1 Introduction

The military and several civilian industries, such as mining, high-energy metalwork, civil engineering, war, and military training and exercise, employ various kinds of explosives extensively [1]. So, munitions production, transportation, and use contribute to significant environmental contamination levels of several toxic elements, including magnesium. Magnesium is used as the precursor component in explosives and warheads. Magnesium is used in explosives as a result of its property to react violently with strong oxidants and some other substances, causing fire and explosion hazards. It also causes fire and explosion hazards by reacting with acids and water forming flammable hydrogen gas. So, after explosions on the battlefield and exercise or training ranges, their fumes, burnt materials, and other residuals go into the air, soil, and water. Recently, 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, hexogen), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX, octogen) are found in soils, surface waters, groundwater [2]. Because of their chemical structure and potential for attaching to organic materials, most explosives are unstable, making remediation challenges. So, after that, it enters into a plant grown through soils, contaminated irrigation water, and deposition of particulate matter over the plant from the surrounding atmosphere. The high toxicity of explosives is another constraint and threat to animal and human health [3]. Hence, it easily enters the animal and human food chain and affects their health.

Magnesium is not a rare element but the eighth most abundant element on Earth, constituting about 2% of Earth’s crust by weight. It’s the third most abundant structural metal in the Earth’s crust, only exceeded by aluminium and iron. Among the elements found in seawater, it is the third most plentiful element. It is found in good quantities in many rocky minerals like dolomite, magnetite, olivine and serpentine. Even though magnesium is abundant in nature, it is not considered hazardous to animal or human health. Irritation of mucous membranes or the upper respiratory tract may be observed on inhalation of magnesium dust. Magnesium particles may embed in the skin or eyes. Viewing burning magnesium powder without fire glasses may result in “Welder’s flash” due to intense white flame. The hazard of magnesium toxicity through ingestion is unlikely; however, ingesting large amounts of magnesium powder could cause severe toxicity.

Several trace metals, including magnesium, have been shown to influence, metabolism, excretion, and transport [4]. Magnesium has actions that are similar to calcium, and excess intake causes drowsiness, whereas magnesium deficit causes agitation. Further, personality changes, hyperirritability, psychosis, sadness, and schizophrenia are all psychological alterations linked to aberrant magnesium metabolism [5, 6]. Patients orally administered magnesium salts have shown symptoms ranging from serious fluid and electrolyte balance to muscle weakness, respiratory arrest and asystole. Serum level-linked symptoms of magnesium toxicity have been reported from mild diarrhoea, nausea and vomiting, muscle weakness to respiratory paralysis and eventually cardiac arrest [7, 8]. Excessive heavy metal body loads have been linked to negative emotional changes and neurological damage [9, 10].

Our environment tolerates higher levels of exposure to various types of explosive materials from World War I. Every country has its own air force, navy, and marine troops who get training with different explosives (RDX, HMX, TNT, perchlorate, magnesium-based explosive, pentaerythritol tetranitrate, 2ADNT, 2,4-Dinitroanisole) [11]. In the US, UK, Russia, India, China, and France, many troops are exercising their explosion training in the respective training places [11, 12]. As the training is going on, many energetic constituents are getting acquainted with our environment. Meanwhile, the world is also experiencing civil war in different countries like Afghanistan, Iraq, Libya, Pakistan, Somalia, Syria, Yemen, etc., even for years when huge explosions occur [13]. The recent ongoing Russia-Ukraine war, which has continued for more than one year, is the latest example of the use of extensive explosives. This war has also resulted in seeping heavy metals, fuel and chemical residues from ammunition and missiles into the soil [14]. As a counter-terrorism exercise, the North Atlantic Treaty Organization (NATO) controlled air strikes and bombing from drones in these countries [15]. In the last decade, due to country-led explosions and explosions due to terrorism, the following diagrams (Figs. 1A, B; 2A, B) present the scenario.

Fig. 1
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A, B Air strike in last decade in different countries [15]

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Fig. 2
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A, B Explosion in last decade in different countries [15]

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However, metals toxicity due to magnesium and other heavy metals, e.g., lead, cadmium, and mercury, etc. are already widespread, so magnesium exposure through munitions and explosives are a matter of great concern to the environment and animal and human health in war and military training regions [2].

2 Chemico-biological interaction of magnesium from explosive materials

Magnesium powder is commonly used as a critical ignition source (fuel) in reactive and energetic composite materials such as pyrotechnic formulations, solid fuels, and explosives [16]. Magnesium is also incorporated in other magnesium explosives, like magnesium hydride with an inorganic oxidizer (Table 1; Fig. 3).

