United nations /MAP/ TS 18-19/12/2003

Distribution of N-NODistribution of N-NO3 3 [river [river Loire (1971 to 1997)]Loire (1971 to 1997)]

Point 4137000

mg/l NNO3

Pseu

do-d

écad

e

0

7

14

20

26

32

0 2 4 6 8

Point 4134500

mg/l NNO3

Pseu

do-d

écad

e

0

6

12

19

28

35

0 2 4 6 8 10 12

United nations /MAP/ TS 18-19/12/2003

N-NON-NO33 at two sampling points at two sampling points [river Loire (1971-1997)][river Loire (1971-1997)]

V ariab les

NNO 31 34

NNO 31 37

2 9.5 87 29.9 52 3 0.3 17 3 0.6 82 3 1.0 47 31.4 12 3 1.7 77 3 2.1 42 3 2.5 07 3 2.8 72 33.2 37 3 3.6 02 3 3.9 67 3 4.3 32 34.6 97 35.0 62 3 5.4 27 3 5.7 92

(X 1000)

0

2

4

6

8

10

12

United nations /MAP/ TS 18-19/12/2003

Reconstructing N-NO3 mass Reconstructing N-NO3 mass discharge at the upper river discharge at the upper river Loire estuaryLoire estuary

0

50

100

150

200

250

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

kT

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000hm3

Point 4134500

Annual water discharge

Reconstructed mass discharge