Whittaker, Taylor & Van Hooser 2013 — King County alternative-solvent dry cleaning waste characterization

This King County hazardous-waste agency report characterizes the process chemicals and waste streams (still bottoms and separator water) generated by 16 commercial dry cleaners using alternative non-perchloroethylene solvents — 13 shops running hydrocarbon DF2000 and three shops running Solvon K4 (System K4). The primary purpose was hazardous-waste designation under federal RCRA and Washington-state dangerous-waste rules; heavy-metals data are a secondary product of the TCLP-extract panel run on still bottoms. For the Heavy Metal Index, the relevant findings are TCLP-extract concentrations of Pb, Cd, Cr, and Ba in dry-cleaning still bottoms from both solvent platforms, none of which exceeded the federal RCRA toxicity-characteristic thresholds at the shops sampled. Separator-water metals analysis was discontinued after early samples failed to exceed regulatory thresholds.

Key numbers

TCLP metals (EPA Method 1311 extraction; Method 6010B for Ba/Cd/Cr/Pb, Method 7470A for Hg), still bottoms (mg/L in the TCLP leachate):

Source: Tables 9 and 11 of the report. Chromium was the only metal detected above the reporting limit in every still-bottom sample of both platforms; the report notes a single hydrocarbon shop (Shop #09) produced 0.26 mg/L on first sample and 0.072 mg/L 75 days later, and a single K4 shop (Shop #01) produced the platform maximum of 0.61 mg/L. Barium was substantially higher in K4 still bottoms than in hydrocarbon still bottoms (statistically significant at p<0.01).

None of the detected TCLP metal concentrations in any still-bottom sample, in either platform, exceeded the federal RCRA toxicity-characteristic thresholds. All still-bottom samples nevertheless designated as Washington-state dangerous waste on other endpoints — primarily acute fish toxicity, halogenated-organic persistence (EOX ≥100 ppm), and ignitability (flash point <140 °F). See report Tables 10, 12, 17.

Separator water (EPA Method 200.8 for metals except Hg; Method 1631E for Hg): metals analysis was initiated but discontinued after early samples failed to exceed regulatory thresholds, so full separator-water metal distributions are not reported. The report explicitly states “metals analysis was also discontinued because no samples exceeded regulatory thresholds” (page 28). No samples of unfiltered separator water from either platform exceeded federal RCRA or Washington-state metals criteria.

Non-metal findings relevant only as context for the waste-stream framing: Diethylphthalate detected in 13/14 hydrocarbon still bottoms (86–2,200 µg/L); bis(2-ethylhexyl)phthalate in 12/14 (67–18,000 µg/L); bis-2-ethylhexyladipate in 2/7 K4 still bottoms at 30,000–46,000 µg/L. PAHs (benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[j,k]fluoranthene, chrysene) detected at concentrations below Washington-state persistence-criteria thresholds. One hydrocarbon separator water sample (Shop #02) contained 13,000 µg/L trichloroethene (TCE), exceeding federal toxicity-characteristic threshold (D040, DW) and the KCIW industrial-wastewater discharge screening level; the shop reportedly used Picrin (~100% TCE) spot cleaner and the separator unit was visually malfunctioning.

Methods (brief)

Voluntary recruitment of 16 King County alternative-solvent dry cleaners (Nov 2011–July 2012) drawn primarily from existing LHWMP / EnviroStars contacts. Questionnaire administered verbally; product inventory and one-time product sampling of detergents, spot cleaners, and sizing agents. Still bottoms collected at routine machine clean-out (typically once monthly); separator water collected the same day from either an external accumulation container or the in-machine reservoir. Still-bottom analyses used TCLP extraction (EPA Method 1311) followed by EPA Method 8260B (VOCs), 8270D (SVOCs), and 6010B/7470A (metals), with virgin-sample testing for pH (Method 9045C), Extractable Organic Halogens (SW846 9023), flash point (ASTM D-93), and acute static fish toxicity (Washington Ecology Method 80-12 Part A). Separator-water analyses used EPA Method 8260C (VOCs), 8270D (SVOCs), 200.8 (metals except Hg), 1631E (mercury), 9040C (pH), 1664 (non-polar fats/oils/grease), SW846 9020 modified (Total Organic Halogens), ASTM D-93 (flash point), and the same fish bioassay. Method Reporting Limits varied by analyte and sample because the chemical complexity of still bottoms required dilution to protect instruments. Statistical comparisons between platforms used Kaplan-Meier-derived distributions and permutation-based logrank chi-squared tests with p<0.01 significance threshold.

