Environmental security of the coastal seafloor in the sea ports and waterways of the Mediterranean region

ARTICLE IN PRESS Nuclear Instruments and Methods in Physics Research A 619 (2010) 419–426

Contents lists available at ScienceDirect

Nuclear Instruments and Methods in Physics Research A journal homepage: www.elsevier.com/locate/nima

Topical Review

Environmental security of the coastal seafloor in the sea ports and waterways of the Mediterranean region Jasmina Obhodas a,n, Vladivoj Valkovic b, Davorin Sudac a, Dario Matika c, Ivica Pavic d, Robert Kollar b a

Institute Ruder Boskovic, Bijenicka c.54, 10000 Zagreb, Croatia A.C.T.d.o.o., Prilesje 4, 10000 Zagreb, Croatia c Institute for Researches and Development of Defense Systems, Ilica 256b, 10000 Zagreb, Croatia d Ministry of Defense, Croatian Navy, Dubrovacka 49, 21000 Split, Croatia b

a r t i c l e in fo

abstract

Available online 18 March 2010

The Mediterranean coastal seafloor is littered with man-made objects and materials, including a variety of ammunition in many areas. In addition, sediments in ports, harbors and marinas are contaminated with elevated concentrations of chemicals used as biocides in antifouling paints. In order to reach a satisfactory level of environmental security of the coastal sea areas, fast neutron activation analysis with detection of associated alpha particles and energy dispersive X-ray fluorescence, both in laboratory and inside an autonomous underwater vehicle for in-situ measurements, has been used for the characterization of the objects on the seafloor. Measurements have shown that gamma ray spectra are able to distinguish threat material from the surrounding material. Analysis of more than 700 coastal sea sediment samples has resulted in concentration distribution maps indicating the locations of ‘‘hot spots’’, which might interfere with threat material identification. & 2010 Elsevier B.V. All rights reserved.

Keywords: Environment Security FNAA EDXRF Explosive Chemical warfare Sediments

1. Introduction The seafloor is littered with a great number of sunken ships, different types of wastes, including chemical weapons (CWs) and numerous explosive devices, which were mostly dumped during the I and the II World War up to the recent war conflicts, military exercises and weapon testing. After the end of WWI and WWII, remnant chemical and other weapons were dumped at different locations in world oceans and seas. The reasons were ecological, legal and economical by nature. Conscience on environment protection was very low up to the mid-20th century and marine environment protection legislative and mitigation measures practically did not exist at that time. The simplest and cheapest solution to eliminate massive destruction weapons and redundant explosive devices was to destroy or neutralize them by dumping them in the sea. Since then the situation has changed significantly and presently there are many different conventions that prohibit sea dumping of chemical and biological weapon for massive destruction [1], but unfortunately none of them regulates procedures or mitigation measures related to possible adverse effects of previously dumped ammunition or

n

Corresponding author. Tel.: + 385 1 4561 161; fax: + 385 1 4680 239. E-mail address: [email protected] (J. Obhodas).

0168-9002/$ - see front matter & 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nima.2010.02.277

sunken ships. A significant percentage of them contain hazardous material, presenting high risk for environment and the human health. Knowing that during WWII alone, some 7800 ships were sunk (of which 10% were tankers) and hundreds of thousands of tonnes of CW and other explosive devices were dumped and left to corrode for more than 60 years [2], it is more than obvious that the contamination of marine environment by this type of pollution is unavoidable and only a matter of time. It poses a constant threat to the sea traffic, fishermen, tourists and local population. In the worst scenario, misuse and accidental explosion of these objects can cause loss of life. The problem has been relatively recently awoken and introduced to the public, and most of the coastal countries are still not sufficiently informed or they do not understand seriously the threatening ‘‘time bomb’’. The most constructive way of dealing with this type of pollution is to prevent it. This brings us to the concept of environmental security, which has been accepted as an element of national security and a direct link between environmental issues and violent conflicts [3]. Unlike the concept of environment protection, which has a passive approach of evaluating the quality of environment and taking ad-hoc actions after appearance of adverse effects, environmental security has an active approach that demands action before an environmental damage occurs [4]. Lot more resources and money need to be allocated for

