This map application depicts the five counties where soil contamination may exist from agricultural practices (lead arsenate pesticides) in former orchard lands. When available, this map shows soil sampling and soil replacement records at the property level. To locate property specific soil sampling information, please enter an address into the address search box.
The orange areas on this map represent the footprint of former orchards in Benton, Chelan, Douglas, Klickitat, Okanogan, and Yakima counties. These counties represent the largest historical use of lead arsenate pesticide application, based on crop acreage. The orchard footprint areas are based on properties that appeared to contain orchard trees in aerial photographs from the 1940’s and 1950’s. To locate information about a specific property, please enter an address into the address search box.
The historic orchards (shown in orange) show the general pattern of lead and arsenic contamination from pesticides legally applied to apple and pear orchards between 1900 and 1950. Orchards that have been planted since 1950 are not included in this map, nor are they subject to contamination from lead and arsenic.
Land use has changed over time and some historic orchards identified in this map may now be in residential or commercial use. Soil testing conducted by the Department of Ecology and other private companies has shown a strong correlation between the historic orchards shown on these maps and contamination with lead and arsenic. However, not all historic orchards grew apples or pears, and not all applied lead arsenate pesticide.
If your property is identified as an historic orchard on this map, it may or may not be contaminated. Please contact the Department of Ecology for free testing of your property.
In the late 1800s, widespread infestations of codling moth were rapidly destroying crops. It burrowed into the fruit, causing it to rot. To control the infestations, lead and arsenic were combined to form lead arsenate and sprayed on fruit trees. Unfortunately, the codling moth grew ever more resistant, with more and more lead arsenate being applied in response.
This resulted in a buildup of lead and arsenic in the soils, sometimes over decades. As elements, lead and arsenic do not break down. They stay in the soil — and stay toxic — for decades after they were used. This is why they are called legacy pollutants.
The result? More than 100,000 acres of former orchard lands across Central Washington contain varying levels of lead and arsenic contamination.
Arsenic and lead soil sampling results are measured in parts per million (ppm). The cleanup level for arsenic is 20 parts per million (ppm). The cleanup level for lead is 250 ppm. Ecology sets cleanup levels based on state law- The Model Toxics Control Act. These cleanup levels protect both human health and the environment.