Tackling Chemical Spill Incidents Biology Essay


The challenge of dealing with HNS is not a new one. Past spill incidences involving HNS have highlighted the scale of environmental destruction as a result of non availability of first hand information. Prioritisation of HNS remains to be one of the most important tools in dealing with such an incident and studies to determine prioritisation has gained impetus over the past few decades. Sheahan et al have proposed three factors that should be considered in order to prioritise HNS. (a) Recurrence of HNS and their properties that are frequently encountered in an event of a spill incident, (b) The sequence or order that the HNS are dealt with in a spill incident and (c) Considering the appropriate approach to be taken, especially post- spill incident (2009). In the broader sense, prioritisation of HNS during a spill incident can be based upon the following criteria.

4.1.1. Prioritisation of HNS based upon behavioural characteristics.

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A report by CEFAS has determined key factors that are unknown prior to a spill incident viz. Time, location, weather conditions, type of hazard, the nature and quantity of the HNS spilled. Although a majority of questions would be answered, some may not be answered until a defined period of time viz, Type of chemical, release rate as well as the amount spilled (2009). HNS unlike oil exhibits diverse physical and chemical characteristics (Kirby HYPERLINK "#_ENREF_2"&HYPERLINK "#_ENREF_2" Law, 2010) . This poses significant challenges to the responders at the time of the incident. Although the IMDG code for transportation of hazardous materials has existed since its inception in the 1960's in order to cover such matters as packing, container traffic and stowage, with particular reference to the segregation of incompatible substances', no risks can be taken during a spill incident (IMO, 2006).

Organizations like CEFAS have concluded that packaged goods that are of significant threats to the responder are those that are classed as flammables and explosive substances, although first hand information can be attained from 'forensic examination' of the ship and its crew as well as the surrounding environment. (2009). Establishment of prioritisation is possible after information is received from initial analyses, immediately following the spill incident. Three key parameters determine are utilised to determine the diverse behaviour of HNS i.e. state of compression and/ or aggregation , density, volatility and solubility and have been the basis for the classification of HNS based upon these properties. (EMSA, 2007, CEFAS, 2009). The European Classification scheme for chemicals for chemicals classifies HNS's into twelve major groups (Table 4.1). Although this scheme is not perfect owing to bipolar properties that some chemical possess, the sole purpose of this scheme is to provide information of the variability of HNS, unlike in the case of oil (ITOPF,

Table 4.1.

2010). HNS's classified based upon their properties are detrimental to humans, avians as well as marine flora and fauna (Fig. 4.1.)

Reports have determined that evaporators pose a significant threat, especially when coupled with explosive, corrosive, radioactive as well as health related properties. Other parameters that need to be considered are the propensity to bioaccumulate etc and are known to affect humans as well as birds and mammals. Floaters and other related HNS are considered as a 'flammable hazard' as well as a nuisance to near shore ecosystems affecting and are known to affect humans, birds and sea mammals. Dissolvers have been concluded to be of significant risk and hazard to the marine system owing to the ability to bioaccumulate and persist in the environment over sustained time periods, thus damaging the economy of the area by affecting future food stocks as well as stalling of fisheries in the affected area. Pelagic fishes are considered to be the most susceptible groups. Sinkers lead to significant bioaccumulation as well as oxygen starvation of marine systems affecting invertebrates as well as benthic fish (EMSA, 2007, CEFAS, 2009, Sheanan et al., 2010, ITOPF, 2010). Modelling tools have also been used to assess spill situations and aid in prioritisation of HNS. Predictive modelling based analysis of bulk cargoes determined that phenol and formaldehyde were hazardous to marine life (French McCay et al., 2006).

4.1.2. Prioritization based upon Persistence, bioaccumulation and toxicity characteristics (P.B.T) etc.

HNS represent a vast group of chemicals that are classified based upon their physical properties and are known to present a significant risk as well as hazard in the area that is affected by the spill incident (GESAMP, 2002,(Kirby HYPERLINK "#_ENREF_2"&HYPERLINK "#_ENREF_2" Law, 2010). The severity of the particular HNS or a group of HNS under evaluation is determined by the potential to Persist (P), Bioaccumulate (B) and be Toxic (T) to the organism(s) as well as produce sub-lethal effects in the organisms ( vPvB). The definition of the criteria stemmed out from discussions from major groups such European Union, Oslo and Paris Commission (OSPAR), United States Environmental Protection Agency (USEPA) etc helped lay down the guidelines for the following criteria. Table 4.2 highlights the standard criteria that are adopted by the European Union as defined by the commission Directive 93/67/EEC on Risk Assessment for new notified substances (European Commission, 2003). The ability of the chemical classified as HNS to persist in the environment would depend upon (a) microbial degradation (b) oxidation and hydrolysis reactions in the marine environment (c) metabolism in marine flora and fauna, avians and mammals (c) photolytic degradation etc (Wildley et al, 2004) Bioaccumulation and bioconcentration would be measured from uptake studies by flora and fauna in air-water-sediment interface as well as water interface respectively