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maintaining and recovering the resulting environmental damage than to prevent it. The largest concentrations of data on ammunition pollution for the Mediterranean Sea are found for its northern part. Here we present data collected for France and Italy on ammunition dumped immediately after WWII by Americans alone. It has been estimated that over 1,000,000 munitions and almost 20,000 CWs mainly loaded with Yperite have been dumped around the Italian coast. Since then, scientists and medical doctors from the University of Bari, Italy, have detected more than 230 cases of Yperite gas exposure in the Adriatic Sea, mostly in fisherman population. An estimated 1700 Lewisite bombs and 1700 Yperite gas bombs were dumped offshore at St. Rafael in the French Riviera [5]. Table 1 lists details and exposure effects of Yperite, Lewisite and other most commonly used CW agents in WWI and WWII. Underwater activities, including exploration of seabed, exploitation of marine resources and underwater constructions, have been continuously growing in the past few decades. These activities, having precisely determined goal and purpose, usually have to be performed on the exact locations occupying rather small areas. In order to avoid accidents that could cause pollution, health hazard and loss of life, sufficient care has to be paid to the segment of environmental security prior to such actions. Special attention has to be paid to the investigation of locations where human activities are most intense—ports and harbors. These are the places where any suspicious object needs to be analyzed for the presence of threat materials. Namely, in the case of underwater explosion, the excess pressure generated will be

detrimental to both people and infrastructure. Fig. 1 shows the effect of explosion caused by EMC II (explosive charge ca. 300 kg), a typical mine found in the Mediterranean Sea. For this antiship mine it is assumed that the excess pressure of 3.4 bar is detrimental to infrastructure, radius of safety zone being 608 m. Excess pressure detrimental to humans is assumed to be 0.4 bar, corresponding to the radius of safety zone of 3337 m [6]. Most of the background in the gamma spectra measured when investigating suspicious objects on the bottom of the sea is generated by surrounding sediment. Therefore, the chemical composition of sediments has to be known. Presented in the form of geochemical maps, the results of sediment chemical composition are very descriptive. These geochemical maps can be used for evaluating background for neutron sensor applications and for evaluating sediment pollution that presents risk for human health. Hence, these two tasks complement each other. The purpose of this paper is to show undertaken research and technology developments for underwater detection of explosive devices, CW and sunken ships, including experimental results as the proof of principles. The GIS based database of different objects on the seafloor and distribution maps of heavy metals for the eastern Adriatic Sea have been produced and data of sediment quality in ports and harbors have been evaluated. In addition, we have collected some of the samples in the vicinity of ammunition on the bottom of the sea in order to investigate the possible effects of its long presence on the environment. The approach to this problem that we have been using in the eastern Adriatic Sea is proposed to be applied to other regions of the Mediterranean Sea.

Table 1 Most common chemical warfare agents in WWI and WWII. Common name

Chemical Abstracts Service (CAS) name

Molecular formula

CAS Registry Number

Exposure effects

Vomiting agents—severe irritation of eyes, nose and throat, tightness of chest and headache, vomiting, fatal at higher concentrations

DA, diphenylchloroarsine, Clark I

Diphenylarsinous chloride

C12H10AsCl

712-48-1

DC, diphenylcyanoarsine, Clark II DM, adamsite

Diphenylarsinous cyanide 10-Chloro-5, 10dihydrophenarsazine

C13H10AsN C12H9AsClN

23525-22-6 578-94-9

GA, tabun

Dimethylphosphoramidocyanidic acid, ethyl ester Methylphosphonofluoridic acid, (1-methylethyl) ester Phosphonofluoridic acid, methyl-, 1,2,2-trimethylpropyl ester

