How Green is Your Lawn- The Use of Pesticides

From the beginning of recorded time humans have utilized pesticides to protect their crops and food stores. Humans tried many substances as pesticides; toxic chemicals were tried in the 1600’s. Arsenic, mercury and lead were applied to crops to kill pests; the fact that these substances also killed larger animals including humans resulted in their abandonment for use as pesticides. One of the results of chemical development during World War II was the widespread manufacture and use of pesticides after the war. With the use of pesticides and herbicides to control unwanted pests came dramatic changes in agriculture and the agricultural business model and increasing crop yields in excess of 10%. Pesticides including herbicides and insecticides are used to control harmful and annoying organisms. They can be used to protect from diseases carried by mosquitoes or parasites. Herbicides can be used to kill invasive weeds in gardens, parks and public spaces, to clear roadside weeds, trees and brush. They are also used to prevent algae from taking over ponds and pools. Pesticides are used to control termites and mould that can damage buildings and homes. Pesticides are used in grocery stores and food storage facilities to prevent mice and insects that infest food such as grain. Much of our very clean and sanitary American life is the result of pesticide use. Each use of a pesticide carries some associated risk and controlled and limited use of these pesticides is believed to reduce the risks to a level deemed acceptable by the US EPA.

DDT became the most widely used pesticide in the world in the 1950’s. It’s potential to do harm was not fully recognized until, the 1960’s when it was identified as the cause of diminished populations of eagles, hawks, gulls and other birds. DDT use was banned. The recent reemergence of support by the World Health Organization for the use of DDT to prevent malaria is an example of the questions raised by pesticide use. The WHO argued that used sparingly DDT was the most effective method to control the spread of malaria and that saving human lives from malaria was more important than potential impact to lesser species. DDT’s potential as an endocrine disruptor was not full appreciated at that time and it has recently been implicated in increased incidence of breast cancer in women exposed before or at puberty in the California study. The wide spread use of herbicides and their potential presence in water resource was also ignored. The fate and transport model for understanding chemicals added to the environment has not always been fully appreciated. However, by the 1980’s alachlor, atrazine, cyanazine and metolachlor (all common corn and soybean herbicides) were being detected in surface water and near surface groundwater. The US EPA began to restrict use of these herbicides, too, and they were phased out over the next decade.

A new generation of herbicides was developed during the phase out period encouraged by the US EPA. The newer herbicides were applied at much lower levels, broke down more quickly in the environment and were less toxic to animals. Applying ounces of herbicides per acre that broke down in days rather than pounds of chemicals that persisted for weeks or months was a victory to the US EPA. These new herbicides were based on sulfonylurea an imidazolinone. The lower concentrations of the new herbicides and their breakdown products rendered them virtually invisible in water. We could not detect them and assumed they were not present. Now it seems that the degradation products of these new herbicides are far more persistent in the environment that originally believed or hoped.

Recent studies have documented endocrine disruption in a wide variety of marine gastropods, frogs, and fish associated with exposure to low levels of non specific endocrine disrupting chemicals of unknown sources. The current state of analysis only allowed the documentation of EDC presence. EDCs are a structurally diverse group that includes natural and synthetic estrogens, alkyl phenols surfactants, phthalates, bisphenol A, brominated flame retardants and some pesticides. Studies in recent years have documented a wide occurrence of endocrine disrupting compounds (EDCs) throughout aquatic ecosystems. This could indicate non-point sources of contamination from run off or an additive effect, which may have serious implications for US water quality. Suspect EDCs are used in large quantities by consumers and industry. Domestic and industrial wastewater and agricultural run-off are believed to be the major sources of EDCs today. The impacts of trace concentrations of EDC on wildlife do beg the question about the potential effects on humans. Drinking water is not tested for minute quantities of endocrine disrupting chemicals; we simply do not have the knowledge of what to look for nor the technical ability to identify all the trace contaminants of that nature.

