#  **[Investigation and comparison of the water quality of the "Mosel" and of the "Saar"]{.underline}**

# Gymnasium Konz, Germany

Kopp, Jürgen; Hübner, Tobias; Rausch, Alexander; Formella, Andreas;
Bettinger, Christian;

Kind, Daniel; Bauer, Johannes; Kiefer, Sebastian; Schmitt, Michael;
Eurich, Martina

**1. Abstract**

We pursued the question of which parameters the quality of water depends
on and decided to research the pollution of two rivers (the Mosel and
the Saar). As far as the measuring points are concerned our class chose
specific parts of the rivers which we expected to affect the water
quality:

1.   A shallow arm of the Saar not used by shipping (a strong current).

2.   A part of the Saar before a dam (a weak current).

3.   A part of the Saar influenced by a sewage plant.

4.   The Mosel before the confluence of the Saar and the Mosel.

Our analysis is based on chemical investigations (according to BACH and
GLOBE) which we compared with a biological determination of the water
quality (according to MEYER). We gathered our data with the aid of a
photometer and our own calibration absorbance curves for the following
parameters: nitrate, phosphate, ammonium and chloride. In addition to
these parameters we established the pH-value, nitrite concentration,
electrical conductivity, temperature, dissolved oxygen and the
consumption of oxygen by biological organisms over a five-day period (in
complete darkness). Finally we calculated the water quality in
accordance with the guidelines of "BACH\'s method to determine the
quality of water", a very common procedure in Germany. The result of
these calculations is that the chemical quality of the water in the
Mosel is better than that in the Saar. Comparing the various data it is
evident that both the sewage plant and the dam have a negative effect on
the water quality.

**2. Research Questions**

After a special research ship ("MS Burgund") -- which gathers readings
of the water quality -- had berthed at the port of Konz, we had the good
fortune to be introduced into their methods of water analysis by the
captain. Since this excursion we have pursued the question of which
factors might affect the water quality. We were interested in
researching the interaction between specific components of the water and
the water quality. As our school is situated near the confluence of the
Mosel and Saar, we decided to research the above-mentioned interaction
with the aid of water samples taken from the two rivers.

**3. Research Method**

At the beginning of our project it was necessary to determine various
measuring points[^1] which we expected to affect the water quality:

1.  \[M1\] A part of the Saar before a dam (a weak current).

2.  \[M2\] A shallow arm of the Saar not used by shipping (a strong
    current)

3.  \[M3\] A part of the Saar influenced by a sewage plant.

> 4\. \[M4\] The Mosel before the confluence of the Saar and the Mosel.

At this time we were not really sure, what influence sewage plants,
ships, dams etc. might have on the water quality. These connections will
be illustrated in the ensuing paragraphs of this report[^2].

The water samples were taken on the *30^th^ of August*, the *24^th^ and
27^th^ of March*. We gathered our data with the aid of a photometer[^3]
and our own calibration absorbance curves, established with
investigation kits[^4]: phosphate, nitrate, ammonium and chloride. In
addition to these parameters, we established: pH-value, nitrite
concentration[^5], alkalinity, water transparency, electrical
conductivity, temperature, dissolved oxygen and the consumption of
oxygen by biological organisms over a five-day period (in complete
darkness). But the parameters "alkalinity", "water transparency" and
"salinity" (concentration of chloride-ions) are only required by the
\"GLOBE protocol\"[^6] and not mentioned in the BACH method used in our
investigation (this method is common in Germany). But one must also
acknowledge that the data on "alkalinity", "water transparency" and
"salinity" were very useful for rounding off our "BACH results".

As our class was also interested in comparing the results of our
chemical investigation of the water with biological data, we carried out
a biological determination[^7] of the water quality (according to
"MEYER").

**4. Data Summary**[^8]

**4.1. Data Summary \[30.08.2002\]**[^9]

[Collecting all readings, we obtain the following table:]{.underline}

+---------------+-----+------+----+------+----+------+----+------+
| **Table 1)**  | **[ |      | ** |      | ** |      | ** |      |
|               | (1) |      | ([ |      | [( |      | ([ |      |
|               | S   |      | 2) |      | 3) |      | 4) |      |
|               | aar |      | S  |      | S  |      | Mo |      |
|               | ]{. |      | aa |      | aa |      | se |      |
|               | und |      | r] |      | r] |      | l] |      |
|               | erl |      | {. |      | {. |      | {. |      |
|               | ine |      | un |      | un |      | un |      |
|               | }** |      | de |      | de |      | de |      |
|               |     |      | rl |      | rl |      | rl |      |
|               | >   |      | in |      | in |      | in |      |
|               |  ** |      | e} |      | e} |      | e} |      |
|               | \[d |      | ** |      | ** |      | ** |      |
|               | am\ |      |    |      |    |      |    |      |
|               | ]** |      | *  |      | ** |      | \[ |      |
|               |     |      | *\ |      | \[ |      | be |      |
|               |     |      | [s |      | b. |      | fo |      |
|               |     |      | ha |      | co |      | re |      |
|               |     |      | ll |      | nf |      | t  |      |
|               |     |      | ow |      | lu |      | he |      |
|               |     |      | a  |      | en |      | co |      |
|               |     |      | rm |      | ce |      | nf |      |
|               |     |      | \] |      | of |      | lu |      |
|               |     |      | ** |      | t  |      | en |      |
|               |     |      |    |      | he |      | ce |      |
|               |     |      |    |      | M  |      | \] |      |
|               |     |      |    |      | os |      |    |      |
|               |     |      |    |      | el |      |    |      |
|               |     |      |    |      | a  |      |    |      |
|               |     |      |    |      | nd |      |    |      |
|               |     |      |    |      | t  |      |    |      |
|               |     |      |    |      | he |      |    |      |
|               |     |      |    |      | Sa |      |    |      |
|               |     |      |    |      | ar |      |    |      |
|               |     |      |    |      | \] |      |    |      |
|               |     |      |    |      | ** |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
|               | *re | *in  | *  | *in  | *r | *in  | *r | *in  |
|               | sul | dex* | re | dex* | es | dex* | es | dex* |
|               | ts* |      | su |      | ul |      | ul |      |
|               |     |      | lt |      | t* |      | t* |      |
|               |     |      | s* |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***Dissolved  | 59  | 41   | 69 | 63   | 84 | 86   | 64 | 53   |
| Oxygen*** %   |     |      | ,6 |      | ,4 |      | ,6 |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***Oxygen     | 4   | 53   | 4, | 57   | 4, | 58   | 2, | 88   |
| Consum        | ,65 |      | 22 |      | 25 |      | 31 |      |
| ption***[^10] |     |      |    |      |    |      |    |      |
| mg/l          |     |      |    |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***Nitrate*** | 18  | 46,5 | 15 | 55,5 | 22 | 35,5 | 19 | 43,5 |
| mg/l          |     |      |    |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| **            | 2   | 4    | 1, | 6    | 1, | 10,5 | 1, | 5,5  |
| *Phosphate*** | ,43 |      | 51 |      | 19 |      | 61 |      |
| mg/l          |     |      |    |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| *             | 0   | 88   | 0  | 94   | 0  | 82   | 0  | 97   |
| **Ammonium*** | ,15 |      | ,0 |      | ,2 |      | ,0 |      |
| mg/l          |     |      | 73 |      | 17 |      | 43 |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***T          | 1   | 77   | 19 | 77   | 19 | 77   | 19 | 73   |
| emperature*** | 9,2 |      | ,3 |      | ,2 |      | ,5 |      |
| °C            |     |      |    |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| *             | 6,7 | 87,5 | 6  | 87,5 | 7  | 98,5 | 7  | 99,5 |
| **pH-Value*** |     |      | ,7 |      | ,0 |      | ,4 |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***Electrical | 494 | 64   | 6  | 47   | 5  | 59,5 | 9  | 23   |
| Co            |     |      | 25 |      | 21 |      | 15 |      |
| nductivity*** |     |      |    |      |    |      |    |      |
| μS            |     |      |    |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| *             | 27  |      | 2  |      | 3  |      | 3  |      |
| **Salinity*** | 3,7 |      | 66 |      | 19 |      | 26 |      |
| mg/l          |     |      | ,8 |      | ,3 |      | ,3 |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***Chemical   |     | 4    |    | 5    |    | 6    |    | 6    |
| index         |     | 7,37 |    | 4,95 |    | 5,81 |    | 5,63 |
| CI***[^11]    |     |      |    |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+
| ***Class of   | #   | cr   | #  | cr   | #  | mo   | #  | mo   |
| water         | ### | itic | ## | itic | ## | dera | ## | dera |
| qu            | ##  | ally | ## | ally | ## | tely | ## | tely |
| ality***[^12] | II- | poll | #  | poll | #  |      | #  |      |
|               | III | uted | II | uted | II | poll | II | poll |
|               |     |      | -I |      |    | uted |    | uted |
|               |     |      | II |      |    |      |    |      |
+---------------+-----+------+----+------+----+------+----+------+

