Effect of Abiotic Signals on the Accumulation of Saponarin in Barley Leaves in Hydroponics Under Artificial Lights.

Functional flavonoid production is a new agenda in the agricultural industry, and young barley leaves (YBL) are one of the highlighted crops due to their health-beneficial flavonoid, saponarin. For the year-round cultivation of a high saponarin content of YBL, abiotic signal effects on the biosynthesis and metabolism in YBL need to be understood clearly. In this research, the effects of reactive oxygen species (ROS)-related abiotic signals, such as light, potassium, and sodium, were investigated on the biosynthetic metabolism in YBL cultivation under artificial lights. A higher quantity of blue-rich white light (6500 K of light temperature) irradiation enhanced ROS levels and the related enzyme activities (APX and CAT), as well as photosynthesis and saponarin amount, while red-rich white light (3000 K of light temperature) increased the photosynthesis only. In addition, 1.0 g L-1 K+ treatment in water slightly reduced ROS levels and increased saponarin accumulation in YBL. These blue-rich light and K+ supplemental conditions relatively increased OGT expression and reduced 4-coumaric acid and isovitexin as saponarin precursors. Furthermore, the relative ratio of lutonarin as an oxidized product of saponarin increased in increments of light quantity. Finally, the abiotic conditions for saponarin production were optimized with the mixture solution treatment of 1.0 g L-1 Na+ and 1.0 g L-1 K+ under 500 PPFD of 6500 K light, and the saponarin amount per leaf was 219.5 µg plant-1; it was comparable amount with that under sunlight condition.

The Potency of Abamectin Formulations against the Pine Wood Nematode, Bursaphelenchus xylophilus.

Abamectin offers great protection against Bursaphelenchus xylophilus, a well-known devastating pathogen of pine tree stands. Trunk injection of nematicides is currently the most preferred method of control. This study aimed to evaluate the potency of the commonly used formulations of abamectin against B. xylophilus. Twenty-one formulations of abamectin were evaluated by comparing their sublethal toxicities and reproduction inhibition potentials against B. xylophilus. Nematodes were treated with diluted formulation concentrations in multi-well culture plates. And, populations pre-exposed to pre-determined concentrations of the formulations were inoculated onto Botrytis cinerea culture, and in pine twig cuttings. Potency was contrastingly different among formulations, with LC95 of 0.00285 and 0.39462 mg/ml for the most, and the least potent formulation, respectively. Paralysis generally occurred at an application dose of 0.06 µg/ml or higher, and formulations with high sublethal toxicities caused significant paralysis levels at the tested doses, albeit the variations. Nematode reproduction was evident at lower doses of 0.00053-0.0006 µg/ml both on Botrytis cinerea and pine twigs, with significant variations among formulations. Thus, the study highlighted the inconsistencies in the potency of similar product formulations with the same active ingredient concentration against the target organism, and the need to analyze the potential antagonistic effects of the additives used in formulations.

Photochemical advanced oxidative process treatment effect on the pesticide residues reduction and quality changes in dried red peppers.

Pesticide residues in crops are widely monitored, and the residue reduction techniques at the post-harvest stage are important to maintain food safety. In dried crops, pesticide residues can be concentrated after dehydration, which increases concerns regarding residue risk. Therefore, the residue reduction effects of ultraviolet (UV), ozone, and photochemical advanced oxidative process (pAOP) were investigated for dried peppers at the post-harvest stage. UV254 treatment reduced 59.7% of the residue concentration on average, while UV360 showed a reduction of only 13.3% under 9.6 W m-2 of UV exposure for 24 h. Gaseous ozone treatments reduced the residue concentrations up to 57.9% on average. In contrast, the pAOP treatment reduced the concentration up to 97% and was superior to UV or ozone treatment alone. Increased drying temperature under pAOP condition resulted in higher reduction ratios at 40-80 °C. The pAOP conditions with 12 and 24 µmol/mol of ozone and UV254 irradiation for 24-48 h reduced the residue concentrations to 39-67%. Particularly, difenoconazole, fludioxonil, imidacloprid, and thiamethoxam residue concentrations were drastically reduced by over 50% under 12 µmol/mol ozone of the pAOP condition, while carbendazim, fluquinconazole, and pyrimethanil were relatively stable and their concentrations reduced below 50% under 24 µmol/mol ozone of the pAOP treatment. Various drying-related quality parameters of drying peppers such as water-soluble color, capsanthin, capsaicinoids, acid value, peroxide value, and thiobarbituric acid value were slightly altered, but not significantly, under 12 µmol/mol ozone of the pAOP condition, while the peroxide value was significantly altered under the higher ozone conditions. Therefore, pAOP treatment combined with gaseous ozone can be used for reducing residual pesticides in peppers without greatly reducing quality.

