INTRODUCTION

Road run-off includes	chlorides, de-icing compounds products of road deterioration products of car deterioration nutrients toxic metals and organic chemical
Treatment is by So:-	interception clarification by settling skimming
motorway run-off might affect stream biology including macro-invertebrates, macrophytes heavy metal concentrations in mosses fish populations microbiological communities (periphyton)
AIM to investigate impact of motorway drainage on periphyton

METHODS

• Motorway in Northern England sampled April/March
• 7 streams (4-10 m width)
• 4 rocks from shallow stony riffles
• Sampled via 10 mm x 10 mm hole in a celluloid template
• Periphyton (‘auchwuss’)
  • cropped with forceps
  • scraped with a scalpel
  • removed by irrigation with a pipette
  • uni-cells counted
  • filamentous relative abundance estimated
  • identified to species level at a x400 with light microscope

Intensive survey

• more intensive survey undertaken at one site (Sparishaw)
• Upstream (US) and downstream (DS) sites divided into 3 major zones
• 4 replicate samples taken in each zone

Factors under consideration for general survey

• difference between streams
• US-DS location
• variation between replicates

Factors under consideration for intensive survey

• US-DS location,
• variation between zones
• variation between replicates

RESULTS

So, analysis of variance shows

1. no variation between replicates – expected
2. differences between rivers – expected
3. no differences between zones – expected
4. US/DS differences
5. few interactions (expected because of 1 and 3)

DISCUSSION

Stresses may be due to

• physical non-conformity where the river is culverted under the motorway.
• motorway pollution from
  • petrol – Pb and toxic light oil fractions
  • tyres – rubber, soot, heavy metal oxides, Cr, Cu, Pb and Zn
  • engine oil – Cr, Ni, Cu and organic phosphates
• ice, snow and de-icing agents
  • de-icing salt (a pulse of 2165 mg/l Cl can cause drift of invertebrates)
  • chemicals accumulated in the snow pack at the side of the road.

One site showed lower diversity DS of the motorway due to both

• a farm US of the motorway
• erosion DS of the motorway

Anova shows differences US and DS but are conditions WORSE downstream of the motorway ?

Look at graphs of the data per square mm

• number of species
• number of non filamentous algal cells
• relative abundance of filaamentous algae
• diversity (Shannon Wiener)

Note …

• At almost all sites there was a more diverse epiphyton DS of the motorway
• Nutrient poor water – eutrophication ?
• If so, there should be more downstream biomass of
  • macroinvertebrates
  • fish
• But DS of the motorway there are
  • fewer macroinvertebrates
  • more fish

CONCLUSION

• Little evidence of a bad chemical impact of the motorway when surveyed in Spring.
• There appears to be an effect of the
  • engineering structure on the fish
  • which in turn affects the macroinvertebrates…
  • which in turn affects the periphyton.
• So, use appropriate engineering techniques