The study of environmental impact quotient (EIQ) of pesticides used in wheat and barley farms in Mashhad

The environmental impact quotient (EIQ) developed by Kovach et al (1992) is used an effort to fill an important gap; i.e. the need to provide farmers and others with easy-to-use information about the adverse effects of pesticides. It represents a method for calculating the environmental impacts of pesticides, and the values obtained from these calculations can be used to compare different pesticides and pest management programs with each other to ultimately determine which program or pesticide is likely to have the lowest environmental impact. The EIQ value for a particular active ingredient is calculated according to a formula that includes parameters for toxicity (dermal, chronic, bird, bee, fish, and beneficial arthropod), soil half-life, systemicity, leaching potential, and plant surface half-life. Each of these parameters is given a rating of 1, 3 or 5 to reflect its potential of causing harm. Six of these ratings are based on measured or known properties and the other five are based on judgments according to their potentially low, moderate or severe impact. Since the EIQ value is mainly a hazard indicator, additional calculations are required to obtain an indication of the pesticide risk. To account for exposure, an equation called the Field Use EIQ has been developed. This rating is calculated by multiplying the EIQ value for a specific chemical from the tables by the percent active ingredient in the formulation and its dosage rate used per hectare (usually in liters or kilograms of the formulated product). EIQ is used in different studies to compare the environmental effects of different pesticides and/or different production systems (Avila et al., 2011; Doris et al., 2011; Gallivan et al., 2001; Macharia et al., 2009). The aim of this study was to evaluate management strategies in using pesticides in wheat and barley farms in the city of Mashhad located in the Khorasan Razavi province in Iran.

Data related to pesticides (insecticides, herbicides and fungicides) used in wheat and barley in the city of Mashhad located in the Khorasan Razavi province were gathered through face to face filling questionnaires by the users. The indices measured in this study include Environmental Impact Quotient (EIQ) and its components (farm worker, consumer, leaching and ecology) and Field Use Rate - EIQ (FUR-EIQ). EIQ is calculated based on the work of Kovach et al. (1992). The formula is: EIQ={C[(DT×5)+(DT×P)]+[(C×((S+P)/2)×SY)+(L)]+[(F×R)+(D×((S+P)/2)×3)+(Z×P×3)+(B×P×5)]}/3 In this formula: DT: Dermal Toxicity; C: long term health effects; SY: mode of action; F: fish toxicity; L: leaching potential; R: surface runoff potential; D: bird toxicity; S: soil residue half-life; Z: bee toxicity; B: beneficial arthropod toxicity; P: plant surface half-life. EIQ field use rating was calculated by multiplying the EIQ value for a specific chemical from the table by the percent active ingredient in the formulation and the rate of its dosage used per hectare: EIQ Field Use Rating = EIQ × % active ingredient × Rate

A large degree of variation was observed in the amount of EIQ and its components. The results showed that in wheat cultivation, Carbendazim had the most effect on the farm worker component and Diazinon had the least effect on this component. The most risk of the consumer and leaching component in wheat fields were shown in fungicides. The fungicide Carbendazim had the most effect on the consumer and leaching component. The least effect on consumer and leaching component were obtained in Deltamethrin. Replacement of Carbendazim with Iprodione, Thiram and Carboxin which are used for disinfection of seeds will improve the consumer and leaching component. In terms of ecology, the Diazinon component had the most dangerous environmental risk in wheat fields. In this section, pesticides were more importance than fungicides. The use of Deltamethrin to control Eurygaster integriceps in wheat, is not recommended and it should be replaced by Trichlorfon because of the risk of ecological destruction. Such ecological destruction is not much different among the various fungicides. The maximum and minimum amount of EIQ among the pesticides used in wheat farms in Mashhad were obtained in Diazinon and Deltamethrin, respectively. 2, 4- D and Fenoxaprop ethyl had the lowest and highest EIQ indices among the herbicides used in wheat farms. The lowest FUR-EIQ index in wheat fields was observed for the application of herbicides. The maximum value of this index was shown in the usage of fungicides. The highest value of the EIQ-FUR related to the Carbendazim fungicide. Due to low consumption of Detamethrin, it had the small value of this index. Considering EIQ-FUR, the use of Deltamethrin is considered to be more appropriate than Trichlorfon. Use of Iprdion for the disinfection of seeds, and Tribenuron-methyl for the elimination of weeds in wheat fields are the best choices since they had the lowest FUR-EIQ index. In barley cultivation, Carbendazim and Diazinon had the most and the least effects on farm worker component, respectively. In the consumer and leaching component, the most and the least effects were to the observed in Carbendazim as a fungicide and in the Deltamethrin as an insecticide, respectively. In terms of ecology, the Diazinon and Tribenuron-methyl components had the most and the least effect respectively. In this respect, the fungicides used for seed treatment did not show much difference. The maximum EIQ among the pesticides used in barley fields in Mashhad was observed in Carbendazim. Iprdion used for the disinfection of seeds had the lowest EIQ. Considering the herbicides 2, 4- D and Fenoxaprop ethyl had the lowest and highest values of EIQ, respectively. The evaluation of FUR-EIQ in barley fields in Mashhad showed that cyproconazole was the best fungicide used for seed disinfection and it is a good alternative for Carbendazim. Carbendazim was assessed as the most dangerous environmental pesticide. Considering the pesticides dosage and FUR-EIQ, Deltamethrin was found to be a suitable insecticide against Eurygaster integriceps and Tribenuron-methyl was found to be a less dangerous herbicide. The results showed that in wheat and barley farms in Mashhad, the biggest danger in farm worker consumer and leaching components was Carbendazim fungicide. Diazinon pesticide had the lowest risk in the farm laborer component. The lowest risk in consumer and leaching component related to the Deltamethrin pesticide. In terms of the ecology components, the most environmental degradation was created by the Diazinon pesticide. Carbendazim is the most dangerous pesticide. Based on the measurements of FUR-EIQ, the fungicides had the highest risk and the herbicides had the lowest risk.