Comparative Bioactivity of Emamectin Benzoate Formulations against the Pine Wood Nematode, Bursaphelenchus xylophilus.

The pine wood nematode (PWN), Bursaphelenchus xylophilus is a well-known devastating pathogen of economic importance in the Republic of Korea and other countries. In the Republic of Korea, trunk injection of nematicides is the preferred method of control. In this study, the efficacy of 16 locally produced formulations of emamectin benzoate against the PWN are compared through determining their sublethal toxicities and reproduction inhibition potentials. Nematodes were treated with varying concentrations of the tested chemicals in multi-well culture plates, and rates of paralysis and mortality were determined after 24 h. Reproduction inhibition potential was tested by inoculating pre-treated nematodes onto Botrytis cinerea, and in pine twig cuttings. Despite the uniformity in the concentration of the active ingredient, efficacy was contrastingly different among formulations. The formulations evidently conformed to three distinct groups based on similarities in sublethal activity (group 1: LC95 of 0.00768-0.01443 mg/ml; group 2: LC95 of 0.03202-0.07236 mg/ml, and group 3: LC95 of as high as 0.30643-0.40811 mg/ml). Nematode paralysis generally occurred at the application dose of 0.0134-0.1075 µg/ml, and there were significant differences in nematode paralysis rates among the products. Nematode reproduction was only evident at lower doses both on B. cinerea and pine twigs, albeit the variations among formulations. Group 1 formulations significantly reduced nematode reproduction even at a lower dose of 0.001075 µg/ml. The variations in efficacy might be attributed to differences in inert ingredients. Therefore, there is need to analyze the potential antagonistic effects of the large number of additives used in formulations.

The association between occupational stress level and health-related productivity loss among Korean employees.

OBJECTIVES: Occupational stress management is particularly important for successful business operations, since occupational stress adversely affects workers' health, eventually lowering their productivity. Therefore, this study aimed to investigate the correlation between occupational stress and health-related productivity loss (HRPL) among Korean workers. METHODS: In 2021, 1,078 workers participated in a web-based questionnaire survey. HRPL was measured using the Work Productivity and Activity Impairment Questionnaire, and occupational stress was measured using the Korean Occupational Stress Scale-Short Form. The occupational stress level was divided into tertiles (low, intermediate, and high), and the low occupational stress group was used as the reference group. Using a generalised linear model, differences in labour productivity loss according to the level of occupational stress were tested after adjusting for demographic characteristics such as age, gender, education level, household income, occupation, and underlying medical conditions. RESULTS: Non-parametric regression analysis of HRPL according to occupational stress showed a direct association between occupational stress and HRPL. A statistically significant difference was observed in HRPL between participants with intermediate and high occupational stress and those with low occupational stress. CONCLUSIONS: Our results support the hypothesis that high occupational stress is associated with decreased labour productivity.

Fate of endosulfan in ginseng farm and effect of granular biochar treatment on endosulfan accumulation in ginseng.

Endosulfan was widely used as an insecticide in the agricultural sector before its environmental persistence was fully understood. Although its fate and transport in the environment have been studied, the effects of historic endosulfan residues in soil and its bioaccumulation in crops are not well understood. This knowledge gap was addressed by investigating the dissipation and bioaccumulation of endosulfan in ginseng as a perennial crop in fresh and aged endosulfan-contaminated fields. In addition, the effect of granular biochar (GBC) treatment on the bioaccumulation factor (BAF) of endosulfan residue in ginseng was assessed. The 50% dissipation time (DT50) of the total endosulfan was over 770 days in both the fresh and aged soils under mulching conditions. This was at least twofold greater than the reported (6- > 200 days) in arable soil. Among the endosulfan congeners, the main contributor to the soil residue was endosulfan sulfate, as observed from 150 days after treatment. The BAF for the 2-year-old ginseng was similar in the fresh (1.682-2.055) and aged (1.372-2.570) soils, whereas the BAF for the 3-year-old ginseng in the aged soil (1.087-1.137) was lower than that in the fresh soil (1.771-2.387). The treatment with 0.3 wt% GBC extended the DT50 of endosulfan in soil; however, this could successfully suppress endosulfan uptake, and reduced the BAFs by 66.5-67.7% in the freshly contaminated soil and 32.3-41.4% in the aged soil. Thus, this adsorbent treatment could be an effective, financially viable, and sustainable option to protect human health by reducing plant uptake of endosulfan from contaminated soils.