**4.2 Data Summary \[24.03.2003\]**[^13]

[Collecting all readings, we obtain the following table:]{.underline}

+-----------------+----+------+----+------+----+------+----+-------+
| #### Table 2)   | ** |      | ** |      | ** |      | ** |       |
|                 | [( |      | ([ |      | ([ |      | ([ |       |
|                 | 1) |      | 2) |      | 3) |      | 4) |       |
|                 | S  |      | S  |      | S  |      | Mo |       |
|                 | aa |      | aa |      | aa |      | se |       |
|                 | r] |      | r] |      | r] |      | l] |       |
|                 | {. |      | {. |      | {. |      | {. |       |
|                 | un |      | un |      | un |      | un |       |
|                 | de |      | de |      | de |      | de |       |
|                 | rl |      | rl |      | rl |      | rl |       |
|                 | in |      | in |      | in |      | in |       |
|                 | e} |      | e} |      | e} |      | e} |       |
|                 | ** |      | ** |      | ** |      | ** |       |
|                 |    |      |    |      |    |      |    |       |
|                 | >  |      | *  |      | ** |      | \[ |       |
|                 |  * |      | *\ |      | \[ |      | be |       |
|                 | *\ |      | [s |      | be |      | fo |       |
|                 | [d |      | ha |      | fo |      | re |       |
|                 | am |      | ll |      | re |      | t  |       |
|                 | \] |      | ow |      | t  |      | he |       |
|                 | ** |      | a  |      | he |      | co |       |
|                 |    |      | rm |      | co |      | nf |       |
|                 |    |      | \] |      | nf |      | lu |       |
|                 |    |      | ** |      | lu |      | en |       |
|                 |    |      |    |      | en |      | ce |       |
|                 |    |      |    |      | ce |      | of |       |
|                 |    |      |    |      | of |      | t  |       |
|                 |    |      |    |      | M  |      | he |       |
|                 |    |      |    |      | os |      | M  |       |
|                 |    |      |    |      | el |      | os |       |
|                 |    |      |    |      | a. |      | el |       |
|                 |    |      |    |      | Sa |      | a  |       |
|                 |    |      |    |      | ar |      | nd |       |
|                 |    |      |    |      | -- |      | t  |       |
|                 |    |      |    |      | "b |      | he |       |
|                 |    |      |    |      | ri |      | Sa |       |
|                 |    |      |    |      | dg |      | ar |       |
|                 |    |      |    |      | e" |      | \] |       |
|                 |    |      |    |      | \] |      |    |       |
|                 |    |      |    |      | ** |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
|                 | *  | *in  | *  | *in  | *  | *in  | *  | *i    |
|                 | re | dex* | re | dex* | re | dex* | re | ndex* |
|                 | su |      | su |      | su |      | su |       |
|                 | lt |      | lt |      | lt |      | lt |       |
|                 | s* |      | s* |      | s* |      | s* |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Dissolved    | 1  | 87   | 1  | 6    | 1  | 76   | 1  | 100   |
| Oxygen*** %     | 24 |      | 57 | 2,75 | 39 |      | 05 |       |
|                 | ,2 |      |    |      |    |      | ,3 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Oxygen       | 1  | 8,3  | 1  | 8,7  | 1  | 8,2  | 8, | 16,7  |
| Cons            | 1, |      | 1, |      | 1, |      | 64 |       |
| umption***[^14] | 43 |      | 12 |      | 52 |      |    |       |
| mg/l            |    |      |    |      |    |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Nitrate***   | 20 | 40   | 23 | 31,4 | 25 | 28   | 6  | 82    |
| mg/l            | ,2 |      | ,5 |      | ,2 |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Phosphate*** | 1, | 5    | 1, | 5,9  | 2, | 4,75 | 1, | 5,7   |
| mg/l            | 99 |      | 53 |      | 12 |      | 57 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Ammonium***  | 0, | 72   | 0  | 94   | 0, | 47   | 0, | 93,8  |
| mg/l            | 31 |      | ,0 |      | 52 |      | 08 |       |
|                 |    |      | 75 |      |    |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
| **              | 9  | 100  | 10 | 100  | 9  | 100  | 9  | 100   |
| *Temperature*** | ,6 |      | ,3 |      | ,6 |      | ,9 |       |
| °C              |    |      |    |      |    |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***pH-Value***  | 8, | 68,5 | 8, | 4    | 8, | 58,7 | 8, | 78    |
|                 | 22 |      | 71 | 6,05 | 43 |      | 05 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Electrical   | 6  | 42   | 6  | 42   | 6  | 41   | 9  | 20    |
| Conductivity*** | 56 |      | 57 |      | 65 |      | 85 |       |
| μS              | ,6 |      |    |      | ,3 |      | ,6 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Salinity     | 1  |      | 1  |      | 98 |      | 2  |       |
| mg/l***         | 04 |      | 09 |      | ,6 |      | 43 |       |
|                 | ,7 |      | ,2 |      |    |      | ,0 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| *               | 1  |      | 1  |      | 1  |      | 1  |       |
| **Alkalinity*** | 52 |      | 44 |      | 48 |      | 60 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Nitrite***   | \  |      | \  |      | \  |      | \  |       |
| mg/l            | <\ |      | <\ |      | <\ |      | <\ |       |
|                 | <1 |      | <1 |      | <1 |      | <1 |       |
+-----------------+----+------+----+------+----+------+----+-------+
| **water         | 54 |      | 60 |      | 52 |      | 1  |       |
| transparency**  |    |      |    |      |    |      | 49 |       |
| (Turbidity      |    |      |    |      |    |      |    |       |
| Tube) cm        |    |      |    |      |    |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Chemical     |    | 3    |    | 3    |    | 2    |    | 44,43 |
| Index CI ^1^*** |    | 4,48 |    | 2,37 |    | 9,64 |    |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Class of     | ## | hea  | ## | hea  | ## | hea  | #  | criti |
| Water           | ## | vily | ## | vily | ## | vily | ## | cally |
| Q               | ## | poll | ## | poll | ## | poll | ## | pol   |
| uality(chemical |  I | uted |  I | uted |  I | uted | #  | luted |
| det.)^2^***     | II |      | II |      | II |      | II |       |
|                 |    |      |    |      |    |      | -I |       |
|                 |    |      |    |      |    |      | II |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Biol         | #  | 2,25 | #  | 2,03 | #  | 2,46 | #  | 2,07  |
| ogicaliIndex*** | ## |      | ## |      | ## |      | ## |       |
|                 | ## |      | ## |      | ## |      | ## |       |
|                 | #  |      | #  |      | #  |      | #  |       |
+-----------------+----+------+----+------+----+------+----+-------+
| ***Class of     | #  | mo   | #  | mo   | #  | cr   | #  | moder |
| water           | ## | dera | ## | dera | ## | itic | ## | ately |
| qua             | ## | tely | ## | tely | ## | ally | ## | pol   |
| lity(biological | #  | poll | #  | poll | #  | poll | #  | luted |
| d.)^2^***       | II | uted | II | uted | II | uted | II |       |
|                 |    |      |    |      | -I |      |    |       |
|                 |    |      |    |      | II |      |    |       |
+-----------------+----+------+----+------+----+------+----+-------+

[Annotations:]{.underline}

1)  The chemical determination of the water quality only indicates the
    present state of water and it is a short-term determination.