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Fig.4.1. Fate of HNS in the marine environment and their effects in the marine environment. Reprinted from S


PBT Criterion

vPVB criteria


Half-life >60 d in marine water or >40 d in freshwater

or half-life >180 d in marine sediment or >120 d in freshwater sediment

Or not readily or inherently biodegradable

Or predicted biodegradability in a time frame of weeks-months

Half-life >60 d in marine- or freshwater or >180 d in marine or freshwater sediment

Or not readily or inherently biodegradable

Or predicted biodegradability in a time frame of weeks-months


BCF >2,000

Or log Kow >4.5

BCF >5,000

Or log Kow >5


Chronic NOEC <0.01 mg/l or CMR or endocrine disrupting effects

Or acute L(E)C50 <0.1 mg/l


Table 4.2. Persisitence (P), Bioaccumulation (B), Toxicity (T) criteria and vPVB criteria for prioritisation of HNS as defined by the Europen Union Technical Guidance document.

(Reproduced from Wildey et al., 2004)

(Wildley et al, 2004, European Commission, 2003). Toxicity as defined by the European Union technical guidance document would classify toxicological effects to those that are (a) Carcinogenic (b) endocrine disrupters and (c) reprotoxic and (d) the ability to cause 'long term NOEC ≤ 0.01 mg/l (Bernes, 1999, European Commission, 2003, Lipnick, 2001, Willey et al, 2004).

4.1.3. The GESAMP EHS working Group: The GESAMP Hazard Evaluation Procedure for HNS.

These criteria, though defined over the last few decades are still relatively new to HNS prioritisation, attempts to 'evaluate the hazards' are not. The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) had defined a process for the evaluation of hazards carried by ships, particularly with regards to HNS and the creation of a database for suitable reference and incorporates all relevant data pertaining to HNS as discussed in 4.1.1 and 4.1.2 respectively (Wells, 1999 Kirby & Law, 2010, GESAMP, 2002). The data generated can be an added asset to understanding the problem in the broader sense. Figure 4.2 illustrates the significance of the GESAMP classification scheme in the determination of dominant sub-types of HNS (Sheahan et al, 2009).

The collaborative efforts of the Marine Environmental Protection Committee (MEPC) as well as the GESAMP (Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection) on dealing with spill situations occurring due to chemical as well as petrochemical discharges in the sea has been considered to be the one of the first serious attempts to prioritize HNS's (Wells, Höfer HYPERLINK "#_ENREF_3"&HYPERLINK "#_ENREF_3" Nauke, 1999). The latter, which, consists of the scientific fraternity from over fifty nation states and is sponsored by the United Nations (UN) provides scientific expertise on (a) Marine pollution Assessment and advice on monitoring programs (b) a link for the sharing of relevant scientific information pertaining to marine pollution and (c) providing a scientific 'link' to aid legal instruments amongst others ().A significant achievement by GESAMP was the proposal of methods to assess substances based on hazard in 1973, followed by the formation of the 'GESAMP Working Group of the Evaluation of hazards of Harmful substances Carried by Ships'. The sole objective of the GESAMP- EHS working group is "To examine and evaluate data and to provide such other advice as may be requested, particularly by IMO, for evaluating the environmental hazards of harmful substances carried by ships, in accordance with the rationale approved by GESAMP for this purpose". (IMO, 2010)

