Guidance For Sediment Quality Evaluations
November
1998
Previous  Table of Contents
3.0 Sediment Screening Values for Use in the Baseline
Ecological Evaluation
To aid in the identification of contaminants
of potential ecological concern, site-related sediment data
are compared to established screening level criteria in
the Baseline Ecological Evaluation (BEE). SRP’s Bureau of
Environmental Evaluation and Risk Assessment, Environmental
Toxicology and Risk Assessment Unit (BEERA/ETRA) recommends
the use of the sediment screening values on the three (3)
attached tables for the purpose of identifying sediment
contaminants of concern for a BEE. These values supersede
those provided in Guidance for Sediment Quality Evaluations,
Final Draft for Internal Use Only, March 1991 and are
applicable to traditional sediments and to wetland sediments
if a benthic community is supported.
3.1 Inorganics, Semivolatile
Organics, Pesticides/PCBs
The values presented in the Ecological Screening Criteria Table at http://www.nj.gov/dep/srp/guidance/ecoscreening/ are extracted from references cited in N.J.A.C. 7:26E-3.11 and are used by USEPA Region II BTAG for EPA Screening Level Ecological Risk Assessments [and other published sources]. Freshwater sediment screening values used for the BEE are the Ontario Lowest Effects Levels (LEL) (Persaud et al., 1993), and marine/estuarine sediment screening values used for the BEE are the Effects Range-Low (ER-L) values (Long et al., 1995). Additional screening values to be used in the BEE are listed in the LEL and ER-L columns with sources cited.
3.2 Volatile Organics
The values indicated in the Ecological Screening Criteria Table at http://www.nj.gov/dep/srp/guidance/ecoscreening/ are to be used as sediment screening criteria. The values were obtained from Environment Canada’s The Development of Canadian Marine Environmental Quality Guidelines (MacDonald et al., 1992) and other sources as cited.
3.3 Total Petroleum
Hydrocarbons (TPHC)
There is currently no sediment screening
value for TPHC, therefore TPHC-contaminated sediment should
be analyzed for volatile and semivolatile organics and resultant
data evaluated on a chemical-specific basis. If chemical
analyses produce low or nondetectable levels of the expected
organic compounds, but petroleum product is observable,
the product is likely to cause adverse ecological effects
(physical impairment of biota, loss of available substrate,
etc.). A benthic macroinvertebrate survey (Section
4.2) in the affected area and in an appropriate reference
location can be conducted to guide remedial decision-making.
In general, sediments with TPHC contamination are managed
on a case-by-case basis in consultation with BEERA/ETRA.
Comparison of Site-Related Data to Sediment Screening Values
The following should be considered when
comparing data from potentially impacted samples to sediment
screening values:
- In the BEE, maximum and mean concentrations of site-related
and reference sample data are compared to the sediment
screening values. No contaminants can be excluded from
the evaluation without adequate justification. Contaminants
may not be excluded from consideration based on comparison
with background/reference location data until completion
of the BEE because an evaluation of total site risk is
appropriate at this stage.
- The Long et al. marine/estuarine ER-L (Effects
Range-Low) screens represent a concentration at which
adverse benthic impacts are found in approximately 10%
of studies. A level greater than the ER-M (Effects
Range-Median) indicates a greater than 50% incidence of
adverse effects to sensitive species and/or life stages.
A concentration between the ER-L and ER-M therefore indicates
an expected impact frequency between 10% and 50%.
Ontario's freshwater LEL (Lowest Effects Level)
screen is generally comparable to Long et al., ER-Ls.
Ontario has no ER-M, but does provide an SEL (Severe
Effect Level) indicating severe benthic impacts in 95% of studies. For non-polar organics, the SEL is
calculated via site-specific total organic carbon (TOC).
See Table 1 footnotes for details on SEL calculation.
The ER-L and LEL screens were developed based on benthic
community studies and do not directly address biomagnification
(food chain toxicity) to water column species (fishes),
birds, and mammals. However, values found to be protective
of the food chain are generally similar (within an order
of magnitude) to ER-L/LEL values. When PCBs, organochlorine
pesticides and mercury (Hg) are found
in sediments at or above these screens, potential wildlife
risks exist and case-by-case evaluation is warranted.
Other known biomagnifiers without Ontario or Long et al.
screening numbers that warrant case-by-case evaluation
are dioxins, furans, other chlorinated organics, and selenium (Se).
- The attached ER-L and LEL values are not
cleanup standards but screening guidelines for use in
the BEE. An exceedence indicates a potential risk
(adverse impact) to the benthic community and need for
further investigations, which would reduce uncertainty
and better characterize risk and natural resource injury.
Such investigations include toxicity testing, macroinvertebrate
community surveys, and tissue bioassays. The determination
for more rigorous studies should be made on a case-by-case
basis in consultation with BEERA/ETRA.