2)  The biological determination of the water quality indicates the
    state of water before the actual investigation and is a long-term
    determination.

**4.3. Data Summary \[27.03.2003\]**[^15]

By collating all the readings, we obtain the following table to
establish the influence of the sewage plant:

<table>
<colgroup>
<col style="width: 28%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 8%" />
<col style="width: 0%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td rowspan="2"><h6 id="table-3">Table 3)</h6></td>
<td colspan="2"><p><strong><u>(1) Saar</u></strong></p>
<p><strong>[100m before confluence of the Mosel and the Saar, near
sewage plant]</strong></p></td>
<td colspan="3"><p><u>(2) Saar</u></p>
<p>[550m before the confluence of the Mosel and the Saar]</p></td>
<td colspan="4"><p><strong><u>(3) Saar</u></strong><a href="#fn1"
class="footnote-ref" id="fnref1" role="doc-noteref"><sup>1</sup></a></p>
<p><strong>[350m before the confluence of the Mosel and the Saar –
“bridge”, 3m]</strong></p></td>
<td colspan="4"><p><strong><u>(4) Saar</u></strong></p>
<p>[350m before the confluence of the Mosel and the Saar –
“bridge”]</p></td>
</tr>
<tr class="even">
<td><em>results</em></td>
<td><em>index</em></td>
<td colspan="2"><em>results</em></td>
<td><em>index</em></td>
<td colspan="2"><em>results</em></td>
<td colspan="2"><em>index</em></td>
<td colspan="2"><em>results</em></td>
<td colspan="2"><em>index</em></td>
</tr>
<tr class="odd">
<td><em><strong>Dissolved oxygen</strong></em> %</td>
<td>110,16</td>
<td>97</td>
<td colspan="2">125,1</td>
<td>87</td>
<td colspan="2">129,5</td>
<td colspan="2">83</td>
<td colspan="2">135,5</td>
<td colspan="2">79</td>
</tr>
<tr class="even">
<td><em><strong>Oxygen consumption</strong></em><a href="#fn2"
class="footnote-ref" id="fnref2" role="doc-noteref"><sup>2</sup></a>
<em>mg/l</em></td>
<td><em>11</em></td>
<td><em>8,7</em></td>
<td colspan="2"><em>11</em></td>
<td><em>8,7</em></td>
<td colspan="2"><em>11</em></td>
<td colspan="2"><em>8,7</em></td>
<td colspan="2"><em>11</em></td>
<td colspan="2"><em>8,7</em></td>
</tr>
<tr class="odd">
<td><em><strong>Nitrate</strong></em> mg/l</td>
<td>24,6</td>
<td>28,8</td>
<td colspan="2">23</td>
<td>31</td>
<td colspan="2">23,5</td>
<td colspan="2">31</td>
<td colspan="2">23,8</td>
<td colspan="2">30</td>
</tr>
<tr class="even">
<td><em><strong>Phosphate</strong></em> mg/l</td>
<td>1,51</td>
<td>6,05</td>
<td colspan="2">1,103</td>
<td>12,5</td>
<td colspan="2">1,13</td>
<td colspan="2">8</td>
<td colspan="2">0,708</td>
<td colspan="2">30,9</td>
</tr>
<tr class="odd">
<td><em><strong>Ammonium</strong></em> mg/l</td>
<td>1,06</td>
<td>33,6</td>
<td colspan="2">0,08</td>
<td>93,5</td>
<td colspan="2">0,09</td>
<td colspan="2">92,9</td>
<td colspan="2">0,1</td>
<td colspan="2">82,1</td>
</tr>
<tr class="even">
<td><em><strong>Temperature</strong></em></td>
<td>9,9</td>
<td>100</td>
<td colspan="2">9,8</td>
<td>100</td>
<td colspan="2">10,3</td>
<td colspan="2">100</td>
<td colspan="2">9,6</td>
<td colspan="2">100</td>
</tr>
<tr class="odd">
<td><em><strong>pH-value</strong></em></td>
<td>7,58</td>
<td>97</td>
<td colspan="2">8,42</td>
<td>59</td>
<td colspan="2">8,34</td>
<td colspan="2">62,9</td>
<td colspan="2">8,48</td>
<td colspan="2">54,6</td>
</tr>
<tr class="even">
<td><em><strong>Electrical conductivity</strong></em> μS</td>
<td>580</td>
<td>53,6</td>
<td colspan="2">650,6</td>
<td>44</td>
<td colspan="2">630</td>
<td colspan="2">43,4</td>
<td colspan="2">632,3</td>
<td colspan="2">43,4</td>
</tr>
<tr class="odd">
<td><em><strong>Chemical Index CI</strong></em><a href="#fn3"
class="footnote-ref" id="fnref3"
role="doc-noteref"><sup>3</sup></a></td>
<td></td>
<td>32,964</td>
<td></td>
<td colspan="3">36,38</td>
<td colspan="2"></td>
<td colspan="2">39,78</td>
<td colspan="2"></td>
<td>38,23</td>
</tr>
<tr class="even">
<td><em><strong>Class of Water Quality</strong></em> <a href="#fn4"
class="footnote-ref" id="fnref4"
role="doc-noteref"><sup>4</sup></a></td>
<td><h6 id="iii-3">III</h6></td>
<td>heavily polluted</td>
<td><h6 id="iii-4">III</h6></td>
<td colspan="3">heavily polluted</td>
<td colspan="2"><h6 id="iii-5">III</h6></td>
<td colspan="2">heavily polluted</td>
<td colspan="2"><h6 id="iii-6">III</h6></td>
<td><p>heavily</p>
<p>polluted</p></td>
</tr>
</tbody>
</table>
<aside id="footnotes" class="footnotes footnotes-end-of-document"
role="doc-endnotes">
<hr />
<ol>
<li id="fn1"><p>The same measuring point as in 4.2. (table 1) – (3)).
But we took the water samples three metres away from the bank of the
Saar.<a href="#fnref1" class="footnote-back"
role="doc-backlink">↩︎</a></p></li>
<li id="fn2"><p>i.e.: The consumption of oxygen by biological organisms
over a five-day period (in complete darkness) – The data are printed in
italics because they were taken from the 24<sup>th</sup> of March;
compare 4.2. (table 2)).<a href="#fnref2" class="footnote-back"
role="doc-backlink">↩︎</a></p></li>
<li id="fn3"><p>Compare 9.4.<a href="#fnref3" class="footnote-back"
role="doc-backlink">↩︎</a></p></li>
<li id="fn4"><p>Compare 9.4. (table b))<a href="#fnref4"
class="footnote-back" role="doc-backlink">↩︎</a></p></li>
</ol>
</aside>

**5. Analysis:**

**5.1. Detailed evaluation of the data obtained by analysing the water
samples of August 8, 2002**[^16]**.**

**5.1.1. Temperature -- Dissolved oxygen -- Consumption of oxygen by
micro-organisms over a five-day period (in complete darkness)**

The quantity of dissolved oxygen depends on the temperature of the
water: The higher the water temperature the smaller the amount of
dissolved oxygen.

a\) (1) Saar \[dam\]

At this measuring point we found the lowest amount of dissolved oxygen
because the current is relatively weak, which leads to a reduced
diffusion of oxygen in the water. In addition, this part of the Saar is
characterized by a high quantity of nutrients which are decomposed under
aerobic conditions -- that means under-consumption of oxygen -- by
diverse bacteria. (=\> "self-purifying power of the water")

b\) (2) Saar \[shallow arm\]

At this measuring point the concentration of oxygen is slightly higher,
which can be traced back to the fact that the current in the shallow arm
is much stronger than before the dam. Additionally, extended growth of
aquatic plants (=\> higher activity of photosynthesis) and a lower
concentration of nutrients (=\> not many dead organic substances) are
two other reasons for the relatively high concentration of oxygen.

c\) (3) Saar \[confluence of the Mosel and the Saar\]

On the one hand, the higher content of dissolved oxygen can be explained
by high concentration of algae, which add oxygen to the water
(photosynthesis). On the other hand, certain turbulences -- which are
primarily caused by the confluence of the Mosel and the Saar and by
ships' propellers -- contribute to a higher concentration of oxygen.

d\) (4) Mosel \[before the confluence of the Mosel and the Saar\]

At this measuring point the relatively low concentration of dissolved
oxygen is either connected with a large number of nutrients -- which are
decomposed by bacteria under the consumption of oxygen -- or with a
reduced growth of algae in comparison to the Saar (=\> lower activity of
photosynthesis). Evidence to support these assumptions might be the more
distinctly greenish colour of the water in the Saar (=\> extended
vegetation of algae) and the data on the oxygen consumption by bacteria
over a five-day period.

