300
study the worst case scenario was evaluated. Other
very hazardous substances were sulphuric acid and
ammonia (Häkkinen et al. 2012). Similarly, the
HASREP (2005) project identified top 100 chemicals
whicharetransportedbetweenmajorEuropeanports
andinvolvedintradethroughtheEnglishChannelto
therestoftheWorld.
Theassessmentwasbasedboth
on tra nsport volumes and the GESAMP hazard
profile. The project highlighted chemicals such as
benzene, styrene, vegetable oil, xylene, methanol,
sulphuric acid, phenol, vinyl acetate, and
acrylonitrile. It was concluded that these chemicals
weretheonesthathavehighspillageprobabilitybut
may not result
in significant environmental impact.
Similarly, French McKay et al. (2006) applied a
predictivemodelingapproachforaselectedrangeof
chemicals that are transported by sea in bulk and
concludedthatphenolandformaldehydepresentthe
greatest risks to aquatic biota. Harold et al. (2011)
evaluated human health risks of transported
chemicals,basedontheGESAMPratingsfortoxicity
and irritancy. This gives more weight to chemicals
thatarefloaters;formgasclouds;orareirritableand
toxiclikechlorine(Haroldetal.2011).Itisclearthat
different weightings have a certain impact on the
difference in results in these
studies. However, the
chemicalsofrealconcernvarydependingonthesea
areaforwhichtheriskassessmentisconductedsince
theamountsandtypesofchemicalsdifferindifferent
seaareasasdomarineenvironmentandbiota(Kirby
&Law2010).
Theimpactsof areleaseoraspill depend
onthe
behaviorofthechemical orchemicalsinquestion. It
canbeconcludedthatthemostharmfulchemicalsfor
humanhealthhavequiteoppositepropertiestothose
thatare most hazardous for water biota. Forhuman
health, the most hazardous chemicals are those that
arevery reactive, formeither
very toxic or irritating
(orexplosive)gasclouds,andalsohavepossiblelong‐
term effects, such as carcinogenic effects. From the
environmental point of view, the most hazardous
chemicalsare thosethatsink,havea highsolubility,
possibly stay at the water column, are persistent,
bioavailable and very toxic and can
have possible
long‐termeffects(FrenchMcKayetal.2006,Häkkinen
etal.2012,Haroldetal.2011).
3.4 Responseactionsincaseofmaritimechemicalspills
There are many excellent reviews (e.g. Marchand
2002, EMSA 2007, Purnell 2009), based on lessons
learnedfrompastaccidents,whichalsocontaindata
aboutresponseactionsincaseofchemicalspills.Even
ifresponseactionstakendifferineveryaccidentcase
according to special conditions and chemicals
involved, it is nevertheless possible to demonstrate
certain significant or specific elements valid in all
chemicalincidentsatsea(Marchand2002).
Firstly, like the information concerning the
ship
cargo, an evaluation of chemical risks is of primary
importancebeforeanyoperationaldecisionsaretobe
made,especiallyiftheshipiscarryingawidevariety
ofchemicals(Marchand2002).Followingthechemical
spill at sea, the response authorities must
immediatelytakemeasuresinorder tominimizethe
chemical exposure to the public as well as
contamination of the marine environment. The
primary factors which determine the severity and
extentoftheimpactoftheaccidentarerelatedtothe
chemicalandphysicalpropertiesofthechemicalsin
question. It should be noted that in the case of oil
spills, the hazard to human health is generally
consideredtobelow,andthemoretoxicandlighter
fractionsoftenevaporatebefore responseactions are
able to be started. However, in case of chemical
accidents, an initial assessment and monitoring of
potentialhazardsshouldbeundertakenfirstinorder
to
ensureasafe workingenvironment.Inthatstage,
theprimaryhazardsandfateofthechemicalinthat
marine environment are evaluated. The monitoring
techniques need to be designed to measure the key
parametersthatcouldgiverisetoahazard.Itshould
alsobenotedthatinsomecasesdoing
nothingmight
be the best option, as long it happens under
observation(Marchand 2002,Purnell2009).LeFloch
et al. (2010) stated that in case of an instantaneous
chemical spill, response usually follows three
accepted scenarios: 1) response is not possible,
because the spill occurred in a geographical
environment that
is incompatible with reasonable
response times, 2) response is not possible due to
reactivityofthesubstances(major,imminentdanger),
and 3) response is possible. Gases and evaporators,
very reactive substances, and explosives are the
biggestconcernforhumanhealthandsafety.Several
monitoring devices and dispersion models exist
which may
aid decision making and help protect
responders and the public. The floaters can be
monitoredbyusingthesametechniquesthatareused
for oil spills. Chemicals that prove to be the most
difficult to be monitored are sinkers and dissolvers
(suchasacrylonitrileinthecaseofAlessandroPrimo
in Italy in 1991), even if some techniques e.g.
electrochemical methods and acoustic techniques
exist(EMSA2007,Purnell2009).
Several international, regional and national
authorities have published operational guides to
describe the possible response options in case of a
chemical spill. For example Cedre and IMO have
mademanualsprovidinginformation
aboutdifferent
response techniques that can be used in case of
chemical spills (Cedre 2012, HELCOM 2002, IMO
2007). Usually response techniques depend on the
behavior of a chemical in the environment, and on
whether it is released or still contained in pa ckaged
form. In pra ctice, the response action varies
substantially.Techniquesthatareapplicableincaseof
oil accidents may be suitable for only some floating
chemicals. However, it should not be forgotten that
some floating chemicals can also potentially create
toxic and maybeexplosive vapor clouds (e.g. diesel,
xyleneandstyrene).Ifthishappens,thespark/static‐
free equipment should
be used. Moreover, foams or
sorbent materials can also be used near the spill
source. Risks associated with evaporators or gases,
such as ammonia and vinyl chloride, could be
diminished by diluting or using release methods
(Purnell 2009). In shallow water areas, neutralizers,
activated carbon, oxidizing or reducing agents,
complexing
agents, and ion‐exchangers canbe used.
Chemicals that are heavier than seawater, in turn,
maycontaminatelargeareasoftheseabed.Recovery
methodsthatareusedincludemechanical,hydraulic
orpneumaticdredges,buttherecoveryworkistime‐