Environmental Engineering Reference
In-Depth Information
Table 6
Oil and grease averages determined in highway runoff in Portugal
Road
No. samples
ADT
Average (mg/L)
Reference
A1
5
30,299
19.2
[12]
A2
7
16,344
3.1
A6
23
2,918
11.2
IP6
8
6,539
0.5
[7]
A23
20
9,855
0.58
[1]
Table 7
Salt deposition rate (chloride deposition) measure in a variety of studies in different
environments, using wet candle device
Distance from
the sea (m)
Salt deposition
rate (mg/m
2
day)
Marine environment/country
Reference
Atlantic Ocean/Portugal
5,600
59-84
Antunes and Barbosa,
(working paper)
Atlantic Ocean/Nigeria
45-365
800-140
[2]
Indian Ocean/Malaysia
30-400
400-100
[15]
Mediterranean Sea/Spain
20-170
111-7
[14]
Atlantic Ocean/Brazil
10-1,100
460-6
[13]
concentrations, 35%, 14% and 3% of samples, respectively, were above the dis-
charge limits of this law. The atmospheric chloride deposition rate values (Table
5
),
when compared to data from in several studies reported in Table
7
, show clear
evidences of the presence of salt.
These results were expected, considering: the sea proximity and the A25 road
platform altitude, nearly corresponding to the sea level, and the absence of signifi-
cant obstacles to the transport of the marine aerosols.
Final Remarks
In 2005 and 2006 researchers from Portugal realized that coastal roads showed a
specific pattern for some pollutants in highway runoff, namely the TSS, COD, and
chlorides and salinity
[5, 7]
. A 3 year project, G-Terra, funded by the Portuguese
Science and Technology Foundation, intends to study among others, this issue. One
important task of the G-Terra is to gather monitoring data at different road sites.
The study started in January 2008.
The first results concerning monitoring were obtained at the A25 coastal
zone pilot case study. They are represented by the sampling of a total of ten events.
The site has been previously monitored in 2003/2004
[5]
. Procedures for moni-
toring highway runoff included automatic water sampling, and rain and flow
measurements.