The oxygen consumption by micro-organisms over a five-day period is an
indication of the quantity of bacteria and algae and serves as a clue to
the organic pollution of the water. The higher the oxygen consumption
over a five-day period the higher the organic pollution of the water.

With the aid of the data in the table (compare 4.1.2. (table a)) one can
draw the conclusion that the Saar contains more micro-organisms and
algae than the Mosel. In the water samples from the Saar the oxygen
consumption over a five-day period was much higher than in the samples
from the Mosel. Taking these facts into consideration one can draw the
conclusion that the measuring points 1, 2 and 3 are characterized by a
higher organic pollution than at point 4.

**5.1.2. pH-value**[^17]

The Saar is characterized by slight acidity whereas the Mosel shows
slight alkalinity. These phenomena can be explained with the aid of
geological investigation. In the area of the upper Mosel the water runs
through the geological formation "Muschelkalk" (shell limestone).
Rainwater absorbs calcium hydrocarbonate and carries it into the Mosel.
As calcium hydrocarbonate reacts in a slightly alkaline way, the
pH-value of the Mosel increases. After Merzig (a town in the German
state: Saarland), the Saar runs either through Devonian slate or through
new red sandstone.

5.1.3. Nutritional Salts (PO~4~^3-^, NO~3~^-^, NH~4~^+^)[^18]

a\) (1) Saar \[dam\]

At this measuring point the water shows relatively high concentrations
of nutritional salts, especially of phosphate. One reason for this is
presumably the sewage plant situated above the dam which discharges its
"purified" sewage into the Saar. But the relatively high concentrations
of nitrate, ammonium and phosphate can be traced back not only to the
discharge from the sewage plant, but also to agriculture (including
wine-growing) along the banks which implies an increased use of chemical
fertilizers[^19]. In addition, the Saar runs through the Saarland which
is characterized by high population density. Most of the sewage plants
in the Saarland discharge their "purified" sewage into the Saar. The
relatively high concentration of ammonium is also connected with reduced
nitrification[^20] which can be traced back to the relatively low
content of dissolved oxygen before the dam (weak current).

b\) (2) Saar \[shallow arm\]

The shallow arm of the Saar is characterized by a stronger current (=\>
more dissolved oxygen), by a reduced quantity of water and by extended
growth of aquatic plants (algae and rushes). As aquatic plants absorb
mineral salts, the concentration of phosphate, nitrate and ammonium-ions
is reduced (compare 5.1.3. a)). Another reason for the drop in the
ammonium concentration is certainly the increased amount of dissolved
oxygen which leads to greater nitrification.

c\) (3) Saar \[confluence of the Mosel and the Saar\]

Comparing the readings at this measuring point with the results of
samples 1, 2 and 4 one can observe that the concentration of nitrate and
ammonium-ions is highest at the confluence. This can presumably be
explained by the Konz sewage plant, which discharges its more or less
purified sewage into the Saar (a few meters before the confluence of the
Saar and the Mosel.). Strangely enough the concentration of
phosphate-ions is lowest at the confluence. On the one hand this
paradoxical situation can be traced back to a reduced discharge of
phosphate-ions by the modern sewage plant, which combines mechanical,
biological and chemical water purification. The chemical purification
involves the precipitation of phosphate-ions with the aid of
iron(III)-chloride[^21]. On the other hand the water in the Saar showed
a distinct greenish colour. This points to extended growth of algae.
Phosphate-ions are increasingly absorbed by algae.

d\) (4) Mosel \[before the confluence of the Mosel and the Saar\]

At this measuring point there are three factors which influence the
concentration of nutritional salts. Firstly it must be pointed out that
the Mosel runs through France and Luxembourg before it enters Germany.
In France and Luxembourg the EC guidelines on the construction of sewage
plants have not yet been fully implemented. Secondly one must take into
consideration that the countryside along the Mosel is intensively used
for farming, above all wine-growing, which is inevitably linked with an
increased use of chemical fertilizers. These two factors -- despite
reduced concentrations along the course of the Mosel -- contribute to
the relatively high concentration of phosphate and nitrate-ions in the
upper Mosel. The ammonium concentration attains its lowest value at this
measuring point. This situation can partly be explained by the
self-purifying ability of the water. The oxygen saturation is 64,6% and
the last 60 kilometres of the Mosel up to our measuring point are
characterized by low population density and reduced agriculture (=\> not
many organic substances). Consequently practically all ammonium-ions can
be oxidized by micro-organisms (nitrification) within this part of the
river.

5.1.4. Concentration of chloride-ions[^22]

a\) (1) Saar \[dam\] and

b\) (2) Saar \[shallow arm\]

The relatively high concentration of chloride-ions before in the Saar
can partly be traced back to the "purified" sewage which is discharged
into the Saar by sewage plants and industry in the Saarland. Most of the
sewage plants and industrial works precipitate phosphate-ions with the
aid of iron(III)-chloride. The chemical equation of the reaction shows
that chloride-ions remain in the water[^23]. As the Saarland is a
densely populated state it has a lot of sewage plants which in most
cases discharge "purified" sewage into the Saar. As a consequence, the
concentration of chloride-ions in the Saar is increasing.

It is necessary to mention that there are other factors which might also
influence the concentration of chloride-ions.

c\) (3) Saar \[confluence of the Mosel and the Saar\]

The relatively high concentration of chloride-ions can partly be
explained by the fact that the water in the Mosel -- which shows the
highest concentration of chloride-ions -- mixes with that of the Saar at
the confluence. In addition, the Konz sewage plant precipitates
phosphate-ions with iron(III)-chloride. Thus the Konz sewage plant also
contributes to a higher chloride concentration.

d\) (4) Mosel \[before the confluence of the Mosel and the Saar\] [^24]

The river Meurthe in Bouxière (France) shows a chloride concentration of
973 mg/l. This is linked to the fact that there is a potash mine between
Azerailles and Bouxière. This mine discharges its waste salts (very high
concentrations of chloride-ions) into the Meurthe. Between Liverdun and
Millery, the Meurthe finally flows into the Mosel. This leads to an
increase in the Mosel's chloride concentration from 15mg/l (Liverdun) to
356 mg/l (Millery). Another reason for the high concentration of
chloride-ions are the discharges from sewage plants and other industrial
works.

The results of our measurement before the confluence of the Mosel and
the Saar (326 mg/l) is linked to the fact that along its course other
rivers, which show a relatively low concentration of chloride-ions --
for instance the "Sauer" - , flow into the Mosel (=\>dilution).

5.1.5. Comparison of the four measuring points

On the 30^th^ of August 2002 the Saar (in the area of the confluence of
the Saar and the Mosel) and the Mosel were both already moderately
polluted (water quality: class II). This should be the very least that
is strived for in the case of such relatively large, navigable rivers.
Generally speaking the water quality of the Saar is positively
influenced by the Mosel in the area of the confluence (=\> effect of
dilution).

