Chou & Uthe 1993 — Cadmium and other metals in American lobster, Belledune Harbour, New Brunswick, 1980-1992

Chou and Uthe extend an earlier Department of Fisheries and Oceans monitoring series (1980-1984; Uthe et al. 1987, Uthe and Chou 1985) with a further eight years of cadmium data for American lobster (Homarus americanus) captured in and around Belledune Harbour, New Brunswick — a Baie des Chaleurs coastal industrial zone hosting a lead smelter and fertilizer plant whose effluents have driven a closed and controlled-fishery regime for the harbour proper since 1980. Annual geometric mean Cd was measured in lobster digestive gland (tomalley, “hepatopancreas”) and in cooked tail+claw+knuckle meat from individual animals at eight sites, and Hg, As, Cu, Ag, and Pb were measured in pooled cooked-meat composites in selected years (1984-1992). Statistical-trend models published in 1987 had predicted that contamination would have decayed enough by 1989 to allow normal-fishery reopening, but Cd concentrations in digestive gland from the two intra-harbour sites instead spiked in 1987 and remained elevated through 1992 despite major dredging and reconstruction of the harbour in 1991. The authors conclude that ongoing Cd input to the harbour from ill-defined sources, rather than legacy sediment, is now the dominant contamination driver, and that lobsters from inside the harbour remain unfit for an open fishery.

Key numbers

Units: µg·g⁻¹ wet weight (equivalent to mg/kg wet weight; 1 µg·g⁻¹ = 1,000 ppb wet wt.). All Cd values are geometric means (antilog of mean-of-log-transformed values, denoted X̄_g in the source) calculated across individual lobsters per site per year; Hg, As, Cu, Ag, and Pb values are arithmetic means ± SD of three analyses on a single annual pool of 10 cooked-meat composites unless flagged with an asterisk.

Cd in lobster digestive gland (tomalley) — Table 1

Geometric mean (and individual-lobster range) Cd in digestive gland, by site and year. Higher row = inside-harbour site; HRI is the control:

Highlights:

• HW (deep inside-harbour site) Cd peaks at 174 µg·g⁻¹ wet wt. in 1980 (range 47.6–372), declines through 1986 (22.7), rebounds to 70.0 in 1987, drifts down to 30.32 in 1992. The maximum individual-lobster digestive-gland value in HW was 728 µg·g⁻¹ wet wt. (1982).
• HE peaks at 77.0 in 1984 (range 8.24–537), declines to 16.22 by 1992.
• HRI control stays in a narrow 3.30–5.80 µg·g⁻¹ band across the full 13-year record — no upward trend.
• The 1991 dredging and harbour reconstruction (causeway breach, cooling-water-intake channel for a new thermal power station, sediment containment cells in the southwestern harbour) had no major effect on 1992 harbour-Cd: 1992 values do not differ widely from immediately pre-construction 1991 values across the harbour sites.

Cd in cooked lobster meat (tail + claw + knuckle) — Table 1

Geometric mean (range) Cd in cooked meat, by site and year. Cooked-meat is the food matrix that reaches commercial product:

Cooked-meat values are ~100–1,000× lower than digestive-gland values at the same site/year. Highlights:

• HW cooked-meat geometric mean peaks at 0.89 µg·g⁻¹ wet wt. in 1981 (range 0.42–3.06) and at 0.74 in 1982 (range 0.11–3.26); 1992 value is 0.151 µg·g⁻¹ wet wt. (151 ppb). Maximum individual-lobster cooked-meat value at HW was 3.26 µg·g⁻¹ wet wt. (1982).
• HRI control cooked-meat Cd holds at 0.015–0.04 µg·g⁻¹ wet wt. (15–40 ppb) across the full record.
• The 1987 inflection visible in digestive gland is muted but present in cooked meat; the harbour-site declines through the mid-1980s reverse partially.

Hg, As, Cu, Ag, Pb in pooled cooked lobster meat — Tables 2 & 3

Hg and As (Table 2, all years): pools of 10 animals per site per year, 3 analyses per pool, 1 pool per year. Values are mean ± SD of the 3 analyses.

