What Does it Mean When a Substance is Said to Bioaccumulate?

Small doses of the drug are repeatedly administered to experimental animals. When the time interval and dose of the drug causes the rate or total amount of the drug to enter the body exceeds the body's metabolic conversion speed and excretion capacity, the drug is gradually increased and stored in the body. This phenomenon is called accumulation of drugs, and the toxic effect caused by this phenomenon is called accumulation of toxic effects. Accumulation is closely related to the size of the dose and the interval between drug administrations. When the dose of the drug is larger and the interval is shorter, more drugs will exhibit the accumulation effect; on the contrary, the dose is smaller and the interval is longer, and the accumulation effect is generally less likely to occur. Accumulation contains two connotations, material accumulation and functional accu-mulation. The former refers to the phenomenon that the mother of the drug or its metabolites exists in the body or some tissues and organs by chemical analysis after the drug is repeatedly administered to the animal for a certain period of time. The latter refers to the fact that the mother of the drug cannot be detected in the body. Or its metabolites, but with chronic poisoning. ^[1]

Small doses of the drug are repeatedly administered to experimental animals. When the time interval and dose of the drug causes the rate or total amount of the drug to enter the body exceeds the body's metabolic conversion speed and excretion capacity, the drug is gradually increased and stored in the body. This phenomenon is called accumulation of drugs, and the toxic effect caused by this phenomenon is called accumulation of toxic effects. Accumulation is closely related to the size of the dose and the interval between drug administrations. When the dose of the drug is larger and the interval is shorter, more drugs will exhibit the accumulation effect; on the contrary, the dose is smaller and the interval is longer, and the accumulation effect is generally less likely to occur. Accumulation contains two connotations, namely, material accumulation and functional accu-mulation. The former refers to the phenomenon that the mother of the drug or its metabolites exists in the body or some tissues and organs by chemical analysis after the drug is repeatedly administered to the animal for a certain period of time. The latter refers to the fact that the mother of the drug cannot be detected in the body. Or its metabolites, but with chronic poisoning. ^[1]

Chinese name

Accumulated toxicity

Foreign name

Accumulated toxicity

English

accumulative toxicity

It can be divided into

Functional accumulation and material accumulation

Introduction to accumulated toxicity

Refers to the functional or structural damage caused by repeated exposure or poisoning of chemical substances when excretion is greater than excretion or toxic effects accumulate multiple times.

Generally can be divided into functional accumulation and material accumulation. The former refers to the toxicant accumulates gradually with its dose, activity intensity, and the number of exposures, resulting in adaptation or poisoning; the latter refers to the toxicant's repeated exposure to the toxicant in tissues and organs. If the poisoning interval () of a substance is less than the biological half-life (T1 / 2), the smaller the / T1 / 2 ratio, the faster its accumulation appears. For example, the biological half-life of two or three is very long. , It can accumulate in the body and cause harm.

Accumulated toxicity refers to the toxic effects of certain foreign compounds that are repeatedly exposed to doses below the acute poisoning threshold after a certain period of time. Bioaccumulation (physical accumulation and functional accumulation) of foreign compounds is the basis of accumulated toxicity. Accumulated toxicity tests can be used to initially assess the accumulated toxicity of foreign compounds, mainly by conducting studies of subchronic toxicity and chronic toxicity and toxic band dynamics to clarify accumulated toxicity.

Accumulated toxicity evaluation method

There are two types of methods for the detection of accumulated toxicity, one is the physical and chemical method, and the other is the biological method. The physicochemical method is the process of measuring the change in the content of the poison after it enters the body by chemical analysis or isotope technology. This method can determine the half-life of the poison, so it can detect the accumulation of substances. The biological method is to compare the effects of multiple exposures with one exposure, so it cannot be distinguished between material accumulation and functional accumulation. Biological method is divided into accumulation coefficient method and residual rate method. The accumulation coefficient method is commonly used in actual work, and this section focuses on it.

The accumulation coefficient method is a method that uses the biological effect as an index and uses the accumulation coefficient to evaluate the accumulation effect. The basic principle of this method is that the test animal is administered daily with a test substance below a lethal dose for a certain period of time until a certain expected toxic effect occurs. Calculate the cumulative dose that achieves this effect, and find the ratio of this cumulative dose to the dose that produces the same effect in a single exposure to the chemical substance. This ratio is the accumulation coefficient K. ^[2]