This is in response to your inquiry about whether environmental concern is to be had regarding the use of hydrofluoric acid in transportation equipment cleaning, resulting in fluoride concentrations of 50-300 mg/L (ppm) in waste washwaters discharged from cleaning facilities and disposed to natural surface waters or to municipal sewer systems. You indicated that based on contacting over 50 vehicle wash specialists, it appeared no tests have been done within the vehicle wash industry on the fluoride count in the waste stream. Your recent testing in your truck wash in Monee, Illinois indicated fluoride count at about 45 mg/L (ppm) after 5 days of washing and is expected to climb over 300 ppm. Would it be common in the vehicle wash industry, would it be of any concern? The short answer is yes. The following sections briefly summarize the environmental concern, the federal characterization of the transportation equipment cleaning industry wastewater pollutant discharges including fluorides and the resultant federal rules regulating these discharges. ENVIRONMENTAL CONCERNS Fluoride occurs naturally in soils, seawater, freshwater and all foods. Fluoride in soils ranges 76 mg fluoride/kg for sandy soils to 2640 mg/kg for heavy clays. Seawater fluoride levels are usually in the range of 0.86 to 1.4 mg/L. Natural concentrations of fluoride in surface freshwaters are typically less than 1.0 mg/L (0.05-0.14 mg/L in the Great Lakes) to 14 mg/L in some western US waters. Fluoride levels to 50 mg/L may be encountered in some western US groundwaters in contact with fluorosilicic soils. Fluoride is regarded as an essential nutritional element for living organisms, though only very low levels are required. The best-known beneficial effect of low level dietary fluoride is the reduction of the acid solubility of tooth enamel that prevents tooth decay in animals. Fluoridation of public water supplies is common to provide dietary fluoride. Current levels of fluoridation to prevent tooth decay are about 1 mg/L. Conversely, fluoride in water, even in relatively low concentrations, has the potential for noncancerous chronic (low level, long-term, non- fatal) and acute (fatal) toxicity to humans, aquatic life, wildlife, plants, agricultural animals and crops, and may interfere with some industrial and commercial processes. For human health concerns, fluoridosis and tooth mottling can occur at low concentrations of less than 10 mg/L or dosage of 20 mg/kg body weight. Fluoride toxicity in people can start as low as 10 mg/L. Skeletal damage has been observed in children and adults when long-term intake was about 8 mg/L or 20 mg/day. Fluoride toxicity may be worsened if the person being exposed suffers deficiencies in some nutrients or vitamins, such as vitamin C or iodine. It appears that the toxicity is dependent on water hardness (dissolved calcium, magnesium, iron, manganese) content and temperature. There are limited chronic toxicity data for organisms other than humans but it appears that a chronic toxicity level for aquatic life could be less than 100 mg/L, and may be even less than 10 mg/L. Some of the data are summarized below. Acute toxicity to aquatic life appears to be in the low 100s mg/L, although some species may be lower. Some of the LC50 data (concentrations lethal to 50 percent of an exposed population) are presented below. Illustrative Data - Acute toxicity - 96 hr LC50s (Lethal Concentration 50th percentile) Fathead minnow 180-315 mg/L Mosquitofish 418-560 mg/L Stickleback 340-460 mg/L Chronic toxicity - Cladoceran (water fleas) Several studies showed acute and chronic effects from 2.7 mg/L and up. Frog (Rana pipiens) Slowed metamorphosis and growth occurred between 1.0 and 10 mg/L Subchronic toxicity - For an approximate 20 day exposure period rainbow trout sensitivity was at 2.3-8.5 mg/L (but other data were substantially higher, leading to the need for further inquiry). Toxicity information for fluorides is not clear and is potentially contradictory. A full analysis of the literature is needed before specific criteria recommendations could be made for particular circumstances of water use. The US federal government has established uniform nationally applicable water quality criteria and standards for fluoride covering only the public water supply use (2 mg/L). A few governments, for example British Columbia, have derived more extensive water quality guidelines or criteria for fluoride to protect other uses of natural waters in those jurisdictions. British Columbia criteria - aquatic life (hardness dependent): at 50 mg/L hardness, maximum 0.2 mg/L wildlife: 30-day average 1.0 mg/L maximum 1.5 mg/L raw drinking water 30-day average 1.0 mg/L maximum 1.5 mg/L irrigation 30-day average 1.0 mg/L industrial (food services) 30-day average 1.0 mg/L maximum 1.5 mg/L livestock 30-day average 1.0-2.0 mg/L (livestock dependent) maximum 1.5-4.0 mg/L Other Criteria - Manitoba surface water protection 1.0 mg/L Saskatchwan surface water