• All cooked-meat Hg values from all sites and years sit below the 0.5 µg·g⁻¹ wet wt. Canadian tolerance the authors reference (i.e., < 500 ppb).
• Harbour sites HW and HE show slightly elevated Hg relative to HRI and outer sites; the authors describe this as “somewhat elevated, but not to a level believed to be of concern.”
• All cooked-meat As values cluster in a 2.31–4.16 µg·g⁻¹ wet wt. range and sit well below the commercial-lobster-product average of 7.6 µg As·g⁻¹ wet wt. cited from B. Gervais (Fish Inspection Branch, personal communication).

Pb, Cu, Ag (Table 3, 1984-1985 selected sites): pools of 10 animals per site per year, 3 analyses per pool (* = 10 animals analyzed individually).

• HW and HE cooked-meat Pb in 1984-1985 sits near 0.9–1.2 µg·g⁻¹ wet wt. versus HRI ~0.05–0.07 µg·g⁻¹ wet wt. — roughly 15–25× the control. The authors note that commercial packs from harbour lobsters would average less than 1.0 µg Pb·g⁻¹ wet wt. once pack-level dilution and trimming are accounted for.
• Cu in cooked meat does not differ significantly between HRI, L1W, and HW (~20–23 µg·g⁻¹ wet wt.); cooking-related effect on Cu/Ag concentrations in muscle tissue is not characterized in the source.
• Ag in cooked meat does not differ significantly between HRI, L1W, and HW (0.41–0.49 µg·g⁻¹ wet wt.).

Animal-size context (Table 1, all sites and years)

Mean total wet weight ± SD of the sampled lobsters generally ranged 270–530 g with site/year SDs of 30–317 g; minimum individual weight 151 g, maximum 1,515 g (HW 1982). All sites sampled comparable adult-size lobsters; size differences alone do not explain site-Cd differences.

Methods (brief)

Sampling. Lobster sampling sites are shown in Figure 1 of the source. Sampling-site descriptions, capture procedures, tissue dissection, and the analytical procedures for Cd are described in Uthe et al. (1983). Lobsters were captured under DFO management of the contaminated fishery — closed-fishery zone (Belledune Harbour proper, no commercial fishing); controlled-fishery zone (from 1 mile NW of the harbour at the L1W site to 4 miles SW at the L4E site, commercial fishing allowed but lobsters routed through special cooked-frozen processing); and normal fishery (outside the controlled zone). The controlled zone L1E–L4E was reopened to normal fishery in 1986, and the harbour proper was reopened as a controlled-fishery zone in 1985.

Tissue handling. Cd was measured in digestive gland and cooked meat pools from each individual lobster (one digestive-gland sample and one cooked-meat sample per animal). Hg, As, Cu, Ag, and Pb were measured in pooled cooked-meat composites prepared by blending equal weights of homogenized cooked meat from each animal (10 animals per pool, 1 pool per site per year, 3 analyses per pool).

Analyte methods. All concentrations are reported in µg·g⁻¹ wet weight.

• As: method of Freeman, Uthe, and Flemming (1976) — “rapid and precise method for the determination of inorganic and organic arsenic with and without wet ashing using a graphite furnace.” The source reports the result as a single “As” value per pool without separating inorganic from organic species; treat as total As (tAs) for routing purposes.
• Hg: method of Armstrong and Uthe (1971) — semi-automated determination of mercury in animal tissues. The source reports a single “Hg” value per pool without separating methylmercury from inorganic mercury; treat as total Hg (tHg) for routing purposes.
• Cu and Ag: flame atomic absorption spectrophotometry on nitric-acid digests.
• Pb and Cd: graphite-furnace atomic absorption spectrophotometry on nitric-acid digests.

All methods had been used successfully in ICES (International Council for the Exploration of the Sea) intercomparison rounds (Berman 1984; Holden and Topping 1981).

Statistics. Cd concentrations in both digestive gland and cooked meat were positively skewed and were log-transformed for analysis; the source therefore reports the antilog of the mean-of-log-transformed values, denoted X̄_g, which is the geometric mean. The source notes that the wide concentration ranges make ANOVA inefficient and ANCOVA contraindicated (covariate values widely disparate), so the 1980-1992 results in this report are summarized as annual geometric means and ranges rather than as a formal trend test. The earlier 1987 paper (Uthe et al. 1987) applied multiple linear regression (with Gram-Schmidt orthogonalization, per Scott 1986) to the 1981-1985 Cd time series and predicted normal-fishery reopening by 1989; the post-1985 monitoring summarized in this report contradicts that prediction.

Limitations.

