This annex addresses quality guidelines that have been derived according to certain methodologies and using ecotoxicological data. At present, there is still substantial scientific debate on the validity of such quality guidelines and their use for marine environmental management. Quality guidelines encounter one generic limitation that applies to all matrices whether sediments, water or biota. They only address concerns regarding those chemicals for which guidelines have been developed. A sediment, for example, could be below all existing guidelines yet still pose environmental risks due to additional chemicals for which guidelines have not been developed. Existing guidelines provide no means of evaluating such constituents. Moreover, the derivation of sediment quality guidelines (SQG) is hampered by the uncertainties surrounding estimations of the biological availability of sediment-associated contaminants. The actual availability and consequent ecotoxicological effects are strongly influenced by factors such as grain-size distribution, composition of organic matter, occurrence of sulphides and the time period over which the contaminants are present in the sediment. Therefore, in the process of identifying adverse effects of certain sediment compounds, SQGs should merely be used as a first screening tool.

　

　

2.1 Equilibrium partitioning (EqP)

Equilibrium partitioning is usually understood to refer to (1) the partitioning of non-ionic organic chemicals between sedimentary organic carbon and porewater (Di Toro et al., 1991); and (2) the partitioning of ionic metals between sulphides and porewater, as described by the acid volatile sulphides/simultaneously extracted metals (AVS/SEM) process (Di Toro et al., 1992). They are limited by the assumption of equilibrium between sediment and porewater which is questionable in the case of estuarine and coastal sediments (USACE, 1998). Moreover, even if equilibrium between abiotic phases does exist, benthic organisms do not equilibrate with the porewater because they develop strategies to obtain oxygen and waterborne nourishment from the overlying water.

　

2.2 Co-occurrence Analysis
SQGs have been derived on the basis of co-occurrence analyses, i.e., from collections of data on bulk sediment chemical concentrations that were measured along with some measure of biological response. Responses could be results from various bioassays performed in the laboratory, benthic community changes or various sediment quality guidelines from other sources. Examples of such SQGs are the apparent effects threshold (AET), the effects range-low and effects range-medium (ERL/ERM) and the threshold effects level and probable effects level (TEL/PEL). There are potential sources of uncertainty in all co-occurrence approaches, e.g.,:

　

- AET, ERL/ERM or TEL/PEL do not demonstrate cause and effect (O'Connor et al., 1998: USACE, 1998).

　

- AET, ERL/ERM or TEL/PEL provide inconsistent results. Because these types of SQGs are based on statistical correspondence methods and not on mechanistically based descriptions of the process by which effects are caused, the results are inconsistent from one geographical area to another (Becker et al., 1990). It is difficult to see how such processes could be used to derive numerical action levels for international application.

　

- AET, ERM or PEL have a high probability of being false. Some inconsistencies may be caused by correlations among contaminant distributions resulting in false values. It is not uncommon for several contaminants to originate from the same source and for their concentrations in sediment to be closely correlated. When this occurs, the nature of the AET, ERM or PEL process is such that the effects of chemical A cannot be distinguished from the effects of chemical B. Therefore, the value for chemical B reflects combined effects of A and B, resulting in a false effect threshold value (Alden and Rule, 1992).

　

- Uncertainties in AET, ERL/ERM or TEL/PEL are not adequately described. All the potentially important sources of uncertainty in the derivation and use of the values have not been adequately described and evaluated (USACE, 1998). Until this is done, it is not possible to know the confidence that can be placed in evaluations based on such values.

(An example of national experience with a　site-specific assessment)　(大意)

　

　・Amphipod survival test(端脚類の生存試験)…アメリカでは10年前より堆積物の毒性判定試験にこの方法を用いている。堆積物(サンプル)全体に暴露した場合、堆積物の採取場所の汚染源からの距離により、端脚類の反応が異なる。他の種では、汚染源と関連して漠然とした結果しか出なかった。または、堆積物から抽出物を用いて暴露試験を行う、といった、実際的でない試験方法が要求された。

　・本方法はアメリカ国外の地域にも適用できると考えられる。

　・その他の試験についても、国内の試験実績に基づいて、特に実用性、再現性、化学物質の濃度変化に対する感受性の点から見て適当と考えられる試験方法があれば、それも国内外で適用できる試験方法の選択肢に含めてよいと考えられる。

　・アメリカにおけるAmphipod survival testでは、室内での10日間にわたる暴露試験の結果、Amphipodの生存率が80％未満なら有害と判定する。