In April of 2009 the US EPA issued the Final List of Initial Pesticide Active Ingredients and Pesticide Inert Ingredients to be Screened Under the Federal Food, Drug, and Cosmetic Act as potential endocrine disruptors. Pesticide runoff is a large contributor of known pollutants to the watershed. Maybe we should be re-examining the risks associated with what is now known as conventional agricultural practices, and embrace (at the very least) the best management practices for controlling environmental release of agricultural chemicals and waste. Several Provinces in Canada are in the process of banning the use of herbicides for ornamental lawn use.

The Second Age of Water Regulation

In the Index of Leading Environmental Indicators, 14th Edition, April 2009, Stephen Hayward highlights the short falls in the way we have been monitoring water quality in the United States. The National Water Quality Inventory Report to Congress (305(b) report) had been the primary vehicle for informing Congress and the public about general water quality conditions in the United States. In the past, this document characterized water quality based on differing local monitoring efforts. The Report was intended to identify widespread water quality problems of national significance, and describes various programs implemented to restore and protect our waters. This had served as a proxy for the quality of the waters of the nation. However, the methods states use to monitor and assess their waters and report their findings varied from state to state and even over time. Many states target their limited monitoring resources to waters they suspect are impaired and, therefore, assess only a small percentage of their waters. These may not reflect conditions in state waters as a whole. States often monitor a different set of waters from cycle to cycle.

Hundreds of organizations around the country conduct some type of water quality monitoring within the states. These include federal agencies such as the US EPA and the U.S. Geological Survey. They also include state, interstate, tribal and local water quality agencies; research organizations such as universities; industries and sewage and water treatment plants; and citizen volunteer programs. These diverse groups may collect water quality data for various purposes utilizing various levels of testing and targeting specific pollutants. The cost of water quality testing is determined by the number of pollutants tested for and at what level of detection. So, resources were used to target suspected contaminants. The final reports rendered to the US EPA were so inconsistent in their region by region scope as to be meaningless in their ability to measure water quality across the nation or to identify what has emerged as the newest concerns about water quality.

Large fish kills in the late 1990’s began a renewed process of discovery to identify the cause. Researchers from the U.S. Geological Survey observed intersex in bass species collected from the Potomac River and its tributaries in West Virginia, Maryland, and Washington DC, and also quantified endocrine disrupting chemicals, EDCs, in their blood. Though extensive water testing was done, the actual source or sources of EDC was not identified. These recent studies by the US Geological Survey and Fish and Wildlife have prompted the US EPA to change its monitoring and assessment guidance to the states in an attempt to generate a more useful report of the quality of the nation’s water.

Suspect or known endocrine disrupting chemicals are associated with industrial releases; widely used by the general public every day in homes, on farms, by businesses and industry. There are the natural occurring EDC that are part of the ecosystem. Some EDCs can be released directly to the environment after passing through wastewater treatment processes, which are typically not designed to remove low levels of these kinds of pollutants from the effluent. The problem is compounded by the fact that wastewater treatment effluent is released to rivers that are used for drinking water and in some locations like California water treatment effluent is directly mixed with drinking water supplies. In addition, sludge from secondary treatment processes are land-applied providing a route for EDCs to leach or run off into nearby bodies of water. Through either waste water treatment plant effluent or run off endocrine-disrupting chemicals, including synthetic estrogens and androgens, naturally occurring estrogens, as well as many others capable of modulating normal hormonal functions and steroidal synthesis in fish and possibly other animals find their way into rivers and streams. So far studies of septic systems have not found these substances being released to the groundwater in the areas studied. However this research has just begun and only a very limited number of groundwater studies have been performed looking for EDCs.

The occurrence of intersex fish in the Potomac River, and in other areas of the US resulted in Congressional hearings in the fall or 2006 to inquire about the “State of the Science on EDCs in the Environment,” as well as the US EPA’s activities associated with EDCs. The hearings resulted in a White Paper; “AQUATIC LIFE CRITERIA FOR CONTAMINANTS OF EMERGING CONCERN” The next step of this work was the release in April of 2009 by the US EPA of the Final List of Initial Pesticide Active Ingredients and Pesticide Inert Ingredients to be screened under the Federal Food, Drug, and Cosmetic Act as potential endocrine disruptors. The US EPA began with the Clean Water Act. This is a new era of discovery of pollutants of concern. Though the work has just begun, the second age of water regulation has arrived.