Dissipation Dynamics of Doxycycline and Gatifloxacin and Accumulation of Heavy Metals during Broiler Manure Aerobic Composting

Abstract

In this study, broilers were fed with heavy-metal-containing diets (Zn, Cu, Pb, Cr, As, Hg) at three rates (T1: 5 kg premix/ton feed, T2: 10 kg premix/ton feed and T3: 15 kg premix/ton feed) and Doxycycline (DOX) and Gatifloxacin (GAT) at low or high doses (T4: 31.2 mg DOX/bird/day and 78 mg GAT/bird/day, T5: 15.6 mg DOX/bird/day and 48 mg GAT/bird/day) to assess the accumulation of various heavy metals and the fate of two antibiotics in broiler manure after 35 days of aerobic composting. The results indicated that the two antibiotics changed quite differently during aerobic composting. About 14.96–15.84% of Doxycycline still remained at the end of composting, while Gatifloxacin was almost completely removed within 10 days of composting. The half-lives of Doxycycline were 13.75 and 15.86 days, while the half-lives of Gatifloxacin were only 1.32 and 1.38 days. Based on the Redundancy analysis (RDA), the concentration of antibiotics was significantly influenced by physico-chemical properties (mainly temperature and pH) throughout the composting process. Throughout the composting process, all heavy metal elements remained concentrated in organic fertilizer. In this study the Cr content reached 160.16 mg/kg, 223.98 mg/kg and 248.02 mg/kg with increasing premix feed rates, similar to Zn, which reached 258.2 mg/kg, 312.21 mg/kg and 333.68 mg/kg. Zn and Cr concentrations well exceeded the United States and the European soil requirements. This experiment showed that antibiotic residues and the accumulation of heavy metals may lead to soil contamination and pose a risk to the soil ecosystem.

Assessing the Sustainability of Broiler Waste Management Strategies in Thailand through Analytical Hierarchy Process Analysis

“…Thus, increasing composting temperature, extending high-temperature exposure, or increasing pH should facilitate antibiotic breakdown. However, heavy metals remained highly concentrated in the final composted product, which could potentially be transmitted to humans if applied as organic fertilizer [20].…”

Effect of Biochar Addition on Mechanism of Heavy Metal Migration and Transformation in Biogas Residue Aerobic Compost

“…However, due to the use of additives in livestock and poultry breeding, an accumulation of heavy metals may exist in biogas residue, and studies have shown that the biological activities of Cu and Zn in biogas residue after composting treatment increases, and long-term return to farmland will cause potential pollution in the soil. Studies have shown that aerobic composting of biogas residue cannot eliminate and reduce the toxic effect of heavy metals [5,6]. After composting, heavy metal levels have not been effectively decreased, so it is urgent to add additives to adsorb and passivate heavy metals.…”