Development of a standardized test method for investigating the environmental solubility of metal ions from materials used in rifle bullets

作者：Schwarz D; Faeth J; Goettlein A^*

来源：Allgemeine Forst und Jagdzeitung, 2015, 186(9-10): 175-187.

The aim of the present work was the development of a standardized test method for investigating the environmental relevant solubility of heavy metal ions from materials used in rifle bullets. Washed quartz sand was used as a surrogate for the worst case of a low sorption capacity soil.
The standardization of the soil solution was achieved by using three types of solvents (citric acid pH 4, bidest, bicarbonate pH 8), representing acidic, neutral and basic soil conditions. The acidic model solvent was selected on the basis of comparative studies using natural humus lysimeter solutions (Fig. 3).
The standardized method consists of a three-hour percolation of 15 ml of model solution to a composite of washed quartz sand and quartz wool with embedded residual bodies of hunting rifle bullets (Fig. 2). This percolation is conducted every first and fourth day of the week, to a total of four weeks.
For each test date the resulting percolates were collected and analysed with ICP-AES for their content of the heavy metals zinc, nickel, copper, lead, tin and antimony.
Using a hydraulic press, contamination-free and reproducible residual bodies of hunting rifle bullets were produced (Fig. 1), thus ensuring a full standardization of the test method.
Two lead projectiles (ID-Classic, Geco Plus) and three alternative bullets with different metallurgical composition (Bionic Yellow, Evo Green and GlVLY) were investigated and evaluated. The evaluation was based on the limits for heavy metals in seepage water according to the German Soil Protection Directive (Bundes-BodenSchutz-Verordnung).
The alternative projectile Evo Green showed the lowest excesses over limits of all five investigated projectiles. However, supposedly (")lead-free" projectiles may contain lead and release it in extreme rates like the brass projectile Bionic Yellow. Projectiles made of copper alloys (like GMX) may release very high rates of copper comparable to the very high dissolution of lead from lead bullets. Based on literature, copper, which is the main constituent of many alternative bullets, is mostly classified more critical than lead with respect to effects on organisms and soil functions.
With exception of the tin-projectile (")Evo Green" no reduction of the ecotoxicological impact will be made by a substitution of "leaded" with the investigated "leadfree" bullets.
According to the results of this work an exact definition of the term "lead-free" is urgently needed.

• 出版日期2015