Table 1 Hazardous effects of few explosives on animals
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Fig. 3
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Chemical structure of different magnesium based compound in which Mg can be added

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Magnesium toxicity in plants and other vegetation is uncommon and may only occur when there is a high magnesium concentration in the soil in which they are grown. The average magnesium content in the soil is 5 g/kg, which varies in the range of 0.5 g/kg to 40 g/kg and mostly in the range of 3–25 g/kg. [20]. Magnesium becomes toxic to plants when magnesium concentrations exceed 40 g/kg of soil. Magnesium toxicity has been found to change 2 plant hormones, namely abscisic acid (ABA) and gibberellins (GA), and their signalling factors, DELLA and ABI1 [20]. These are two important hormones in plants which control the growth, germination and flowering of the plants. Thus, the excess magnesium produces magnesium toxicity in plants by disturbing the hormonal release.

In men and animals, magnesium is a key electrolyte in the body involved in enzymatic action, transporters, and the synthesis of nucleic acids. It also influences other electrolytes such as sodium, calcium, and potassium. In a normal scenario, hypermagnesemia is a rare but serious electrolytic disorder that can be fatal if not diagnosed and taken care of promptly. Normally hypermagnesemia does not occur in men or animals, and renal excretion takes slightly large intakes. As hypermagnesemia occurs due to under-excretion and over-absorption, excess intake through magnesium-contaminated feed and water, particularly for a few days, is very likely to cause hypermagnesemia leading to magnesium toxicity. Excessive oral intake has been found to cause hypermagnesemia in patients on hemodialysis, as ingestion primarily influences plasma levels [21]. Prolonged use of low bioavailable magnesium oxide may also lead to risks of hypermagnesemia [22]. Hypermagnesemia may also develop in patients with renal insufficiency receiving magnesium or magnesium salts in larger quantities.

In the case of hypermagnesemia, magnesium toxicity takes place through two mechanisms. In the first mechanism, elevated serum magnesium concentrations block neuromuscular transmission by inhibiting acetylcholine release at the motor end-plate and acting as a CNS depressant. Hypermagnesemia also amplifies the response to neuromuscular blockers. As per the second mechanism, magnesium competitively antagonizes calcium at calcium channels, impeding calcium flux and impairing electric conduction and muscle contraction. Moreover, the potential concomitance of hyperkalemia increases the risk of cardiac arrhythmias and cardiac arrest. In large amounts, sulfate salt of magnesium suppresses the secretion of Paratharmone (PTH) secretion and decreases renal tubular reabsorption of calcium, which may further develop hypocalcemia [23, 24]. Moreover, the potential concomitance of hyperkalemia increases the risk of cardiac arrhythmias and cardiac arrest.

3 Possible magnesium sources from explosion to air, soil, and water

The explosive waste is burned in the open air before being carried away by water. As a result, the metal gets absorbed into the soil and the water. Metal percolates deep into the earth during rain and eventually reaches water bodies. This enters the first source of the food chain from water and earth. Magnesium can also be found in the environment as explosive dust in various chemical forms [25, 26].

Cation competition at the soil or plant root exchange sites and compaction tendencies may impede potassium uptake in soils with high magnesium levels [27]. Excess magnesium in soils can also contribute to colloidal soil dispersion, inhibiting soils' regular wetting and drying cycles and the release of potassium from internal soil exchange sites.

The most important reservoir for most pollutants in nature is water. Most research conducted worldwide concluded that sufficient magnesium levels exist in water resources. The maximum permissible level of Mg in water is 20 mg/L [28]. An illustrative view of magnesium exposure to the soil, air, and water are presented in Fig. 4.

Fig. 4
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Exposure of magnesium to environment from explosive and their environmental impacts

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4 Possible magnesium sources from explosion to vegetation and fodders

Magnesium is one of the important mineral nutrients for plant growth, which come from the soil to the plant's roots after being dissolved in water [30]. Many studies indicate that plants in the explosion site tend to uptake TNT, DNT, 2-A-4,6-DNT etc. [29, 30]. The local vegetation is affected by these energetic constituents of the explosion, and the land remains barren for many decades. Few reports indicate the inhibition of seed germination, biomass weight, and root development of T. pretence and T. aestivum due to phytotoxicity as a consequence of soil polluted with explosives [3]. A few studies have been listed in Table 2, where it is crystal clear that the local vegetation and fodders of the surrounding explosion site will accumulate most of the explosive metal elements and other energetic constituents. Through the food chain, all these may increase the ecological risk and biomagnifications into the higher food chains of humans and animals.

