Introduction

Water is the principal ecological component of aquatic ecosystems and is home to diverse groups of species (Irfan et al. 2019). The waters are valuable natural resources that provide long-term rewards in exchange for minimal management and conservation costs (Helfrich et al. 2009). However, they have been impacted by ever-increasing human activities to the extent that the activities alter the quantity and quality of provisioning, regulating, cultural, and supporting services of ecosystems (Irfan et al. 2019; FAO 2020). Among various anthropogenic activities, the releases of pesticide residues to water bodies highly pollute the aquatic ecosystems and contribute to the decline of species populations, including fisheries (Landos et al. 2021).

Pesticides are chemicals used to prevent, eradicate, or control pests that affect food, agricultural products, and animal feedstuffs (WHO and FAO 2014; Ramya and Sunita 2020). Animals might also receive pesticides for the management of endoparasites and exoparasites (WHO and FAO 2014). Pesticides are widely utilized in the developing world, and their demand is rising as a result of the current crop production system, which gives priority to high agricultural yields (Özkara et al. 2016; Human Rights Council 2017). Pesticides enable farmers to avoid up to 78%, 54%, and 32% losses of fruits, vegetables, and cereals, respectively (Tudi et al. 2021). Pesticides are relatively easy to apply, cost-effective, and sometimes the only option to control pests (Tudi et al. 2021; Chala 2022). Though pesticides are very important to minimize losses and improve the quality and quantity of crop production and enhance food security (Teklu 2016; Tessema et al. 2021), they might cause adverse negative effects on biotic resources and affect the basic need for food and health (Human Rights Council 2017; Shegaw et al. 2022). Exposures to pesticide residues adversely disrupt the reproduction, growth, and development of fish and other aquatic lives (Landos et al. 2021).

Pesticide toxicity (i.e., the degree of poisoning caused by the pesticide), exposure time (i.e., the amount of time the animal is exposed to the pesticide), dose rate (quantity), and persistence in the environment all play a significant role on the effects of pesticide residues on fish and other aquatic animals (Helfrich et al. 2009; Maurya et al. 2019). The inherent property of substances to cause undesirable consequences or adverse effects on human health and /or the environment is a hazard (WHO 2018). The severity of adverse effects, the extent and duration of exposure, and its likely occurrence determine the level of risks (WHO and FAO 2014). Thus, pesticide-related risk characterization is a combination of both hazard (extent, duration, and severity of adverse effects), and the likely occurrence of adverse effects from a particular exposure in a given population (FAO and WHO 2016, 2019).

