**4.4 Effects of lead bullet on human and wildlife, diagnosis and therapeutic benefit of plumbism**

About 0.4 million water birds of 33 species die every year from lead shot in European Union wetlands, and it cost European Union 105 million euros to replace 0.7 million captive-bred birds for killed ones. Restriction of water birds hunting cost greater than 100 million euros [85–87]. The milk plasma concentration ratio for lead is 50–100:1 after 24 h in mice, indicating a higher efficient concentration of lead milk of lactating mice as compared to that of non-lactating mice [88]. Linear biokinetic model of prehistories/preindustrial children's blood of 0.06–0.12 g/dl was calculated for two lead intakes, which was lower than CDC threshold limit value of 10 g/dl. Toxicokinetics of bone lead that causes resorption with metabolic stimuli is of great concern for baby growth [89]. However, plumbism in birds cause death in 3 weeks [90]. The metabolizing enzymes that play very great role in the toxicokinetics of lead are d-amino-levulinate dehydratase d–ALA–d and porphobilinogen synthetase [91]. The activity of d-ALA-d, an allosteric enzyme with 28 thiol group is inhibited by lead [92], leading to accumulation of d-amino levulinic acid (d-ALA), whose concentration in urine of human and other animals is used to diagnose lead poisoning [93]. Sublethal dose of lead (0.2–0.5 ppm) has been reported with ≥0.5 ppm showing a significant decreased of d-ALA-d, causing brain damage which can be reversed by zinc. Haemosynthetase, ALA-dehyrotase and ferrochelatase have antidotal effects [94]. The latter enzyme binds iron to protoporphyrin, an indicator of blood lead, 40 ppm of the protoporphyrin is a clear proof of plumbism, over 500 pm affects neuromuscular activity with a consequent change in the motor functions [95–97]. Dimercaprol, a diethylene triamine pentaacetic acid, D-penicillamine, thiamine and calcium disodium ethylene diamine tetraacetate chelate lead for elimination. Highly hunted birds such as red grouse, mallard partridge, pheasant, woodpigeon, woodcock and deer could have lead fragments that exceeded threshold values of 100–10,000 ppb [98]. Many lead fragments in the carcasses of killed animals weighed >12–25 mg each, concentration of blood lead (5.9–18.1 g/dl) has been reported for consumers of game meats in Greenland and Switzerland and >4.1 millions shots have been reported against macropods, deer, red foxes, feral pigs, European rabbits and feral goats in Australia, annually [74], signifying that Australia may have high incidence of plumbism among wildlife. One million wild fowl estimated to have been killed by lead poisoning and ≥3 million sublethally poisoned [17], including Anseriformes, Falconiformes and Accipitriformes. They were severely poisoned with lead blood concentration of (>100 g/dl) [18]. Lethal lead concentration range (56–120 g/dl) has been reported for bearded vulture, Cape vulture and golden eagle [99–103] suggesting variation in susceptibility to lead poisoning among wild birds. However, concentration range of 10–47 g/dl was survived, and associated with different isotopes of lead

[100, 104, 105]. Clinical threshold limit values for lead toxicosis of blood (>0.5 mg/ kg), liver and kidney (>6 mg/kg) have been reported. Fragment sample size of 0.5 to >5 mm radiate from the wound channel [2]. Concentration of lead in the liver (28.9 ppm) for bald eagles and 19.4 ppm for golden eagles are sources for concern [106]. However reduced circulatory erythrocyte volume reduce uptake of lead by blood [107].

### **4.5 Exposure to environment lead**

Exposure to lead arises from air and surfaces, and absorption occurs via ingestion, inhalation, percutaneous and transdermal routes. The first two are relevant to firing ranges, 0.1–5 μm lead can be inhaled, absorbed through the lung and 50% gets distributed to various parts of biological system. Absorption of ingested lead is >8–10% [108]. However, 12.5 g/m<sup>3</sup> of airborne lead particles of ≤1 μm is of public health significance and the particles higher than >1 μm are deposited in the upper respiratory tract [109]. About 70% of workers exposed to lead (50 g/m<sup>3</sup> ) had blood lead of 405 g/ dl and 6% had >505 g/dl respectively [110]. However, 94% of samples of deer killed with bullets contained fragments of lead, which portend very high risk for scavengers [111]. Blood lead levels increased with time after injury up to 3 months with fragments and increasing age, which is 30% higher in the patient whose torsos are affected. Hence, blood level could be higher (11.8%) at 3 months and 2.6% at 12 months, respectively. Therefore, there is need for continued surveillance after gunshot [112]. The uncertainty in predictive power of algometric scales remains a concern in plumbism caused by lead bullet. Hence, the scales can only apply for exploratory research [113]. The uncertainty and availability, both in terms of inter-subject and application associated can be significant [114]. Natural isotopes of lead; 204 pb, 206 pb, 207 pb, and 208 pb constitute manufactured lead in various percentages, and their measurements in human and wildlife could be compared with their potential sources for environment risk assessment [2].

### **4.6 Lead causes cognition impairment**

Lead causes impairment of neurodevelopment, cognition and behavioural development in the foetus and young child. The source of plumbism from wild birds killed by ammunition is significant among 5 million people in European Union countries [45]. The half-life of lead in blood and bone is 30 days and decades, respectively [115]. Unfortunately, maximum level (ML) for lead in game animals has not been set in the Codex Alimentarius General Standard for contaminants and toxicants [116], and by European Union [117], leading to concentration of 690 μg of lead fragments in wildshot moose carcasses in Finland, Norway and Sweden [45]. Daily blood lead (12 μg/l) and lead intake (0.5 μg/kg) can affect intelligence quotient (IQ) of a child [118]. Bullet position may preclude surgical removal in order to avoid exacerbation of neurologic damage. The complication of the removal may be due to immediate migration of the fragment [119]. Retention of lead fragments in joint space is associated with increased risk of lead poisoning, and joint disruption leading to synovial metaplasia [120]. Good radiography and clinical findings are highly essential, for identification and complete surgical removal of bullet fragments, that may have high potential of distribution to various parts of biological system [121]. Injuries from bullet are most severe in brain and liver, causing temporary cavitation far from the actual bullet track. Bone and subcutaneous fats are highly resistant to bullet injury [122, 123]. Toxic leads widely

used to hunt game animals and varmints are a source of environmental pollution. Lead and bismuth are highly frangible [26] and about 90% of the total burden of lead is found in bone and 5% in plasma, which pass through the cell membrane and cause toxic effect in brain, red blood cells, liver among others. In view of this, the knowledge of lead kinetics is of prime importance to a greater and better understanding of lead toxicity, as the risk of its adverse effects is very high [124]. Substitution of toxic lead bullets for non-toxic bullets such as steel, bismuth and tungsten may be possible alternative of curtailing lead poisoning from firearms, and phasing-out period of lead bullets could reduce cognition impairment [125]. Rationales used to remove lead from paints, gasoline and household items should be applied to lead-base ammunition globally, an issue that regularizes international intervention [126]. About 45% of surveyed states and provinces in the USA and Canada have non-toxic short regulation above federal water fowl regulations [127].
