IUPAC name: 1,2,3-Trichloropropane
CAS Number: 96-18-4
EC Number: 202-486-1
Chemical formula: C3H5Cl3
Molar mass: 147.43 g
1,2,3-Trichloropropane (TCP) is an organic compound with the formula CHCl(CH2Cl)2.
1,2,3-Trichloropropane is a colorless liquid that is used as a solvent and in other specialty applications.
1,2,3-Trichloropropane is produced the addition of chlorine to allyl chloride.
1,2,3-Trichloropropane also may be produced as a by-product also is produced in significant quantities as an unwanted by-product of the production of other chlorinated compounds such as epichlorohydrin and dichloropropene.
Historically, 1,2,3-Trichloropropane has been used as a paint or varnish remover, a cleaning and degreasing agent, and an solvent.
1,2,3-Trichloropropane is also used as an intermediate in the production of hexafluoropropylene.
1,2,3-Trichloropropane is a crosslinking agent for polysulfide polymers and sealants.
Effects of exposure
Humans can be exposed to 1,2,3-Trichloropropane by inhaling its fumes or through skin contact and ingestion.
1,2,3-Trichloropropane is recognized in California as a human carcinogen, and extensive animal studies have shown that it causes cancer.
Short term exposure to 1,2,3-Trichloropropane can cause throat and eye irritation and can affect muscle coordination and concentration.
Long term exposure can affect body weight and kidney function.
Proposed federal regulation
As of 2013 1,2,3-Trichloropropane was not regulated as a contaminant by the federal government, but research shows that it could have severe health effects; only the state of California had significant regulation of this compound.
In a drinking water project proposed by the United States Environmental Protection Agency (EPA), 1,2,3-Trichloropropane was one of sixteen suspected human carcinogens being considered for regulation in 2011.
Pre-1980s, agricultural use of chloropropane-containing soil fumigants for use as pesticides and nematicides was prevalent in the United States.
Some soil fumigants, which contained a mixture of primarily 1,3-dichloropropene and 1,2-dichloropropane, and in which 1,2,3-1,2,3-Trichloropropane was a minor component, e.g., trade name of D-D, were marketed for the cultivation of various crops including citrus fruits, pineapples, soy beans, cotton, tomatoes, and potatoes.
D-D was first marketed in 1943, but is no longer available in the United States, and has been replaced with Telone II, which was first available in 1956.
Telone II reportedly contains as much as 99 percent 1,3-dichloropropene and up to 0.17 percent by weight 1,2,3-1,2,3-Trichloropropane.
Before 1978, approximately 55 million pounds/year of 1,3-dichloropropene were produced annually in the United States, and approximately 20 million pounds/year of 1,2-dichloropropane and 1,2,3-1,2,3-Trichloropropane were produced as by-products in the production of 1,3-dichloropropene.
Over 2 million pounds of pesticides containing 1,3-dichloropropene were used in California alone in 1978.
Telone II is still used for vegetables, field crops, fruit and nut trees, grapes, nursery crops, and cotton.
The California State Water Resources Control Board's Division of Drinking Water established an enforceable Maximum Contaminant Level (MCL) of 5 ng/L (parts per trillion).
The state of Alaska has promulgated standards establishing cleanup levels for 1,2,3-Trichloropropane contamination in soils and groundwater.
The state of California considers 1,2,3-Trichloropropane to be a regulated contaminant that must be monitored.
The state of Colorado has also promulgated a groundwater standard although there is no drinking water standard.
Although there is not much regulation on this substance, it has proved that 1,2,3-Trichloropropane is a carcinogen in laboratory mice, and most likely a human carcinogen as well.
On a federal scale, there is no MCL for this contaminant.
The Permissible Exposure Limit (PEL) in occupational setting for air is 50 ppm or 300 mg/m3. The concentration in air at which 1,2,3-Trichloropropane becomes an Immediate Danger to Life and Health (IDLH) is at 100 ppm. These regulations were reviewed in 2009.
1,2,3-Trichloropropane as an emerging contaminant.