Obsolete pesticides are pesticides banned from being used for any intended purposes (WHO 2008; Ministry of Agriculture 2014), and persistence is a period in which a chemical or its derivatives remain unchanged in its structure in environmental compartments such as soil, sediment, water, air, animal, or plant tissues (Greenhalgh 1980; Environment Directorate 2005; Hassaan and Nemr 2020). The persistence of a pesticide is affected by its chemical and physical properties, the composition and characteristics of its environment, and the climatic conditions (Greenhalgh 1980). Persistency in soil has received the greatest attention (Environment Directorate 2005) and if it requires more than 100 days to degrade half of its original amount in the soil, it is under the category of persistent chemicals (Rahman et al. 2020). The obsolete and persistent pesticides are still used for crop production in Ethiopia and are found beyond the maximum residual limit in several foodstuffs and the environment (Pesticide Action Nexus Association 2020). Pesticide residues from different sources enter the aquatic ecosystems through stormwater runoff, vapor, spray drift, and wastewater, and pollute the water resources (Bashir et al. 2020). The pesticide residues in water might harm non-target plants and animals to the extent that the species become extinct regionally or nationally (Darçın and Darçın 2017; Kassa 2017). Furthermore, the pesticide residues drain into water bodies in the course of pesticide mixing might contaminate the aquatic ecosystems and cause adverse effects on organisms (Gulliya et al. 2021; Teklu et al. 2016). However, most Ethiopian farmers couldn’t notice the impacts of pesticide residues on aquatic lives and water qualities (Amera and Abate 2008; Mengistie et al. 2017). Among pesticide users, 23% to 74% of Ethiopians mix their pesticides close to water sources that might be used by local people for drinking, cooking, and other household purposes (Mengistie et al. 2017; Agmas and Adugna 2020; Rahman et al. 2020). The pesticide residues from irrigation and farm activities drain into aquatic and wetland ecosystems and adversely affect the organisms (Dominik et al. 2010; Rahman et al. 2020). Though the effects of pesticide residues on aquatic ecosystems are significant, farmlands are sprayed with huge amounts of toxic pesticides 17 to 26 times per cropping season (Mengistie et al. 2017; Pesticide Action Nexus Association, 2019, 2020; Abaineh et al. 2024). The excess pesticides in farmlands are washed by runoff and contaminate the water sources. Such contaminated water sources exposed fish, birds, beneficial insects, grazing animals, and humans to effects of pesticide residues (Anderson et al. 2013; Mengistie et al. 2016; Human Rights Council 2017; Abaineh et al. 2024). A study in lake Chad of north east Nigeria confirmed that pesticide residues in fish were above the maximum residual limit (Akan et al. 2014). The pesticide mixing practices, fishing by pesticide poisoning, spray drift during pesticide applications, and washing the sprayer equipment near canals, lakes, and rivers pose risks to aquatic ecosystems of Ethiopia including fish, birds, beneficial insects, and humans drinking surface water, and raised the need to monitor pesticide use regularly (Anderson et al. 2013; Loha et al. 2020; Abaineh et al. 2023).

To minimize the negative effects of development activities including pesticide applications, Ethiopia declared a number of environmental protection laws, including the constitution, criminal code of Ethiopia, conventions, and proclamations (FDRE 1995, 2002a, 2002b, 2002d). Though there are a number of ratified pesticide management rules in Ethiopia, the country is ineffective in enforcing the laws and there are signs of human and environmental health problems (Ministry of Finance and Economic Cooperation 2016). The difference between the intention and implementation of pesticides’ law enforcement; the effects of pesticide residues on humans and biodiversity; and the effects of pollution on ecosystems’ services including potable water sources are concerns of many Ethiopians (Chala 2022).

To date, there are no comprehensive national studies conducted on the types of pesticides used, the effects of pesticide residues on aquatic ecosystems, and the pesticide laws’ enforcement in Ethiopia. Therefore, the focus of this review paper is to summarize the trends of pesticide use, the effects of pesticide residues on aquatic ecosystems, the pesticide application practices, and the level of enforcement of pesticide laws in the country and to forward the possible mitigation measures. In order to summarize the risks of pesticide residues on aquatic ecosystems and the extent of the enforcement of pesticide laws in Ethiopia, a literature search was done using databases such as Google Scholar, Research Gate, Science Direct, PubMed, Science-Hub, internet archives, and others. We searched the scientific articles published over the past 30 years. We used keywords such as food contamination, effects of pesticide residues, obsolete and persistent pesticides, aquatic ecosystems, pesticide use in Ethiopia, pesticide laws in Ethiopia, and types of pesticides use in Ethiopia. The total publications searched were about 969 of which only 103 articles and government reports were selected, while 866 documents were rejected due to their scientific standard and reliability. Importance to the thematic area, impact factors, novelty, and reliability were taken into consideration while selecting the articles and documents. The study was carried out from December 2022 to July 2023.