Table 2 Presence of energetic constituents in different vegetation after explosion
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So far, to the best of our knowledge, little study has been carried out on the accumulation of magnesium in local vegetation around the explosion site. However, as the above table indicates, the possible accumulation of different energetic constituents may accumulate in plants; therefore, it might be possible for a higher accumulation of magnesium in the local vegetation. Therefore, all the data on mines, air strikes, air-dropped bombs, missiles, rockets, suicide bombings, etc. (Fig. 5) in civil war countries can potentially increase the magnesium level in plants and may stimulate the consequent magnesium toxicity.

Fig. 5
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(Source: CSIS)

NATO led air strike in Afganistan

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5 Human and animal exposure to environmental magnesium from explosive

Magnesium is an essential component of several enzyme systems in the animal body and the maintenance of mineral balance [45]. As a result, a magnesium deficit or excess can disrupt these physio-chemical activities, resulting in toxicity or disease. As stated, magnesium is available to animals through water, feed, and fodder. When it reaches an excessive amount in the body, it can cause severe toxicity; an illustrative view is presented in Fig. 6. In humans, less than 1% of total body magnesium is found in serum and red blood cells. It is distributed principally between bone (53%) and the intracellular compartments of muscle (27%), and soft tissues (19%) [46]. Only 1% of magnesium is found in blood vessels present as ionized (62%), protein-bound (33%) and complexed to anions such as citrate and phosphate (5%) [47]. Hypermagnesemia occurs due to under-excretion by the kidneys, over-absorbance by the small intestine or displacement of stored magnesium into the serum, and leads to magnesium toxicity. Similarly, excess intake through magnesium-contaminated feed and water, particularly for a few days, is likely to cause hypermagnesemia and, consequently, magnesium toxicity. Even though no study has been reported on clinical symptoms of toxicity of magnesium originating from magnesium-based explosives, toxicity effects have been reported in patients orally administered magnesium salts where symptoms ranging from serious fluid and electrolyte balance to muscle weakness, respiratory arrest and asystole have been found. The toxic effects of magnesium are directly linked to the levels (mEq/litres) of magnesium in the blood. As magnesium level rise, toxicity symptoms start to manifest, and the severity of the symptoms occurs in proportion to the levels of magnesium in the serum. Mild symptoms usually start at 5 to 10 mEq/L, which become a little more severe to loss of deep tendon reflexes and muscle weakness at 10 mEq/L. As the levels of magnesium increase, clinical signs also advance towards severity. At 15 mEq/L, patients begin to experience respiratory paralysis. At 20 mEq/L or higher level, the patient will likely experience cardiac arrest [48,49,50]. Serum-level-linked symptoms of magnesium toxicity have been reported, from mild diarrhoea, nausea and vomiting, and muscle weakness to respiratory paralysis and cardiac arrest [7, 8]. Dust of magnesium-based explosives irritates the respiratory tract, mucus membrane and eyes. Magnesium has not been tested, but it's not suspected to be carcinogenic, mutagenic or teratogenic. Exposure to magnesium oxide fume after burning can result in metal fume fever with temporary symptoms like fever, chills, nausea, vomiting and muscle pain. These usually occur 4–12 h after exposure and last up to 48 h. Magnesium oxide fume is a by-product of burning magnesium. According to Sahinduran et al. [51], magnesium-rich hard water causes urolithiasis in cattle. The urolithiasis impact of magnesium has been observed to be enhanced by high phosphorus and potassium concentrations [52]. Animals have had diarrhoea after consuming large amounts of magnesium sulfate. High magnesium intake also decreased feed intake and weight gain [53]. Severe magnesium toxicity symptoms have been observed in dogs with ionized serum magnesium levels > 4 mg/dL (normal below 2.5 mg/dL). Horses show clinical signs of sweating and muscle weakness within 4 h of receiving excessive oral doses of magnesium sulfate administered for treatment, followed by recumbency, tachycardia and tachypnea. Hypermagnesemia has been reported in cats with renal failure receiving IV fluid treatment. Endocrine, metabolic, and lipid disorders have also been observed in small animals with hypermagnesemia, such as dogs and cats. Furthermore, the situation worsens if renal-impaired animals are exposed to water and feed containing high magnesium levels. Magnesium is an essential cofactor for many enzymes in the body, including phosphor-transferases, and plays a critical role in macromolecule attachment to organelles; hence magnesium poisoning due to excess magnesium resulting from magnesium-based explosives is likely to disrupt these processes. Muscle excitability, neurochemical transmission, and cardiovascular activity may be affected. The increased plasma concentration may cause neuromuscular (paralysis) and cardiac problems (hypotension, bradycardia, heart block). The explosives' dust may irritate the upper respiratory tract, resulting in bronchoconstriction and cough. Metal fume fever is caused by prolonged exposure to magnesium oxide fumes due to burning, welding, or molten metal work [18].