1,2,3-Trichloropropane does not contaminate soil.
Instead, it leaks down into groundwater and settles at the bottom of the reservoir because 1,2,3-Trichloropropane is more dense than water.
This makes 1,2,3-Trichloropropane in its pure form a DNAPL (Dense Nonaqueous Phase Liquid) and it is, therefore, harder to remove it from groundwater.
There is no evidence that 1,2,3-Trichloropropane can naturally decompose, but it might in favorable conditions.
Groundwater remediation of 1,2,3-Trichloropropane can occur through in situ chemical oxidation, permeable reactive barriers, and other remediation techniques.
Several 1,2,3-Trichloropropane remediation strategies have been studied and/or applied with varying degrees of success.
These include extraction with granular activated carbon, in situ chemical oxidation, and in situ chemical reduction.
Recent studies suggest that reduction with zerovalent metals, particularly zerovalent zinc, may be particularly effective in 1,2,3-Trichloropropane remediation.
Bioremediation may also be a promising clean-up technique
Appearance: colorless or straw yellow transparent liquid
Melting point: −14 °C
Boiling point: 156.85 °C
Solubility in water: 1,750 mg/L
log P: 2.27
Vapor pressure: 3 mmHg
Flash point: 71 °C
Explosive limits: 3.2%-12.6%
XLogP3: 1.8 Computed by XLogP3 3.0
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 0
Rotatable Bond Count: 2
Exact Mass: 145.945683
Monoisotopic Mass: 145.945683
Topological Polar Surface Area: 0 Å²
Heavy Atom Count: 6
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
About of 1,2,3-Trichloropropane
1,2,3-Trichloropropane is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 1 000 to < 10 000 tonnes per annum.
1,2,3-Trichloropropane is used at industrial sites and in manufacturing.
Uses at industrial sites of 1,2,3-Trichloropropane
1,2,3-Trichloropropane has an industrial use resulting in manufacture of another substance (use of intermediates).
1,2,3-Trichloropropane is used for the manufacture of: chemicals, rubber products and plastic products.
Release to the environment of this substance can occur from industrial use: as an intermediate step in further manufacturing of another substance (use of intermediates) and for thermoplastic manufacture.
Manufacture of 1,2,3-Trichloropropane
Release to the environment of 1,2,3-Trichloropropane can occur from industrial use: manufacturing of the substance.
1,2,3-Trichloropropane is a synthetic, colorless to light yellow liquid that is soluble in polar organic solvents and only slightly soluble in water.
1,2,3-Trichloropropane is used as both a chemical intermediate and cross-linking agent in the production of polymers.
1,2,3-Trichloropropane is flammable and, when heated to decomposition, emits toxic fumes of hydrogen chloride.
Exposure of humans to 1,2,3-trichloropropane vapor causes irritation of the eyes and throat. 1,2,3-Trichloropropane is reasonably anticipated to be a human carcinogen.
1,2,3-Trichloropropane is a synthetic chemical that is also known as allyl trichloride, glycerol trichlorohydrin, and trichlorohydrin.
1,2,3-Trichloropropane is a colorless, heavy liquid with a sweet but strong odor.
1,2,3-Trichloropropane evaporates very quickly and small amounts dissolve in water.
1,2,3-Trichloropropane is mainly used to make other chemicals.
1,2,3-Trichloropropane is also used as an industrial solvent, paint and varnish remover, and cleaning and degreasing agent.
Very little information is available on the amounts manufactured and the specific uses.
1,2,3-Trichloropropane is a chlorinated hydrocarbon with high chemical stability.
Synonyms include allyl trichloride, glycerol trichlorohydrin and trichlorohydrin.
1,2,3-Trichloropropane is exclusively a man-made chemical, typically found at industrial or hazardous waste sites.
1,2,3-Trichloropropane has been used as an industrial solvent and as a cleaning and degreasing agent; it has been found as an impurity resulting from the production of soil fumigants.