At the dam on the Saar the CI-result is just above the "heavily
polluted" limit. This situation can primarily be traced back to the high
concentration of phosphate, ammonium and nitrate-ions and to the
relatively low amount of dissolved oxygen is tied up with high oxygen
consumption by micro-organisms over a five-day period. Generally
speaking the biochemical conditions in the water before the dam are
comparable to the conditions in a lake.

As the shallow arm of the Saar drops relatively sharply from time to
time and is characterized by rapids, the content of dissolved oxygen is
much higher than before the dam. This condition is also connected with
lower oxygen consumption by bacteria over a five-day period and a lower
concentration of ammonium-ions. This is the reason why the CI-result of
the shallow arm of the Saar almost reaches the limit: "moderately
polluted".

**5.2. Evaluation and comparison of the data obtained by analysing the
water samples of the 24^th^ of March, 2003 and the 27^th^ of March,
2003**[^25]

**-- Comparison with our results of the 30^th^ of August, 2002**[^26]

**5.2.1. \[24.3.2003\]:**

Comparing the water samples of the Saar and the Mosel with regard to
water transparency, one can see that all the samples from the Saar are
less transparent than those taken from the Mosel. The reason for this
reduced water transparency is a higher concentration of algae (in
comparison to the Mosel). This phenomenon *mainly* explains why the
Mosel (CI = 44,425) has a better water quality than the Saar (CI \< 35):

After a period of long fine weather high concentrations of algae lead to
supersaturation of oxygen, a high consumption of oxygen by
micro-organisms over a five-day period (in complete darkness) and a high
pH-value[^27].

In addition, the Saar shows higher concentrations of nutritional salts
than the Mosel. This is the crucial factor to which the extended growth
of algae in the Saar can be traced back.

**5.2.2. Differences between the measuring points on the Saar:**

In summer and at the end of winter, the shallow arm of the Saar has a
better CI-value.

Reasons for this situation are, for instance, a stronger current and the
fact that considerably more ammonium-ions can be oxidized
(nitrification). As a consequence organisms that are sensitive to the
concentration of oxygen have a better chance of surviving. This is
proved by the better biological index of water quality in the area of
the shallow arm (2,03) in comparison with the dam (2,25) and the area of
the confluence of the Saar and the Mosel (2,46) \[24.03.2003\].

The area of measuring point M1 (the dam at Kanzem[^28]) and measuring
point M3 (area of the Saar-Mosel confluence -- influenced by the dam on
the Mosel in "Trier"[^29]) is characterized by a very weak current. This
phenomenon explains the lower water quality index at these measuring
points.

Our interpretation of the widely divergent readings at the confluence of
the Saar and the Mosel presents us with certain difficulties. On the
30^th^ of August 2002 the Saar (at the confluence) and the Mosel showed
a virtually identical water quality index. Given that the Mosel has
considerably higher concentrations of chloride-ions and that
approximately the same concentrations were noted in the Saar (at the
confluence), one may conclude that the Mosel's water mixes with that of
the Saar in the area of the confluence. As a consequence both negative
as well as positive influences of the Mosel, the Saar and the Konz
sewage plant (effect of dilution) had been combined, producing a
positive overall result. That is also the reason why we decided
(24.03.2003) to shift our measuring point at the confluence
approximately 250 metres upstream. However, this shifting does not
sufficiently explain the considerable decline in the water quality index
from 65,81 to 29,64[^30] which means a decline in water quality from
class II to class III. This drop can be explained with the aid of an
overall comparison of the readings which we obtained by analysing the
water samples taken on the 30^th^ of August 2002 and the 24^th^ of March
2003.

Firstly, there was a considerable decline in the water quality index at
all measuring points on the 24^th^ of March 2003. Reasons for this
decline are -- above all -- the supersaturation of oxygen, the
considerably higher pH-values which are connected with the relatively
high consumption of oxygen by micro-organisms over a five-day period (in
complete darkness) (=\> increased growth of algae). The change of these
parameters can be explained by the weather:

August 2002 was characterized by heavy rainfall (overall precipitation
in Konz: 94,6mm)[^31] which obviously involved a large amount of cloud
cover. During the ten days before our sampling the average amount of
cloud had been 67/80 (=\> 84% of the sky was covered by clouds). On the
other hand February 2002 (13,7mm) and March 2002 (approx. 30,3mm) -- all
together -- were characterized by an overall precipitation of 44mm (in
Konz). In addition, during the ten days before our sampling the average
amount of cloud had been 3/20 (=\> 15% of the sky was covered by
clouds). On the 22^nd^, 23^rd^ and 24^th^ of March there was no cloud
cover. These data make it clear that the concentration of algae was much
higher on the 24^th^ of March than in August 2002. Compared with these
parameters the concentrations of nutritional salts have only changed
slightly. However, one exception is shown by the readings of the water
samples which were taken approximately 350 metres before the confluence
of the Saar and the Mosel on the 24^th^ of March 2003. The
concentrations of nutritional salts were much higher than those of the
30^th^ of August, 2002. This phenomenon also explains the considerable
decline in the chemical index of water quality.

*We presume that the increased concentrations of nutritional salts can
be traced back to the discharges of the Konz sewage plant*. This sewage
plant daily receives the organic waste of about 50,000 people (app.
50,000 "EWG"[^32]). But it is necessary to mention that the distance
between our measuring point (before the confluence of the Saar and the
bridge over the Mosel) and the place where the sewage plant discharges
its "purified" sewage into the Saar is approximately 250 metres. But how
is it possible for ions to "move" against the current?

**5.2.3. \[27.03.2003\]**

On the 27^th^ of March 2003 we decided to repeat a major part of our
investigation with water samples taken from two additional parts --
\[M3.3\], \[M3.4\] -- of the Saar[^33] in order to prove our hypothesis:

1.  \[M3.1\]: identical with measuring point \[M3\] (30.08.2002)  near
    the part of the Saar where the Konz sewage plant discharges its
    "purified" sewage, 100 m before the confluence

2.  \[M3.2\]: The Saar 350m before the confluence of the Mosel and the
    bridge across the Saar. The samples were taken at the bank of the
    Saar. (compare with 24.3.2003)

3.  \[M3.3\]: At the same place like \[M3.2\] but three meters away from
    the bank of the Saar.

4.  \[M3.4\]: With regard to measuring point \[M3.2.\], 200 metres
    upstream.

The table for March 27, 2003 illustrates that in spite of contrary
index-values of dissolved oxygen and electrical conductivity, the water
samples of \[M3.1\] show the lowest water quality index. Thus, near the
part where the Konz sewage plant discharges its "purified" sewage into
the Saar, the concentrations of nutritional salts reach their highest
level. In addition, the table shows that these concentrations decline
upstream. The concentrations of nutritional salts at measuring point
M3.3 are even slightly higher than those at the bank of the Saar. These
facts can only be explained by the presence of heavy barges (e.g. 4,000
tons) which cause a distribution of the nutritional salts.

The following illustration shows how a heavy ship causes the water to
mix. This clarifies why we find relatively high concentrations of
nutritional salts above the part of the Saar where the Konz sewage plant
discharges its "purified sewage".

![](media/image1.jpeg){width="4.863194444444445in"
height="1.7326388888888888in"}

**6. Conclusions**

Taking all the mentioned facts and interactions into consideration one
can draw the conclusion that the Konz sewage plant causes reduced water
quality in the area of the confluence of the Mosel and of the Saar. We
requested data from the head of the Konz sewage plant, who told us that
up to 44mg/l nitrate-ions, up to 1,3 mg/l ammonium-ions and up to 3 mg/l
phosphate-ions are discharged into the Saar throughout the year. The
daily discharge of approximately 5,000m³ make our results plausible.
After rainy days the discharge from the sewage plant is considerably
increased (i.e. \>\> 5,000m³). This situation leads to a dilution effect
in the Saar. Such dilution is always accompanied by reduced electrical
conductivity. Comparing the results of our three measurements
(30.8.2002, 24.3.2003, 27.3.2003), it can be seen that the samples of
August, 30^th^ and March, 27^th^ show a lower electrical conductivity
than those of March, 24^th^. Indeed, the days before August, 30^th^ and
March, 27^th^ are characterized by rain whereas this does not apply to
March, 24th.