C5H11N2O2P

77-81-6

C4H10FO2P

107-44-8

C7H16FO2P

96-64-0

H, mustard gas, Yperite, sulphur mustard

1.1-Thiobis[2-chloroethane]

C4H8Cl2S

505-60-2

HN-1, nitrogen mustard

2-Chloro-N-(2-chloroethyl)-Nethylethanamine 2-Chloro-N-(2-chloroethyl)-Nmethylethanamine 2-Chloro-N,N-bis(2chloroethyl)ethanamine

C6H13Cl2N

538-07-8

C5H11Cl2N

51-75-2

C6H12Cl3N

555-77-1

L, lewisite

(2-Chloroethenyl) arsonous dichloride

C2H2AsCl3

541-25-3

Extreme irritation to eyes and skin, redness and blisters, blindness, can penetrate a variety of rubber products

Benzyl bromide

(Bromomethyl)benzene

C7H7Br

100-39-0

BA, bromoacetone Xylyl bromide

1-Bromo-2-propanone Bromoxylene

C3H5BrO C8H9Br

598-31-2 35884-77-6

Tear agents—irritating to eyes, respiratory system and skin, crying, sneezing, coughing, hard breathing

GB, sarin GD, soman

HN-2, nitrogen mustard, mechlorethanamine HN-3, nitrogen mustard, nitrogen lost

Nerve agents—runny nose and tightness in throat or chest, restlessness, contraction of pupil, excessive salivation, difficulty in breathing, sweating, slow heartbeat, loss of consciousness, convulsions, flaccid paralysis, loss of bladder and bowel control, lung blisters and stopped breathing

Blister agents—delayed onset of clinical symptoms, intense itching and skin irritation, chemical burns, contraction of pupil, large blisters filled with yellow fluid, sore eyes, conjunctivitis, bleeding and blistering within the respiratory system, pulmonary edema, mutagenic and carcinogenic effects

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Fig. 1. (A) EMC II antiship mine on the seafloor, explosive charge  300 kg. (B) Safety zone for infrastructure objects corresponding to the excess pressure of 3.4 bar and diameter 608 m and (C) Safety zone for people corresponding to the excess pressure of 0.4 bar and diameter 3317 m.

Fig. 2. (A) Measurement of active 60 mm mortal shell in air and (B) Measurement of Teflon behind 10 cm of fresh water.

2. Methods A system for underwater inspection of CW, explosive devices and sunken ships has been constructed using a sealed 14 MeV neutron generator with the detection of associated alpha particles [7]. The neutron generator can be rotated by two step motors around its axis, resulting in the movement of electronically collimated neutron beam. In this way different volume and profile of elements concentrations can be inspected. Gamma detector is placed inside an aluminum made holder of 5 mm thickness. The detector is shielded on one side by 5 cm thick lead shield. The submarine body is made of polyester and Kevlar of wall thickness 1.5 cm. Below the detector there is an aluminum window of dimensions (46  26  0.5) cm3. Experiments presented in this paper were performed in air (Fig. 2a) or behind 10 cm of fresh water (Fig. 2b). In order to evaluate marine sediments as a source of background in underwater material identification, 723 coastal sea sediment samples have been collected in the eastern Adriatic sea and analyzed in laboratory for 16 chemical elements using energy dispersive X-ray fluorescence (EDXRF) as an analytical tool. This corresponds to approximately one sediment sample per 12.5 km of the coastal line. Measurements were done with a W anode and Mo secondary target in orthogonal geometry, with measurement parameters of 40 kV and 35 mA. The irradiation time was 1000 s. X-ray spectra were collected with a Si(Li) detector (FWHM¼170 eV at 5.9 keV) and were analyzed using QXAS program package—direct comparison method. IAEA ‘‘Lake Sediment’’ was used as a reference material. Relative measuring errors were between 10% and 15% for most elements.