Limitations

• Small sample size (16 shops; only 3 of which used System K4) limits inferences about platform differences and prevents shop-level generalization to the wider King County dry-cleaning population.
• Voluntary recruitment via EnviroStars and prior LHWMP contacts likely biases the sample toward shops with above-average regulatory engagement.
• Metals analysis on separator water was discontinued mid-study, so the report cannot provide the full distribution of Pb, Cd, Cr, or Ba in dry-cleaning separator water at MRL-level resolution.
• TCLP leachate is a regulatory-designation test, not a totals-basis concentration measurement; the report does not provide totals-basis Pb/Cd/Cr/Ba in raw (undiluted) still bottoms.
• One shop (Shop #02) with the only TCE-failing separator water dropped out of follow-up; the operational drivers (malfunctioning separator, residual Picrin) cannot be verified independently.
• MRLs for VOCs/SVOCs in still bottoms were elevated by mandatory dilution; analytes present below MRL could not be quantified.
• The report does not measure metals in the consumer-grade spot cleaners (Picrin, Pull-Out Premium-V, MultiSpot, Spotless) it inventories; product-level metals data is not extractable.

Implications

• Certification: Out of scope for HMT&C product certification — this is industrial-waste characterization of commercial dry-cleaning operations, not a consumer product or food matrix. Useful only as occupational-exposure and environmental-fate context for jurisdictions where dry-cleaning waste streams interact with municipal sewer systems or where fabric finishing chemistry (sizing agents, spot cleaners) overlaps with consumer fabric-contact product chemistry.
• Courses: A worked example of how a state hazardous-waste designation framework (RCRA + Washington dangerous-waste rules) operates in practice, including the TCLP-extract metals panel and the four federal characteristic-waste endpoints. Useful for any course module on industrial-waste regulation as it intersects supply-chain chemistry.
• App: No direct input to ingredient contamination_profile blocks. The TCLP-extract Pb/Cd/Cr/Ba data are not totals-basis measurements on a consumable matrix and should not be pooled with food or personal-care occurrence data.
• Microbiome: Not applicable.

Provenance notes

PDF retrieved through the manual-fetch backlog from a Kimi-agent download attempt for the King County / Public Health Seattle & King County publication LHWMP_0155 (August 2013). US-government work, public-domain, redistributable. The companion file is referenced internally as DryCleanWasteFinal_rev2.docx. No DOI assigned. New matrix terms dry-cleaning-still-bottom and dry-cleaning-separator-water introduced because the matrices vocabulary did not have an industrial waste-stream entry adequate for this source; flag for taxonomy review.

Wiki pages updated on ingest

• lead
• cadmium
• chromium
• barium

Verification notes

• Audit subagent (2026-06-03) flagged tier_rationale incorrectly lumping VOC method numbers as “8260C/8270D”; verified against source Tables 5, 6, 7 (pages 14–15) — still-bottom TCLP VOCs use 8260B, product and separator-water VOCs use 8260C, both still-bottom and other SVOCs use 8270D (with 1311 leach for still bottoms). Corrected tier_rationale to distinguish the two VOC methods. Methods (brief) section was already accurate (8260B for still-bottom VOCs).
• Audit subagent flagged Ba as outside the HMI 10-metal abbreviation set and the two matrix slugs (dry-cleaning-still-bottom, dry-cleaning-separator-water) as new vocabulary. Both are deliberate, consistent with existing sibling source pages that use measured non-core metals (e.g., Cu, Zn, Mn, Co in alkahachi2022-soil-metals-kirkuk-iraq) and explicitly flagged in Provenance notes. No change required; surfacing here for taxonomy-review queue.

Page history

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