Rachel Carson, 1940
Fish & Wildlife Service employee photo, Public Domain

Rachael Carson’s 1962 book, Silent Spring, was the catalyst that resulted in the eventual ban of DDT, which is a persistent insecticide with adverse effects on the environment.  However Rachael Carson did not solely focus on the impact of DDT on birds in this seminal work.  Much of the discussion in Silent Spring details personal stories, tales, and narratives of farmers, fishermen, and townspeople and their exposure to a number of different pesticides.  In nearly all cases, exposure to these pesticides led to their acute illness and untimely death.

Today, there are a number synthetic chemicals that have been banned due to their adverse interaction with biological organisms.  Some areas in the United States have been saturated so thoroughly with legacy pollutants that they have been designated a Superfund site.   “Superfund” is a federal program with the aim to clean up the nation’s uncontrolled hazardous waste sites in order to protect the environment and the health of it’s people.

However, United States policy still operates on an “innocent until proven guilt” system, which leaves the burden of proving the safety of chemicals primarily on the public.  As a result, we are still experiencing a flourishing chemical industry that releases a number of under-researched products; one of which may be the next DDT.

Columbus Skyline from the Scioto River Julian Rosario, 2008

A quick internet search on “pesticides” reveals a number of current concerns.   Ian Simpson’s Scientific American article, Pesticides a Concern for Aquatic Life in Most U.S. Urban Streams, describes the “potentially worrisome levels of [agricultural] pesticides for aquatic life” in 90% of United States urban streams.  While the concern for aquatic species is readily apparent, Simpson also describes how people are exposed to agricultural chemicals through “drinking water and other means”.   This article is of particular relevance here at The Ohio State University, where the drinking water source for Columbus, Ohio originates from the Scioto River watershed.  This massive watershed, which also contains the Olentangey River, the Big Walnut Creek and the Alum Creek drainage basins, experiences intense agricultural activity within its boundaries.  (Learn more about Columbus, Ohio’s drinking water.)

In addition to surface water contamination, pesticides have also received criticism when used in wide spread applications.  Last month, an NPR broadcast told of an all too familiar story of blanket pesticide use in Florida.   In this story, the target organism of the chemical pesticide were mosquitoes, the same target as DDT.  Blanket applications of pesticides have long been known to negatively impact populations of non-target species and, in Florida, are thought to have been the cause for two butterfly species being placed on the engendered species list.  The “innocent until proven guilty” mentality allows critics to hold tight to the argument of “lack of causal evidence” and claim that blanket pesticide use is necessary to protect citizens from mosquito-borne disease.  

Listen to the NPR story “Pesticides Used On Florida’s Mosquitoes May Harm Butterflies”.

This situation should remind us of social traps like the sliding reinforcer which states that blanket applications select for individuals who are immune to the chemical.  The blanket application results in an obsolete chemical where the pest population is unaffected by the product.  Rachael Carson knew this social trap well.  In Silent Spring, she quotes the advice given by the director of Holland’s Plant Protection Service: “Practical advice should be ‘Spray as little as you possibly can’ rather than ‘Spray to the limit of your capacity’ … Pressure on the pest population should always be as slight as possible.”

Although the use of every chemical has its pros and cons, use always carries a level of risk.  It is up to the people to decide how much risk we are willing to take.