Dillon Consulting
3200 Deziel Drive, Suite 608
Windsor, Ontario, Canada, N8W 5K8
Telephone: (519) 948-5000
Fax: (519) 948-5054

Our File: 99-6976-2000

January 18, 2000

Windsor Port Authority
251 Goyeau Street, Suite 502
Windsor, Ontario, N9A 6V2

Attention: Mr. David S.H. Cree, President

Riverside Marina
Proposed Dredge Material Sampling and Analyses

Dear David:

At your request, Dillon Consulting Limited (Dillon) has conducted sampling and analysis of the proposed dredge area sediment material at the former Riverside Marina. The objective and scope of work for this project were discussed with Dave Diemer, P. Eng., Environmental Engineer, Dillon on December 23, 1999.

1.0 BACKGROUND

The Authority is planning to dredge the marina basin to remove approximately two to three metres of sediment and/or soil. In addition, there is potential for re-development of this site, which would require the extension of the existing south wall to allow filling a portion of the marina basin in the southeast corner. It may be desirable to dredge the sediment in the southeast corner of the marina and dispose of this material in the Detroit River prior to in-filling with Marina soils.

Sediment sampling activities were conducted by Diemer on December 23, 1999.

2.0 SEDIMENT SAMPLING AND ANALYSES

Dillon personnel collected five sediment samples from the marina basin with the assistance of Hotte Construction personnel. A shallow steel boat was used to access the sampling locations. A layer of ice ranging from 1 to 2 inches thick was present on the surface of the Marina waters on the sampling date.

Four sediment samples were obtained from the proposed dredging area in the marina basin. One sample was obtained approximately half the distance into each of the three means slips and the fourth sample was obtained from the main passage at the east side of the marina. Equal amounts of each of these samples were combined to form a composite sample to represent the dredge area sediment. One sediment sample was obtained from the southeast corner of the marina in the area to be in-filled.

Samples were obtained using a long stainless steel pole equipped with a stainless steel sample container at one end. The probe and sample container were sunk into the loose surface sediment and dragged along the firm material at the base of the settlement. Several scoops were required to obtain enough soil/sediment for sample analysis. The opposite end of the sampling probe was used to estimate the depth of the loose sediment by forcing the probe vertically downward into the sediment, retrieving the probe and measuring the depth of the sediment adhered to the probed surface.

Sediment samples were transferred to appropriate sample containers in the Dillon laboratory. Two samples were submitted to Philip Services Corporation in London, Ontario for selected analysis.

3.0 RESULTS

The depth of the sediment measured during sampling activities ranged from 6 inches to 16 inches in the marina basin. At the sampling location in the area to be in-filled, the sediment depth was measured to be 12 inches.

Table 1 contains the results of the inorganic compound analysis (metals) for the two samples with Ontario fill quality guidelines for lakefilling(1) and Ontario soil clean-up guidelines(2) provided for comparison. Table 2 contains the results of selected organic compound analysis with applicable provincial guidelines provided for comparison.

Appendix 1 contains the laboratory Certificate of Analysis for the two sediment samples.

4.0 DISCUSSION OF RESULTS

The disposition of fill materials into water bodies is addressed by the document entitled "Fill Quality Guidelines for Lakefilling in Ontario - Application of Sediment and Water Quality Guidelines to Lakefilling", MOE Water Resources Branch. The fill which may be used for lakefilling projects will be divided into two categories: confined fill and unconfined fill. Confined fill may be used for lakefilling provided it is placed within the confines of a structure which is capable of withstanding the waves of a-once-in-50-year storm. The structure is required to prevent the fill from coming into contact with the open water and being washed away. Unconfined fill for lakefilling projects may be placed directly into the water.

Table 1: Inorganic Compound Analyses Results

Analyte Concentration (µg/g) Lakefilling Criteria (µg/g) MOE Soil Clean-up Criteria(1) (µg/g)
Dredge Area Sediment Fill Area Sediment Unconfined Fill Confined Fill
Antimony <0.5 0.5 ---- 0.43 13
Arsenic 5.4 5.8 6 11 25
Barium 98 106 ---- 160 1000
Beryllium 1 1 ---- 1.1 1.2
Cadmium 1 1 0.6 0.7 12
Chromium IV <0.3 <0.3 ---- 1 10
Chromium (total) 41 44 26 58 1000
Cobalt 11 12 ---- 16 50
Copper 60 110 16 41 300
Lead 51 41 31 45 200
Mercury 0.30 0.26 0.2 0.2 10
Molybdenum 2 3 ---- 1 40
Nickel 55 54 16 38 200
Selenium 1.2 <0.5 ---- 0.93 10
Silver <1 <1 ---- 0.27 25
Vanadium 35 38 ---- 77 250
Zinc 157 171 120 120 800
EC (mS/cm) 0.386 0.432 ---- 0.36 0.70
SAR 0.25 0.23 ---- 0.7 5.0
pH 7.1 7.0 ---- 3 to 10 5 to 9
Notes:
  1. Provincial sediment quality for metals - lowest effect level.
  2. Residential/parkland use in a non-potable groundwater situation.

