Clarity:  Clarity can be caused by dirt and algae in the river.  The effects that can be caused from clarity is: the prevention of photosynthesis to the river plant, as the light is unable to pass through the water.  The major effects from this will be a lack of oxygen in the water will cause the wildlife within the river to die.

      We found that site E (embankment) had the lowest clarity compared to the others.  Although at site C (behind college) the clarity was low as well.  The reasons for site E having a low clarity may be due to: The footbridge running across site E and with the recent rain any waste will have been washed off in to the river. 

                                                                                                                        Jode/trace

pH:  pH can be caused by atmospheric pollution.  Extreme pH’s will have an adverse effect to plant and animal life.   The pH level will also effect whether animals can reproduce (fish egg hatching) 

     We found that at all sites there wasn’t a great deal of fluctuation and all levels remained within a reasonable limit.

                                                                                                                        Jode/Trace

Nitrate

Nitrates in river water often come from nitrogenous fertilizers used by farmers.  Nitrates are very soluble and may move down through the soil horizons into the groundwater.  High nitrate levels in the water lead to eutrophication in the water.  Eutrophication leads to a rapid algae growth in the water, which causes the oxygen levels to decrease as well as competition for light to occur.  Although algae photosynthesise they severely reduce the amount of light in the water by blanketing the surface.  Dead algae are broken up by aerobic bacteria which use up much of the oxygen in the water.   As oxygen levels decrease, BOD is increased (biochemical oxygen demand) meaning many plants and animals die, causing the break down of many food chains.

We tested water samples from five different points along the River Ouse, as it passes through Bedford.  There was no variation in the nitrate levels in any of the five samples; they all measured 10mg per litre.

These results show that the nitrate levels in the River Ouse in Bedford are stable and reflect historical levels of nitrate at the points tested.  Therefore human activity appears not to be having any discernable adverse effect on nitrate levels in the water.  This may be due to the fact that many farmers do not use large amounts of nitrogenous fertilizers at this time of year as many crops are now reaching maturity.  Recent long periods of rain may have diluted the concentration of nitrate in the water.

Investigators: Neill Campbell and Sam Hammond

Phosphate

Phosphate:  Phosphates are used in agriculture, domestic settings and also industry.  They may appear in river water samples as a chemical input.  High readings would indicate that they have been added to the water through agricultural runoff or industrial or domestic effluent.

If excessive levels are present it can lead to eutrophication and increased algal bloom.  This may lead to competition for light which may cause plants to die and decay.  The resulting detritus will lead to more decomposition which will use up more oxygen and lead to an increased biological oxygen demand.

In extreme conditions anaerobic bacteria will thrive and release NH₄, CH₄, H₂S into the water; aerobes such as invertebrates and fish will die.

Due to the different collection points for the water samples, we expected to see a slight increase in the phosphate levels due to the different land uses along the course of the river. A previous study highlighted the fact that a commercial Car Wash had temporarily discharged their waste water into the river, leading to increased phosphate levels over a period of a few weeks.

 The general trend along the testing points on the river revealed a slight increase in the phosphate levels as the river passed through Bedford. This may be due to the differing land uses within the town. Sampling on this occasion revealed that the phosphate levels were significantly higher at collection point E and then dropped by the time it reached point D, further downstream.

Investigators: LK/KG

Nitrite

is a product of the nitrogen cycle; it results from the decomposition of natural sources, such as leaves, roots and plants, through the process of nitrification. It has little or no effect on the environment. The closer to arable land the samples were taken from, we expected to find higher concentrations of nitrite.

There is little variation found in all samples taken, except in samples E and D; this could be due to the build up of concentration levels during its transition through the more built up areas of Bedford.

MM. SM. KC. LB

Chlorine

does not appear naturally in water but is added to drinking water by water companies. It can be considerably damaging to the environment. The sample taken from more built up areas were expected to contain higher concentration levels of chlorine. There was very little variation found in the samples taken, except in sample E; this could be due to the build up of concentration levels during its transition through the more built up areas of Bedford.

MM. SM. KC. LB

Chloride

1)      Chloride is found in the form of sodium, salt.  This is from surface run off, obtained through precipitation washing the salt used from the roads gritted during the winter months.

2)      Excess sodium chloride can have osmotic effects on the environment.

3)      Expect to find high levels of sodium chloride in built up areas.

4)      At site A there were low levels of sodium chloride.  Site D had the highest level of sodium chloride,

5)      Site A is an area away from roads which contain the lowest level of sodium chloride.  The sodium chloride levels increased as samples were taken along the river at various points in higher built up areas.

6)      Ben Young & Karalyne Donoghue