　・本試験を用いた結果によると、堆積物(底質)が汚染されているアメリカ国内の沿岸域は10％未満とされた(Long et al.,1996)。

　・化学測定だけでは堆積物の毒性判定はできないが、有毒な堆積物中にはほとんど見つからないような化学濃度のセットをリストアップしていくことには価値がある。このような濃度のセットは、極めて限定的な価値を持っている。高濃度で含まれていても毒性を示さない場合もあるからである。

　・とはいっても、サンプル中の物質がいずれも無影響濃度を超えない場合は、生物試験は必要ではない。

　

　―同様の検体において、1725検体のうち1370検体(1725検体に対して80％)については無影響濃度を超えていたが、生物試験の結果は無害であった。無影響濃度を超えるということは、生物試験が必要となるということにすぎない。

　

During a period of over 10 years of development in the United States, it has been found that amphipod survival during 10-day laboratory exposures to whole sediment varies in proportion to sediment proximity to chemical sources. Other tests with other species have shown ambiguous results in relation to sources or require unrealistic exposures to sediment extracts. Therefore, in the United States, the amphipod test has been chosen for classifying sediments as toxic. This same test could apply in other regions. Other choices are possible on the basis of national experience with tests, particularly in respect to their practicality, reproducibility and sensitivity to gradients in chemical contamination.

　

In the United States, sediments are classified as toxic if they allow less than 80% survival of amphipods in 10-day laboratory tests. This sensitive test has found that less than 10% of the United States coastal area has toxic sediments (Long et al., 1996). While no chemical measurements can identify toxic sediments, there is some value in listing sets of chemical concentrations that are rarely found in toxic sediments. These have limited value because higher concentrations co-occur with the very common condition of non-toxicity. However, if a sediment sample has no chemical concentration above the no-effect level, biological tests of toxicity are unnecessary. Long et al. (1995) provided a set of 25 no-effect concentrations that are all higher than background for metals and above global deposition levels for organic compounds.

　

In a set of 2,500 samples of sediment chemical data paired with amphipod toxicity measurements, O'Connor and Paul (2000) found only 33 toxic samples among 730 samples where all 25 concentrations were below the no-effect range. This less-than-5% occurrence of toxicity in the no-effect range as calculated by Long and Morgan (1990) may be due to chemicals not included among the 25 with no-effect levels but may also be an irreducible minimum rate of error. In the same dataset 1,370 (80%) of the 1,725 sediment samples with concentrations above the no-effect levels were also non-toxic. Exceedance of a no-effect concentration means only that biological considerations are necessary.

　

　

Alden, R.W., III, and Rule, J.H. (1992). "Uncertainty and sediment quality assessments; II. Effects of correlations between contaminants on the interpretation of apparent effects threshold data", Environmental Toxicology and Chemistry 11: 654-61.

　

Becker, D.S., Barrick, R.C., and Read, L.B. (1990). "Evaluation of the AET approach for assessing contamination of marine sediments in California", State Water Resources Control Board Report No. 90-3SQ, Sacramento, CA.

　

Daskalakis, K.D., and O'Connor, T.P. (1995). "Normalization and elemental sediment contamination in the Coastal United States", Environmental Science and Technology 29: 470-477.

　

Di Toro, D.M., Mahoney, J.D., Hansen, D.J., Scott, K.J., Carlson, A.R., and Ankley, G.T. (1992)."Acid volatile sulfide predicts the acute toxicity of cadmium and nickel in sediments", Environmental Science and Technology 26(1): 96-101.

　

Di Toro, D.M., Zarba, C.S., Hansen, D.J., Berry, S.J., Swartz, R.C., Cowan, C.E., Pavlou, S.P., Allen, H.E., Thomas, N.A., and Paquin, P.R. (1991). "Technical basis for establishing sediment quality criteria for non-ionic organic chemicals using equilibrium partitioning", Environmental Toxicology and Chemistry 10: 1541-83.

　

Long, E.R., Field, L.J., and MacDonald, D.D. (in press). "Predicting toxicity in marine sediments with numerical sediment quality guidelines", Environmental Toxicology and Chemistry.

　

Long, E.R., and Morgan, L.G. (1990). "The potential for biological effects of sediment-sorbed contaminants tested in the National Status and Trends Program," NOAA Tech. Memo NOS OMA 52, National Oceanic and Atmospheric Administration, Seattle, WA.

　

Loring, D.H. (1990). "The Li solution - a new approach for the granulometric normalization of trace metal data". Marine Chemistry 19: 155-168.

　

Loring, D.H. (1991). "Normalization of heavy-metal data from estuarine and coastal sediments". ICES Journal of Marine Science 48: 101-115.

　

O'Connor, T.P., Daskalakis, K.D., Hyland, J.L., Paul, J.F., and Summers, J.K. (1998). "Comparisons of sediment toxicity with predictions based on chemical guidelines", Environmental Toxicology and Chemistry (173): 468-71.

