North East File Collection - NEFC

The OSPAR Convention is a treaty that aims to prevent and eliminate pollution and conserve the marine ecosystems of the North-East Atlantic. It was adopted in 1992 and entered into force in 1998, and covers land-based, offshore and dumping sources of pollution.

The UK is a signatory to the OSPAR Convention and so this governs the UK licencing of disposal of dredged material at sea.

The OSPAR Convention organisation issues guidelines which the signatories sign into as agreements. OSPAR Agreement 2014-06 is the relevant guideline which the UK regulations need to be compliant with.

Paragraph 5 of OSPAR Agreement 2014-06 specifies the requirements for sampling procedure before material can be licensed for disposal at sea.

Paragraph 5 is very explicit as to the purpose of sampling and quantitative as to the way in which sampling should be carried out.

5.1 Dredged material will require sampling and analysis (cf. Technical Annex I) to provide sufficient information for permitting purposes. Local conditions will dictate what information is relevant to a particular operation.

5.2 The location and depth of sampling should represent the horizontal and vertical extent of the area, and the quantity of material to be dredged. In many maintenance dredging campaigns, grab sampling will be sufficient. Sampling from dredged material within disposal vessels or barges is not advisable for permitting purposes.

5.3 Samples should provide a good spatial (surface) and vertical (depth) representation of the material to be dredged and should take account of the exchange characteristics of the area, i.e., more samples may be required in a low energy enclosed and semi-enclosed areas, and less in high energy environments such as open areas. The minimum number of separate sampling stations recommended to obtain representative results, assuming a reasonably uniform sediment distribution in the area to be dredged is as follows. The number of sample stations can also be determined on the basis of the size of the area to be dredged:

Where projected depth of dredging is significant, samples will be required at depth, usually by vibracore. The volume of the dredge material should be taken into consideration to determine the number of samples, as below.

Contracting Parties are encouraged to use the Guidelines for the Sampling and Analysis of Dredged Material Intended for Disposal at Sea (IMO, 2005) to inform sampling regimes.

5.4 Normally, the samples from each sampling station and different depths in the sediment should be analysed separately. However, if previous analyses have shown that the sediment is clearly homogenous with respect to sediment texture and known contamination it is possible to analyse composite samples. OSPAR recommends no more than three adjacent sampling stations at a time be composited, and providing there are no distinctly different observable attributes (same colour, consistency, odour) in different sub samples. Care should be taken to ensure that the results allow derivation of valid mean contaminant values.

The original individual samples should be stored or preserved according to procedures in the JAMP Guidelines for Monitoring Contaminants in Sediments (OSPAR Agreement 2002-16) until the permitting procedure has been completed, in case further analyses are necessary.

Frequency of sampling

5.5 The period between sampling has been agreed as three years, but if the results of the analyses indicate that the material meets national assessment criteria (e.g. below lower action level), sampling in the same area may be reduced to every five years, provided that there are no material changes to the sediment (e.g. dredging) or new sources of contamination likely to lead to deterioration of the quality of the material in the meantime.

5.6 It may be possible, following assessment of the results of an initial full survey, to reduce either the number of sampling stations or the number of determinants and still provide sufficient information for permitting purposes. If a reduced sampling programme does not confirm the earlier analyses, the full survey should be repeated. If the list of determinants is reduced, further analysis of the complete list of determinants is advisable every five years. The second and third sentence of this paragraph needs to be applied consistent with the provisions of the primary list of chemical determinants in Technical Annex I.

5.7 In areas where sediment chemistry has been shown to exceed action levels, i.e. demonstrates high levels of contamination, or where contamination can be expected, then analysis of all the relevant determinants should be frequent and linked to the permit renewal procedure.

The UK Government Regulations (Marine licensing: Sediment Analysis) do not rewrite the guidance supplied by OSPAR, rather they state that “MMO licenses disposing of dredged materials at sea and uses guidelines produced by OSPAR to regulate this activity.”

So the wording of OSPAR Agreement 2014-06 is key to understanding how sampling plans are developed for Marine Licence applications.

The sediment sampling plan (SAM/2024/00054) was initially produced in fulfilment of the requirement for a final mid-licence sampling scheme for the previous 10 year maintenance dredging licence. However, the MMO subsequently agreed that the sediment sampling plan (SAM/2024/00054) was sufficient to support the 10-year maintenance dredge disposal licence (L/2025/00366/1) for Tees and Hartlepool.

