The Environmental Yardstick for Pesticides is a grading system which indicates how harmful a pesticide is for the environment. Before using pesticides, it gives you the opportunity not only to consider the effectiveness or price of the pesticide, but also the side-effects of pesticides on the environment. The Environmental Yardstick for Pesticides can also be used to determine the total environmental impact of all pesticides applied in one season and for instance to compare your outcomes to the outcomes of your colleagues.
The indicator calculates and compares the effects of pesticides on five criteria:
The environmental effects of pesticides on water organisms, soil organisms and groundwater are assigned so called environmental impact points (EIP). The environmental impact points increase when pesticides have a greater impact on the environment. Originally the environmental impact points are expressed for an application of 1 kg/ha or 1 l/ha. The points should be multiplied by the actual applied quantity per hectare. For soil organisms and groundwater a score of 100 EIP is in line with the acceptable level set by CTGB (Board for the authorisation of pesticides). CTGB is an organisation which has the duty of taking decisions on the authorisation of pesticides for the Dutch market. The acceptable level for aquatic organisms is 10 EIP per application (since 1995). The acceptable level is a concentration which implicates not too much risk for the environment.
The environmental impact on aquatic organisms is dependent on the toxicity of a pesticide for aquatic organisms. In addition the impact of a pesticide depends on the spray drift to watercourses. The percentage that reaches the watercourses depends on the application technique. Furthermore factors like wind speed, wind direction, crop size, distance to the watercourse, temperature and atmospheric humidity play a part in the amount of drift.
Originally the Environmental Yardstick for Pesticides assumes 1% spray drift to surface water (watercourses). Therefore the EIP for aquatic organisms must be multiplied by the actual percentage spray drift of the application technique. For example there is a greater chance on spray drift by using a conventional sprayer than by using a full-air sprayer or by spray application with a untreated bufferzone zone.
The Environmental Yardstick for Pesticides takes the organic matter content into account. The organic matter content determines, just like the pesticide characteristics (degradationrate and mobility in soil), the amount of pesticides that in course of time stays behind in the soil. This concentration in the soil, along with the toxicity, determines the risk of a pesticide for soil organisms.
The Environmental Yardstick for Pesticides distinguishes five classes of organic matter content:
A farmer uses 0,5 litre/ha Sencor WG as a post-emergence treatment in the potato cultivation. The organic matter content is 5%. There are 9 environmental impact points (EIP) assigned for an application of 1 l/ha.
The total score is:
0,5 kg/ha x 9 = 4,5 EIP
This score is well below the admissible level of 100 EIP, therefor the risk for soil organisms is small.
In most casesthe organic matter content also determines the risk of leaching of pesticides to the groundwater. Organic matter can bind pesticides. When the organic matter content is high, the risk of leaching is low and less environmental impact points will be assigned. The lutum content of the soil determines leaching as well, but it is of less importance than the organic matter. Pesticide characteristics also determine the degree in which a pesticide leaches to groundwater.
At last the amount of environmental impact points for groundwater is dependent on the moment of the application. The risk of leaching is larger byapplication in fall. The reason for this is a slower degradation of the pesticide in fall because of low temperatures and the precipitation surplus in this period. A difference is madebetween application in spring and in fall by the calculation of environmental impact points,. The boundaries between those periods are as follows:
For groundwater there are environmental impact points assigned to pesticides for every combination of organic matter classes and application time.
A farmer uses 1,5 litres/ha Gallant 2000 for weeds in spring. The organic matter content is 3,5%. There are 600 EIP assigned for a dosage of 1 l/ha. The total score for the application of 1,5 l/ha is:
The total score is:
1,5 l/ha x 600 = 900 EIP
This is 9 nine times the accepteble level of 100 EIP, therefor the chance of groundwater pollution is high.
The risk for biological controllers (e.g. ladybirds, predatory mites, hymenopteran parasitoids) and pollinators (e.g. bumble bees) is indicated with a symbol. This symbol shows the usability for integrated cropping systems and is a combination of all pesticide effects for individual beneficial organisms. More detailed information can be found in the Side Effect Guide and internet pages of suppliers of beneficial organisms. The data for the Environmental Yardstick for Pesticides is based on the Side Effect Guideof Koppert Biological systems.
The risk of a pesticide for human health is indicated with a symbol. The symbols are deducted from the symbols (cross, skull) that can be found on the labels of pesticide products.
The Environmental Yardstick for Pesticides assigns points to pesticides for six criteria. A farmer can decide for his company which environmental effects are most important. Farming in an area with many watercourses requires more attention for aquatic organisms than areas with hardly any surface water. In groundwater protection areas the EIP score is very important.
The data from the Environmental Yardstick for Pesticides are derived from the following sources: