TOXICITY

Alachlor has been evaluated for carcinogenic activity in rats and mice. In accordance with the 1996 EPA proposed Guidelines for Carcinogen Risk Assessment, alachlor was classified as “likely” to be a human carcinogen at high doses, but “not likely” at low doses. Based on numerous studies submitted by the registrant that were reviewed by Agency scientists, as well as an external peer review panel, it was agreed that a margin of exposure (MOE) approach (indicative of a non-linear dose-response) should be used for the risk assessment.
The scientific validity of the MOE approach has been documented by various review panels, such as the FIFRA Scientific Advisory Panel, and the Cancer Review Committee. However, the policy implications, methodology, and appropriateness of using a MOE approach in regulatory decision-making have not yet been fully developed by the Agency. Perhaps, the most critical of the decision criteria to develop are those for determining the appropriate regulatory level. While informed by science, this determination is ultimately a risk management decision. Once this methodology has been developed, then the available chemical-specific data would be used to determine whether or not the MOEs identified in the risk assessment constitute acceptable risks.

ASSAY PRINCIPLES

The Alachlor Plate Kit uses polyclonal antibodies that bind both Alachlor and an Alachlor-enzyme conjugate. Alachlor in the sample competes with Alachlor-enzyme conjugate for a limited number of antibody binding sites. Antibodies, which bind Alachlor compounds, are immobilized to the inside of the test wells. In the assay procedure, you will:

•Add a sample containing Alachlor to a test well, followed by Alachlor-enzyme conjugate. The conjugate competes with any Alachlor in the sample for the same antibody binding sites.
•Wash away any unbound molecules, after you incubate this mixture for 60 minutes.
•Add clear substrate solution to each well. In the presence of bound Alachlor-enzyme conjugate, the substrate is converted to a blue compound. One enzyme molecule can convert many substrate molecules.

Since the same number of antibody binding sites are available in every well, and each well receives the same number of Alachlor-enzyme conjugate molecules, a sample containing a low concentration of Alachlor allows the antibody to bind many Alachlor-enzyme conjugate molecules. The result is a dark blue solution.
Conversely, a high concentration of Alachlor allows fewer Alachlor-enzyme conjugate molecules to be bound by the antibodies, resulting in a lighter blue solution.

NOTE: Color is inversely proportional to Alachlor concentration.
Darker color = Lower concentration
Lighter color = Higher concentration