Pesticide use in Ethiopia and its effects on aquatic ecosystems

Trends of pesticide use in Ethiopia

To increase production and alleviate suffering from sickness and hunger, Ethiopia imported huge amounts of pesticides, fertilizers, and related chemicals (Sisay 2017; Loha et al. 2020). There are about 1011 pesticides registered in Ethiopia, of which 313, 358, and 287 are insecticides, herbicides, and fungicides, respectively. Among the remaining 53 registered pesticides, 32 are rodenticides, miticides, avicides, adjuvants, sticker, Nematicides, and household pesticides and 21 of the pesticides are used in public health (Ministry of Agriculture Plant Health Regulatory Directorate 2022). More than 58% of the pesticides registered in Ethiopia are highly hazardous pesticides (HHPs) (Pesticide Action Nexus Association 2019, 2020). Ethiopia is still formulating the HHPs, including endosulfan and its derivatives and is distributing to commercial farms and smallholder farmers throughout the country (Pesticide Action Nexus Association 2019). Among HHPs, DDT and endosulfan are used by 87 and 98% of small-scale irrigation farmers for crop production, respectively (Negatu et al. 2016). Farmers also use DDT and malathion to soften the leaves of khat crops (Weyesa 2021). There are also large stocks of pesticides, left in stores or in the open for a number of years, and have remained a serious threat to the public (Wodajo 2015; Mekonen 2016). There were over 2500 tons of obsolete pesticides accumulated in Ethiopia (Haylamicheal and Dalvie 2021). Due to the absence of storage facilities and poor pesticide store management, most pesticide containers are torn and large quantities of pesticides are leaking in almost all stores in the country (Ministry of finance and economic cooperation 2016). About 67% of these obsolete pesticides were obtained by donation and the stocks mostly contain dichlorodiphenyltrichloroethane (DDT), chlordane, dieldrin, and linden (Mekonen 2016; Mengistie 2016). In addition to importing huge amounts of pesticides into the country, the Adami Tulu pesticide processing Share Company formulated and distributed highly hazardous pesticides, including DDT, endosulfan, and its derivatives (Sahilu 2016; Mengistie et al. 2021). Recently, the company has produced malathion, diazinon, dimethoate, fenitrothion, deltamethrin, chloropyrifos, mancozeb, propiconazole, 2,4-D dimethyl amine salt, vetazinon 60% EC, amitraz, and propoxur, which are used for control pests, exoparasites, and vectors (Adami tulu Pesticides Processing Factory 2023). Since its full operation in the year 2000, it has produced insecticides, herbicides, and fungicides pesticides as well as other chemicals to control vectors and exoparasites(Adami tulu Pesticides Processing Factory 2023). The amount of pesticides produced by the company has increased from 108.96 metric tons in 2000 to 9800 metric tons in 2023 and is produced in dust, liquid, and water-dispersible powder form (Sahilu 2016; Teshome et al. 2023). Similarly, the amount of pesticides imported into Ethiopia in the year 2000 was about 1015.9 metric tons and increased to 3647.7 metric tons of different types in the year 2012 (Ministry of Agriculture 2013). The amount of pesticides imported into the country in the year 2012 was more than threefold of the year 2000.

In general, there has been a rapid increment in pesticide formulation and importation in the country (Sahilu 2016). Of all imported pesticides, about 72% are insecticides, 25% are herbicides, 2.6% are fungicides, and 1.3% are other products, including rodenticides and disinfectants(Mekonen 2016). Among such imported pesticides, 80% are used by commercial farms/agricultural investors and the remaining 20% are used for small-scale farming, home pests, health institutions, and industrial purposes (Mengistie et al. 2016). Pesticide consumption has increased in parallel with an increment in food crops production and floriculture sector expansion (Amera and Abate 2008; Sisay 2017; Birkie 2019). In addition to floriculture farms, most farmers in Ethiopia over-sprayed pesticides on their farmlands, i.e., 5–17 times per cropping season (Teklu 2016; Mengistie et al. 2017).

