Pesticides are hazardous, they are designed to repel, kill, or otherwise disrupt the lifecycle of living organisms. Pesticides can be toxic and even poisonous. These are all true statements, but a hazard, by itself, is not necessarily a problem. A hazard cannot be changed – something is either toxic or not – but what can be altered is the amount of “contact” or “exposure” someone or something has with that hazard. Hazard + Exposure = Risk, and risk management is what pesticide registration, labels, PPE, and overall pesticide safety is all about. In this series we will discuss some of the parts of pesticide risk, primarily pesticide exposure. To get started we will explore Pesticide exposure: What are the types of toxicity and symptoms?
There three words that are typically associated with pesticide exposure are, acute, sub-chronic, and chronic. However, these words are used to describe actual exposure AND symptoms, which can make things more confusing. A symptom is describing the observed impacts of an exposure and the duration of those impacts. Describing the exposure is more about the quantity of contact with the pesticide and how long that exposure occurred. We will discuss both symptoms in general and exposure for each of these definitions.
These exposures and symptoms are short-lived, single events, that are of sufficient severity to be “noticed”. Acute symptoms show up rapidly after exposure, (hours or days later), and are often considered “more severe”. Acute exposure is short-term, high quantity, contact with a pesticide that is “noticeable”. As an example, let’s look at an acute exposure to something we are familiar with, the sun. An acute exposure to the sun might be: “I was at the beach all day and got a terrible sunburn”. The exposure was short, definable, and the symptoms came on quickly and were noticed. You can tell a story about that “exposure “and the same applies to pesticides. That might be “I was loading into our spray tank, and pesticide splashed in my eyes and burned”. Short, definable, noticeable.
These exposures and symptoms will last longer than acute, but not are permanent. Sub-chronic might be noticed, but more likely not, and are sporadic in nature. The symptoms may take days, weeks, or longer to show up and can last for a considerable amount of time. However, the symptoms begin to subside after exposure is stopped. This does not mean an immediate reversal, but the symptoms can’t be permanent. This exposure is of lower quantity than acute, but not continual and on-going like our last exposure we will discuss. Staying with the sun analogy, a sub-chronic exposure might be the summer tan one gets after spending significant time outside during that time of year. You slowly notice the impacts, are aware you might be exposed, but not how much. Additionally, a tan will fade if sun exposure stops, demonstrating that this exposure/symptom is not permanent. A pesticide example could be the drift of fine spray particles into your face over the course of a full day that causes a headache, or eye irritation. You didn’t notice the exposure and if you aren’t being re-exposed the symptoms will subside.
These exposures and symptoms can be permanent, are rarely noticed, and occur over a very lengthy period. Chronic symptoms can take months or even years to be noticed and the impacts are typically permanent. The exposure quantity is usually very small, unnoticeable, and sustained for a prolonged period, typically years. For the sun example this would be skin cancer resulting after years and years of sun exposure with no protection. This does NOT ever require an acute exposure like a sun burn but was caused by continuous “low dose” exposure over years. For pesticides it is possible for cancer to be the outcome of chronic exposure, but more common is sensitization. This is basically an allergic reaction that builds up in the body after repeated low dose exposures.
This gives us a basis for understanding some of the types of exposure and the overall types of impacts that can happen when working with pesticides. Sometimes the exposure can be obvious and severe (acute) or unnoticed and take years to develop (chronic). Yes, pesticides are hazardous, but they only pose a risk when exposure is added in. Hazard + Exposure = Risk. To better manage risk, we must understand exposure. This blog covered Pesticide Exposure: What are the types of toxicity and symptoms? Stay tuned for part 2 of the series next week where we begin to look at types of exposure and how to mitigate the effects.