Effect of soil organic matter on the plant uptake of perfluorooctanoic acid (PFOA) and perfluorooctanesulphonic acid (PFOS) in lettuce on granular activated carbon-applied soil.

The presence of perfluorooctanoic acid (PFOA) and perfluorooctanesulphonic acid (PFOS) in crops is an important consideration for food safety. The soil organic matter (SOM) content may affect the adsorption potential of PFOA and PFOS in water and soil and their subsequent uptake in crops. To better understand these dynamics, the adsorption and uptake of PFOA and PFOS in lettuce were investigated using granular activated carbon (GAC)-treated soils with varying SOM content. The adsorption potential of GAC was investigated, with maximum adsorption capacities for PFOA and PFOS calculated to be 9.091 mg g-1 and 27.778 mg g-1, respectively. These values decreased to 5.208 mg g-1 and 17.241 mg g-1, respectively, after the addition of 0.04 wt% humic acid. The average plant uptake factor (PUF) in low and high perfluoroalkyl and polyfluoroalkyl acid (PFAA)-contaminated soils with 4.0 wt% SOM was restricted to 0.353 for PFOA and 0.108 for PFOS. The PUFs were approximately two times lower than those for soil with 2.6 wt% SOM. Addition of 1 wt% GAC to the soil successfully reduced the PUF by up to 99.4%, with values of 0.006 (PFOA) and 0.005 (PFOS) in 2.6 wt% SOM-treated soil and 0.079 (PFOA) and 0.023 (PFOS) in 4.0 wt% SOM-treated soil. Although the PUF in the GAC-treated soil was drastically decreased, the PUF of the soil with 4.0 wt% SOM was at least four times higher than that with 2.6 wt% SOM. Therefore, SOM content is an important consideration in the remediation of PFOA- and PFOS-contaminated farmland soil using carbonaceous adsorbent.

A comparison of the effectiveness of QuEChERS, FaPEx and a modified QuEChERS method on the determination of organochlorine pesticides in ginseng.

This study provides a review of methods used in the determination of organochlorine pesticides (OCPs) in ginseng and compares the effectiveness of three extraction methods (Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS), a modified QuEChERS and a Fast Pesticide Extraction (FaPEx)) in the analyses of 20 OCPs in ginseng root samples. For each method, sample mass, solvent volume and sorbent mass were varied to identify the optimum combination to effectively isolate analytes of interest from the complex sample matrix. Extracts were analyzed using the gas chromatography-µ-electron capture detector (GC-µ-ECD), and confirmatory analyses performed by gas chromatography-tandem-mass spectrometry (GC-MS/MS). Eighteen out of 20 OCPs spiked onto in-house prepared ginseng samples produced acceptable recoveries (51-156%) when extracted using QuEChERS and FaPEx. All 20 analytes, including dichlorodiphenyldichloroethane (p, p'- DDD) and dichlorodiphenyltrichloroethane (o, p'-DDT), produced acceptable recoveries (51-129%) with the use of a modified QuEChERS method. The applicability of the modified QuEChERS method was demonstrated through the analysis of ginseng samples grown in endosulfan-treated soil. The samples were analyzed by both GC-µ-ECD and GC-MS/MS with no significant difference identified in the results of each analytical method. This study highlights the applicability of the modified QuEChERS method, in combination with GC- µ-ECD, to determine organochlorine pesticides in ginseng. This may be especially useful for laboratories in developing countries and less advanced institutions without access to MS/MS instrumentation.

Environmental and dietary exposure of perfluorooctanoic acid and perfluorooctanesulfonic acid in the Nakdong River, Korea.