Effects of pesticide residues on aquatic ecosystems

Organochlorine and organophosphate pesticides, which are used by farmers of Ethiopian, are endocrine disrupting pesticides (EDPs) (UNEP and WHO 2013; Özkara et al. 2016). They cause developmental abnormalities and reduce the immunities of organisms and make them vulnerable to disease and parasites (Johnson et al. 2013; Landos et al. 2021). They are also proven to cause premature sexual development, change in the sexual characteristics of animals, decrease the body weight of organisms, and affect the regulatory genes (Özkara et al. 2016). At times of extreme exposure to EDPs, animals including aquatic species will develop both male and female sexual characteristics (Hayes et al. 2011; Landos, Smith and Immig 2021). EDPs in water bodies might also reduce the hatching rates of eggs, alter the thyroid hormone levels, inhibit the growth rates, and reduce the avoidance of offspring from their predators if their parents are exposed to persistent pesticide residues (Helfrich et al. 2009). Thus, pesticide residues might cause a population decline in fish and other aquatic life by affecting their survival and ability to reproduce (Johnson et al. 2013). The exposures of organisms to such pesticide residues at their sensitive developmental stages disrupt their natural processes by changing their structures and/or functions (UNEP and WHO 2013). In Ethiopia, the pesticide residues in some lakes might pose low to high acute risks to aquatic organisms (Yohannes et al. 2013; Teklu et al. 2016). Studies on levels of organochlorine pesticide residues in different fish species from Lake Tana, Lake Awassa, Lake Koka, and Lake Ziway indicated that the pesticide residues could pose a health risk/threat to fish species and consumers (Teklu 2016; Wodajo 2020; Agmas and Adugna 2022). The toxic chemicals might biomagnify as they move up across the aquatic food chain, reaching very high concentrations in top-order predators (Gill and Garg 2014a, b; Wolde and Abirdew 2019; Rahman, Awal and Misbahuddin 2020).

As humans are at the top of the aquatic food chain, exposure to pesticide residues through food consumption become a key health concern of consumers (Wumbei et al. 2019; Mekonnen et al. 2021). The persistent pesticides might bioaccumulate and pass through the food chain to humans (Bashir et al. 2020). The applications of intoxicating insecticides by several horticultural farmers and the use of persistent pesticides to store seed for longer periods have resulted in food poisoning when family members have consumed it (European Union 2021). Some farmers know the toxic effects of pesticides and use them without worrying about their negative effects on consumers (Wang et al. 2018; Abaineh et al. 2023). This excessive use and misuse of pesticides might also reduce the nutritional values of different food sources (Human Rights Council 2017; Bashir et al. 2020).

In addition to the food chain, water pollution from the unsafe use of pesticides might expose the general population to pesticide-related health risks through drinking water contaminated by pesticide residues (Human Rights Council 2017; Mengistie et al. 2021). Previous studies conducted in different parts of the country confirmed that more than 48% of farmers mix their pesticides near water bodies in a situation that causes water pollution. The pesticide mixing practices of farmers near water bodies are summarized below (Table 1).

Table 1 Exposure of water bodies to pesticide pollution from the pesticides mixed/diluted near water bodies
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The effects of pesticide residues on aquatic life could be influenced by water temperature, oxygen levels, pH, pathogens, turbidity, kind of aquatic vegetation present, nutrient levels, chemical concentration and formulation, and other physical and chemical water variables (Mischke and Avery 2013; Landos et al. 2021). An increase in water temperature rises the release and emission of persistent toxic pesticides, deposition of CO2 and acidity, and reduces the availability of oxygen (Abate 2019). The toxicity of pesticides on aquatic animals is also influenced by the types of species, and their age, sex, and condition (Mischke and Avery 2013). In addition to stressors, water pollution might reduce the availability of forage for fish larvae, with no doubt reduces the fish larval survival and decline in fish populations (Gibbons et al. 2015). The pesticide mixing practices of most Ethiopian farmers, the possible effects of pesticide residues on the farmers applying it and the water pollution are presented in the Fig. 1 below.

Fig. 1
figure 1

Source: Field photo, 2022

A young farmer breaking the package of a pesticide container with his teeth and mixing different types of pesticides at the edge of a river.

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Losses to the public health, the emergence of pesticide-resistant pests, crop losses due to chemical damage, and ground and surface water contamination are some of the consequences of pesticide uses (Mekonnen and Ejigu 2005). Losses to the public health, animals and aquatic ecosystems in general, and costs to reduce environmental and social health risks are disadvantages of using the pesticides (Lakhani 2015). The costs of environmental and economic losses from pesticide residues are in billions of USD per year per country (Khan et al. 2020).