Further remedial investigations/actions need not be triggered
by BEE screening exceedences if sediments proximal to
the site display contaminant concentration ranges similar
to upgradient sediments, which may be impacted by other
sources, diffuse anthropogenic contamination, etc. However,
upgradient sediment data must not be used to eliminate
contaminants of concern until the BEE has been completed.
At that point, the determination of chemicals of concern
retained for further evaluation will be addressed through
the risk management process in consultation with the case
team. Justification for no further action must be provided
in the BEE for Department review and must contain site-specific
upgradient data (refer to Section
2.3).
Risk assessment and risk management should
be clearly distinguished. Local reference contaminant
levels comparable to site levels do not indicate absence
of site risk, but do indicate reference area and site
risks that are similar. A risk management decision to
forego further action is based on no observable additional
site-generated risk.
- A number of screening values for Polynuclear Aromatic
Hydrocarbons (PAHs) are below Practical Quantitation Limits
(PQLs) and Contract Required Detection Limits (CRQLs).
To screen site data that are below the CRQL, the estimated
values (indicated by a "J" data qualifier) are
to be compared with the screening criteria.
- Generally, sediments containing ppb-levels of non-persistent
(log10 KOW < 3), photodegradable,
non-polar volatile organics are not of ecological
concern and further remedial investigation or remediation
would not be warranted. However, this approach is conditioned
upon no observable acute or chronic toxicity in the sediments,
source removal, and compliance with associated Surface
Water Quality Standards.
- Where analytical detection limits are higher than screening
criteria, contaminants must be retained as contaminants
of concern. For this reason, detection limits for all
analytes, including undetected contaminants, must be provided
with all data summaries.
- Particle/grain size, pH, and TOC analyses
are required for all sediment investigations. These data
confirm whether samples were collected in depositional
zones, as indicated by relatively higher TOC values and
a higher percentage of fine-grained particles, and provide
a qualitative indication of bioavailability. Depositional
zones are areas of highest potential contamination and
must be targeted during sampling events.
TOC results may be used to interpret borderline screening
exceedences in a "weight of evidence"/professional
judgement decision, or to generate site specific screening
values via an Equilibrium Partitioning (EP) approach (non-polar
organics only, e.g., PCBs, PAHs, organochlorine pesticides).
Some EPA sediment screening numbers, and some Ontario
SELs, are generated via this approach; however, BEERA/ETRA
and the USEPA Region II BTAG no longer use the EP approach
for general screening purposes due to uncertainties regarding
some of the assumptions used. Please consult BEERA/ETRA
(609-633-1348) if a No Further Action (NFA) remedial
decision is based on an EP approach or an EP approach
is considered to have site-specific utility.
References for TOC (Kahn, 1988) and particle/grain size
(ASTM, 1992) analyses are provided below. At a minimum,
particle size analysis results must provide the percent
clay, silt, sand and gravel.
- If contaminant levels are marginally higher than screens
or background, consult BEERA/ETRA prior to requiring
additional studies, as a "weight of evidence"/professional
judgment approach may preclude the need for the studies.
- If a screening value is not provided for a specific
contaminant, it must be retained as a contaminant of concern.
It is also recommended that BEERA/ETRA be contacted prior
to conducting a literature search, since ETRA may be able
to determine if a screening value is presently available.
Published sediment screening values other than those cited
in this guidance may be used on a case-by-case basis following
consultation with ETRA .
References
- American Society for Testing and Materials
(ASTM). 1992. Standard guide for selection of methods
of particle size analysis of fluvial sediments (manual
methods). Method D4822-88. American Society for Testing
and Materials. 1916 Race Street, Philadelphia, PA. Volume
11.02, pg. 622-624.
- Kahn, L. 1988. Determination of total
organic carbon in sediment. U.S. Environmental Protection
Agency, Region II. Environmental Services Division, Monitoring
Management Branch, Edison, NJ.
- Long, E.R., MacDonald, D.D., Smith, S.L.,
and Calder, F.D. 1995. Incidence of adverse biological
effects within ranges of chemical concentrations in marine
and estuarine sediments. Environmental Management Vol.19,
No.1. pp. 81-97.
- MacDonald, D.D., Smith, S.L., Wong, M.P.
and Murdroch, P. Environment Canada. 1992. The development
of Canadian marine environmental quality guidelines. Marine
environmental quality series no. 1. Ecosystem Sciences
and Evaluation Directorate. Eco-Health Branch. Ottawa, Ontario.
121 pp.
- Persaud, D., Jaagumagi, R., and Hayton,
A. 1993. Guidelines for the protection and management
of aquatic sediment quality in Ontario. ISBN 0-7729-9248-7.
Ontario Ministry of the Environment, Ottawa, Ontario. 23p.
Next
|
Sections
|