1,2,3-Trichloropropane is currently used as a chemical intermediate in the production of
other chemicals (including polysulfone liquid polymers and dichloropropene), and in the synthesis of hexafluoropropylene.
In addition, 1,2,3-Trichloropropane is used as a crosslinking agent in the production of polysulfides.
1,2,3-Trichloropropane is not likely to sorb to soil based on its low soil organic carbonwater partition coefficient; therefore, it is likely to either leach from soil into groundwater or evaporate from soil surfaces.
1,2,3-Trichloropropane is a chlorinated hydrocarbon with high chemical stability.
1,2,3-Trichloropropane is a manmade chemical found at industrial or hazardous waste sites.
1,2,3-Trichloropropane has been used as a cleaning and degreasing solvent and also is associated with pesticide products.
1,2,3-Trichloropropane causes cancer in laboratory animals.
1,2,3-Trichloropropane is reasonably anticipated to be a human carcinogen, and probably carcinogenic to humans, based on sufficient evidence of carcinogenicity in experimental animals.
In 1992, 1,2,3-Trichloropropane was added to the list of chemicals known to the state to cause cancer, pursuant to California's Safe Drinking Water and Toxic Enforcement Act.
In 1999, we established a 0.005-micrograms per liter (μg/L) drinking water notification level for 1,2,3-Trichloropropane (1,2,3-TCP).
This value is based on cancer risks derived from laboratory animals studies.
The notification level is at the same concentration as the analytical reporting limit, as described below.
Certain requirements and recommendations apply if 1,2,3-Trichloropropane is detected above its notification level.
The 1,2,3-Trichloropropane notification level was established after its discovery at the Burbank Operable Unit (OU) — a southern California Superfund hazardous waste site because of concerns that the chemical might find its way into drinking water supplies.
1,2,3-Trichloropropane had been found in several drinking water wells elsewhere in the state at that time.
Subsequently 1,2,3-Trichloropropane was found in more drinking water sources
In 2001, to obtain information about the presence of 1,2,3-Trichloropropane in drinking water sources, we adopted a regulation that included it as an unregulated contaminant for which monitoring is required (UCMR).
Given the number of sources with detections of 1,2,3-Trichloropropane under the UCMR sampling, the Drinking Water Program considered this chemical to be a good candidate for future regulation.
Thus, in July 2004 we requested a public health goal (PHG) from the Office of Environmental Health Hazard Assessment.
1,2,3-Trichloropropane (TCP) is a chlorinated hydrocarbon that was historically used as an industrial solvent and a degreasing agent. TCP is utilized as an intermediate in the production of polymer cross-linking agents, pesticides, and glycerol.
In 1,2,3-Trichloropropane's pure form, 1,2,3-Trichloropropane is a colorless to yellow liquid with limited solubility in water, a strong chloroform-like odor, moderate volatility, and high flammability.
In the agrochemical industry, 1,2,3-Trichloropropane is formed via the manufacture of dichloropropene-derived nematicides (pesticides used to kill parasitic nematodes), and it is also present as an impurity in these soil fumigants.
As a result, application of these products has produced significant atmosphere, soil, and groundwater contamination, which in turn can induce various health problems in wildlife and humans.
The toxicological effects of TCP depend on dose and duration, but can range from kidney and liver damage to tumors and cancers.
1,2,3-Trichloropropane (TCP) is a chlorinated volatile organic compound (CVOC) that has been used in chemical production processes, in agriculture, and as a solvent, resulting in point and non-point source contamination of soil and groundwater.
1,2,3-Trichloropropane is mobile and highly persistent in soil and groundwater.
1,2,3-Trichloropropane is not currently regulated at the national level in the United States, but maximum contaminant levels (MCLs) have been developed by some states.
Current treatment methods for 1,2,3-Trichloropropane are limited and can be cost prohibitive. However, some treatment approaches, particularly in situ chemical reduction (ISCR) with zero valent zinc (ZVZ) and in situ bioremediation (ISB), have recently been shown to have potential as practical remedies for TCP contamination of groundwater.
