Charlie Bedwell discusses the use of pesticides in agriculture; could they be to blame for mass ecosystem disruptions?
Pesticides have successfully assisted with the growth of food, ensuring that there is enough yield to provide for an expanding population, for over 150 years. So why are we now introducing bans and having global discussions about their continued use?
Unfortunately, the worldwide use of pesticides has had some unforeseen effects on the environment and wildlife within it. The US geological survey found that 90% of the major rivers were contaminated with pesticides. Even more staggering is their presence in all rivers with mixed agricultural and urban land and 99% of subsequent streams. Recently, this effect has been seen on an individual as well as corporate level with lawn care pesticides making their way into water systems. This makes the use of pesticides a critical issue to discuss due to their ever-increasing presence in our waters.
By applying chemicals to plant life, we are changing the way that plants grow, threatening species that we did not intend to reduce, and leaving hazardous chemicals in the earth that react unexpectedly with the world around them. Scientists now believe we are in the sixth major extinction period and the use of pesticides is partially responsible for this.
Animals are exposed to pesticides directly and indirectly. Whilst pesticides may aim to target only a single species, that does not mean other animals don’t attempt to eat the crops too. A single-target pesticide may result in the inadvertent deaths of many other species. Even if animals are not directly exposed to the pesticides, they are still not safe from its effects. Pesticides can enter groundwater and fresh water sources when heavy irrigation or rainfall carries the chemicals into streams and rivers in a process known as ‘run off’. This affects terrestrial wildlife using the local water source and the aquatic ecosystems of the polluted waterbodies.
Recent findings suggest that more than 1,800 species of sea creature face extinction as a result of pesticides. One frequently used component of pesticides contributing to this statistic is glyphosate. It has been causing second-hand death in fish and sea creatures, slowly disrupting ecosystems. The chemical causes erratic swimming and laboured breathing; increasing the fishes’ chance of being eaten. Mammals and birds that eat these fish are also affected; such as the dolphins of China and Pakistan which are fast approaching extinction as a result of this.
The effects of pesticide use are not limited to water corruption. One of the first animal groups to be affected by pesticides were amphibians. 1998 saw huge reductions in amphibian populations, which were linked to the growth of a particular type of fungus. However, population declines still showed a strong correlation with pesticide exposure and scientists grew concerned about the effects of pesticides on animals’ immune systems. This concern was then confirmed in 2006 when bat populations started to decline as a result of white-nose syndrome, a disease that their immune systems could no longer combat.
The recent plunge in bee population was again partially a result of pesticide use. Due to the efforts of campaigners across the world, we are starting to see an increase in bee numbers as they are being kept away from farming and the pesticides they would previously have been exposed to. Public opinion does influence action, so this gives us hope for the future. Unfortunately, the damage extends far beyond a single species; there has been a 60% decline in mammal, fish, amphibian, bird and reptile populations and a further 220,000 human deaths as a result of pesticide poisoning. This means a big effort on all our parts is needed to allow humanity and the natural world to co-exist.
The challenge that we face is how to protect our crops without damaging the environment around us. Even with the use of pesticides, we lose 37% of our crops to animal feeding so imagine how much we might lose without them. A larger loss of crop means more farmland to achieve the same amount of food and that will come at the cost of animal habitats.
American Extension Educator in Agronomy, Jeff Graybill, discusses the process all pesticides must go through before being put on the market. He states that every pesticide will experience 10 or more years of safety tests before being released for public use and also notes the EPA (environmental protection agency) reviews that take place every 10-15 years. The recent banning of Chlorothalonil highlights to us how important these reviews are. After further testing scientists couldn’t rule out the potential damage to DNA and it was found to be highly toxic to fish and amphibians. So, if our pesticides are tested, reviewed and withdrawn when necessary – what seems to be the problem?
Numerous studies are continuing to demonstrate the damaging effects of pesticides in our environment. People and animals are losing their lives, soils are being rendered useless and our water is being contaminated. These statistics tell us that there have been unforeseen effects of pesticides in our environment and recently, some scientists have begun to act on this. The way that plants grow is being manipulated to make them more pest-resistant and the introduction of “pest management systems” (introducing species that feed on another species) suggests that things are improving. But there’s still a lot of work to do. We need to continue to fund research that aims to reduce the use of toxic pesticides and in the meantime; consider where we are buying our food. Organic food cannot use synthetic pesticides and so researching local food shops that grow this is a good place to start. Always check the label and shop around to get the most for your money. Organic food will always be a little more expensive, so be smart about how you cook. Make sure multiple meals use the same ingredients and nothing goes to waste!
About the Author: Charlie Bedwell is a recent Psychology graduate from the University of Reading.