The MARPOL 73/78 convention consists of vital elements of the GESAMP hazard evaluation guidelines. The expertise of the GESAMP EHS group has been utilised in the creation of Annexes II (noxious liquid substances carried in bulk) and III (harmful substances carried by sea in packaged form). A 'hazard evaluation procedure' was devised in order to address key issues relating to (a) Bioaccumulation/ tainting effects in marine organisms (b) Damage assessment to marine life, utilising LC 50 (for fish) and/ or EC 50 (crustaceace) assessments respectively (c) Hazards to human life based on LD 50 assessments (oral intake) as well as skin and eye contact and (d) Reduction in usage of amenities related to the marine environment. Calls for an updated and harmonised system of analysis and classification were proposed during the United Nations Conference on Environment and Development (UNCED-1992) as well as the Inter-Organization Programme for the Sound Management of Chemicals (IIOMC-1995). Subsequent revisions in the hazard profile (Table 4.3) led to the resolution of the same with emphasis upon the environment and human health. GESAMP based assessments have employed standard and trusted analyses which include BCF's, QSAR's etc. To elaborate, the basis of acute toxicity (marine life and human) relies upon standard toxicity tests of individual HNS's and/ or mixtures of HNS's to mammals, fish as well as other marine based organisms. Chemoleptic tests and odour detection thresholds (ODT's) are done to assess tainting of sea foods. The database is constantly updated in order to meet the ever growing list of new chemicals. Epidemiological data is considered to assess impacts on human health. Qualitative and quantitative assessments with regards to damage on beaches caused by spillage of HNS's are considered as datasets for the hazard profile. GESAMP hazard profiles conform to the following codes/ conventions (a) The International Maritime Dangerous Goods Code (IMDG), (b) The International Convention on Liability and Compensation for Damage in Connection with the carriage of Hazardous and Noxious Substances by the Sea (HNS convention). A majority of bulk liquid chemicals contained in the IBC code have been evaluated by GESAMP. More than 20,000 chemicals have been assessed and reported in the database, however owing to sheer volumes of newly introduced chemicals GESAMP has agreed to evaluate newer chemicals with the new evaluation procedure whereas older profiles would not be updated (). Benefits of the GESAMP system in prioritisation of HNS.

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The Centre for Environment, Fisheries and Aquaculture Science (CEFAS), in their report (C3157) concluded that prioritisation of HNS's was 'being best handled' using the GESAMP hazard profile approach and provides a significant advantage to the responder, especially when expert support is not present, by providing preliminary prioritisation of the chemicals in the spill incident as 'first hand information' (CEFAS, 2009). Reports also state that GESAMP provides the additional and 'straightforward' information to create data sets for prioritization to aid emergency response as well as in the development of future chemical models to determine, in advance, the fate of the chemical during the spill incident. Practical uses of the GESAMP profile has also been demonstrated, The EU funded project titled 'Response to Harmful substances spilt at sea' (HASREP) determined the top 100 HNS that were commercially transported amongst major European ports utilising the GESAMP hazard profile and data from volumes spilled. Data revealed HNS such as Benzene, Vegetable oil, styrene, xylene, methanol, molasses etc. were the major contributors to spill incidents, although pesticides and radioactive substances were considered as potential contributors (HASREP, 2005).

4.1.4. Proposed Priority list for HNS. Strategies employed by key Agencies/ Projects.

Many attempts have been made to generate a priority list for HNS with major sea faring states/ consortium of states generating lists highlighting the top spills in respective ports.. Several EU funded projects have been developed to address this problem (HASREP, 2005, RESPIL, 2007). Schemes employed for prioritisation have been diverse employing different tools and strategies, whilst adhering to the guidelines enforced by GESAMP. For example Fingas and his team in his report created a priority list for top HNS spills in Canada with suitable updates after each decade with impetus to toxicity data (Fingas and Lau, 1996, Fingas, 2001). Priority lists were also generated for EU waters with importance to toxicity and bioaccumulation/ bioconcentration potential (RESPIL, 2007). Strategies by HASREP have utilised desk based research collating information comprising of major chemical suppliers in Europe, trade corridors, data from the International Code for the Construction and Equipment of Ships carrying Dangerous Chemicals in Bulk (IBC code), Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO), European Chemical Industry Council (CEFIC) and European Communities Trademark Association (ECTA) including other sources (2005). Other EU funded projects (CLARA, ECOPEL) have also contributed to the prioritisation process employing similar strategies (cite reference). Proposed prioritisation scheme by RAMOCS.

The RAMOCS project, which is funded by the European Coordination Action to Foster Prevention and Best Response to Accidental Marine Pollution (AMPERA ERA-NET) has considered prioritisation of HNS to be one of the vital elements as part of its strategy in the co-ordinated prevention and best response to chemical spill incidents (RAMOCS, 2010). Methodology.

The HNS considered for prioritisation were derived from the IMO/ EHS composite list and were based upon frequency and volume of spill (IMO, 2008). Suitable rankings were assigned based upon the revised GESAMP hazard profile (Table 4.3.) with numerical scoring attributed to Bioaccumulation, Biodegradation, Aquatic toxicity, Toxic effects to mammals and interferences with other uses of the sea. Normalised ratings were generated by dividing the individual data sets by the 'top of scale rating'. Numerical ratings were also given to account for categories A2 (biodegradability) and D3 (long term effects) (A2: 1 if the substance is non-readily biodegradable, D3: 1 if the substance has one type of long-term health effect, 2 if it has more than one long-term health effect). Ratings were not assigned to account for tainting effects and/ or whether the HNS would sink/ float or evaporate once elaborated into the marine environment. Final ratings that were generated were used to rank the substances (Appendix 1). Data was further processed in the form of graphs in order to support the parameters as represented in the revised GESAMP hazard profile system. Data was represented in the form of 'radar graphs' to summarize the position of HNS within the revised GESAMP system. (Appendix 1). Raw data used for generating the prioritisation scheme was collected as a result of desk research and processed using Microsoft Windows Excel TM. Results and discussions.

