Encyclopedia of Environmental Science and Engineering, Volume I and II

TOXICOLOGY 1153

TABLE 1

Some common references on environmental and occupational toxicology

Klaassen CD (1996), Casarett and Doulls Toxicology:

the basic science of poisons

An excellent reference on toxicology, although generally written at the

graduate level.

ACGIH® (2004), TLV’s and BEI’s Threshold limit values (TLVs) and biological exposure indices (BEIs) values,

which provide the upper exposure limit for many chemicals.

Hathaway et al. (1991), Proctor and Hughes’ chemical hazards of

the workplace

Provides information on many chemicals—including regulatory exposure

limits and basic information on the chemical.

OSHA (29 CFR 1910. 1000) Permissible exposure limits (PELs), which are the maximum exposure limit

set by the U.S. government.

NIOSH Criteria Documents Information on a specific chemical as provided by NIOSH. However, these

reports are not updates and some that are older will not have the most

up-to-date information.

Niesink et al. (1995), Toxicology: principles and applications General toxicology reference that focuses on the occupational environment.

Lippmann (1992), Environmental toxicants: human exposures and their

health effects

Provides information through chapters on specific topics that relate to both

environmental and occupational toxicology.

Rand and Petrocelli (1985), Fundamentals of aquatic

toxicology: methods and applications

A good basic textbook on aquatic toxicology.

NIOSH (1994), NIOSH pocket guide to hazardous chemicals Provides exposure values, physical properties, and keywords on health

hazards for many chemicals of industrial interest.

ACGIH ® —American Conference of Governmental Industrial Hygienists

OSHA—U.S. Occupational Safety and Health Administration

NIOSH—National Institute for Occupational Safety and Health (an example of these documents is NIOSH, Criteria for recommended standard

occupational exposure to hydrogen fluoride, Department of Health and Human Services (DHHS) (NIOSH) Pub Nos. 76–141)

the same organism. This is illustrated by the chemical copper

for Strongylocentrotus purpuratus using the endpoint EC 50 ,

which is the median effective concentration (where 50% of

the organisms are affected at a given period of time). ED 50 is

the median exposure dose,^ which is the concentration in air

or water. The other commonly used endpoint of measure for

industrial (occupational) toxicology is the median lethal dose

(LD 50 ; again, this is a value where 50% of the organisms die at

the given concentration, assuming that the mean and median

values are equal, as in a normal curve, although used in more

studies to refer to the median concentration). Obviously the

LD 50 is not useful in setting occupational-exposure limits, but

provides a relative comparison for different chemicals. Similar

in nature to the LD 50 is the EC 50. Here the concentration has

to be in some unit of air or liquid (water) for the endpoint

to be measured. The variability for a chemical as related to

effective endpoints (dose) can be illustrated using copper in

aquatic organisms (Table 3). The LD 50 of copper for the vari-

ous organisms listed have a large variation (log order). This

variation is commonly observed when evaluating a chemi-

cal among different organisms and even the same organism

between laboratories.

A toxic response can be reported as any endpoint mea-

surement that is reproducible. This can include death, as rep-

resented by an LD 50 or another, such as a behavior endpoint

measurement, which could be an EC 50. When evaluating

TABLE 2

Some areas of toxicology

Environmental Concerned with effects on the environment, which can

be considered pollution. This can be further divided

into air, soil, and water systems. There can also be a

measurement on a species as well.

Forensic The occurrence of toxic effects on people and possibly

other organisms, such as livestock, that is in relation

to a crime.

Occupational Effects of chemicals or substances on those in the

working environment and industry.

Regulatory Effects of chemicals (may also be drugs) in regard to

the risk associated with the purposes or in some

cases prevention of that chemical’s use. This is

often associated with some regulation or law, like

the U.S. Clean Air Act (CAA).

Mechanistic Evaluates a chemical’s mechanism of action and how

this action causes a toxic effect on the organism.

TABLE 3

Aquatic toxicology values of various organisms for copper

Organism LD 50 Reference

Mesocyclops peheiensis 75 g/l Wong and Pak, 2004

Tilapia zillii 6.1 mg/l Zyadah and Abdel-

Baky, 2000

Mysis sp. (from Nile River) 2.89 mg/1 Zyadah and Abdel-

Baky, 2000

Mugil cephalus 5.3 mg/1 Zyadah and Abdel-

Baky, 2000

Photobacterium phosphoreum 100 mg/1 Thomulka

et al., 1993

Strongylocentrotus purpuratus 15.3 g/1 Phillips

et al., 2003

Penaes merguiensis 0.38 mg/1 Ahsanullah and Ying,

1995

^ An EC 50.

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