Fig. 6
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Explosive sources of magnesium with the effects on human health

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Increased magnesium concentrations from anthropogenic sources can stress aquatic ecosystems as they can in animals and humans. The acute and chronic toxicity of magnesium to freshwater mussel species has been documented by Kleinhenz et al. [54].

6 Strategies and control measures of environmental protections from magnesium toxicity due to explosive

Tissue and serum minerals analysis could be used to examine acute and chronic magnesium exposure and adopt control strategies. High exposure to magnesium in humans occurs mainly through contamination of the human food chain, e.g. drinking contaminated water, consuming magnesium-rich animal-origin food, magnesium-rich eatable vegetation, food supplements, and pharmaceuticals. Therefore, restricting iatrogenic magnesium concentrations in water, air, and soil near a human or animal-populated area should focus on strategies to prevent and reduce human magnesium toxicity. Magnesium-based explosives should not be used in areas where people or animals are. If an explosion is unavoidable, such as in mining, metalworking, or civil engineering, care should be taken to ensure that explosion dust and magnesium residues do not reach the water and vegetation sources, preventing animal and human food chain contamination.

Individual clinical cases should be managed using general health measures similar to those used to control other toxicants, such as stopping the source of extra magnesium, removing excess magnesium through medications and fluid therapy, using an antidote, and with supportive treatment available. Remove the patient to fresh air if the magnesium exposure was dust due to an explosion. Artificial breathing support is highly beneficial in the event of a respiratory ailment.

Various known plants that absorb magnesium should be grown in the mining and explosive test ranges. A large tower-air purifier should be installed for magnesium-based dust/particle removal.

7 Significance of the study

The study of the ecotoxicology of magnesium-based explosives and their impact on the animal and human food chain is significant because these explosives can release toxic chemicals that can accumulate in the environment and ultimately affect the entire food chain.

When magnesium-based explosives are detonated, they can release heavy metals and other toxic chemicals into the environment. These substances can contaminate the soil, water, and vegetation in the surrounding area, and can ultimately enter the food chain through the consumption of plants by animals.

If these toxic substances accumulate in the bodies of animals, they can cause a variety of health problems, including reproductive and developmental issues, organ damage, and even death. In addition, if humans consume these contaminated animals, they can be exposed to these toxic substances and may also experience negative health effects.

Furthermore, magnesium-based explosives can have an impact on the entire ecosystem. For example, if the explosions occur in a wetland or near a river, the toxic chemicals released can accumulate in fish and other aquatic organisms, leading to the potential for bioaccumulation and biomagnification in the food chain. This can ultimately result in a loss of biodiversity and ecosystem health.

Therefore, the study of the ecotoxicology of magnesium-based explosives and their impact on the food chain is crucial for understanding the potential risks associated with these explosives and for developing strategies to mitigate their impact on the environment and human health. By identifying the potential risks associated with these explosives, we can better protect both the environment and the health of the communities that may be affected by their use.

8 Conclusions

Explosive and munitions materials are the new source of magnesium and its derivatives to environmental contamination. So, eco-toxicology due to higher magnesium in the biotic and abiotic components of the ecosystem may hamper the total trophic level and further enter the animal and human body through the food chain. In addition to the ecological impacts, magnesium-based explosives can also pose a risk to human health. When these explosives are detonated, they can release toxic chemicals into the air that can be inhaled by humans. This can cause respiratory problems and other health issues, particularly for people who are already vulnerable due to pre-existing health conditions. Overall, the use of magnesium-based explosives can have the ecotoxicological impacts that can be very harmful to both the environment and human sustainability in explosive hit regions and in increasing conflicts scenario across the world. It is important to carefully consider the potential environmental and health impacts of these explosives and to explore alternative methods that are less harmful to the environment and human health. As no studies on potential threat of magnesium based explosives on environment and human health have been reported, adequate studies are needed to have closer look on the environmental impact of various explosives and munitions in the surrounding ecosystem and ameliorative measures to limit magnesium toxicity accordingly. Further, we need to develop bioremediation technology to detoxify the contaminated ecosystem and food chain to benefit animal and human health.