This study performed the first environmental and dietary exposure assessment to explore plant uptake of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) from agricultural soil and irrigation water in the Nakdong River delta, South Korea. Annual average concentrations of total PFOA and PFOS ranged from 0.026 to 0.112 µg L-1 (irrigation water), and from 0.818 to 1.364 µg kg-1 (soil), respectively. PFOA and PFOS hotspots were identified downstream of the Nakdong River and were influenced by seasonal climatic variations. The observed average biennial concentration of the sum of PFOA and PFOS decreased in irrigation water, from 0.112 µg L-1 in 2013 to 0.026 µg L-1 in 2015, suggests that the 2013 Persistent Organic Pollutants Control Act may have helped to reduce levels of PFAS at this location. This study calculated some of the highest plant uptake factors reported to date, with values ranging from 0.962 in green onions to < 0.004 in plums. Leafy vegetables and rice are important components of the Korean diet; these groups had the largest contribution to the estimated dietary intake of PFOA and PFOS, which was calculated at 0.449 and 0.140 ng kg bw -1 day-1, respectively. This corresponded to 66.4% for PFOA and 7.9% for PFOS of the EFSA reference dose (RfD). The dietary intake of PFOA and PFOS from crops alone did not exceed the RfD. However, when the estimated daily intake (EDI) from other sources such as tap water, meat, fish, dairy, and beverages was included in the exposure risk assessment, both of the EDIs to PFOA and PFOS exceeded the RfDs, indicating that there may be a risk to human health. This study concludes that consumption of crops might, therefore, be a significant and underappreciated pathway for human exposure to PFAS.

Per- and Polyfluoroalkyl Substances in the Air Particles of Asia: Levels, Seasonality, and Size-Dependent Distribution.

Information regarding the size-dependent distribution of per- and polyfluoroalkyl substances (PFAS) in atmospheric particulate matter (PM) is very limited. In this study, 248 size-specific PM samples were collected from 9 Asian cities using a portable 4-stage cascade impactor for the analysis of PFAS. Of the 34 investigated PFAS, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were the major compounds. In particular, the emerging PFAS, hexafluoropropylene oxide dimer acid, was quantified in the PM for the first time, with concentrations ranging from <0.086 to 21.5 pg/m3. Spatially, PFOA and PFOS were the predominant compounds in China, while precursors, emerging PFAS, and short-chain PFAS dominated in India, Japan, and South Korea, respectively. Seasonal variations of PFAS may be controlled by regional climate, local or seasonal emission sources, and long-range transport of air masses. Size-dependent distribution was investigated, showing that the majority of PFAS predominantly affiliated in fine particles, while PFOS and its alternatives tended to attach on coarser particles. Moreover, PFOS distributed on specific sizes exhibited seasonal and regional dependency, while no such patterns were observed for PFOA. These findings will provide useful information on the geographical and size-dependent distribution of PFAS in the atmospheric PM.

Chlorfenapyr Residue in Sweet Persimmon from Farm to Table.

The use of the pesticide chlorfenapyr has been increasing over time, with a consequent wider application to crops. However, there is limited information available on the amount and safety of the residues it leaves on crops. The amount of chlorfenapyr residues in sweet persimmon (Diospyros kaki L.) at both the pre- and postharvest stages were investigated in this study by calculating its biological half-life. The half-life at the preharvest stage was 8.8 days, shorter than that found during the storage periods at 4 and 20°C, when the half-lives were 11.0 and 23.9 days, respectively. In addition, peeling and washing after harvesting reduced residue content. The majority of the chlorfenapyr residues in sweet persimmon were found in the peel of the fruit, with the pulp containing less than 25% of the total. Thus, peeling effectively removed chlorfenapyr residues and diminished the residues below the limit of quantification in the pulp. In addition, washing with 1.0% alcohol and 0.2% Tween 20 solutions effectively removed 47.8 and 55.6% of the residues, respectively. Furthermore, a 1.0% alcohol solution showed high reduction efficiency for other hydrophobic pesticides, such as dimethomorph and fluquinconazole, up to 78.0%. Chlorfenapyr residues in sweet persimmon can be effectively reduced via storage or peeling and washing practices or a combination of them.

Phenylephrine, a small molecule, inhibits pectin methylesterases.