Knowledge, attitudes, and practices of farmers about the effects of pesticide residues

Smallholder farmers' pesticide application practices are the primary sources of pesticide hazards in Ethiopia (Mekonnen and Ejigu 2005; Negatu et al. 2016; Weyesa 2021). Though farmers are at very high health risks, they do not wear protective equipment when applying pesticides (Hiluf and Abebe 2015; Mengistie et al. 2017; Agmas and Adugna 2020). Studies conducted in different parts of Ethiopia confirmed that more than 89% of the farmers do not use personal protective equipment when applying pesticides (Negatu et al. 2016; Agmas and Adugna 2020). The reason why pesticide users do not wear safety equipment is that they don’t know and understand the long-term effects of pesticide residues (Mekonen 2016; Abaineh et al. 2023). So the effects of pesticide residues in Ethiopia are much more aggravated by inadequate knowledge about the properties of pesticides among pesticide users (Amera and Abate 2008). The worst is that most farmers mix such hazardous pesticides without wearing gloves to protect their hands. A study conducted by (Mengistie 2016) confirmed that 94% of farmers mix pesticides with a stick, but with bare hands, and 6% of them mix with their bare hands as shown below (Fig. 2). Among Ethiopian farmers who use pesticides, 41% had the experience of pesticide poisoning (Tessema et al. 2021). All the farmers overuse the pesticides than the recommended quantity (Mengistie 2016; Pesticide Action Nexus Association 2020). Moreover, pesticide users in Ethiopia select and buy the types of pesticides they want by their own decision, and then they use it for the intended purpose (Wolde and Abirdew 2019; Mengistie et al. 2021). They buy the pesticides without any restriction and expert recommendation (Mengistie et al. 2017). Among higher and lower-income groups of farmers in Ethiopia, the higher-income groups are more likely to buy appropriate pesticides while the lower-income groups use less expensive and broad-spectrum products available in the open market (Mengistie et al. 2017).

Fig. 2
figure 2

Source: Field photo, 2022

Pesticide mixing of practices of farmers (self-field observation).

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Most pesticide users disposed of the pesticide containers in the field, including water bodies in a situation that raised the water pollution (Negatu et al. 2016) and some farmers reused the pesticide containers for home consumption (Hiluf and Abebe 2015). The management of empty pesticide containers are summarized in table (Table 2).

Table 2 Awareness and practices of farmers and toxicity of pesticides used in Ethiopia
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As shown in the table, more than 98% of empty pesticide containers are either reused for home consumption or thrown on the field, including water bodies. Farmers’ inability to read labels of pesticides including expiry dates and recommended doses aggravated the risks of pesticide residues on human health and the environment (Mengistie 2016). Furthermore, it should be noted that reading the labels of pesticides does not mean they understand the instructions. This is why the number of farmers who use pesticides without wearing protective equipment is greater than the number of farmers who do not read the labels. Studies confirmed that more than 75% of farmers are not able to read the labels of pesticides. Access to training about application practices and the effects of pesticides is very low. Access to trainings on pesticide management, the ability of farmers to read and understand instructions for pesticides use are summarized in Table 2. Though most pesticides used in Ethiopia are too toxic to fish, farmers have mixed them near water bodies without any concern about their effects on aquatic ecosystems (Pesticide Action Nexus Association 2019). One of the herbicides, atrazine, could alter male fish, amphibians, reptiles, and mammals to a partial or a complete female one (Hayes et al. 2011). Atrazine, an EDP, reduced the amount of spermatogenesis, and triggered the rise of ovaries and the production of eggs in male fish (Lushchak et al. 2018). Though atrazine has adverse effects on aquatic life, it is currently in use in Ethiopia with various combinations and formulations (Pesticide Action Nexus Association 2019).