“1.2 PD Teesport Limited undertakes maintenance dredging of the Tees Estuary and Hartlepool Channel to maintain navigable depths as part of their statutory harbour authority responsibilities. Under marine licence L/2015/00427, this dredged material is disposed of at Tees Bay A (TY160) offshore disposal site. Marine licence L/2015/00427 is valid until 30th December 2025 and permits the annual disposal of 2,438,420 wet tonnes (1,875,700m3) of material from the Tees and 451,280 wet tonnes (347,400m3) from Hartlepool.”

The MMO and Cefas considered that 31 samples were sufficient for the annual disposal of the stated 2,223,100m³ per year, based on the volume table from OSPAR Agreement 2014-06 paragraph 5.3.

“1.1 This advice relates to sampling to support mid-licence condition compliance for the disposal of material from the Tees Estuary and Hartlepool Channel. It is understood that this advice will also be used to support the submission of a marine licence application in 2025 to continue disposal activities.”

It is not immediately obvious why the full 10 year volume or at least 3 years volume isn't used as sampling is only repeated every 3 years and the licence covers the dredging for the full 10years.

Paragraph 2.2 licence L/2025/00366/1 almost quotes OSPAR Agreement 2014-06 paragraph 5.3, but it inverts it so that rather than the samples needing to represent the area sampled it is stated they should represent the volume sampled instead and just reflect the area.

“2.2 In accordance with the recommendations of the OSPAR Guidelines for the Management of Dredged Material, samples should be taken to provide a good representation of the volume of material to be dredged. The distribution and depth of sampling should reflect the size and depth of the area to be dredged, the amount to be dredged and the expected variability in the horizontal and vertical distribution of contaminants. The MMO also uses the OSPAR guidelines to inform our advice on sampling requirements for other activities which are likely to lead to the mobilisation of sediments. Based on the information submitted (as described above), the following sampling and analysis is required.”

There are 2 distinct areas which PD Ports as the statutory harbour authority are responsible for the River Tees and the Port of Hartlepool.

In this marine licence application, the River Tees had a defined area of 1612.66 hectares and the Port of Hartlepool had a defined area of 55.92 hectares, giving a total area for which the maintenance dredging licence applies to of 1668.58 hectares.

From the Marine Coordinate Schedules (kml), which give an area of 16685800m² it is possible to use the area table of paragraph 5.3 to determine the number of samples necessary to fulfil the area requirement of the OSPAR Guidelines.

These figures are based on the map supplied by PD Ports to define the area they want to dredge in, which defines the whole river and port areas, as such 839 stations would have been required. In the whole 10 years of the L/2015/00427 less than 150 samples were taken at the locations shown in the figure above.

In this marine licence application, the River Tees had a defined area of 1162.37 hectares and the Port of Hartlepool had a defined area of 54.77 hectares, giving a total area for which the maintenance dredging licence applies to of 1217.14 hectares.

From the Marine Coordinate Schedules (kml), which give an area of 12171400m² it is possible to use the area table of paragraph 5.3 to determine the number of samples necessary to fulfil the area requirement of the OSPAR Guidelines.

These figures are based on the map supplied by PD Ports to define the area they want to dredge in, which defines the whole river and port areas, as such 614 stations would be required. Less than 150 samples were taken in during the 10 years of the previous licence L/2015/00427 for the licensed area of 1,669hectares and the last mid-licence samples were consider appropriate to represent the state of the whole 1,217hectares for which a new licence was requested.

It is obvious that in order for the L/2025/00366 to be in compliance with the OSPAR Convention that considerably more samples need to be obtained to “represent the horizontal and vertical extent of the area” with a subsequent check that “the quantity of material to be dredged” is also properly represented.“ (OSPAR Agreement 2014-06 paragraph 5.2).

OSPAR 2014-06 paragraph 5.3: “Where projected depth of dredging is significant, samples will be required at depth, usually by vibracore. The volume of the dredge material should be taken into consideration to determine the number of samples, as below.”

This is well reflected in the number of samples calculated based on these tables, where dredging more than 5m depths shows that the volume table recommends a greater number of samples than the area station numbers.