1,2,3-Trichloropropane (TCP) (Figure 1) is a man-made chemical that was used in the past primarily as a solvent and extractive agent, as a paint and varnish remover, and as a cleaning and degreasing agent.
Currently, 1,2,3-Trichloropropane is primarily used in chemical synthesis of compounds such as polysulfone liquid polymers used in the aerospace and automotive industries; hexafluoropropylene used in the agricultural, electronic, and pharmaceutical industries; polysulfide polymers used as sealants in manufacturing and construction; and 1,3-dichloropropene used in agriculture as a soil fumigant.
1,2,3-Trichloropropane may also be present in products containing these chemicals as an impurity.
For example, the 1,2-dichlropropane/1,3-dichloropropene soil fumigant mixture (trade name D-D), which is no longer sold in the United States, contained 1,2,3-Trichloropropane as an impurity and has been linked to TCP contamination in groundwater.
Soil fumigants currently in use which are composed primarily of 1,3-dichloropropene may also contain TCP as an impurity, for instance Telone II has been reported to contain up to 0.17 percent 1,2,3-Trichloropropane by weight.
1,2,3-Trichloropropane contamination is problematic because it is “reasonably anticipated to be a human carcinogen” based on evidence of carcinogenicity to animals.
Toxicity to humans appears to be high relative to other chlorinated solvents, suggesting that even low-level exposure to 1,2,3-Trichloropropane could pose a significant human health risk.
1,2,3-Trichloropropane’s fate in the environment is governed by its physical and chemical properties.
1,2,3-Trichloropropane does not adsorb strongly to soil, making it likely to leach into groundwater and exhibit high mobility.
In addition, 1,2,3-Trichloropropane is moderately volatile and can partition from surface water and moist soil into the atmosphere. Because 1,2,3-Trichloropropane is only slightly soluble and denser than water, it can form a dense non-aqueous phase liquid (DNAPL) as observed at the Tyson’s Dump Superfund Site.
1,2,3-Trichloropropane is generally resistant to aerobic biodegradation, hydrolysis, oxidation, and reduction under naturally occurring conditions making it persistent in the environment.
1,2,3-Trichloropropane has been detected in approximately 1% of public water supply and domestic well samples tested by the United States Geological Survey.
More specifically, 1,2,3-Trichloropropane was detected in 1.2% of public supply well samples collected between 1993 and 2007 by Toccalino et al and 0.66% of domestic supply well samples collected between 1991 and 2004 by DeSimone.
1,2,3-Trichloropropane was detected at a higher rate in domestic supply well samples associated with agricultural land-use studies than samples associated with studies comparing primary aquifers (3.5% versus 0.2%).
The United States Environmental Protection Agency (USEPA) has not established an MCL for 1,2,3-Trichloropropane, although guidelines and health standards are in place.
1,2,3-Trichloropropane was included in the Contaminant Candidate List 3 and the Unregulated Contaminant Monitoring Rule 3.
The UCMR 3 specified that data be collected on 1,2,3-Trichloropropane occurrence in public water systems over the period of January 2013 through December 2015 against a reference concentration range of 0.0004 to 0.04 μg/L.
The reference concentration range was determined based on a cancer risk of 10-6 to 10-4 and derived from an oral slope factor of 30 mg/kg-day, which was determined by the EPA’s Integrated Risk Information System.
Of 36,848 samples collected during UCMR 3, 0.67% exceeded the minimum reporting level of 0.03 µg/L.
1.4% of public water systems had at least one detection over the minimum reporting level, corresponding to 2.5% of the population.
While these occurrence percentages are relatively low, the minimum reporting level of 0.03 µg/L is more than 75 times the USEPA-calculated Health Reference Level of 0.0004 µg/L.
Because of this, 1,2,3-Trichloropropane may occur in public water systems at concentrations that exceed the Health Reference Level but are below the minimum reporting level used during UCMR 3 data collection.
These analytical limitations and lack of lower-level occurrence data have prevented the USEPA from making a preliminary regulatory determination for 1,2,3-Trichloropropane.