The Saar dam also has a negative influence on the water quality. The
biochemical conditions in the water before the dam are comparable to the
conditions in a lake (a very weak current etc.). This water is mostly
characterized by high concentrations of nutritional salts, a relatively
low content of dissolved oxygen and the high consumption of oxygen by
bacteria over a five-day period (in complete darkness).

Generally speaking, the chemical quality of the water in the Mosel is
better than that in the Saar. It is evident that the Mosel has a
positive influence on the water quality of the Saar in the area of the
current. The chemical pollution of the Mosel can mainly be traced back
to agriculture and French and Luxembourgian discharges. In France and
Luxembourg the EC guidelines -- with regard to the construction of
sewage plants -- have not yet been fully implemented. The Saar is
heavily polluted where it runs through the Saarland with its dense
population. Agriculture also contributes to the Saar's chemical
pollution but on a smaller scale than that of the Mosel.

**7. Discussions**

BACH's method has proved to be worthwhile for analysing water quality,
especially if one interprets the results by referring to the parameters
proposed in the "GLOBE-protocol", namely: salinity, alkalinity and water
transparency.

**8. Bibliography**

1)  Chemie / Biologie -- Ökologie; Leybold Didactic, Hürth, 1998

2)  Chemie heute -- Sekundarstufe II, Schroedel, 1998

3)  Gewässer im Stadtteil -- Das Umweltprojekt G.R.E.E.N.; Behörde für
    Schule, Jugend und Berufsbildung der Freien und Hansestadt Hamburg
    und IPN Kiel, Hamburg, 1994

4)  Globe -- "HYDROLOGY INVESTIGATION" a GLOBE Learning Investigation,
    1997

5)  Gottschalk, Tim: Weather of Konz, see: www.wetterworld.de

6)  Internationale Kommission zum Schutze der Mosel und der Saar gegen
    Verunreinigungen: Wasserbeschaffenheit von Mosel, Saar und
    Nebenflüssen 1997; Trier 1998

7)  Nau, Jochen: Quantitative chemische Gewässeranalyse der Mosel,
    "Jugend-forscht"-Arbeit, Gymnasium Konz 1998 / 99

8)  Philipp, Eckhard: Experimente zur Untersuchung der Umwelt, München
    1993

9)  The head of the Konz sewage plant gave us information about the
    discharges into the Saar.

> Further informations about the environmental projects of the Gymnasium
> Konz: [www.konz4globe.eu.tf](http://www.konz4globe.eu.tf/) and
> [www.gymnasium-konz.bildung-rp.de](http://www.gymnasium-konz.bildung-rp.de/)
> among projekts.
>
> We thank Mrs. Zwingelberg-Woods for the correction of our translation.

**9. Appendix**

**9.1.** [Map]{.underline}:

Luxemburg France: 50 km Germany![](media/image2.png){width="2.6375in"
height="1.8833333333333333in"}

![](media/image3.png){width="7.998611111111111in"
height="5.702083333333333in"}

**9.2. Establishing our calibration absorbance curves:**

With the aid of calibration solutions it was possible to establish our
calibration absorbance curves for the various parameters (phosphate,
nitrate, ammonium, chloride):

**9.2.1. Phosphate -- calibration absorbance curve:**

![](media/image4.wmf)

**9.2.2. Nitrate -- calibration absorbance curve**[^34]**:**

![](media/image5.wmf)

**9.2.3. Ammonium -- calibration absorbance curve:**

![](media/image6.wmf)

**9.2.4. Chloride -- calibration absorbance curves:**

![](media/image7.wmf)

![](media/image8.wmf)

##### 9.3. "LAMBERT and BEER's law"

After establishing our calibration absorbance curves, the next step in
our investigation was to ascertain the absorbance of the various water
samples[^35]:

We mixed the samples with specific indicators in order to "dye
characteristic ions". After establishing the absorbance of the samples
(=\> photometer), the concentrations of the various ions in the water
samples could be calculated, according to Lambert and Beers's law:

E(λ) = ε~λ~ \* c \* d ⇒ c = E(λ) \* (ε~λ~ \* d)^-1^ [^36]

a)  E(λ): absorbance at λ nm

b)  λ: wavelength \[nm\]

c)  ε~λ~: molar absorbance coefficient \[cm² \* μg^-1^\] (proportional
    factor, this factor depends on the substance, being analysed, and
    the wavelength of the used light)

d)  c: concentration of the analysed parameter in the water sample \[mg
    \* l^-1^\]

e)  d: thickness of the cuvette \[cm\]

**9.4. "BACH\'s method to determine the quality of water"**[^37]

In the following paragraphs BACH\'s method of determining the quality of
water is illustrated.

In this context the water quality index(= CI) is the crucial quantity:
The higher the CI-result the better the water quality of the
investigated sample.

The chemical index of the water quality is calculated according to the
following formula:

CI = I~1~^E^~1~ \* I~2~^E^~2~ \* \... \* I~8~^E^~8~

In this formula, I~1\...8~ are indices and E~1\...8~ are specific
exponents. The tables on the following pages illustrate which indices
and which exponents are assigned to our various parameters.

With the aid of readings it is easy to assign an I~x~-value to a
parameter.

CI = I~1~^0,2^ \* I~2~^0,2^ \* I~3~^0,08^ \* I~4~^0,1^ \* I~5~^0,1^ \*
I~6~^0,15^ \* I~7~^0,1^ \* I~8~^0,07^

Finally, a certain class of water quality (I; I-II; II; II-III; III;
III-IV; IV) can be assigned to the calculated CI-value[^38].

table a)

  ----------------------------------- -----------------------------------
  **Oxygen consumption**[^39]         0,2
  **(*E~1~*)**                        

  **Dissolved oxygen (*E~2~)***       0,2

  **Temperature (*E~3~*)**            0,08

  **Phosphate (*E~4~*)**              0,1

  **Nitrate (*E~5~*)**                0,1

  **Ammonium (*E~6~*)**               0,15

  **pH-value (*E~7~*)**               0,1

  **Electrical conductivity           0,07
  (*E~8~*)**                          
  ----------------------------------- -----------------------------------

1)  The exponents E~1...8~ correspond to the weighting of the various
    parameters with regard to the scale of their influence on the water
    quality. The higher the E-value the higher the influence of the
    corresponding parameter on the water quality.

2)  E~1~+E~2~+E~3~+...+E~8~ = 1

table b)

  -------------- ----------- ------------- ------------- ----------- ----------- --------------
  *100 -- 83*    *83 -- 73*  *73 - 56*     *56 - 44*     *44 - 27*   *27 - 17*   *17 - 1*

  **I**          **I - II**  **II**        **II - III**  **III**     **III -     **IV**
                                                                     IV**        

  *unpolluted*   *slightly   *moderately   *critically   *heavily    *very       *excessively
                 polluted*   polluted*     polluted*     polluted*   heavily     polluted*
                                                                     polluted*   
  -------------- ----------- ------------- ------------- ----------- ----------- --------------

