2-methoxyethanol

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: A well reported published study containing key information to judge it as reliable.

Data source

Reference

Reference Type:

publication

Title:

A cross sectional study of ethylene glycol monomethyl ether process employees

Author:

Cook RR, Bodner KM, Kolesar RC et al

Year:

1982

Bibliographic source:

Arch Env Health, 37 (6), p346-51

Materials and methods

Study type:

cross sectional study

Endpoint addressed:

toxicity to reproduction / fertility

immunotoxicity

Test material

Test material information

Constituent 1

Reference substance name:

2-methoxyethanol

EC Number:

203-713-7

EC Name:

2-methoxyethanol

Cas Number:

109-86-4

Molecular formula:

C3H8O2

IUPAC Name:

2-methoxyethanol

Constituent 2

Reference substance name:

2037137

IUPAC Name:

2037137

Details on test material:

- Other: Dow Chemicals, Michigan commercial production quality product

Method

Type of population:

general

occupational

Ethical approval:

not specified

Details on study design:

METHOD OF DATA COLLECTION
- Type: Primarily clinical tests

STUDY PERIOD: No data but after 1976 and before 1982.


SETTING: Glycol ethers production plant, Dow Chemicals, Midland, Michigan, USA.


STUDY POPULATION
- Total population (Total no. of persons in cohort from which the subjects were drawn): Total exposed population was those recorded as employees working for the glycol ethers business in production or distribution. 53 eligible for study.
- Selection criteria: Those with incomplete data profiles eliminated or preexisting medical conditions
- Total number of subjects participating in study: 40 actually examined in study group
- Sex/age/race: white males
- Smoker/nonsmoker: mixed
- Total number of subjects at end of study:
- Matching criteria:
- Other: Of the 40 in study group, 17 showed no sperm, 10 were vasectomised, 4 were medically excluded and 3 showed incomplete fertility indices. Complete fertility indices only therefore available for 6 exposed workers.


COMPARISON POPULATION
- Type: Control or reference group
- Details: Workers from alkanolamine and salicylates plant on same site. Those with previous potential exposure to methoxyethanol eliminated. 25 actually used in control group. Of these, 7 showed no sperm, 7 were vasectomised, 1 was medically excluded and 1 had prior exposure to another known reprotoxin. Complete fertility indices only therefore available for 9 controls..


HEALTH EFFECTS STUDIED
- Disease(s): Infertility
- Other health effects: Parameters assessed: testicular size, complete haematology, semen analysis (collected after 3 days abstinence and analysed within 3hrs of collection.)

Exposure assessment:

measured

Details on exposure:

TYPE OF EXPOSURE: Inhalation


TYPE OF EXPOSURE MEASUREMENT: Area air sampling / Personal sampling

Statistical methods:

On way analysis of variance. Influences of duration of exposure by linear regression

Results and discussion

Results:

EXPOSURE
Exposure measurements in early 1976 showed plant exposures of 0.42ppm (8hr TWA. Personal monitoring of plant mechanics in late 1976 showed measurements below detection limits In July 1980 personal monitoring in the packaging area showed measurements of 5.4-8.5ppm (2hr TWA). Wearing of gloves was recommended practice


FINDINGS
There were no significant differences in clinical abnormalities between controls and exposed cases and no anaemia or leucopenia. There were no reported differnces in ability to conceive. The unadjusted means and percentage differnces for the haemaological and fertility parameters also showed no significant differences, although testes width showed a 10% reduction in exposed males which was close to statistical significance (p=0.08). Results of using linear regression to model the effect of exposure to increased concentration of methoxyethanol showed a highly significant correlation with reduced WBC but increased sperm count. Similar modeling to account for exposure duration showed a tendency towards macrocytosis and perhaps decreased testicular size, although the former may be age related.

Confounding factors:

Following factors taken into account to minimize confounding: recent ejaculation (3 day abstinence), race, previous diseases or conditions with potential to influence fertility (hydrocele, variocele, mumps, infertility due to employment or previous chemical exposure. Also smoking (categories of smoker, never smoked and other assessed). There was a positive correlation between one physician and a tendency to measure lower testicular size. This specific physician measured more exposed than control workers.

Strengths and weaknesses:

Limited number of cases. Slight differences in smoking and age distributions between exposed groups and controls. Inherent weaknesses of study design (selection bias and inability to delineat the temporal relationship between exposure and response.)

Applicant's summary and conclusion

Conclusions:

No gross abnormalities nor clinically meaningful differences in haematology nor fertility indices were noted. The study did highlight that WBC, haemoglobin and FSH would be good biological markers to monitor for evidence of potential adverse effects following human exposure.

Executive summary:

In a cross–sectional study of workers exposed to methoxyethanol during the manufacturing and packaging operations in the early 1980’s, no gross abnormalities or meaningful differences were noted in haematogical or fertility parameters.  Exposures ranged from approximately 0.5-2ppm (8hr TWA).  The number of subjects examined in the study was relatively small however.