Potential 1,2,3-Trichloropropane degradation pathways include hydrolysis, oxidation, and reduction.
These pathways are expected to be similar overall for abiotic and biotic reactions, but the rates of the reactions (and their resulting significance for remediation) depend on natural and engineered conditions.
The rate of hydrolysis of 1,2,3-Trichloropropane is negligible under typical ambient pH and temperature conditions but is favorable at high pH and/or temperature.
For example, ammonia gas can be used to raise soil pH and stimulate alkaline hydrolysis of chlorinated propanes including 1,2,3-Trichloropropane.
Thermal Conduction Heating (TCH) may also produce favorable conditions for 1,2,3-Trichloropropane hydrolysis.
Compared to more frequently encountered CVOCs such as trichloroethene (TCE) and tetrachloroethene (PCE), 1,2,3-Trichloropropane is relatively recalcitrant.
1,2,3-Trichloropropane is generally resistant to hydrolysis, bioremediation, oxidation, and reduction under natural conditions.
The moderate volatility of 1,2,3-Trichloropropane makes air stripping, air sparging, and soil vapor extraction (SVE) less effective compared to other VOCs.
Despite these challenges, both ex situ and in situ treatment technologies exist.
Ex situ treatment processes are relatively well established and understood but can be cost prohibitive.
In situ treatment methods are comparatively limited and less-well developed, though promising field-scale demonstrations of some in situ treatment technologies have been conducted.
Ex Situ Treatment
The most common ex situ treatment technology for groundwater contaminated with 1,2,3-Trichloropropane is groundwater extraction and treatment.
Extraction of 1,2,3-Trichloropropane is generally effective given its relatively high solubility in water and low degree of partitioning to soil.
After extraction, 1,2,3-Trichloropropane is typically removed by adsorption to granular activated carbon.
TCP contamination in drinking water sources is typically treated using granular activated carbon.
In California, GAC is considered the best available technology (BAT) for treating 1,2,3-Trichloropropane, and as of 2017 seven full-scale treatment facilities were using GAC to treat groundwater contaminated with 1,2,3-Trichloropropane.
Additionally, GAC has been used for over 30 years to treat 60 million gallons per day of 1,2,3-Trichloropropane-contaminated groundwater in Hawaii.
GAC has a low to moderate adsorption capacity for 1,2,3-Trichloropropane, which can necessitate larger treatment systems and result in higher treatment costs relative to other organic contaminants.
Published Freundlich adsorption isotherm parameters indicate that less 1,2,3-Trichloropropane mass is adsorbed per gram of carbon compared to other volatile organic compounds (VOCs), resulting in increased carbon usage rate and treatment cost. Recent bench-scale studies indicate that subbituminous coal-based GAC and coconut shell-based GAC are the most effective types of GAC for treatment of TCP in groundwater.
To develop more economical and effective treatment approaches, further treatability studies with site groundwater (e.g., rapid small-scale column tests) may be needed.
In Situ Treatment
In situ treatment of 1,2,3-Trichloropropane to concentrations below current regulatory or advisory levels is difficult to achieve in both natural and engineered systems.
However, several in situ treatment technologies have demonstrated promise for 1,2,3-Trichloropropane remediation, including chemical reduction by zero-valent metals (ZVMs), chemical oxidation with strong oxidizers, and anaerobic bioremediation.
In Situ Chemical Reduction (ISCR)
Reduction of 1,2,3-Trichloropropane under conditions relevant to natural attenuation has been observed to be negligible.
Achieving significant degradation rates of TCP requires the addition of a chemical reductant to the contaminated zone.
Under reducing environmental conditions, some ZVMs have demonstrated the ability to reduce 1,2,3-Trichloropropane all the way to propene.
As shown in Figure 2, the desirable pathway for reduction of TCP is the formation of 3-chloro-1-propene (also known as allyl chloride) via dihaloelimination, which is then rapidly reduced to propene through hydrogenolysis.