The majority of pesticides used in and near aquatic ecosystems might cause acute or chronic toxicities on organisms (Grewal et al. 2017; Abate 2019). Acute toxicity effects occur rapidly in animals following a single dose or single exposure to a chemical (Helfrich et al. 2009; Akashe 2018). The acute toxicity of pesticides on aquatic animals is reported as a lethal dose 50 (LD50) or lethal concentration 50 (LC50) (Hoff et al. 2010). It is the amount (concentration) of a chemical that kills 50% of the test animals in a given period of time, usually 24, 48, or 96 h (Mischke and Avery 2013). If the toxicity of the pesticide is very high, a very low amount (concentration) of it will kill the organisms. The types of pesticides in use and their toxicity classes on fish are shown in the table (Table 2).

Chronic toxicity refers to a pesticide's capacity to have harmful health effects that persist for a longer period of time, typically following repeated or continuous exposure, and may even remain for the whole life of the exposed organism (Adekunle et al. 2017). Some of the chronic health effects resulting from extended exposure to pesticide residues include cancer, infertility, early maturity, hormonal malfunctioning, endometriosis, diabetes and obesity, developmental disorders, loss of memory and coordination, reduced visual ability and motor skills, respiratory illness, autism, and hypersensitivity to humans (Özkara, Akyıl and Konuk 2016; Hashimi et al. 2020; Pironti et al. 2021).

Insufficient education and training, improper application techniques, negligence for safety rules, inappropriate spraying equipment, inadequate storage facilities, and the reuse of empty pesticide containers for home consumption exposed farmers to various diseases (Adekunle et al. 2017). The real pesticide application practices of farmers in Ethiopia are represented in the Fig. 3.

Fig. 3
figure 3

Source: Field photo, 2022

Application of pesticides without wearing personal protective equipment (field observation).

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Farmers, sprayers, retailers, and extension workers require continuous trainings and technical supports to minimize the negative effects of pesticides. Non-governmental organizations, health professionals, private business owners, and agrochemical companies should offer trainings and provide support to the aforementioned community members (Mengistie et al. 2017).

Effectiveness of management of pesticides in Ethiopia

Ever-increasing trends in use of pesticides and their negative effects on human health and ecosystems call for the requirement to manage pesticide formulation, transportation, and application (Teklu et al. 2016). In line with the need to manage pesticides, Ethiopia declared pesticide management laws to reduce adverse effects on the environment and society (FDRE 2018b). A detailed discussion about the general provisions, the offenses and penalties for environmental crimes, and the extent of law enforcement is given in the following sub-sections.

Legal frameworks to manage pesticides in Ethiopia

Ethiopia declared, in its constitution, the right to live in a healthy and clean environment, and the responsibility of the government to protect the environment from the effects of development activities (FDRE 1995). The criminal code of Ethiopia also clearly states the obligations of citizens to protect the environment, and the penalties for the offenses (FDRE 2005b). Ethiopia also ratified conventions that declared the rights and obligations of the government and citizens (FDRE 2002a, 2002d; Ministry of finance and economic cooperation 2016). Ethiopia ratified the Stockholm Convention, which aims to forbid the use of persistent organic pollutants (FDRE 2002b) and the Rotterdam Convention to enforce prior informed consent in international markets on certain hazardous industrial chemicals and pesticides (FDRE 2002a). The national action plan for the implementation of the Stockholm Convention was prepared for the effective management of persistent organic pesticides (POPs) in the Ethiopian context and to reduce the use and release of pollutants to the environment (FDRE 2006). Ethiopia approved its environmental policy in harmony with the declaration of the constitution on the environment and development which aims to enhance the health and living standards of all Ethiopians. The goal of the policy is to encourage sustainable social and economic growth while protecting the environment, i.e., addressing the demands of the current generation without jeopardizing the ability of future generations to address their own needs (FDRE 1997). Ethiopia also declared chemical registration and administration proclamations to establish a national chemical registry system. This is to prevent and control adverse effects of chemicals on humans and the environment (FDRE 2018a, b). The proclamations declare the need to maintain a separate central database containing an inventory of all pesticides in order to regulate the movement or use of pesticides at each stage of the pesticide life cycle within the country (FDRE 2010, 2018b). The country also declared a floriculture code of conduct to limit the minimum standard of social and environmental compliance requirements for horticulture projects (Ethiopian Horticulture and Agricultural Investment Authority 2017). According to this code of conduct, a bronze-level environmental clearance certificate will be given if and only if the project uses unbanned or registered agrochemicals, assesses risks related to environmental and occupational safety, ensures the existence of safe agrochemical storage and use, installs a complete waste management technology, and provides onsite medical services (FDRE 2011). The laws that the country declared to safeguard humans and the environment from adverse effects of pesticide residues are summarized in the table (Table 3).