• Reporting basis. This is a Canadian government technical report, not a peer-reviewed journal article. Methods are referenced to earlier papers (Uthe et al. 1983; Freeman et al. 1976; Armstrong and Uthe 1971) rather than re-stated in full; LODs, LOQs, certified reference materials, and digestion conditions are not tabulated here.
• Pooled cooked-meat analyses (Hg, As, Cu, Ag, Pb). The cooked-meat data for these analytes is one pool per site per year, with the within-pool SD reflecting analytical replication (3 analyses), not animal-to-animal variation. Inter-animal variance for non-Cd analytes cannot be estimated from this design.
• Cd in cooked meat at HRI in 1980 and at most sites in 1980 is missing because the cooked-meat program was not started at all sites until 1981.
• Speciation. The source does not separate iAs from organic As nor MeHg from inorganic Hg; the As and Hg routing in this page uses tAs and tHg per CLAUDE.md Part 14 speciation discipline.
• Pb-cooking effect not characterized. The source notes uncertainty about how cooking affects Cu and Ag concentrations in muscle tissue (and implicitly Pb as well); cooked-meat values may differ from raw-meat values by an unquantified factor.
• Brand-level reporting absent. The source does not name commercial brands; processed lobster from the controlled fishery was sold as “cooked, frozen lobster meat” with no brand-by-brand contamination listing.

Implications

This source contributes a long-term (13-year) industrial-pollution time series for Cd in Homarus americanus digestive gland and cooked meat from a coastal lead-smelter zone (Belledune Harbour, New Brunswick, Canada), with paired control data from Heron Island (HRI) and a transect of sites at increasing hydrographic distance from the harbour. It is one of the longest single-site lobster contamination records available and the only one this corpus has so far that directly contrasts intra-harbour, controlled-fishery, and normal-fishery zones at the same study with the same analytical methods.

For occurrence-distribution work on shellfish and seafood, the cooked-meat Cd values (0.015–0.89 µg·g⁻¹ wet wt. across all sites and years; harbour-site cooked meat peaks at 3.26 µg·g⁻¹ wet wt. as an individual maximum) define the upper tail of a contaminated-source distribution rather than the typical commercial range — the source’s own implication is that normal-fishery cooked meat from outside the controlled zone is the appropriate comparator for typical North Atlantic lobster. For Pb, the 1984-1985 cooked-meat values from harbour sites (0.9–1.2 µg·g⁻¹ wet wt.) are similarly far above the HRI control (~0.05–0.07 µg·g⁻¹ wet wt.) and again represent an upper-tail industrial-contamination signal.

Cd in lobster digestive gland (tomalley) is included as an exposure-route data point, not an occurrence value: tomalley is consumed by some traditional preparations (lobster tomalley sauces, head-on whole-lobster dishes) and the digestive-gland Cd levels here are 100–1,000× the cooked-meat values, so any wiki discussion of lobster Cd should treat “lobster meat” and “lobster tomalley” as distinct exposure pathways.

The pooled-tissue Hg values are uniformly below 0.5 µg·g⁻¹ wet wt. and add a small-N tHg occurrence contribution; the pooled-tissue As values cluster 2.31–4.16 µg·g⁻¹ wet wt. and add a small-N tAs occurrence contribution. Both should be flagged as total species and pooled with caution against papers that report iAs or MeHg.

Wiki pages this source may touch

• shellfish
• seafood
• shellfish
• seafood
• cadmium
• lead
• mercury-total
• arsenic-total
• copper
• silver

Sources

• Chou CL, Uthe JF. 1993. Cadmium in American lobster (Homarus americanus) from the area of Belledune Harbour, New Brunswick, Canada: 1980-1992 results. Canadian Technical Report of Fisheries and Aquatic Sciences No. 1916. Department of Fisheries and Oceans, Physical and Chemical Sciences Branch, Scotia-Fundy Region, Halifax, Nova Scotia. vi + 25 p. ISSN 0706-6457; Cat. No. Fs 97-6/1916E.
• Manual-fetch PDF: raw/manual-fetch/Kimi_Agent_Download Corruption Issue/seafood_papers/04_Shellfish/Cadmium in American lobster (Homarus americanus) from the area of Belledune Harbour, New Brunswick,.pdf (SHA-256 5e9a5f7be6f26433f3b4fdd741053f92a28013de070df319661b5cac2e5d3a2d).