EDXRF is a mature technique, very suitable for bulk samples. It is fast and requires very small quantity of a sample, 2 g or less. It cannot measure light elements typical for explosives and CW like C, O, H and N, but it can provide information on additional elements in sediments (11oZo92), which present background and therefore can interfere with the signal from the threat material (especially with the chemical warfare). EDXRF can be used for chemical element concentration analysis on collected sediment samples in laboratory conditions. The method has many applications and has been often used in archeological and cultural heritage studies [8], health studies [9], planetary science missions [10] and in many other scientific fields [11]. Here we use it for large area screening in order to obtain distributions of chemical elements in the coastal sea sediments. Of special interest have been small ports and harbors, where the seafloor has to be inspected in detail. At the same time, anthropogenic pollution in ports and harbors can increase the concentrations of elements to the level at which they can interfere with the neutron probe inspection. Descriptive statistics for data used to produce GIS based elemental concentration distribution maps is shown in Table 2. For each sample the following information has been recorded: exact GPS coordinates, their local name, site description, depth and category. Sediment samples were grouped into 8 categories: bays (418 samples), beaches (26 samples), settlements (67 samples), ports (89 samples), marinas—pier area (69 samples), marina— service areas (42 samples), sea mud (7) and others (river inflows and similar—5 samples). The distribution maps were created by the inverse distance weighted method using computer software package ArcGIS 9.3.

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3. Results and discussion

by a surplus of carbon with respect to oxygen, and the rock spectrum, in addition, contains the 0.755 MeV calcium line. Measurements behind 10 cm of water resulted in a higher content of oxygen.

3.1. Detection of explosive devices Explosives are determined by the elements C, N, O and H, by the specific ratio of these elements and by the elements characteristic for their casing. Of special interest for the present study are grenades, mines and similar objects. Here we present target in/ target out measurements of 60 mm mortal shell in air (Fig. 3a), measurements of TNT vs. typical rock found in the Adriatic Sea in air (Fig. 3b) and behind 10 cm of water (Fig. 3c). After years and decades of lying at the seafloor, the appearance of explosive devices can change dramatically and it is easy to replace them for rocks using visual inspection only, especially for an untrained eye. Gamma ray spectra obtained from the inspection of 60 mm mortal shell and the background (target out) is characterized by the presence of aluminum gamma rays from the window of the inspection system (additional experiments with different window materials are in progress). In addition, the spectrum of mortal shell contains clearly distinguished carbon and iron lines. The experiment has showed that grenade has its characteristic signature, even though the presence of oxygen and nitrogen has not been well established. The spectra of TNT explosive and rock were dominated by carbon and oxygen peaks. The explosive is clearly distinguished from the rock

3.2. Detection of chemical weapons In addition to the elements C, N, O and H, CWs contain one or more of the elements F, P, S, Cl, As or Br (see Table 1 for the chemical composition of the most common CW). The gamma ray spectra of the irradiation of sulphur, sodium chloride, arsenic trioxide and teflon (material rich in F and C) as bulk targets for simulation of a CW behind 10 cm thick water layer are shown in Fig. 4. The distance between the investigated object and the neutron sensor (both source and detector) has to be minimized, not to exceed 10 cm of water. The results show that the presence of S, Cl, As, F and C (as main compounds of CW) can be easily determined in underwater inspection when they appear in the form of bulk targets having mass not less than 1 kg. 3.3. Inspection of sunken ships One important factor to be considered in the inspection of sunken ships is the thickness of the container wall, usually made

Table 2 Descriptive statistics for analyzed sediment samples.

K ppm Ca % Ti ppm Cr ppm Mn ppm Fe % Ni ppm Cu ppm Zn ppm Ga ppm As ppm Br ppm Rb ppm Sr ppm Y ppm Pb ppm

Valid N

Mean

Conf. -95%

509 722 589 435 718 723 702 723 723 202 711 723 723 723 721 721

6022.2 22.2 862.9 57.3 104.0 0.6 22.5 241.4 234.0 10.4 19.7 114.7 27.2 1004.6 20.7 41.8

5626.3 21.5 781.9 52.2 96.1 0.6 20.3 124.1 154.6 8.5 15.7 105.4 25.3 966.1 19.3 31.8

Conf. + 95% 6418.1 22.9 943.9 62.3 111.9 0.7 24.6 358.7 313.3 12.3 23.7 123.9 29.1 1043.0 22.0 51.8

Geom.

