Geoscience Reference
In-Depth Information
Table 5.4 General count (cfu/100 ml) of microbes (coliforms,
E. coli
) in the runoff from different
land uses
General court
Cfu/1 ml
Escherichia coli
MGG
Cfu/100 ml
Escherichia coli
Cfu/100 ml
Coliforms Cfu/
100 ml
Examination
date
57,000
Covered plate
Covered plate
Covered plate
14/3/2007
222,000
ND
32,000
81,000
15/3/2007
450,000
ND
65
83,000
15/3/2007
60,000
ND
1,000
5,000
15/3/2007
<
130,000
ND
1,000
3,000
15/3/2007
<
590,000
ND
Covered plate
Covered plate
15/3/2007
240,000
ND
28,000
Covered plate
15/3/2007
150,000
ND
3,000
4,000
15/3/2007
60,000
ND
2,000
4,000
15/3/2007
480,000
ND
Covered plate
Covered plate
15/3/2007
290,000
ND
9,700
Covered plate
15/3/2007
5.5.4 Microbial Pollution
Sampling and analyzing microbial pollution was performed during the first 2 years
of the study. High concentrations of microbes, fecal e-coli and coli forms were
found in runoff water from all land uses (Table
5.4
). Fecal coliform concentrations
were observed in runoff water at values of tens up to hundreds of thousands (cfc/
100 ml). Similar values were observed in runoff water in Ashdod (Nativ et al.
2001
). Water polluted with microbes, whose source was from sewage leaks from
the drainage system and from animal and pet feces, was found in many locations
in the urban domain. These finding requires initial water treatment before any reuse
of the urban stormwater.
5.5.5 Semi-Volatile and Volatile Organic Compounds
Organic compounds have been found in all land uses. The quantification of these
substances was done by means of authentic standards (substances for which precise
values appear in the table of results). The quantification of fuel substances was done
on the basis of aliphatic compounds alone; therefore some of the results appear as
an imprecise value. Additional substances found in the samples for which the
laboratory did not have authentic standards were semi quantified (crude estimate)
on the basis of the response of the substance in the GC/MS in comparison with that
of the standard in the literature.
In the runoff water from the industrial area the highest number of organic
compounds was observed. In addition, higher concentrations of compounds coming
from fuels, pesticides and various industrial compounds were also found. Maximum
rates of fuels and Mathlyene pesticide, which is used to control mosquitoes and as
an insect exterminator, were found on the roads of the airport and in the industrial
area. Generally, concentrations in runoff water in residential areas were
characterized by lower concentrations than in industrial areas.