protection 1.5 mg/L Britain salmonid/cyprinid 1.8 mg/L Detailed information websites - USEPA Water Quality Criteria - http://www.epa.gov/waterscience/pc/revcom.pdf http://www.epa.gov/waterscience/drinking/standards/dwstandards.pdf British Columbia Water Quality Criteria - http://wlapwww.gov.bc.ca/wat/wq/BCguidelines/fluoride/index.html *** TRANSPORTATION EQUIPMENT CLEANING INDUSTRY The Federal Water Pollution Control Act Amendments of 1972 established a comprehensive program to restore and maintain the chemical, physical and biological integrity of the Nation's waters. To implement the Act, the USEPA is to issue effluent limitations guidelines, pretreatment standards, and new source performance standards for industrial dischargers that define minimum treatment performance standards reflecting the Best Practicable Control Technology Currently Available, Best Conventional Pollutant Control Technology, Best Available Technology Economically Achievable, New Source Performance Standards and Pretreatment Standards for Existing Sources and New Sources that dispose of wastewaters to municipal sewage collection and treatment systems. The Act and subsequent amendments further require, when these technology based minimums are not sufficient to protect the quality of surface waters needed to support the uses for which the waters are designated, effluent discharge limitations shall be set to protect the water quality values required to support the designated uses. During the period 1992 - 1996, USEPA conducted an extensive series of studies of the transportation equipment cleaning industry serving trucking, rail, barges, and ships for the purpose of establishing technology-based effluent limitations guidelines for this industrial category. Aircraft cleaning was separately studied. An exhaustive search was done to inventory all facilities potentially performing cleaning operations - owners, operators, maintainers - about 30,280. About 7,940 had potential to clean tank/container interiors. Facilities were further characterized by a screening questionnaire in 1993 administered to a statistical sampling of about 3,240 facilities potentially cleaning tank interiors, to characterize facilities' business type, operational structure, size, business production (tank/ container/ hopper types, cargoes, types and numbers of cleanings), pollution prevention and cleaning practices, wastewater generation, treatment technologies and disposal practices. This was followed by a detailed questionnaire administered to a stratified sampling of 275 facilities in 1994, to obtain engineering and cost data. The Agency conducted 44 engineering site visits to select facilities, including 22 in the truck category, followed by 20 sampling episodes, including 7 at selected representative truck cleaning facilities. The sampling episodes yielded quantitative pollutant concentration profiles of the raw wastewater, and treated discharges of the principal subcategories of facilities using a wide range of applicable treatment technologies for more than 200 pollutants, including organic and inorganic, priority and classical pollutants, including fluoride. For truck cleaning facilities, raw wastewater fluoride content measured (mg/L): Subcategory Min Mean Max No. truck/chemical facilities 0.30 21 180 10 truck/petroleum 1.1 1.5 2.0 5 truck/food 0.28 0.57 0.85 2 Mathematical models were employed to estimate the effectiveness of the pollution prevention and wastewater treatments practiced, calculating raw and treated wastewater pollutant loadings at the facilities identified and characterized by the survey questionnaires. Mathematical models also were employed to estimate the effects of the cleaning industry facilities' treated discharges (loadings) on the quality of the surface waters receiving facility discharges, either directly, or indirectly passed through the municipal sewage collection and treatment systems to which the cleaning industry facilities disposed of treated washwaters. Modeling results were verified for a representative sample of industry facilities, including 40 truck-chemical and truck-petroleum facilities discharging 84 pollutants to 34 municipal systems with outfalls on 34 receiving streams, by comparison with the treatment performance measurement records of the municipal systems involved and state and federal surface water quality measurement records. The results indicated that, at the existing discharge levels, instream pollutant concentrations would exceed one or more chronic aquatic life criteria or toxic effects levels used to evaluate environmental effects in 3 percent of the receiving streams (1 of 34 of the verification set, 7 of the total 255 such streams nationally). Water quality criteria for fluoride used in the environmental effects evaluation were not exceeded by the existing discharges of any of the facilities of the verification set. The study concluded that to reduce pollutant loadings discharged by industry facilities sufficiently