Pectin methylesterases (PMEs) catalyze pectin demethylation and facilitate the determination of the degree of methyl esterification of cell wall in higher plants. The regulation of PME activity through endogenous proteinaceous PME inhibitors (PMEIs) alters the status of pectin methylation and influences plant growth and development. In this study, we performed a PMEI screening assay using a chemical library and identified a strong inhibitor, phenylephrine (PE). PE, a small molecule, competitively inhibited plant PMEs, including orange PME and Arabidopsis PME. Physiologically, cultivation of Brassica campestris seedlings in the presence of PE showed root growth inhibition. Microscopic observation revealed that PE inhibits elongation and development of root hairs. Molecular studies demonstrated that Root Hair Specific 12 (RHS12) encoding a PME, which plays a role in root hair development, was inhibited by PE with a Ki value of 44.1 µM. The biochemical mechanism of PE-mediated PME inhibition as well as a molecular docking model between PE and RHS12 revealed that PE interacts within the catalytic cleft of RHS12 and interferes with PME catalytic activity. Taken together, these findings suggest that PE is a novel and non-proteinaceous PME inhibitor. Furthermore, PE could be a lead compound for developing a potent plant growth regulator in agriculture.

Antifungal Effect of Arabidopsis SGT1 Proteins via Mitochondrial Reactive Oxygen Species.

The highly conserved SGT1 (suppressor of the G2 alleles of skp1) proteins from Arabidopsis are known to contribute to plant resistance to pathogens. While SGT1 proteins respond to fungal pathogens, their antifungal activity is not reported and the mechanism for this inhibition is not well understood. Therefore, recombinant Arabidopsis SGT1 proteins were cloned, expressed, and purified to evaluate their antifungal activity, resulting in their potent inhibition of pathogen growth. Dye-labeled proteins are localized to the cytosol of Candida albicans cells without the disruption of the cell membrane. Moreover, we showed that entry of the proteins into C. albicans cells resulted in the accumulation of reactive oxygen species (ROS) and cell death via altered mitochondrial potential. Morphological changes of C. albicans cells in the presence of proteins were visualized by scanning electron microscopy. Our data suggest that AtSGT1 proteins play a critical role in plant resistance to pathogenic fungal infection and they can be classified to a new plant antifungal protein.

Phytotoxic mechanisms of bur cucumber seed extracts on lettuce with special reference to analysis of chloroplast proteins, phytohormones, and nutritional elements.

Bioherbicides from plant extracts are an effective and environmentally friendly method to prevent weed growth. The present investigation was aimed at determining the inhibitory effect of bur cucumber seed extracts (BSE) on lettuce plant growth. Bur cucumber seeds were ground with water, and two different concentrations of seed extracts (10% and 20%) were prepared and applied to lettuce plants. Decreased plant height, number of leaves, leaf length, leaf width, anProd. Type: FTPd leaf area were found in lettuce exposed to BSE as compared with controls. A significant reduction in lettuce biomass was observed in 20% BSE-treated plants due to the presence of higher amounts of phenolic content in the extracts. Moreover, a significant inhibitory chemical, 2-linoleoyl glycerol, was identified in BSE extracts. The mechanism of plant growth inhibition was assayed in lettuce proteins by 2-dimensional electrophoresis (2-DE) and the LC-MS/MS method. In total, 57 protein spots were detected in plants treated with 20% BSE and control plants. Among these, 39 proteins were down-regulated and 18 proteins were up-regulated in plants exposed to 20% BSE as compared with controls. The presence of low levels of chlorophyll a/b binding protein and oxygen-evolving enhancer protein 1 in BSE-exposed plants reduced photosynthetic pigment synthesis and might be a reason for stunted plant growth. Indeed, the plant-growth stimulating hormone gibberellin was inhibited, and synthesis of stress hormones such as abscisic acid, jasmonic acid, and salicylic acid were triggered in lettuce by the effects of BSE. Uptake of essential nutrients, Ca, Fe, Mg, K, S, and Mo, was deficient and accumulation of the toxic ions Cu, Zn, and Na was higher in BSE-treated plants. The results of this study suggest that extracts of bur cucumber seeds can be an effective eco-friendly bioherbicide for weed control that work by inhibiting mechanisms of photosynthesis and regulating phytohormones and nutritional elements.

Mangosenone F, A Furanoxanthone from Garciana mangostana, Induces Reactive Oxygen Species-Mediated Apoptosis in Lung Cancer Cells and Decreases Xenograft Tumor Growth.