Med.

Min.

Max.

St. dev.

Skew.

Kurt.

4727.5 19.3 474.1 42.4 73.4 0.3 17.2 27.1 53.5 7.7 8.1 78.5 19.2 840.9 14.7 13.8

4535.0 24.5 415.0 44.8 67.1 0.3 14.6 17.1 35.8 6.6 7.3 74.5 17.0 987.0 13.9 9.9

1121 0.72 8.6 6.1 14.9 0.008 5.4 1.8 3.9 3.1 1.1 5.3 1.7 112.2 1.8 2.1

34.120 39.00 6283 418 896.5 5.55 558 31.100 16.800 117.3 938 1667 170.4 3937 138.0 2307

4546.2 9.2 1000.8 53.4 107.8 0.7 29.2 1606.4 1086.8 13.5 54.2 126.4 25.9 527.0 18.3 136.9

1.7  0.5 2.0 3.4 3.1 2.3 10.3 13.1 9.6 5.0 10.3 4.6 2.1 0.4 1.9 10.1

4.2  0.9 4.9 16.5 13.4 7.0 166.9 211.6 110.5 29.7 141.6 38.4 4.8 0.3 4.8 133.7

Fig. 3. (A) Gamma ray spectra from 60 mm mortal shell (gray) and background (grenade removed—black), TOTN¼ 18  107, measurement time  3975 s. Fe and C as the main components of the mortal shell are clearly distinguished. The main contributor to the intensities of Al lines in both spectra is the window of the inspection system. (B) Gamma ray spectra from TNT (gray, measurement time¼ 2414 s) and rock (black, measurement time¼ 2472 s), TOTN¼ 12  107, in air. TNT is clearly distinguished from the rock by its characteristic C/O ratio. In addition, gamma ray spectrum of rock contains Ca line. (C) TNT (gray) and rock (black) behind 10 cm of water. Parameters of measurements were the same as in the air experiment. Water suppresses the peak of Ca in the gamma ray spectrum of rock and contributes to intensities of O lines in both spectra, but C/O ratio remains as a relevant characteristic of both materials [12,13].

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Fig. 4. Gamma ray spectra (black lines) obtained behind 10 cm thick water layer under the following experimental conditions: (A) sulphur, mass 1 kg, measurement time 6351 s, 24  107 emitted tagged neutrons; (B) sodium chloride, mass 1 kg, measurement time 10,969 s, 36  107 emitted tagged neutrons; (C) arsenic trioxide, mass 2 kg, measurement time 7000 s, 24  107 emitted tagged neutrons and (D) Teflon (material rich in F and C), mass 1 kg, measurement time 10,026 s, 36  107 emitted tagged neutrons. The background spectra indicated in gray are obtained for the same experimental conditions with the target out. The obtained spectra show that increased concentrations of S, Cl, As, F and C, which are the main chemical compounds of the most common CW (see Table 1), can be easily distinguished in water.

been done for a long period of time in order to obtain good statistics. Conclusions on the existence of peaks can be reached in a much shorter time.

3.4. Sediments analysis

Fig. 5. Number of counts in carbon 4.44 MeV peak (black) and oxygen 5.62 MeV peak—first escape peak of oxygen 6.13 MeV line (gray) as a function of iron plate thickness.

of iron. It is variable and for some types of hull it can be up to several centimeters. We have investigated this in some detail by varying the thickness of the iron plate positioned between the submarine and explosive [14]. The submarine to explosive distance was 11 cm. The graph in Fig. 5 shows the number of counts in carbon 4.44 MeV peak (black) and oxygen 5.62 MeV peak—first escape peak of oxygen 6.13 MeV line (gray) obtained from explosive as a function of iron plate thickness. The solid lines correspond to the exponential fit (ae  bx). The total number of tagged neutrons in each measurement was 3.6  108, with the neutron beam of 107 n/s corresponding to the measurement time of 176 min. The measurements have

