Q.Chlorinated pesticides such as DDT are described as 'persistent' pollutants. Explain what this means chemically, and describe how persistence leads to bioaccumulation and biomagnification as the pesticide moves up a food chain.

Chlorinated pesticides such as DDT are called 'persistent' because the carbon-chlorine bonds in their structure resist the normal microbial and chemical breakdown pathways that degrade most organic matter in soil and water -- instead of disappearing over weeks or months, they can remain chemically intact for years or decades. This persistence is what drives bioaccumulation: because DDT is fat-soluble and not readily excreted, an organism exposed to it accumulates it in its fatty tissue faster than its body can eliminate it, so the concentration inside the organism steadily rises above the (much lower) concentration in the surrounding soil or water. When a predator eats many such contaminated organisms, it accumulates their combined pesticide burden, and this effect compounds at each successive step up a food chain -- a process called biomagnification. As a result, a top predator c …

Explain the three terms as a causal chain in order -- persistence enables bioaccumulation, which in turn compounds into biomagnificat …

Using 'bioaccumulation' and 'biomagnification' interchangeably -- one describes buildup within a single organism, the other describes …