　

O'Connor, T.P., and Paul, J.F. (2000). "Misfit between sediment toxicity and chemistry," Marine Pollution Bulletin 40: 59-64.

　

USACE (1998). "Use of sediment quality guidelines (SQGs) in dredged material management", Dredging Research Technical Note EEDP-04-29, U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MS.

　

U.S. Environmental Protection Agency (1989). "Evaluation of the apparent effects threshold (AET)approach for assessing sediment quality", USEPA Report No. SAB-EETFC-89-027, Science Advisory Board, Washington, DC.

　

U.S. Environmental Protection Agency (1993). "Technical basis for establishing sediment quality criteria for non-ionic organic contaminants for the protection of benthic organisms by using equilibrium partitioning", Draft EPA 822-R-93-011, Office of Science and Technology, Health and Ecological Criteria Division, Washington, DC.

　

　

Dr. Helge Bergmann

Federal Institute of Hydrology

Post Box 20 02 53

56002 Koblenz

Germany

Tel: +49 261 1306 5407

Fax: +49 261 1306 5610

Email: bergmann@bafg.de

　

Dr. Mike Bewers

Grand Quercy

47350 Montignac Toupinerie

France

Tel.: +33 5 53 83 81 02

Fax: +33 5 53 83 81 02

E-mail: john.bewers@wanadoo.fr

　

Mr. Rick Boelens

QSR Office

Marine Institute

c/o Enterprise Ireland Laboratory

Shannon Town Centre

Co. Clare

Ireland

Tel.: +353 61 361 499

Fax: +353 61 360 863

E-mail: qsr@marine.ie

　

Mr. Rene Coenen

Senior Technical Officer

International Maritime Organization

4 Albert Embankment

London SE1 7SR

United Kingdom

Tel: +44 20 7587 3239

Fax: +44 20 7587 3210

Email: rcoenen@imo.org

　

Prof. Michael Depledge

Plymouth Environmental Research Centre

University of Plymouth

Drake Circus

Plymouth PL4 8AA

United Kingdom

Tel: +44 1752 233038

Fax: +44 1752 233039

Email: m.depledge@plymouth.ac.uk

　

Dr. Bob Engler

USAE Waterways Experiment Station

CEWES-EN

3909 Halls Ferry Road

Vicksburg, MS 39180

USA

Tel: +1 601 634 3624

Fax: +1 601 634 3528

E-mail: englerr@wes.army.mil

　

Mr. John Karau (Chairman)

Chief, Marine Environment Division

Environment Canada

Ottawa, Ontario

Canada K1A 0H3

E-mail: John.Karau@ec.gc.ca

　

Dr. Manfred Nauke

Chief, Office for the London Convention 1972

International Maritime Organization

4 Albert Embankment

London SE1 7SR

United Kingdom

Tel: +44 20 7587 3124

Fax: +44 20 7587 3210

Email: mnauke@imo.org

　

Dr. Tom O'Connor

NOAA N/SCI1

1305 East West Hwy.

Silver Spring, MD 20910

USA

Tel: +1 301 713 3028 ext. 151

Fax: +1 301 713 4388

Email: tom.oconnor@noaa.gov

　

Dr. Richard K. Peddicord

Environmental Consultant

Science Adviser to IAPH

PO Box 300

Weems, VA 22576

USA

Tel: +1 804 438 5658

Fax: +1 804 438 6558

Email: dp@rivnet.net

　

Mr. Joost Stronkhorst

Ministry of Transport, Public Works and Water Management

National Institute for Coastal and Marine Management/RIKZ

PO Box 20907

2500 EX The Hague

The Netherlands

Tel: +31 70 3114377

Fax: +31 70 3114300

Email: j.stronkhorst@rikz.rws.minvenw.nl

　

Dr. Umit Unluata

Intergovernmental Oceanographic Commission

UNESCO

7 place de Fontenoy

75700 Paris

France

Tel: +33 1 45 684008

Fax: +33 1 45 685812

E-mail: u.unluata@unesco.org

　

Dr. Chris Vivian

CEFAS Burnham Laboratory

The Centre for Environment Fisheries

and Acquaculture Science

Remembrance Avenue

Burnham-on-Crouch

Essex CM0 8HA

United Kingdom

Tel: +44 1621 787200

Fax: +44 1621 784989

Email: c.m.g.vivian@cefas.co.uk

　

Dr. Herb Windom

Acting Director

Skidaway Institute of Oceanography

10 Ocean Science Circle

Savannah, GA 31411

USA

Tel: +1 912 598 2490

Fax: +1 912 598 2310

Email: herb@skio.peachnet.edu