Sediments on which the object is placed on the seafloor will be a source of background, so the knowledge of concentration levels is of paramount importance. In our previous experiments we have shown that the gamma ray spectra obtained from measurements of the seafloor sediments are dominated by the lines of silicon or calcium, oxygen and carbon [15]. Sediments of volcanic origin (magmatic rocks) in the Adriatic Sea do not contain calcium as a dominant element. If silicon lines are absent, the sediments are of biologic origin (limestones and dolomites, recent sedimentation) and the spectra are then characterized by the presence of calcium, oxygen and carbon lines. Hence, the sediments should be easily distinguished from the threat materials such as explosives and CW if they do not contain unusually high concentrations of elements that can interfere with the threat material inspection as a consequence of pollution or natural variability of the sediment chemical composition. In this report, special attention has been paid to the investigation of coastal sea sediments in ports and harbors. Any seabed activities to be undertaken within or close to these locations should be subject to full assessment of the potential risk prior to the approval of these activities by national authorities. Fig. 6 shows the distribution of As in the surface layer of coastal sea sediments in the Adriatic Sea, Croatia. From these figures the presence of ‘‘hot spots’’ is evident. These are locations with concentration values significantly increased with respect to the background, indicating the anthropogenic influence. These hot spots for As, as well as for other biocide

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elements like Cu, Zn and Pb, are invariably connected to ports, harbors (civilian and military) and marinas, where ship repairs and antifouling coating are performed. Concentrations of antifouling elements in sediments at these locations are several orders of magnitude higher than in the background, strongly impacting the marine environment diversity, health and vitality of its ecosystem and its productive capacity. Besides, these are locations where matrix effects have to be carefully examined before the application of neutron methods for threat material inspection. In Fig. 6, details from the1945 map of WWII mine fields (zones with possible remnant mines) are presented as well as recently reported cases of explosive devices. Comparing concentration distribution maps and data on dumped ammunition, a possible migration spreading of toxic agents in marine sediments and the marine environment can be evaluated (especially for the CW agents). Such a relation has not been established on a large scale in the northern part of the Eastern Adriatic. In order to examine the effects of long presence of ammunition in the environment on a small scale, we collected sediments samples at three locations in the vicinity of ammunition that were dumped during WWII on the bottom of the sea as shown in Fig. 7. Table 3 presents the results of chemical

composition of the collected samples obtained by the EDXRF method. Spreading of heavy metals in the vicinity of dumped ammunition depends on local environmental conditions. Some interesting results are presented in Fig. 8a–c in the form of the small scale distribution maps of Cr, Ni and Br concentrations, respectively. From Fig. 8 one can see that the dumped ammunition, besides the security threat caused by uncontrolled explosion, also presents the threat of heavy metal pollution.

4. Conclusions In this paper we have shown in some detail the problem of ammunition pollution in the Mediterranean Sea and the undertaken research and technology developments towards its solution. In conclusion it can be stated that a ‘‘proof of principle’’ for the inspection of explosive devices, chemical warfare agents and sunken ships by a sealed tube neutron generator placed inside an underwater vehicle has been established. The study shows that sediments in ports and harbors contain increased amounts of biocide elements like As, Cu, Zn and Pb.

Fig. 6. Distribution of As in the eastern Adriatic Sea with positions of the WWII mine fields.

Fig. 7. Sampling schemes of the sediment samples collected in the vicinity of the ammunition dumped in the Adriatic during WWII: (a) mortal shell, (b) torpedo and (c) torpedo in the field of gunpowder rods dumped during WWI.