Table 4.4 shows the top 20 HNS that are associated with European Waters. The comprehensive list shows the four main groups of HNS being presented in the Table i.e. Floaters, Evaporators, Dissolvers and Sinkers (F, E, D, S) and the major sub groups. For example HNS like Styrene have been associated with the loss of the Ievoli Sun in the 2001 and although classified as a Floater Evaporator has been to accumulate in the tissues of Crabs after a week of the chemical incident, although known to be of lesser risk for human consumption, apart from causing immediate animal mortality if present at the site containing high volumes. Other serious risks as reported by the CEDRE are the risk of explosion (due to ineffective polymerisation inhibitor- para tert-butyl cathecol/pTBC). Xylenes poses significant risks and causes significant bioaccumulation and tainting and exhibit behaviour generally associated with Floater evaporators (CEDRE, 2007, a). Dissolvers such as Sulphuric acid are corrosive and dangerous owing to its potential to violently react with other compounds and hydrogen generation and near-boiling temperatures in the water potentially killing all life in the vicinity. However, it poses no risk to life over a temporal scale owing to the its ability to readily dissolve leading to an eventual decrease in concentration (CEDRE, 2007, b). Dissolver Evaporators such as Ammonia carry a significant risk such as the potential to kill marine flora and fauna owing to violent interaction in water, oxygen starvation and the risk of fire and explosion (CEDRE, 2007 c). Sinkers such as Phenol (also classified as a major Volatile Organic Compound) are known to be genotoxic to all orders of marine flora and fauna. However, a majority of sinkers are prone to dissolution as well bacterial degradation (Environment Agency, 2010). Benzene exhibits similar characteristics to Floater

Table 4.4. Suggested priority lists RAMOCS highlighting Top 20 HNS spilled in European Waters.




Styrene Monomer




Sodium Hydroxide


Sulphuric acid




Phosphoric Acid








Palm Oil and Vegetable Oil


Methyl-tert-butyl-ether (MTBE)












Animal Oil/ Fish Oil







Evaporators although gas cloud formation is a significant risk factor, apart from other properties (CEDRE, 2007, c).Other known properties of Benzene are the ability to biodegrade and volatilise with time (CEDRE, 2007 c, INERIS, 2000). Vegetable oils although non toxic are known to possess properties similar to other known oils and are especially hazardous to life forms when found in high volumes, in water and exhibit various properties at different depths viz. Polymerization, slick formation etc. (Add reference).

An alternate priority list (Table 4.5) can be generated considering the importance of volatilisation and half life of the substance as well as the E3 classification in the revised GESAMP hazard profile system. The classification (as shown in table 4.4) is altered. This however does not change the contents in the list but mostly, the relative ranks of the substances. (What is the significance of this?!?)

4.2. Response Strategies for Hazardous and Noxious Substances.




Hazard Criterion


A Bioaccumulation and Biodegradation



Log PoW (Octanol Water partition coefficient) and bioconcentration factor (BCF)


Tendency of substance to bioaccumulate in aquatic organisms

Helps to identify substances with biodegradation characteristics. (%degradation to Co2 and water in 28 days).

B Aquatic toxicity



Acute aquatic toxicity

Chronic aquatic toxicity

Fish, crustacean and other marine organisms (based on laboratory tests)

Chronic aquatic toxicity studies on fish and crustaceaens.

C Acute mammalian toxicity




Based on toxicity assessments by exposure through following routes.




Results obtained based upon appropriate tests involving animals as well as human experience and other evidence.



Hazard criterion


D Irritation, corrosion and long term mammalian health effects




Based on toxicity assessments by exposure as a result of.

Skin Irritation and corrosion

Eye irritation and corrosion

Long term health effects

Results obtained based upon appropriate tests involving animals as well as human experience and other evidence.

Carcinogenic, Mutagenic,Reprotoxic, Sensitiser,Aspiration hazardTarget Organ SystemicToxicity: Lung injury,Neurotoxic, Immunotoxic

E Interference with other uses of the sea





Behaviour of chemicals in the marine environment as well as effects on marine life

Interference with coastal amenities

Analysis of off-flavours of sea food due to spillage of cargo

Based upon behaviour in sea water e.g. slick formation.

Closure of beaches as result of physical hazards and health impacts