Mangosenone F (MSF), a natural xanthone, was isolated form Carcinia mangotana, and a few studies have reported its glycosidase inhibitor effect. In this study we investigated the anti lung cancer effect of MSF both in vitro and in vivo. MSF inhibited cancer cell cytotoxicity and induced and induced apoptosis via reactive oxygen species (ROS) generation in NCI-H460. MSF treatment also showed in pronounced release of apoptogenic cytochrome c from the mitochondria to the cytosol, downregulation of Bcl-2 and Bcl-xL, and upregulation of Bax, suggesting that caspase-mediated pathways were involved in MSF-induced apoptosis. ROS activation of the mitogen-activated protein kinase signaling pathway was shown to play a predominant role in the apoptosis mechanism of MSF. Compared with cisplatin treatment, MSF treatment showed significantly increased inhibition of the growth of NCI-H460 cells xenografted in nude mice. Together, these results indicate the potential of MSF as a candidate natural anticancer drug by promoting ROS production.

Multiple Leader Candidate and Competitive Position Allocation for Robust Formation against Member Robot Faults.

This paper proposes a Multiple Leader Candidate (MLC) structure and a Competitive Position Allocation (CPA) algorithm which can be applicable for various applications including environmental sensing. Unlike previous formation structures such as virtual-leader and actual-leader structures with position allocation including a rigid allocation and an optimization based allocation, the formation employing the proposed MLC structure and CPA algorithm is robust against the fault (or disappearance) of the member robots and reduces the entire cost. In the MLC structure, a leader of the entire system is chosen among leader candidate robots. The CPA algorithm is the decentralized position allocation algorithm that assigns the robots to the vertex of the formation via the competition of the adjacent robots. The numerical simulations and experimental results are included to show the feasibility and the performance of the multiple robot system employing the proposed MLC structure and the CPA algorithm.

Residual perfluorochemicals in the biochar from sewage sludge.

Biochar has been recently considered as a candidate for soil amendment and soil remediation. Some pollutants have been screened in the biochar for safety purposes except for perfluorochemicals (PFCs). In this study, the contamination of biochars from plant residues and sewage sludge with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) was examined. The total residual concentrations of PFOA and PFOS in the sludge biochar were 15.8-16.9 ng/g and these values did not decrease significantly after pyrolysis. On the other hand, these PFCs were not found in the biochar from plant sources. In conclusion, the use of the sludge biochar in the agricultural environment should be re-evaluated, since the concentrations of PFCs in the sewage sludge showed no significant decrease after thermal process.

Saponarin from barley sprouts inhibits NF-κB and MAPK on LPS-induced RAW 264.7 cells.

Saponarin (SA), a natural flavonoid, is known for its antioxidant and hepatoprotective activities. SA is the predominant compound (1142.7 ± 0.9 mg per 100 g) in barley sprouts, constituting 72% of the total polyphenol content. We investigated, for the first time, the effects of SA from barley sprouts on cellular anti-inflammatory responses. In lipopolysaccharide (LPS)-induced RAW 264.7 macrophages, SA suppressed the activation of NF-κB, as evidenced by the inhibition of NF-κB DNA binding, nuclear translocation, IκBα phosphorylation, and reporter gene expression, and it downregulated the expression of the pro-inflammatory mediator IL-6. Furthermore, SA reduced the transcription of NF-κB target molecules COX2 and FLIP inhibited the phosphorylation of mitogen-activated protein kinases ERK and p38. These results suggest that SA isolated from barley sprouts exerts anti-inflammatory effects in LPS-induced RAW 264.7 macrophages via inhibition of NF-κB, ERK and p38 signaling. Thus, SA may be a promising natural anti-inflammatory agent.

Polycyclic aromatic hydrocarbon generation in heat-processed sundried salt.

An investigation of polycyclic aromatic hydrocarbon (PAH) generation in sundried salt samples was conducted. Of the 16 priority PAHs tested for, naphthalene was revealed as the most dominant PAH, with residual concentrations measured as 0.33 to 7.02 ng/g after sundried salt heat processing over temperatures ranging from 250 to 700°C. Eleven organic carbon sources were tested to determine the relationship between carbon source and PAH generation under various heat-processing conditions. Citric acid was found to be the most significant contributor to PAH generation in salt. Investigations of PAH contamination levels were conducted for 32 commercial sundried salts and 73 heat-processed salts; none of the PAHs tested for were detected in any of the commercial salts examined.