Table 3 Summary of the pesticide management conventions and national laws in Ethiopia
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The table above confirms that the declarations of environmental and social protection are sufficient enough to manage the transportation, storage, application, and use practices of pesticides in Ethiopia.

Offenses and penalties in pesticide management laws

The Environment Protection Authority and Ministry of Agriculture of Ethiopia are responsible for regulating the transfer of chemicals across the supply chain (FDRE 2010, 2015, 2018a). Accordingly, no person is allowed to make any import order for a pesticide without an import permit issued by the authorized institutes (FDRE 2018a, b). The proclamations also prohibit the disposal of any pesticide or pesticide wastes in a manner that might harm human health or the environment (FDRE 2018b). Furthermore, no one is allowed to import, export, store, and transport any industrial chemicals with a shelf life of less than one and a half years. The proclamation also declares a person’s responsibility to label all the necessary information on the container of pesticides that he produces, import, store, and transport, and build safe storage facilities to avoid risks (FDRE 2018b).

There are fines and imprisonments for pesticide-related offenses as stated in the criminal code of Ethiopia (FDRE 2005b). To mention some among others, article 517 states that anybody who intentionally poisoned water bodies including reservoirs, springs, water holes, rivers, or lakes will be penalized for up to fifteen years of imprisonment. Similarly, article 519 states that anybody /institute that commits an offense that might cause serious consequences on the health of a person or on the environment will be penalized with up to ten years of imprisonment. An offense committed via producing and distributing substances hazardous to the health of humans and animals will be punishable with imprisonment of up to ten years and a fine of up to 3717.83 USD (FDRE 2005b).

In addition to the criminal code, the environmental pollution control proclamation of Ethiopia states that violation of the permitted standards while discharging any pollutant into the environment is a crime and is punishable by a fine of up to 92.95 USD or imprisonment of up to ten years, or both (FDRE 2002d). If the offense is committed by a juridical person, it is liable to a fine of not less than 92.95 USD and not more than 464.73 USD (FDRE 2002d). Regarding the failure to manage the hazardous wastes, the officer in command could face a prison sentence of between five and ten years, a fine of between 92.95 USD and 185.89 USD, or both (FDRE 2002d). Provision of poisonous or dangerous substances to the public without a special permit from the concerned authority is a crime and the criminal will be punished with imprisonment of up to seven years. If the criminal commits the crime for gain, he will be punished by a fine of up to 3700 USD and with imprisonment of more than ten years (FDRE 2005b). Any person who imports, produces, uses, and distributes industrial chemicals without getting an environmental clearance certificate will be punished by 2 to 5 years of imprisonment or by a fine between 1858.92 and 9294.59 USD (FDRE 2018b). National and regional environmental laws give the power to Environmental protection authority to suspend, cancel, and/ or translocate projects having adverse impacts on the environment (FDRE 2002c, 2008; Amhara National Regional State 2012). Environmental laws of Ethiopia oblige the licensing agencies to cancel the work permit they gave for the projects, following the decisions of Environmental Protection Authorities (FDRE 2002a, 2002b, 2008; Amhara National Regional State 2012). The Amhara National Regional State Environment Protection Authority (the second largest region in Ethiopia) and its lower-level structures have been given the power to take action on institutions that fail to properly undertake their environmental responsibilities (Amhara national reginal state 2016). The above articles and proclamations confirmed that the environmental laws of the country on paper are sufficient enough to safeguard society and the environment from adverse effects of pesticides.

