Environmental Engineering Reference
In-Depth Information
not allow an estimation of the hydrodynamic exchange processes. The treat-
ment of the chemical fate processes is in many respects similar to the first
version of the Mam-Pec model. Several default combinations of emissions and
estuary types are included in the model: a small estuary that dries out, well-
mixedestuarieswithnarrowandwidemouth,andalargecomplexestuary.
The model has been validated successfully for these estuaries. The treatment
of emissions is not flexible, fixed surface areas are included in the model for
pleasure crafts and medium-sized ships and changing emission settings can
only be done indirectly. The REMA model is limited to mainly emissions from
pleasure crafts in typical estuaries in the UK and cannot be adapted to ma-
rine exposure scenarios for large commercial harbors or open sea shipping
lanes. Model software and documentation can be obtained via the website
of the HSE (www.hse.gov.uk) and the Environmental Chemical Bureau (ECB;
www.ecb.jrc.it/biocides) of the European Commission.
The Mam-Pec model [5] is an integrated 2D (10
10 grid) hydrodynam-
ical and chemical fate model based on DELWAQ and SILTHAR of Delft Hy-
draulics. The DELWAQ model has previously been linked to hydraulic models
for the North Sea [41]. The SILTHAR model [28] has been used for the
description of hydrodynamic exchange and sedimentation in several large
international harbors (Port of Rotterdam, Hong Kong). Models runs are ex-
ecuted after entry or editing of input data in three different panels for (1)
environment and hydrology, (2) compound properties, and (3) emission sce-
narios. The environmental and hydrodynamical parameters included in the
model are: currents, tides, salinity, DOC, suspended matter load, sedimen-
tation, port dimensions. The model allows estimation of hydrodynamical
mixing in five generalized “typical” marine environments (open sea, shipping
lane, estuary, commercial harbor, yachting marina). The default environ-
ments can easily be adapted to local situations. Several of the recently adopted
environmental emission scenarios for the Biocide Directive [6] were based
on slightly modified Mam-Pec scenarios (commercial harbors, shipping lane,
marina) and the estimation and calculation routines in the model. Compound
properties
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process included in model are: K ow , K d , K oc , H , volatilization,
speciation, hydrolysis, photolysis, and biodegradation. The emission estima-
tion is based on leaching rates, shipping intensities, residence times, ship
hull underwater surface areas according to the principles described in Sect. 2
(Eq. 1). The model contains default emission settings for the matching envi-
ronments. The EU-OECD environmental emission scenarios [6] are included
in an updated version of the model, which will be available end of 2005. The
model allows easy comparison of predicted environmental concentrations of
PECs of different compounds. The model has been validated based on the re-
sults of a few recent monitoring studies. Model-predicted concentrations of
TBT, Irgarol, Diuron, Seanine and other compounds matched within order
of magnitude with measured concentrations [11, 42-44]. A full quantitative
sensitivity analysis has not yet been conducted. On the basis of preliminary
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