ZVMs including granular zero-valent iron (ZVI), nano ZVI, palladized nano ZVI, and zero-valent zinc (ZVZ) have been evaluated by researchers.
ZVI is a common reductant used for ISCR and, depending on the form used, has shown variable levels of success for 1,2,3-Trichloropropane treatment.
The Strategic Environmental Research and Development Program (SERDP) Project ER-1457 measured the 1,2,3-Trichloropropane degradation rates for various forms of ZVI and ZVZ. Nano-scale ZVI and palladized ZVI increased the TCP reduction rate over that of natural attenuation, but the reaction is not anticipated to be fast enough to be useful in typical remediation applications.
Commercial-grade zerovalent zinc (ZVZ) on the other hand is a strong reductant that reduces 1,2,3-Trichloropropane relatively quickly under a range of laboratory and field conditions to produce propene without significant accumulation of intermediates.
Of the ZVMs tested as part of SERDP Project ER-1457, ZVZ had the fastest degradation rates for 1,2,3-Trichloropropane.
In bench-scale studies, 1,2,3-Trichloropropane was reduced by ZVZ to propene with 3-chloro-1-propene as the only detectable chlorinated intermediate, which was short-lived and detected only at trace concentrations.
Navy Environmental Sustainability Development to Integration (NESDI) Project 434 conducted bench-scale testing which demonstrated that commercially available ZVZ was effective for treating 1,2,3-Trichloropropane.
Additionally, this project evaluated field-scale ZVZ column treatment of groundwater impacted with 1,2,3-Trichloropropane at Marine Corps Base Camp Pendleton (MCBCP) in Oceanside, California.
This study reported reductions of TCP concentrations by up to 95% which was maintained for at least twelve weeks with influent concentrations ranging from 3.5 to 10 µg/L, without any significant secondary water quality impacts detected.
Following the column study, a 2014 pilot study at MCBCP evaluated direct injection of ZVZ with subsequent monitoring. Direct injection of ZVZ was reportedly effective for TCP treatment, with TCP reductions ranging from 90% to 99% in the injection area. Concentration reduction downgradient of the injection area ranged from 50 to 80%.
1,2,3-Trichloropropane concentrations have continued to decrease, and reducing conditions have been maintained in the aquifer since injection, demonstrating the long-term efficacy of ZVZ for TCP reduction.
Potential in situ applications of ZVZ include direct injection, as demonstrated by the MCBCP pilot study, and permeable reactive barriers (PRBs).
Additionally, ZVZ could potentially be deployed in an ex situ flow-through reactor, but the economic feasibility of this approach would depend in part on the permeability of the aquifer and in part on the cost of the reactor volumes of ZVZ media necessary for complete treatment.
In Situ Chemical Oxidation (ISCO)
Chemical oxidation of 1,2,3-Trichloropropane with mild oxidants such as permanganate or ozone is ineffective.
However, stronger oxidants (e.g. activated peroxide and persulfate) can effectively treat 1,2,3-Trichloropropane, although the rates are slower than observed for most other organic contaminants.
Fenton-like chemistry (i.e., Fe(II) activated hydrogen peroxide) has been shown to degrade 1,2,3-Trichloropropane in the laboratory with half-lives ranging from 5 to 10 hours, but field-scale demonstrations of this process have not been reported.
Treatment of 1,2,3-Trichloropropane with heat-activated or base-activated persulfate is effective but secondary water quality impacts from high sulfate may be a concern at some locations.
No naturally occurring microorganisms have been identified that degrade 1,2,3-Trichloropropane under aerobic conditions.
Relatively slow aerobic cometabolism by the ammonia oxidizing bacterium Nitrosomonas europaea and other populations has been reported, and genetic engineering has been used to develop organisms capable of utilizing 1,2,3-Trichloropropane as a sole carbon source under aerobic conditions.
Like other CVOCs, 1,2,3-Trichloropropane has been shown to undergo biodegradation under anaerobic conditions via reductive dechlorination by Dehalogenimonas (Dhg) species.