Table 2: Organic Compound Analyses Results

Analyte Concentration (µg/g) Lakefilling Criteria (µg/g) MOE Soil Clean-up Criteria(1) (µg/g)
Dredge Area Sediment Fill Area Sediment Unconfined Fill Confined Fill
TPH - Heavy Oils
(>C25)		 1320 7530 10,000 N/A 1000
TPH - Gas/Diesel
(C10-C24)		 270 1250 1000
PCBs (total) <0.05 <0.05 0.07 0.3 5.0
PAHs (total) <0.4(3) <0.4(2) 2 N/A N/A(4)
Notes:
  1. Provincial sediment quality guidelines - lowest effect level.
  2. Residential/parkland use in a non-potable groundwater situation.
  3. Concentrations for individual PAH compounds are <0.4 µg/g (limit detection).
  4. Criteria are listed for individual PAH compounds - no criteria for total PAHs.

To dispose of the loose sediment dredged from the southeast corner of the marina prior to in-filling, the sediment is required to meet criteria for unconfined fill. Of the eight criteria for unconfined fill listed in Table 1, seven of these criteria are exceeded by the fill area sediment concentrations. This sediment cannot be directly deposited into a water body.

The Windsor Port Authority proposes to erect a sheet piled barrier across the southeast corner of the marina and place the material dredged from the marina basin into this area. The dredged material is subject to the criteria for confined fill used in lakefilling projects. The inorganic compounds concentrations, listed in Table 1, exceed confined fill criteria for cadmium, copper, lead, mercury, molybdenum, nickel, selenium and zinc. The analytical limit of detection for antimony and silver is higher than the confined fill criteria, therefore these two compounds may or may not exceed the confined fill criteria. Based on these results, the dredge material is not acceptable for placement behind the sheet pile wall confinement.

It should be noted that the marine basin sediment samples were obtained from the upper 12 inches or 0.3 metres (approximate) of the river bottom. The proposed dredging operation would see 2 to 3 metres of soil excavated from the marina basin. The soils underlying the loose sediment are expected to be primarily native silty clay soils. Contaminant concentrations in the silty clay soils are expected to be lower than those reported for the sediment samples.

If an impermeable barrier were formed along the inside of the sheet pile structure for the fill area, which would prevent storm water from washing dredge materials into the river, the placement of dredged materials into the fill area would be comparable to placing the material on-shore. In this case, the applicable guideline for evaluating compliance would be the MOE soil clean-up guidelines. These clean-up criteria for inorganic compounds are provided in the final column of Table 1.

All contaminant concentrations for both the dredge area sediment and fill area sediment are below MOE soil clean-up criteria for residential/parkland land use in a non-potable groundwater situation with the exception of total petroleum hydrocarbons (TPH) as heavy oils which exceeds the MOE criteria value by 30%.

5.0 CONCLUSIONS/RECOMMENDATIONS

The sediment located in the area to be in-filled does not meet the criteria for unconfined fill and is not acceptable for disposal in the Detroit River.

The dredge area sediment does not meet the criteria for confined fill and is not acceptable for placement along the inside of the proposed sheet pile wall containment.

The dredge area sediment and fill area sediment meet the MOE soil clean-up criteria for inorganic compounds, polyaromatic hydrocarbons and PCBs for residential/parkland use. The dredge area sediment exceeds the MOE soil clean-up criteria for total petroleum hydrocarbons as heavy oils by 30%. The dredge area sediment sample was obtained essentially from the surface of the proposed 2 to 3 metre deep excavation and is expected to provide worst-case contaminant levels. That TPH concentration for a sample obtained from the full depth of the excavation is expected to be well below MOE soil clean-up criteria.

Dillon recommends that the sheet pile containment wall be lined with an impermeable barrier, such as clay, to prevent fill materials from washing into the river. The dredged soils/sediment may then be placed within the containment area.

We trust this report satisfies your requirements at this time. Please contact us if we can be further assistance to you in this matter.


Yours truly,

Dillon Consulting Limited


Dave Diemer, P. Eng.
Environmental Engineer


Carl St. Pierre, Ph.D., P. Eng.
Senior Environmental Consultant


1. Fill Quality Guidelines for Lakefilling in Ontario - Application of Sediment and Water Quality Guidelines to Lakefilling, Ontario Ministry of Environment and Energy, Water Resources Branch, 1992.

2. Guidelines for Use at Contaminated Sites in Ontario, Ontario Ministry of Environment and Energy, June 1996, Revised September, 1998.