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Research & development
TABLE 1 Environmental Quality Standards (EQS), Annual
Average value (AA-EQS) and Maximum Allowable
*VUJLU[YH[PVU4(*,8:KLÄULKI`[OL+PYLJ[P]L exceeding 100 ng lí1, even if hot spots have been
on Environmental Quality Standards (2008/105/EC)
for TBT, Diuron and Irgarol in seawater coastline restrictions have not been applied.When concentration
and sediment. N.A Not Available
In all the seawater samples collected by spot sampling,
the concentration of TBT and biocides were below the
limit of detection, i.e. 2.5 ng/l for TBT, 2.0 ng/l for DBT,
1.5 ng/l for MBT and 1 ng/l for all the other biocides.
For diuron, irgarol, chlorothalonil and dichlofluanid the
absence of detectable traces in seawater samples and
the LOD of the analytical method are such to state that the
presence of these biocides are well below the EQS defined
by WFD or internationally recognized (Table 1).
Other studies have shown the absence of diuron,
irgarol, chlorothalonil and dichlofluanid in areas of the
Mediterranean sea [7] including other MPAs.
Since the marine environment is not affected by these
biocides, at the moment, their utilization as antifoulants
and in farming activities as herbicides and/or fungicides
seems to have a limited or not relevant impact on the
seawater.
Despite the total ban of TBT-based paints [11], TBT
was still a commonly encountered contaminant in the
seawater, and the presence of organotin compounds
is yet recorded in the coastline sites. Many studies
have involved surveys on TBT distribution in the water
column, sediments, and biota [12-14]. Measurements
taken prior to restrictions on TBT have shown levels
higher than 500 ng lí1 in North American and European
34 EAI Energia, Ambiente e Innovazione 4/2015
TABLE 2 Concentration of TBT in SPMD samples from 2012
monitoring campaign. All results are expressed
as ng/l cations
marinas. In recent investigations, it has been reported
that TBT concentrations have generally declined, rarely
reported especially in those countries where IMO
in the seawater is at least 3-5 ng/l, the conventional
methods of spot sampling, coupled with classical
methods of analysis,are sufficient to detect the presence
of TBT and its degradation products. In this study, TBT
concentration in seawater samples collected by spot
sampling was always lower than the method detection
limit (2.5 ng/l); consequently it was impossible to verify
water contamination and quality standards, considering
that EQS values for TBT are 0.2 and 1.5 ng/l, for AA and
MAC, respectively (Table 1), that is well below the LOD.
Passive sampling devices are therefore necessary
for levels below 2 ng/l. Passive samplers have been
validated and provide high sampling rates (liters/day)
for various contaminants, thus allowing to quantify
extremely low pollution levels in water, using similar
methods of analysis as for grab sampling. In particular,
SPMD can be used for the analysis of TBT [15, 16] thanks
to its octanol/water partition coefficient logKOW >3. The
TBT data of passive samples are in agreement with the
results obtained with samples collected with classical
procedures (Table 2). Indeed, all the samples collected
by passive devices have showed a concentration
around or lower than 2.5 ng/l, which is the LOD of
TBT with grab sampling. The lowest concentration of
0.3 ng/l was found in the B zone of the protected area
(Faraglioni), 1.0 ng/l in the Preveto samples and, finally,