However, the kinetics are slower than for other CVOCs.
Bioaugmentation cultures containing Dehalogenimonas (KB-1 Plus, SiREM) are commercially available and have been implemented for remediation of 1,2,3-Trichloropropane-contaminated groundwater.
One laboratory study examined the effect of pH on biotransformation of 1,2,3-Trichloropropane over a wide range of 1,2,3-Trichloropropane concentrations (10 to 10,000 µg/L) and demonstrated that successful reduction occurred from a pH of 5 to 9, though optimal conditions were from pH 7 to 9.
As with other microbial cultures capable of reductive dechlorination, coordinated amendment with a fermentable organic substrate (e.g. lactate or vegetable oil), also known as biostimulation, creates reducing conditions in the aquifer and provides a source of hydrogen which is required as the primary electron donor for reductive dechlorination.
A 2016 field demonstration of in situ bioremediation (ISB) was performed in California’s Central Valley at a former agricultural chemical site with relatively low 1,2,3-Trichloropropane concentrations (2 µg/L).
The site was first biostimulated by injecting amendments of emulsified vegetable oil (EVO) and lactate, which was followed by bioaugmentation with a microbial consortium containing Dhg.
After an initial lag period of six months, 1,2,3-Trichloropropane concentrations decreased to below laboratory detection limits
The 2016 field demonstration was expanded to full-scale treatment in 2018 with biostimulation and bioaugmentation occurring over several months.
The initial 1,2,3-Trichloropropane concentration in performance monitoring wells ranged from 0.008 to 1.7 µg/L.
As with the field demonstration, a lag period of approximately 6 to 8 months was observed before 1,2,3-Trichloropropane was degraded, after which concentrations declined over fifteen months to non-detectable levels (less than 0.005 µg/L).
1,2,3-Trichloropropane degradation was associated with increases in Dhg population and propene concentration. Long term monitoring showed that 1,2,3-Trichloropropane remained at non-detectable levels for at least three years following treatment implementation.
Treatment Comparisons and Considerations
When selecting a technology for TCP treatment, considerations include technical feasibility, ability to treat to regulated levels, potential secondary water quality impacts and relative costs.
The relatively high toxicity of 1,2,3-Trichloropropane has led to the development of health-based drinking water concentration values that are very low.
1,2,3-Trichloropropane is sometimes present in groundwater and in public water systems at concentrations that exceed these health based goals.
While a handful of states have established MCLs for 1,2,3-Trichloropropane, US federal regulatory determination is hindered by the lack of low concentration occurrence data.
Because 1,2,3-Trichloropropane is persistent in groundwater and resistant to typical remediation methods (or costly to treat), specialized strategies may be needed to meet drinking water based treatment goals.
In situ chemical reduction (ISCR) with zero valent zinc (ZVZ) and in situ bioremediation have been demonstrated to be effective for 1,2,3-Trichloropropane remediation.
1,2,3-Trichloropropane (TCP) is a man-made chemical commonly used as an industrial solvent (for oil, fats, waxes, and resins), a degreasing agent, a paint and varnish remover, and to manufacture other chemicals.
Additionally, 1,2,3-Trichloropropane was an impurity in dichloropropane- and dichloropropene- containing soil fumigants used as pesticides and nematocides until the late 1980’s.
Some of these soil fumigants, which contained a small amount of 1,2,3-Trichloropropane, were used in growing citrus fruits, pineapples, soy beans,
tomatoes and potatoes.
1,2,3-Trichloropropane is stable in the environment and has been detected in public water systems, private wells, and in ground water in New Jersey and other states.
Large public water systems in the U.S. and a subset of smaller water systems were required to test for 1,2,3-Trichloropropane as part of the U.S. Environmental Protection Agency’s Unregulated Contaminant Monitoring Rule (UCMR) program in 2013-2015.
In New Jersey, 2 of the 174 (1.2%) water systems that tested as part of the UCMR program detected 1,2,3-Trichloropropane greater than 0.03 µg/L.
