Environmental Engineering Reference
In-Depth Information
Table 3
Results from the 2003/2004 monitoring study at the A25 site
[5]
Range of values
Parameter
No. samples
Min.
Max.
Average
Median
St. Dev.
40
67.3
1,790.0
305.1
156.5
354.4
Conductivity (mS/cm)
Salinity (mg/L)
40
36
950
161
81
188
Turbidity (FNU)
40
1.2
152.7
55.9
47.2
39.4
TSS (mg/L)
40
<5.0
295.0
49.3
33.8
52.6
Total hardness (mg
CaCO
3
/L)
40
28.3
181.8
91.0
91.4
48.9
Chlorides (mg/L)
40
6.6
139.5
51.3
52.3
38.8
NH
4
+
(mg/L)
40
<0.1
1.2
<0.1
<0.1
-
Total P (mg/L)
40
<0.16
0.72
0.25
0.23
0.15
COD (mg/L)
40
<0.3
170.0
84.1
84.2
53.1
BOD
5
(mg/L)
25
<2
66
25
12
13
contains results of the previous characterization of A25 highway runoff that will be
considered in the present study, as well.
Methodologies
In February 2008 the field monitoring system was installed at the site, in a shelter.
It consisted of a rain-gauge, a flowmeter (ISCO 730 Bubbler flow module), a bub-
bler flow and a Thel-Mar volumetric weir (fit to a 400 mm pipe), and an automatic
water sampler (ISCO 6700) working in synchronization. Figure
3
presents such
system, the same as used by
[5]
.
An innovation for the G-Terra studies is the use of a methodology based on
[7]
,
named the wet candle device, selected as a sound methodology to determine the
atmospheric chloride deposition rate (amount of chlorides salts deposited from
the atmosphere on a given area per unit time). The wet candle device was placed at the
top of the shelter (Fig.
3
).
The Meteorological Station of Aveiro University is located approximately 2 km
to the East from the monitoring site, as can be seen in Fig.
2
. A second wet candle
device will be placed there and meteorological and atmospheric data will be col-
lected and analyzed. This station continuously records meteorological and atmo-
spheric data, useful to explain the air mass transport and salt deposition. The saline
aerosol production is induced by sea conditions. Data concerning wave height,
direction and period, will be gathered in the research.
Between February and April 2008, ten different rainfall events were monitored
and 72 runoff samples were collected. The sampling routine was trigged by the runoff
flow. Around eight samples were collected during each event that had an average
duration of approximately two hours. The samples were transported to the laboratory
as soon as possible, and the preparation, conservation and analysis procedures were
