Investigation of copper and zinc contaminations in bioponic systems using chicken manure fertilizer

Abstract

The bioponic system is a system that utilizes biological waste as a nutrient-rich source such as chicken manure fertilizer for plant growth integrated with aquaponic. At present, chicken manure fertilizer is contaminated with Cu and Zn may have the potential health effects through vegetable consumption. The objective of this study was to evaluate nitrogen transformation, nitrogen recovery, and plant growth in chicken manure-based bioponics at Cu (50–150 mg/kg) and Zn (200–600 mg/kg) supplementation and investigate the effects of Cu and Zn supplementations on plant bioaccumulation, root microbial community, and dietary health risk. Cu and Zn concentrations were analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES). The result found that the average TKN was ranged from 11.2 ± 0.5 to 19.4 ± 1.8, TAN was 1.1 ± 0.8 to 1.5 ± 1.8 and NO3¯ was 11.6 ± 4.0 to 14.9 ± 4.7 mgN/L for lettuce cultivated, while pak choi cultivated TKN was ranged from 16.3 ± 0.1 to 19.4 ± 1.8, TAN was 0.7 ± 0.4 to 0.9 ± 0.5 and NO3¯ was 8.8 ± 6.8 to 10.1 ± 6.8 mgN/L respectively. These studies have shown that heavy metal contamination in chicken manure does not significantly affect nitrogen concentration and nitrogen use efficiency by plants ( significant level p < 0.05). The concentrations of Cu and Zn were found in lettuce shoot and root ranged 5.6 ± 0.1 to 7.2 ± 1.0 mg/kg and 64.8 ± 13.8 to 89.9 ± 2.6 mg/kg, while in pak choi was ranged 1.3 ± 0.3 to 4.1 ± 2.9 mg/kg and 43.3 ± 1.5 to 119.8 ± 34.1 mg/kg, respectively. Furthermore, the relative abundance of bacterial communities of lettuce and pak choi roots-based bioponics at phylum level was found Proteobacteria and Planctomycetes are dominant highest relative abundance respectively. However, the result of the health risk assessment was showed that HQ and HI < 1, which does not exceed the acceptable level. This study indicated that consuming lettuce and pak choi-based bioponic systems did not cause any human health effects or health risks to children and adults.