**[Tables of the index-values and exponents for the various parameters
(according to BACH)]{.underline}**[^40]

+-----------+-----+--------+----+------------+-----+------------+----+
| **Oxygen  | **  | **Dis  | *  | **T        | **  | *          | *  |
| consumpti | *in | solved | ** | emperature | *in | *Phosphate | ** |
| on**[^41] | dex | ox     | in | \[°C\]**   | dex | conce      | in |
|           | *** | ygen** | de |            | *** | ntration** | de |
| **\       |     |        | x* |            |     |            | x* |
| [mg/l\]** | *   | **\    | ** |            | *   | **         | ** |
|           | **I | [%\]** |    |            | **I | \[mg/l\]** |    |
|           | ~1~ |        | ** |            | ~3~ |            | ** |
|           | *** |        | *I |            | *** |            | *I |
|           |     |        | ~2 |            |     |            | ~4 |
|           |     |        | ~* |            |     |            | ~* |
|           |     |        | ** |            |     |            | ** |
+-----------+-----+--------+----+------------+-----+------------+----+
| 0         | 100 | 0      | 2  | \< 14      | 100 | 0          | 1  |
|           |     |        |    |            |     |            | 00 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 0,5       | 9   | 5      | 2  | 14         | 100 | 0,1        | 95 |
|           | 9,5 |        |    |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
| 1         | 98  | 10     | 3  | 15         | 99  | 0,2        | 84 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 1,5       | 95  | 15     | 4  | 16         | 9   | 0,3        | 72 |
|           |     |        | ,5 |            | 7,5 |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
| 2         | 90  | 20     | 6  | 17         | 95  | 0,4        | 60 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 2,5       | 84  | 25     | 9  | 18         | 90  | 0,5        | 48 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 3         | 76  | 30     | 12 | 19         | 79  | 0,6        | 39 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 3,5       | 68  | 35     | 15 | 20         | 6   | 0,7        | 31 |
|           |     |        |    |            | 7,5 |            | ,5 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 4         | 61  | 40     | 19 | 21         | 56  | 0,8        | 25 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 4,5       | 54  | 45     | 24 | 22         | 45  | 0,9        | 20 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 5         | 48  | 50     | 30 | 23         | 3   | 1          | 16 |
|           |     |        |    |            | 3,5 |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
| 5,5       | 42  | 55     | 36 | 24         | 22  | 1,1        | 12 |
|           |     |        |    |            |     |            | ,5 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 6         | 37  | 60     | 43 | 25         | 15  | 1,2        | 10 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 7         | 28  | 65     | 53 | 26         | 9   | 1,3        | 8  |
+-----------+-----+--------+----+------------+-----+------------+----+
| 8         | 2   | 70     | 63 | 27         | 5,5 | 1,4        | 7  |
|           | 0,5 |        |    |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
| 9         | 1   | 75     | 71 | 28         | 3   | 1,5        | 6  |
|           | 4,5 |        |    |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
| 10        | 10  | 80     | 79 | 29         | 1,5 | 1,6        | 5  |
|           |     |        |    |            |     |            | ,5 |
+-----------+-----+--------+----+------------+-----+------------+----+
| 15        | 4   | 85     | 86 | 30         | 1   | 1,8        | 5  |
+-----------+-----+--------+----+------------+-----+------------+----+
| \> 15     | = 3 | 90     | 93 | \> 30      | 1   | 2          | 5  |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 95     | 99 |            |     | 2,5        | 4  |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 96     | 1  |            |     | 3          | 3  |
|           |     |        | 00 |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 106    | 1  |            |     | 4          | 2  |
|           |     |        | 00 |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 110    | 97 |            |     | 5          | 1  |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 115    | 95 |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 120    | 90 |            |     |            |    |
|           |     |        | ,5 |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 125    | 87 |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+
|           |     | 130    | 83 |            |     |            |    |
+-----------+-----+--------+----+------------+-----+------------+----+

+-----------+----+----------+-----+----------+-----+-----------+-----+
| **Nitrate | *  | **       | **  | **pH     | **  | **E       | **  |
| concen    | ** | Ammonium | *in | -value** | *in | lectrical | *in |
| tration** | in | conce    | dex |          | dex | condu     | dex |
|           | de | ntration | *** |          | *** | ctivity** | *** |
| **\       | x* | \[       |     |          |     |           |     |
| [mg/l\]** | ** | mg/l\]** | *   |          | *   | **\[      | *   |
|           |    |          | **I |          | **I | μS/cm\]** | **I |
|           | ** |          | ~6~ |          | ~7~ |           | ~8~ |
|           | *I |          | *** |          | *** |           | *** |
|           | ~5 |          |     |          |     |           |     |
|           | ~* |          |     |          |     |           |     |
|           | ** |          |     |          |     |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 0         | 1  | 0        | 100 | 3        | 1   | 0         | 72  |
|           | 00 |          |     |          |     |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 2         | 94 | 0,2      | 84  | 3,5      | 2,5 | 25        | 85  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 4         | 88 | 0,4      | 60  | 4        | 7   | 50        | 91  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 6         | 82 | 0,6      | 49  | 4,5      | 13  | 75        | 95  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 8         | 76 | 0,8      | 40  | 5        | 22  | 100       | 9   |
|           |    |          |     |          |     |           | 7,5 |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 10        | 70 | 1        | 35  | 5,5      | 3   | 125       | 9   |
|           | ,5 |          |     |          | 4,5 |           | 9,5 |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 12        | 64 | 1,2      | 31  | 6        | 5   | 150       | 100 |
|           | ,5 |          |     |          | 6,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 14        | 58 | 1,4      | 2   | 6,5      | 7   | 175       | 9   |
|           | ,5 |          | 8,5 |          | 8,5 |           | 9,5 |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 16        | 52 | 1,6      | 2   | 6,6      | 83  | 200       | 9   |
|           | ,5 |          | 6,5 |          |     |           | 8,5 |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 18        | 46 | 1,8      | 2   | 6,7      | 8   | 225       | 97  |
|           | ,5 |          | 4,5 |          | 7,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 20        | 40 | 2        | 23  | 6,8      | 92  | 250       | 9   |
|           | ,5 |          |     |          |     |           | 5,5 |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 22        | 35 | 2,5      | 20  | 6,9      | 96  | 275       | 93  |
|           | ,5 |          |     |          |     |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 24        | 30 | 3        | 18  | 7        | 9   | 300       | 91  |
|           |    |          |     |          | 8,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 26        | 26 | 4        | 1   | 7,1      | 9   | 350       | 85  |
|           |    |          | 5,5 |          | 9,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 28        | 23 | 5        | 12  | 7,2      | 100 | 400       | 77  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 30        | 20 | 6        | 10  | 7,3      | 100 | 450       | 70  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 36        | 15 | 8        | 6,5 | 7,4      | 9   | 500       | 63  |
|           |    |          |     |          | 9,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| 40        | 10 | 10       | 4,5 | 7,5      | 9   | 550       | 56  |
|           |    |          |     |          | 8,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
| \> 40     | =  | 13       | 3,5 | 7,6      | 96  | 600       | 50  |
|           | 10 |          |     |          |     |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    | \> 13    | = 3 | 7,7      | 92  | 700       | 39  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 7,8      | 8   | 800       | 31  |
|           |    |          |     |          | 7,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 7,9      | 8   | 900       | 24  |
|           |    |          |     |          | 3,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 8        | 7   | 1000      | 19  |
|           |    |          |     |          | 8,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 8,5      | 5   | 1100      | 15  |
|           |    |          |     |          | 5,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 9        | 33  | 1200      | 13  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 9,5      | 18  | 1300      | 11  |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     | 10       | 1   | 1400      | 10  |
|           |    |          |     |          | 0,5 |           |     |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     |          |     | 1500      | 9   |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     |          |     | 2000      | 8   |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     |          |     | 3000      | 6   |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     |          |     | 4000      | 4   |
+-----------+----+----------+-----+----------+-----+-----------+-----+
|           |    |          |     |          |     | 5000      | 2   |
+-----------+----+----------+-----+----------+-----+-----------+-----+

**9.5. The weather**[^42] **-- August 2002 -- February 2003 -- March
2003**[^43]

[**Illustration a)**: temperature and precipitation -- **August 2002**
-- Konz]{.underline} ![](media/image9.png){width="5.610416666666667in"
height="2.9430555555555555in"}

[**Illustration b)**: air pressure and cloud -- **August 2002** --
Konz]{.underline}

![](media/image10.png){width="5.472916666666666in"
height="2.8555555555555556in"}

[**Illustration c)**: temperature, precipitation and depth of snow --
**February 2003** -- Konz]{.underline}

![](media/image11.png){width="5.6875in" height="3.1145833333333335in"}

[**Illustration d)**: air pressure and cloud -- **February 2003** --
Konz]{.underline}

