENS), supported by EU LIFE+, is a new strategic approach to managing England’s Natura 2000 sites. It will enable Natural England, the Environment Agency, and other key partners to plan what, how, where and when they will target their efforts on Natura 2000 sites and on land surrounding them. This project is part of the IPENS programme (LIFE11NAT/UK/000384IPENS) which is financially supported by LIFE, a financial instrument of the European Community.” http://www.naturalengland.org.uk/ourwork/conservation/designations/sac/ipens2000.as px 2 1. Introduction 1.1 Project brief Road networks can impact on aquatic and marine systems by providing both a contaminant source and a pathway of entry to watercourses. In the Mease catchment, there is concern that runoff from the A42 might be having adverse effects on water and sediment quality, and hence aquatic life. The River Mease and the lower part of Gilwiskaw Brook are special lowland rivers that are designated as a Special Area of Conservation (SAC) under the EU Habitats Directive, and as a Site of Special Scientific Interest (SSSI) under the Wildlife and Countryside Act (as amended). They were designated because the River Mease represents one of the best examples of an unspoilt meandering lowland river, which supports characteristic habitats and species. The River Mease SSSI/SAC supports populations of spined loach (Cobitis taenia) and bullhead (Cottus gobio); two notable species of native freshwater fish that have a restricted distribution in England. The rivers also support populations of white-clawed crayfish (Austropotamobius pallipes), otter (Lutra lutra), and a range of river plants such as water crow-foot (Ranunculus sp.). In this context, the aim of this work programme was to establish if contamination from A42 road runoff reaches the River Mease SSSI/SAC (Site of Special Scientific Interest and Special Area of Conservation) in dissolved or particulate from at levels that exceed environmental quality guidelines. 1.2 Literature Review: Road derived contaminants and impacts on aquatic systems Contaminants directly associated with roads, which present potential threats to aquatic systems, can be classed as heavy metals, salts and organic molecules (particularly Polycyclic Aromatic Hydrocarbons (PAHs)) (Beasley and Kneale 2002; Boxall and Maltby 1995). Of these, 4 metals (Cd, Hg, Ni and Pb) and 8 PAHs are included in the Water Framework Directive (WFD) list of priority substances (2008/105/EC). Copper and zinc are identified as Specific Pollutants by the UK under the WFD and site- specific standards are set based on ambient water quality (Table 1).These contaminants can be transported into watercourses via runoff and drainage systems or become stored in neighbouring buffer zones (vegetated verges and banks), to be later mobilised under suitable conditions. Once in a watercourse, changing environmental parameters can influence the remobilisation and bioavailability of contaminants with subsequent bioaccumulation affecting ecological status (Trombulak and Frissell 2000). With vehicle-related contamination predicted to increase with rising traffic volumes, roads present a significant threat to aquatic systems (Napier et al. 2008). Literature surrounding the impact of road networks on watercourses is reviewed here focussing on contaminant sources, pathways of entry to watercourses and ecotoxicity. 3 Sources of road-derived contaminants Beasley and Kneale (2002) described urban runoff as a complex concoction of potential pollutants (Table 2), with roads acting as a principal source, which is evident when comparing heavily trafficked to lightly trafficked areas (Apeagyei et al. 2011; Wijaya et al. 2012). Of those contaminants derived directly from vehicle use, Napier et al. (2008) estimated Cu, Pb, Zn and PAH contributions from tyre and brake wear, oil leakage and exhaust emission from UK passenger cars (Table 3). Tyre and break wear are key sources of Cu and Zn, which are released as particulates (generally < 125 µm) and become a component of road dust (comprised of emitted particulates and natural sediment) (Robertson and Taylor 2007; Zafra et al. 2011). Concentrations of contaminants in