Table 3 Results of EDXRF analysis of the surface sediment samples collected in the vicinity of the ammunition objects as presented in Fig. 7; MDL—maximum detection limit. Sample ID K ppm

Ti ppm

V ppm

15,100 7 1270 6.27 0.6

2690 7220 93.27 16.9

15,410 7 1300 5.37 0.4

2813 7 229 78.17 14.2

15,100 7 1250 6.267 0.53 2870 7249 96.67 16.6

Cr ppm

Mn ppm

Fe %

Ni ppm

1717 45

165 7 14

3.17 70.08

Cu ppm

Zn ppm

Ga ppm

As ppm

Rb ppm

Sr ppm

Y ppm

78.8 7 17.0 147.3 7 29.2 492.8 7 25.6 20.9 7 5.5 106.4 7 12.0 1057 30

86.07 8.6

369 7 19

52.1 73.2 225.6 720.1 240.87 49.0

2237 64

102.37 10.3 344 7 18

2167 69

77.67 8.2

1277 35

181 7 16

2.69 70.07

67.0 7 15

867 30

172 7 14

2.73 70.07

62.2 7 13.5 168.5 7 34.0 629.8 7 32.4 18.3 7 5.0 91.5 7 10.4

124.4 7 25.0 536.3 7 28.4 12.2 7 3.2 72.0 7 8.4

Br ppm

351 7 18

Zr ppm

Pb ppm

53.8 73.3 2747 26

140.07 28.4

56.7v3.5

186.27 38.8

2537 22

15,940 7 1450 6.57 0.5

3062 7250 106.67 16.5 2087 62

228 7 17

2.82 70.07

75.6 7 15.8 167.1 7 33.3 437.5 7 22.3 13.7 7 2.1 79.7 7 9.0

1377 39

91.37 9.2

350 718

56.1 73.4 2847 26

160.97 32.9

15,890 7 1300 5.77 0.4

2633 7 216 71.67 12.8

1547 42

189 7 17

2.607 0.07

75.7 7 16.3 133.6 7 26.8 418.8 7 22.6 11.4 7 3.1 63.0 7 7.3

2317 66

96.37 9.7

500 7 27

51.5 73.4 2357 23

133.87 27.1

14,920 7 1320 5.87 0.4

2744 7 225 757 15

1197 35

177 7 14

2.67 70.07

66.1 7 14.6 140.6 7 28.3 450 724

14.0 7 4.0 79.2 7 9.1

1977 56

95.47 9.6

389 7 21

53.2 73.4 2547 24

152.47 30.9

11,300 7 1060 16.87 1.3

989 7 96

35.27 8.0

93.27 27.0 241 7 16

1.14 70.03

49.3 7 10.8 21.9 7 4.5

o 3.9

15.7 7 2.0

1187 34

45.97 4.6

1295 769

29.1 72.0 1247 21

19.77 4.2

6362 7 816

20.97 1.6

532 7 69

o MDL

o 40.2

221 7 15

0.7707 0.020 32.7 7 7.7

16.2 7 3.6

41.1 7 3.2

o MDL

15.4 7 1.9

877 25

29.27 3.0

1592 784

23.5 71.7 79.5 719.5

13.07 2.9

8727 7 1020

20.27 1.5

830 7101

o 33.8

1127 38

227 7 18

0.8927 0.023 40.3 7 9.2

23.4 7 5.0

38.9 7 2.7

o MDL

14.4 7 1.8

101.07 28.7 36.67 3.8

13407 70

27.6 71.9 937 18

14.47 3.2

10,090 7 1010 12.57 1.0

698 7 82

o 14.5

o 74.1

112 7 10.5 1.18 70.03

33.7 7 7.7

14.8 7 3.4

49.0 7 3.7

o MDL

9.4 7 1.2

2887 81

24.67 3.2

683 7 36

16.6 71.5 o37.7

9.47 2.3

4875 7 853

23.67 2.1

417 7 62

o 19.1

68217

181 7 14

0.6827 0.018 28.0 7 7.6

15.4 7 3.4

33.0 7 2.8

o MDL

20.3 7 2.4

60.27 17.2

22.27 2.3

1657 786

22.6 71.8 o47.7

11.27 2.5

56.4 7 3.9

5742 7 753

22.37 1.7

549 7 64

o 15.3

o 98.7