Verification notes

• 2026-06-03 Claude fresh ingest from manual-fetch/Kimi_Agent_Download Corruption Issue/seafood_papers/04_Shellfish. Three identity checks (DOI grep, raw_handle grep, cite-key grep) returned no existing wiki page; this is a NEW path ingest.
• Source is a Canadian government technical report (Crown copyright, open access via Publications Canada); no DOI exists for this publication series. Cat. No. Fs 97-6/1916E and ISSN 0706-6457 verified from the PDF copyright page (p. ii). evidence_tier: B reflects gray-literature status with ICES-intercomparison-traceable methods rather than peer-reviewed journal indexing.
• Brand firewall (Part 12): the source names no commercial food brands. “Belledune Harbour” is a geographic identifier for the industrial-pollution site (lead smelter, fertilizer plant) and is named as the regulatory-event location; no per-brand contamination ranking is reported.
• Speciation: the source measures total Hg (Armstrong and Uthe 1971 method) and reports a single “Hg” value per pool — recorded as tHg. The As method (Freeman et al. 1976) is capable of separating inorganic from organic arsenic, but the source’s Table 2 reports a single “As” value per pool with no iAs/organic split — recorded as tAs per Part 14 (when the source does not separate, use the total designation).
• Units: the source uses µg·g⁻¹ wet weight throughout. This is equivalent to mg/kg wet weight (1 µg·g⁻¹ = 1 mg/kg = 1,000 ppb). Wiki-page tables preserve the source’s native unit (µg·g⁻¹) and flag the ppb-conversion factor in the Units header rather than silently converting.
• No new ingredient or product slugs needed. American lobster routes to existing shellfish and seafood ingredient and product pages. A more granular crustaceans or lobster ingredient slug does not exist in the current taxonomy snapshot; not flagged as a missing-slug proposal at this single-paper threshold (per Part 10 page-creation rules, freq-2 or higher is the auto-stub trigger).
• The Canadian Hg-in-fish tolerance of 0.5 µg·g⁻¹ wet wt. referenced by the authors is a Health Canada / Canadian Food Inspection Agency regulatory value. No corresponding regulations/canada-hg-fish-tolerance slug exists in the current taxonomy snapshot; flagged here as a potential future regulation page rather than inventing a slug. Page omits the regulation cross-link.
• Eight site abbreviations (HRI, L1W, HW, HE, LOBE, L1E, L4E, PET) and their geographic positions are preserved verbatim from the source’s Figure 1 caption and Table 1 headers to enable later replication or audit.
• 2026-06-03 Claude audit subagent (fresh context) verdict: PROMOTE. Two ⚠️ concerns, neither requiring page changes:
  • Check 2 — metals: [Cd, Pb, tHg, tAs, Cu, Ag] includes Cu and Ag, which are not in the Part 14 abbreviation vocabulary (Pb, Cd, iAs, tAs, iHg, MeHg, tHg, Ni, Al, Cr, Cr-VI, Sn, Sb, U). Both metals were measured by the source and the corresponding metals/copper and metals/silver page slugs exist in the taxonomy. Disposition: leave as recorded — dropping the analytes from frontmatter would silently lose information about what this source measures. Tracked as a Part 14 vocabulary-extension schema question, not a page defect.
  • Check 3 — L4E geographic descriptor: wiki front matter and sampling_locations call L4E “four miles ESE of Chapel Point,” matching PDF Table 1 header text. PDF p.1 Introduction prose calls the controlled-fishery zone L1W → L4E “1 mile northwest … to 4 miles southwest of the harbour,” which is a source-internal inconsistency between the Introduction text and the Table 1 site headers. Disposition: wiki preserves the table-header convention (which is the more granular and the convention used throughout Table 1 and Figure 1). No correction warranted; flagged here so future readers know the source is internally inconsistent.
  • All five checks otherwise clean: ✅ Check 1 (60+ cell values spot-checked across Tables 1, 2, 3 — no transpositions, no Cd/Pb swaps, no DG/cooked-meat swaps, no geometric/arithmetic conflation); ✅ Check 4 (no commercial brand names; Belledune Harbour + lead smelter + fertilizer plant are regulatory-event identifiers permitted under Part 12 Exception 1); ✅ Check 5 (no HMTc threshold proposals, no consumer advisories, no cross-literature synthesis claims).

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.