road dust display enrichment in the fine fractions (< 63 µm) (Zafra et al. 2011) (Table 4) and can exhibit spatial and temporal variability related to traffic volumes and road class (Apeagyei et al. 2011) and weather conditions and maintenance practice (Helmreich et al. 2010; Robertson and Taylor 2007). Another potential toxicant often elevated in road dust is Ni, which is commonly associated with engine wear and anthropogenic inputs of Ni to freshwaters have almost doubled each decade since 1930 (Beasley and Kneale, 2002). Napier et al (2008) suggested that vehicle derived concentrations of other potentially toxic metals such as Cd and Hg are likely to reduce owing to manufacturing restrictions imposed under the EU End of Life Vehicles Directive (2000/53/EC). Cu and Zn emissions are, however, likely to continue to increase with traffic volume given their association with tyre and brake wear. It should also be noted that reduction in vehicle emission of certain metals may not be reflected in reductions in potentially labile concentrations in the short-term, owing to storage and remobilisation from contaminant sinks. This has been demonstrated with regard to the persistence of Pb in soils and sediments since the introduction of lead- free fuels (Hagner 2002; Izquierdo et al. 2012; MacKinnon et al. 2011). Vehicle exhaust catalysts are a major source of Platinum Group Elements (PGE) such as Pt, Pd and Rh, with such elements commonly found to be elevated above background concentrations in road dust and roadside soil (Table 4). Jackson et al. (2007) reported a global concentration range in road dust of 0.22 – 2.25 and 0.22 – 0.56 µg g-1 for Pt and Pd respectively. A general consistency in ratios between Pd, Pt and Rh in environmental samples across urban areas suggests that vehicles are a dominant source of PGE emission (Jackson et al. 2010; Prichard et al. 2009a) with clear spatial patterns evident in sediment concentrations, which trend towards higher values close to road sources (Prichard et al. 2008). 4 Table 1: Examples of Environmental Quality Standards of some priority substances Priority Substance EQS (Maximum Allowable Concentration) Inland Surface Waters (µg L-1) Anthracene 0.1 Cd (and its compounds) a≤0.45 b0.45 c0.6 d0.9 e1.5 Fluoranthene 0.12 Hg (and its compounds) 0.07 Naphthalene 130 Ni (and its compounds) 34 PAH: Benzo(a)pyrene 0.27 Benzo(b)fluoranthene 0.017 Benzo(k)fluoranthene 0.017 Benzo(g,h,i)perylene 8.2 ×10-3 Indeno(1,2,3-cd)pyrene f1.7 ×10-4 Copper 6 or 1.0 as bioavailable metalf,g Zinc 50 or 10.9 as bioavailable metalf,g a Class 1: <40mg CaCO3/L b Class 2: 40 to <50mg CaCO3/L c Class 3: 50 to <100mg CaCO3/L d Class 4: 100 to <200mg CaCO3/L e Class 5: ≥200mg CaCO3/L fAnnual Average concentration g Determined using the Biotic Ligand Model 5 Table 2: Sources of contaminants in road runoff. Adapted from Beasley and Kneale (2002). Vehicle Surface material Surface debris Brakes Tyres Body Fuel/oil Concrete Asphalt Salt Litter Cadmium * * Chromium * Copper * * Iron * * Lead * * * * Nickel * Vanadium * Zinc * * * Chlorides * SolidsO * * SolidsI * * * * PAHs * * Phenols * O Organic I Inorganic Table 3: Estimates of environmental inputs from passenger cars in the UK in 2003. Data taken from Napier et al. (2008) Tyre wear Brake wear Oil loss (t) Exhaust (t) (t) (t) Copper 0.3 24 0.038 0.4 Lead 1.0 1.5 0.02 1.1 Zinc 990 44 2.3 1.0 PAHs 21.7 nv 320 130 Aside from metals, road networks are also sources of salts and PAHs, both of which can impact on the status of freshwater systems (Boxall and Maltby 1995; Cañedo- Argüelles et al. 2013). The use of de-icing salts during cold weather has been shown to raise the salinity of aquatic systems and there is increasing concern over the role of secondary salinisation on freshwater ecology (Cañedo-Argüelles et al. 2013; Gillis 2011). De-icing salts largely consist of soluble chlorides (NaCl) and also soluble sulphates (CaSO4) and anti-caking agent NaFe(CN)6. Moy and Crabtree (2003) suggested a typical application rate of road salt during cold weather in the UK of 0.01 kg m-2 and estimated an annual application totalling 10,389 kg for a short section (~ 700 m in length) of the M4 in England.