Decontamination of Chlorate in Longan Plantation Soils by Bio-Stimulation with Molasses Amendment

Abstract

Potassium chlorate is widely used as an active substance for flower induction in longan plantation fields for off‐season production of longan fruits in northern Thailand. Contamination of groundwater with residual chlorate in soil is a cause for concern because of its toxicity to human health. Based on our previous finding that the addition of glucose or sucrose to soil was effective for accelerating the disappearance of residual chlorate in soil, the effect of the addition of molasses, which contains a high concentration of sucrose, as a substitute for glucose or sucrose was examined in laboratory and pot experiments. Under laboratory conditions, the addition of molasses to soil at the concentrations of 100 to 200 g kg−1 soil strikingly enhanced the rate of disappearance of chlorate applied at 341 mg kg−1 soil. Addition of diluted molasses was also effective for the accelerated disappearance of chlorate in soil when 33 g kg−1 soil of molasses was added repeatedly. The effect of repeated addition of diluted molasses to soil on the decontamination of residual chlorate in soil was also confirmed in an outdoor pot experiment. These results may lead to the development of a practical method of cleaning‐up chlorate‐polluted soil in longan plantation fields.

Bioremediation of Chlorate and Chromium in Soil Columns Using Contaminated Site Native Culture

“…The rate and amount of chlorate reduction (Figure 4) is similar to previous studies that have evaluated various car- bon sources to stimulate local microbiological conditions for chlorate remediation (Hunter 2002;Senoo et al 2004;Sutigoolabud et al 2005;Schwarz et al 2012). In most instances, additional stimulation (e.g., including additional nutrients) was not necessary for sustained microbial reduction of chlorate-either soil chemistry or groundwater chemistry was sufficient in supplying adequate nutrition for the microbial communities.…”

“…It has been hypothesized that the combined effects of abiotic and biotic processes induced by ZVI could affect chromate removal from groundwater (Zhong et al 2017). This finding (control samples demonstrating that abiotic processes do not affect oxyanion degradation) has been observed by others evaluating in-situ, stimulated bioremediation of chlorate (Sutigoolabud et al 2005).…”

Effect of sequential presoaking and chlorine dioxide treatment on the inactivation of pathogenic Escherichia coli and Salmonella spp. on sprout seeds

“…Moreover, chlorate residues that possibly remained on seeds might have been transformed by bacterial action during the sprouting process as chlorate residues are prone to biodegradation in biotic environments conducive to bacterial growth. This is in harmony with consumer preference for safe fresh produce [26].…”

Effect of chlorate on nitrification in longan plantation soil

“…flower induction). Decontamination of chlorate in soil by bio‐stimulation with molasses amendment (Sutigoolabud et al . 2005) is a candidate for such field management.…”