![](media/image12.png){width="5.813888888888889in"
height="3.113888888888889in"}

[**Illustration e)**: temperature and precipitation -- **March 2003** --
Konz]{.underline}

[**Illustration f)**: air pressure and cloud -- **March 2003** --
Konz]{.underline}

![](media/image13.png){width="5.989583333333333in"
height="6.260416666666667in"}

**[RR]{.underline}**: precipitation

**[TDT]{.underline}**: average temperature

**[Tmax]{.underline}**: maximum temperature

**[Tmin]{.underline}**: minimum temperature

**[GSH]{.underline}**: overall depth of snow

**[BW]{.underline}**: cloud \[eighths\]

**[Druck]{.underline}**: air pressure at 1 p.m. \[illustration f)\] / 2
p.m. \[illustration b) + d)\]

**9.6. Connection between a high pH-value and a high algae
concentration**

An extended growth of algae is always linked to an increased
CO~2~-fixation (=\> high activity of photosynthesis). This fixation
affects the chemical equilibrium in the water:

Chemical balances in hard water (water with a high Ca(HCO~3~)~2~
content):

(The salt of a strong base and a weak acid reacts in a basic way)

1\. H~2~O~(l)~ + HCO~3~^-^~(aq)~ H~2~CO~3(aq)~ + OH^-^~(aq)~

> 2\. H~2~CO~3~ ~(aq)~ H~2~O~(l)~ + CO~2(aq)~
>
> 3\. CO~3~^2-^~(aq)~ + H~3~O^+^~(aq)~ HCO~3~^-^~(aq)~ + H~2~O ~(l)~

If the sun ist shining algae need CO~2~ in order to produce
C~6~H~12~O~6~ (photosynthesis)[^44]. As a consequence the chemical
balances are shifted: The concentration of OH^-^- ions and the pH-value
increase and the soluable HCO~3~^-^ - Ions are rebuilt out of the
limestone.

In the night, the organisms in the water produce CO~2~. Thus, the
chemical balances are shifted to the right side of the equation.

> 1\. H~2~O~(l)~ + CO~2(aq)~ H~2~CO~3~ ~(aq)~
>
> 2\. H~2~CO~3(aq)~ + H~2~O~(l)~ H~3~O^+^~(aq)~ + HCO~3~^-^~(aq)~
>
> 3\. HCO~3~^-^~(aq)~ + H~2~O ~(l)~ CO~3~^2-^~(aq)~ + H~3~O^+^~(aq)~

4\. H~3~O^+^~(aq)~ + OH^-^~(aq)~ 2 H~2~O~(l)~

Finally, the product of solubility of CaCO~3~[^45] is exceeded because
of the increase of the CO~3~^2-^- concentration.

> 5\. Ca^2+^ (aq) + CO~3~^2-^ (aq) CaCO~3~ (s)
>
> white "coating of lime"

The last equation explains why an extended growth of aquatic plants is
sometimes characterized by a white coating of lime on the plants'
surfaces, too. This phenomenen can be admired, for instance, at the
"Krka waterfalls" in Kroatia.

[^1]: Compare 9.1. (map)

[^2]: Compare 5.(Analysis) and 6.(Conclusions)

[^3]: Digital Diode Array Photometer (Leybold 667347) / Wavelength
    Resolution: 2nm

[^4]: Spectroquant E. Merck

[^5]: With the aid of test sticks (Macherey-Nagel / Quantofix for
    semiquantitative determination of nitrite)

[^6]: Compare "HYDROLOGY INVESTIGATION" a GLOBE Learning Investigation,
    1997

[^7]: The biological determination was carried out on the 24^th^ of
    March 2003.

[^8]: Nearly all measurements are an average of three values.

[^9]: Weather: 27.08.2002; amount of cloud: 7/8; precipitation: 17 mm;
    28.08.2002; amount of cloud: 8/8; precipitation: 2,2 mm; 29.08.2002;
    amount of cloud: 7/8; precipitation: 0 mm; 30.08.2002; amount of
    cloud: 1/8; precipitation: 0 mm. Much rain in August: 94,6 mm in
    Konz., compare 9.5. (illustration a) + b))

[^10]: i.e.: The consumption of oxygen by biological organisms over a
    five-day period (in complete darkness)

[^11]: Compare 9.4.

[^12]: Compare 9.4. (table b))

[^13]: Weather: a period of fine weather since the 6^th^ of March 2003,
    only the 12^th^ of March 2mm rain,

    compare 9.5. (illustration e) + f))

[^14]: i.e.: The consumption of oxygen by biological organisms over a
    five-day period (in complete darkness)

[^15]: Weather: 25.03.2003; amount of cloud: 5/8; precipitation: 0,3 mm;
    26.03.2003; amount of cloud: 5/8; precipitation: 7 mm; 27.03.2003;
    amount of cloud: 6/8; precipitation: 0 mm;

    compare 9.5. (illustration e) + f))

[^16]: Compare 4.1. (table 1)).

[^17]: Compare 4.1. (table 1))

[^18]: Compare 4.1. (table 1))

[^19]: Chemical fertilizers comprise nutritional salts. These
    nutritional salts are washed out by rain and carried into the Saar.

[^20]: a\) 2NH~4~^+^~(aq)~ + 3O~2(aq)~ + 2H~2~O~(l)~  2NO~2~^-^~(aq)~ +
    4H~3~O^+^~(aq)~ ΔH\<0 (Nitrisomonas spec.)

    b\) 2NO~2~^-^~(aq)~ + O~2(aq)~  2NO~3~^-^~(aq)~ ΔH\<0 (Nitrobacter
    spec.)

[^21]: PO~4~^3-^~(aq)~ + Fe^3+^~(aq)~ + 3Cl^-^~(aq)~  FePO~4(s)~ +
    3Cl^-^~(aq)~

[^22]: Compare with 4.1. (table 1))

[^23]: ^1^

[^24]: Compare **"**Wasserbeschaffenheit von Mosel, Saar und
    Nebenflüssen 1997; Internationale Kommission zum Schutze der Mosel
    und der Saar gegen Verunreinigungen, Trier 1998**"**

[^25]: Compare 4.2. (24.3.) respectively 4.3. (27.3.)

[^26]: Compare 4.1. (30.8.)

[^27]: Compare 9.6.

[^28]: Kanzem: a village situated near the dam on the Saar.

[^29]: Trier: city near Konz (the oldest in Germany)

[^30]: Compare 4.1. (table 1)) + 4.2. (table 2))

[^31]: Compare: 9.5.

[^32]: EWG =**E**in**w**ohner**g**leichwert (Ger.): 1 EWG = average mass
    of organic waste which is daily produced by a single inhabitant of a
    district and which can be decomposed by bacteria.

[^33]: Compare 3. and 9.1. (map)

[^34]: According to Fa. Merck: The standard divergence of the readings
    is +/- 3mg/l

[^35]: Compare 3.

[^36]: Compare the graphs in 9.2.: y = ε~λ~ \* d \* x

[^37]: Compare: "Gewässer im Stadtteil , Behörde für Schule Jugend und
    Berufsbildung der Freien und Hansestadt", Hamburg 1994

[^38]: Compare table b), same page

[^39]: i.e.: The consumption of oxygen by biological organisms over a
    five-day period (in complete darkness)

[^40]: These tables are taken from: "Gewässer im Stadtteil, Behörde für
    Schule, Jugend und Berufsbildung der Freien und Hansestadt"

[^41]: i.e.: The consumption of oxygen by biological organisms over a
    five-day period (in complete darkness)

[^42]: the data are taken from
    [www.wetterworld.de](http://www.wetterworld.de/), the author passed
    our school's final exams last year.

[^43]: The legend is illustrated at the end of this paragraph

[^44]: 6CO~2~ + 6H~2~O  C~6~H~12~O~6~ + 6O~2~ ΔH\>0

[^45]: c(Ca^2+^) \* c(CO~3~^2-^) = 5 \* 10^-9^ mol² \* l^-2^ (compare
    "Chemie heute -- Sekundarstufe II -- Schroedel -- 1998" )