to eliminate exceedances of the water quality criteria used to evaluate environmental effects, it was reasonable to formulate effluent guideline performance requirements on the basis that existing and new-source truck/chemical and petroleum cleaning facilities discharging directly to surface waters could economically provide both a range of pollution prevention measures and wastewater treatment technology equivalent to equalization; oil/water separation; turnkey treatment including chemical oxidation, neutralization, coagulation and clarification; biological treatment; activated carbon adsorption; and sludge dewatering. Facilities discharging to municipal sewage collection and treatment systems could economically provide all of the same; the biological treatment being provided by the servicing sewage utility. In selecting the specific pollutants to be regulated by technology-based effluent discharge limit rules for the transportation equipment cleaning industry, including the truck subcategories, fluoride was one of several not selected for regulation because they are not present at treatable concentrations or are not likely to cause toxic effects due to their presence in the discharges of the facilities evaluated as representative of the industry. The effluent guidelines studies showed that the best treatment technologies being practiced by the transportation equipment cleaning industry achieved a reduction of wastewater fluoride loadings of the industry facilities evaluated by approximately (only) 10 percent. The facilities in the population studied were not likely to cause toxic effects in the receiving surface waters due to the substantial dilution of fluoride provided by blending of industry discharges with large volumes of low fluoride wastewaters from other users of the municipal sewage collection and treatment systems used or due to mixing with large volumes of low-fluoride natural receiving waters. In the US, If a fluoride-discharging facility such as a transportation equipment cleaning facility may cause receiving surface water concentrations greater than 1-2 mg/L after wastewater treatment, dilution and mixing, because of potential impacts to people and maybe chronic exposures to aquatic life, it is appropriate to consider the need for calculating a site-specific water quality criterion and a discharge-specific, water quality-based effluent limit for this pollutant. Detailed Information websites Transportation industry homepage - http://epa.gov/guide/teci/ Discharge Final Rule 40CFR PART 442 - Federal Register - FR 65(157):49666-49706, August 14,2000 http://www.epa.gov/fedrgstr/EPA-WATER/2000/August/Day-14/w15841.pdf Discharge Regulation Development Documents - USEPA, Final Development Document For Effluent Limitations Guidelines and Standards for the Transportation Equipment Cleaning Category, EPA-821-R-00-012, June 2000, 485 pages pdf format, 4 parts: http://www.epa.gov/ostwater/guide/teci/develop1.pdf http://www.epa.gov/ostwater/guide/teci/develop2.pdf http://www.epa.gov/ostwater/guide/teci/develop3.pdf http://www.epa.gov/ostwater/guide/teci/develop4.pdf Electronic copy (HTML) http://www.epa.gov/clariton/clhtml/pubindex.html http://www.epa.gov/cgi-bin/claritgw?op-Display&document=clserv:OW:0498;&rank=4&template=epa Economic Analysis Document - USEPA, Economic Analysis of Final Effluent Limitations Guidelines and Standards For The Transportation Equipment Cleaning Category, EPA-821-R-00-013, June 2000, 144 pages http://www.epa.gov/waterscience/guide/teci/economics.pdf Environmental Review Document Proposed Rule - USEPA, Environmental Assessment of Proposed Effluent Limitation Guidelines and Standards for the Transportation Equipment Cleaning Category, EPA-821-B-98-015, May 1998, 172 pages Electronic copy (HTML) http://www.epa.gov/clariton/clhtml/pubindex.html http://www.epa.gov/cgi-bin/claritgw?op-Display&document=clserv:OW:0480;&rank=4&template=epa Environmental Review Document Final Rule - USEPA, Environmental Assessment of Proposed Effluent Limitation Guidelines and Standards for the Transportation Equipment Cleaning Category, Final Report, Docket File W-97-25, TECI Final DCN T20575, Section 22 Environmental Assessment, June 15, 2000, 124 pages (Electronic copy not website available) Permit Writing Guide - Technology Based Effluent Limits USEPA, Permit Guidance Document - Transportation Equipment Cleaning Point Source Category (40CFR442), EPA-821-R-01-021, March 2001, 75 pages http://www.epa.gov/waterscience/guide/teci/tecguid.pdf Water Quality Based Effluent Limits - USEPA, Technical Support Document For Water Quality-based Toxics Control, EPA/505/2-90-001, March 1991, 336 pages http://www.epa.gov/clariton/clhtml/pubindex.html http://www.epa.gov/cgi-bin/claritgw?op-Display&document=clserv:OSWER:0038;rank=4&template=epa Please contact me if questions arise. Stephen Poloncsik NPDES Programs Branch USEPA Region 5 77 West Jackson Bouevard Chicago IL 60604 312.886.0261 (voice) 312.886.0168 (fax)