Enforcement of pesticide laws

Although there are a number of rules and conventions endorsed to manage the supply chains of hazardous chemicals including pesticides in Ethiopia, there are too weak environmental law enforcement agents in the country (Ministry of finance and economic cooperation 2016). The declarations of pesticide importation, distribution, and use have been repeatedly violated by different actors including importers, wholesalers, retailers, and end users (Mengistie 2016). Though there are a number of legal frameworks to manage pesticides in the country, there is no clear and transparent system of pesticide registration, distribution, and use (Mengistie et al. 2021). There is also no system line to take legal actions against governmental institutions that fail to protect their environment and perform their social responsibilities (FDRE 2015). The justice institutions are not free from political influence to work for the rule of laws; rather they are mediators to resolve any crime among government offices/public enterprises and environmental protection offices (FDRE 2015) This is an indicator of the partiality of laws’ enforcement among private and government projects for the crime they commit. Though there are sufficient management laws in the country, it failed to control pesticide importers and retailers who are aggressively marketing and distributing the pesticides unsafely (Mengistie et al. 2016). Awareness gaps on environmental effects of pesticide residues at the policy level; and lack of complementarities among agricultural, investment, and environmental protection policies and declarations are the major reasons for ineffective pesticide law enforcement (Dominik et al. 2010). There is a very high political commitment to expand the flower farms to earn foreign currency. There are more than 80 active flower farms in the country that directly release huge amounts of hazardous pesticides to the environment (Birkie 2019). This short-term benefit-oriented political decisions are one of the reasons for ineffective environmental law enforcement (Sisay 2017; Birkie 2019) The concerns of environmental protection were omitted in the rural development policy and strategy of Ethiopia. The rural development policy of the country planned to increase agricultural production and productivity by deploying technologies and agricultural inputs, including pesticides, but it failed to include the negative effects of pesticides on the environment and society and its mitigations (FDRE 2003).

Conclusion and recommendation

Aquatic ecosystems are valuable resources that provide long-term benefits in exchange for minimal management costs. However, they have been adversely impacted by human activities. The pesticide residues enter the aquatic ecosystems through mixing the pesticides near water bodies; stormwater runoff and spray drift adversely affect the aquatic life. Moreover, huge amounts of obsolete pesticides are leaked in almost all stores and most of the pesticides registered in the country are in the lists of HHPs. Furthermore, farmers in Ethiopia have been using obsolete and persistent pesticides and higher dosages than the recommended quantity. Such pesticides might disrupt the natural processes of organisms by changing their structures or functions, and cause population decline of different species by affecting their survival and reproduction. Though the country declared rules to protect the adverse effects of pesticides, it is ineffective to enforce the laws.

Therefore, the following mitigation measures should be implemented to reduce the adverse impacts of pesticides, including:

  1. 1.

    Various communication channels, including extension services and electronic media, should be used continuously to raise the awareness of communities about the use, transfer, storage, and side effects of pesticides

  2. 2.

    The country should commit to implementing the demand-driven pesticide registration and supply system, starting from importers through end users

  3. 3.

    There should be a minimum pesticide-free buffer zone between water bodies and pesticide mixing (spraying) sites in order to safeguard organisms of aquatic ecosystems from the effects of pesticide residues

  4. 4.

    The slope, vegetation cover, degree of degradation, sensitivity of the aquatic environment, habitat needs of organisms, and frequency of siltation should be considered while determining the width of the buffer zone.

  5. 5.

    Impartial law enforcement, amongst the private and public institutions, and establishing an independent environmental management court are urgent requirements for effective laws enforcement in the country.

  6. 6.

    There need to establish a clear line of liability for failure to perform environmental responsibilities among all officials of the government.

  7. 7.

    The government of Ethiopia needs to focus on regular monitoring of the types, transfer, and storage of pesticides and their applications. To make it effective, the country needs to put in place sufficient and competent human resources at all levels and take remedial action when necessary.