Use of antimicrobials on swine farms and concentrations of antimicrobials in soils that received manure from these farmsa

AntimicrobialFarm LFbFarm MFFarm HFConcn in soil (ng/g [dry wt])Detection limit (ng/g [dry wt])
UsecConcn in soil (ng/g [wet wt])UsecConcn in soil (ng/g [dry wt])UsecConcn in soil (ng/g [dry wt])Farm OFdFarm OF2dUnamended
MLSB antimicrobials
    Tylosin A+BD+BDBDBDBDBD2
Tetracycline antimicrobials
    Tetracycline9.016.1 (1.5)35.4 (25.8)BDBDBD1
    Chlortetracycline+245.1+211.8 (19.8)+209.8 (157.6)BDBDBD1
    Oxytetracycline+4.121.9 (18.6)≤4.0≤3.2≤3.17.8 (3.7)1
    AnhydrotetracyclineBD≤4.93.6 (0.3)≤3.2≤4.0≤3.62
    β-Apo-oxytetracyclineNAf9.3 (6.3)≤2.64.0 (1.4)≤3.3≤6.52
  • a Concentrations in dry soil are shown, except for farm LF, for which the concentrations in wet soil are shown because the moisture content was not available for the samples. The values in parentheses are the half-ranges for duplicate measurements. In several cases, values above and below the detection limit were recorded for the same samples. In these cases, the values below the detection limit were included in calculations as the detection limit value, and the affected values are indicated by the ≤ symbol.

  • b The antimicrobial values for the farm LF soil sample have been reported previously (33) and are included for comparison.

  • c +, antimicrobial was used; −, antimicrobial was not used. Details concerning antimicrobial doses and timing have been described previously (10).

  • d No antimicrobials were used on farms OF and OF2.

  • e BD, below the detection limit.

  • f NA, not analyzed.