25 7 16

0.800 7 0.021 38.6 7 8.9

19.4 7 4.2

32.2 7 2.5

o MDL

14.4 7 1.8

55.4 715.8

24.77 2.6

1452 776

22.2 71.6 o49.0

11.77 2.6

2566 7 841

28.37 2.2

o MDL

o MDL

o MDL

259 7 18

0.3937 0.010 22.0 7 5.8

15.9 7 3.8

26.5 7 2.2

o MDL

7.6 7 1.0

937 26

19.57 2.1

1789 793

15.7 71.3 oMDL

9.87 2.3

4064 7953

25.17 2.1

170 751

o MDL

o MDL

248 7 17

0.3897 0.010 15.1 7 4.9

17.1 7 4.2

28.9 7 2.5

o MDL

67.9 7 7.8

3097 98

18.57 2.9

1933 7101 14.7 71.4 oMDL

180.67 37.7

11,520 7 1050 17.77 1.5

469 7 65

o MDL

o 47.6

274 7 18

0.7207 0.019 38.3 7 8.6

19.0 7 4.4

41.1 7 3.1

o MDL

8.3 7 1.1

16677 529

33.67 5.4

1691 788.1 18.7 71.5 o49.4

13.17 3.1

6967 7 788

21.57 1.8

243 7 58

o MDL

o MDL

244 7 21

0.4807 0.013 27.9 7 7.1

14.7 7 3.4

33.2 7 3.3

o MDL

7.4 7 1.2

14747 468

23.67 3.9

1748 791

17.8 71.6 o49.4

12.57 1.2

6041 7785

25.27 2.1

254 7 53

o MDL

617 26

192 7 16

0.5277 0.014 29.0 7 7.7

15.8 7 3.5

33.0 7 3.6

o MDL

6.8 7 0.9

3637 100

47.07 5.1

1688 789

18.5 71.5 oMDL

10.77 2.6

5771 7 901

22.57 1.9

199 7 14

o MDL

o MDL

293 7 19

0.5117 0.013 29.8 7 10.1 18.7 7 4.1

38.0 7 3.0

o MDL

8.6 7 1.1

6017 191

16.67 3.0

1829 795

17.5 71.5 oMDL

14.27 3.3

ARTICLE IN PRESS

LG-S1 (0.0 m) LG-S2 (0.5 m) LG-S3 (1.0 m) LG-S4 (0.0 m) LG-S5 (0.5 m) LG-S6 (1.0 m) BK3-S1 (0.0 m) BK3-S2 (0.5 m) BK3-S3 (1.0 m) BK3-S4 (0.0 m) BK3-S5 (0.5 m) BK3-S6 (1.0 m) P-S1 (0.0 m) P-S2 (0.5 m) P-S3 (1.0 m) P-S4 (0.0 m) P-S5 (0.5 m) P-S6 (1.0 m)

Ca %

ARTICLE IN PRESS 426

J. Obhodas et al. / Nuclear Instruments and Methods in Physics Research A 619 (2010) 419–426

Fig. 8. Cr, Ni and Br concentrations in the surface sediments in the vicinity of dumped mortal shell—location LG and dumped torpedo—location P. Samples were collected as presented in Fig. 7.

Their presence modifies the gamma response when irradiated by fast neutrons potentially interfering with the signal from the investigated object, especially when inspecting CW.

Acknowledgment This research has been partially financed by EU FP7 Project UNCOSS. References [1] UN, Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction, Chemical Weapons Convention, 1997, UN Document, A/RES/47/39. [2] R. Monfils, Paper from International Oil Spill Conference 2005, May 15–19 2005, Miami Beach, Florida, USA, American Petroleum Institute, Washington, DC, USA. [3] D.N. McNelis, G.E. Schweitzer, Environ. Sci. Technol. 35 (2001) 108A.

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