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Whole Effluent Toxicity (WET) Testing Services

Analytical + Environmental / Whole Effluent Toxicity Testing

Pace® WET Testing Services

Pace® offers comprehensive Whole Effluent Toxicity (WET) testing services to help our customers evaluate the potential impact of industrial and municipal effluents on aquatic ecosystems. With a team of experienced professionals and a network of state-of-the-art testing laboratories, Pace® provides defensible results for regulatory compliance and in support of sustainable business practices across a wide range of industries. The primary types of WET Testing services offered include:

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What Is Whole Effluent Toxicity (WET) Testing?

Whole Effluent Toxicity or WET Testing is a critical component of environmental management and industrial risk mitigation as it analyzes the aquatic toxicity of wastewater effluent. WET Testing is often required for National Pollutant Discharge Elimination System (NPDES) permitting. A WET test can be used to determine whether effluent may have an adverse impact on aquatic life (vegetation, vertebrates, and invertebrates) or to evaluate the effectiveness of biological treatment processes.

Types Of WET Testing

Pace® offers aquatic toxicity testing in accordance with EPA standards. If you are unsure which type of test your project requires, reach out to us. Our aquatic toxicology experts would be glad to help.
Acute WET Testing

Acute WET Testing measures mortality by exposing living aquatic organisms to various concentrations of wastewater sample, usually from a facility’s effluent stream. Test duration for Acute WET Testing usually ranges from 24 to 96 hours. Acute WET Testing may also be referred to by terms such as "24-hour LC50" or “96-hour LC50.” LC50 refers to the test concentration that is lethal to 50 percent of the test organisms after the specified period.

Chronic WET Testing

Chronic WET Testing measures the long-term effects of exposure to pollutants by observing the response of test species over a longer period, usually spanning several generations or life cycles. Chronic WET Testing also includes sublethal endpoints, which can detect the effects of pollutants on growth or reproduction of test species.

Toxicity Identification Evaluation (TIE)

Toxicity Identification Evaluations are undertaken to characterize and identify toxic constituents in an effluent when bioassay data reveal persistent toxicity. The TIE Phase I Toxicity characterization tests characterize the physical/chemical properties of the effluent toxicants using effluent manipulations and accompanying toxicity tests.

Chemical And Pure Product Testing

Chemical and Pure Product Testing assesses the potential adverse effects caused by chemicals or pure products on aquatic organisms. These tests involve exposing selected groups of organisms to varying concentrations of an aqueous solution of the chemical or pure product to determine if lethal or sub-lethal effects are observed. Chemical and Pure Product Testing can also be used to establish a concentration-response relationship, which relates the endpoint measured in the test (e.g., mortality, growth, reproduction) to the concentration of the chemical or pure product.

Pace® Supports Your Environmental Project Needs

Pace® provides end-to-end support for a wide range of aquatic toxicity projects that call for WET Testing, such as:
Toxicity Reduction Evaluations (TRE)
NPDES Permitting
Stormwater Runoff
Reverse Osmosis Reject Water Toxicity Testing
LC50, IC25, And Noec Determinations
ION Imbalance Evaluation
Toxicity Reduction Evaluations (TRE)

Pace® WET Testing services can be used to identify the type and concentration of contaminants in water to verify the effectiveness of toxicity reduction efforts.

NPDES Permitting

NPDES permits are used to monitor and manage the discharge of toxic pollutants in wastewater, and NPDES permitting may include WET Testing requirements.

Stormwater Runoff

Stormwater runoff is another type of wastewater discharge that may be covered by NPDES permitting requirements.

Reverse Osmosis Reject Water Toxicity Testing

The reject stream from the reverse osmosis water purification process often contains concentrated contaminants. WET Testing can help safeguard aquatic ecosystems and human health.

LC50, IC25, And Noec Determinations

LC50 is the lethal concentration of a pollutant that kills 50% of test organisms. IC25 causes a 25% reduction in biological function. NOEC is the highest concentration causing no observable adverse effects.

ION Imbalance Evaluation

An Ion Imbalance Evaluation is used to determine the imbalance in the concentration of different ions in a body of water. Ion imbalance can be caused by a range of factors, such as wastewater discharges, agricultural runoff, and mining activities.

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Pace® Simplifies The Entire Lifecycle Of Your Project

Pace® offers a variety of services to support our customers’ aquatic toxicology programs as well as compliance with NPDES permitting and other regulatory programs. In addition to WET Testing services, we can also help with:

Additional Resources

Need to find a lab that can handle your unique requirements?
Contact us directly or download our list of environmental certifications across our network.