1,2,3-Trichloropropane was also detected in several additional NJ public water systems prior to the 2013-2015 UCMR monitoring – these water systems have taken measures to stop exposures.
1,2,3-Trichloropropane is a colorless or straw-colored chemical compound which is slightly soluble in water and produced by the chlorination of propylene or the addition of chlorine to certain organic and inorganic compounds.
1,2,3-Trichloropropane is a man-made pollutant that can be found at industrial and hazardous waste sites.
According to findings by the EPA, Trichloropropane originated as an impurity in soil fumigants manufactured by prominent American chemical industries in the 1980s.
These fumigants were used to prevent parasitic organisms from affecting crop yield in the Great Central Valley of California.
However, the chemical leached through the soil into groundwater and eventually contaminated public water supplies.
Since then, there have been reports of cancer-related deaths in states where 1,2,3-Trichloropropane was found in public water supplies.
Historically, 1,2,3-Trichloropropane chemical was used as an industrial solvent, a cleaning/degreasing agent, and as an intermediate for producing other chemical compounds.
Nowadays, 1,2,3-Trichloropropane is a prohibited substance due to significant health hazards in humans after being discovered in large concentrations in public water supplies.
1,2,3-Trichloropropane is a significant groundwater pollutant which is ‘likely to be carcinogenic’ at a certain dosage according to the EPA.
As a result, many states have recognized it as a harmful pollutant and begun to develop local regulations to eliminate the chemical from their public supplies.
1,2,3-Trichloropropane is harmful to humans when inhaled, contacted, or ingested.
An acute (instantaneous) exposure to 1,2,3-Trichloropropane is known to irritate the throat and eyes and impair muscle coordination and memory, while chronic exposure may cause certain types of cancer and kidney failure.
1,2,3-Trichloropropane, also known as TCP, is an organic chemical found in some groundwater supplies.
In July 2017, the State Water Resources Control Board approved the maximum contaminant level (MCL) for 1,2,3-Trichloropropane of 5 parts per trillion (ppt), and compliance monitoring began in January 2018.
1,2,3-Trichloropropane has been detected in some of the groundwater supplies in our Bakersfield, Visalia, Selma, Stockton, South San Francisco, and Chico service areas.
Protecting our customers’ health and safety is our highest priority, and we had been actively monitoring our groundwater supplies and designing potential treatment methods in anticipation of a regulation, so that we could more quickly and efficiently meet any new MCL ultimately set. We have completed construction of treatment facilities that will ensure our water supplies comply with the new MCL, and water serving your system continues to meet or surpass all federal and state water quality standards.
1,2,3-Trichloropropane (TCP) is a persistent groundwater pollutant and a suspected human carcinogen.
1,2,3-Trichloropropane is also is an industrial chemical waste that has been formed in large amounts during epichlorohydrin manufacture.
In view of the spread of 1,2,3-Trichloropropane via groundwater and its toxicity, there is a need for cheap and efficient technologies for the cleanup of TCP-contaminated sites.
In situ or on-site bioremediation of 1,2,3-Trichloropropane is an option if biodegradation can be achieved and stimulated.
This paper presents an overview of methods for the remediation of 1,2,3-Trichloropropane-contaminated water with an emphasis on the possibilities of biodegradation.
Although 1,2,3-Trichloropropane is a xenobiotic chlorinated compound of high chemical stability, a number of abiotic and biotic conversions have been demonstrated, including abiotic oxidative conversion in the presence of a strong oxidant and reductive conversion by zero-valent zinc.
Biotransformations that have been observed include reductive dechlorination, monooxygenase-mediated cometabolism, and enzymatic hydrolysis.
No natural organisms are known that can use 1,2,3-Trichloropropane as a carbon source for growth under aerobic conditions, but anaerobically 1,2,3-Trichloropropane may serve as electron acceptor.
The application of biodegradation is hindered by low degradation rates and incomplete mineralization.
Protein engineering and genetic modification can be used to obtain microorganisms with enhanced 1,2,3-Trichloropropane degradation potential.