Little is known about associations between depression and serum heavy metal levels, dietary vitamin intakes. Thus, we sought to determine the nature of these associations and to predict risks of depression using marginal effects. A data set of 16,371 individuals aged ≥10 years that participated in Korea National Health and Nutrition Examination Surveys (KNHANES) conducted from 2009 to 2017 (excluding 2014 and 2015) was used to obtain information on sociodemographics, family histories, lifestyles, serum heavy metal levels, food intakes, and depression. Serum cadmium (Cd) and lead (Pb) levels were analyzed by graphite furnace atomic absorption spectrometry and mercury (Hg) levels using a mercury analyzer. Daily vitamin intakes were calculated by 24-h dietary recall. The results obtained showed that females are at higher risk of depression than males. A doubling of serum Cd was associated with a 21% increase in depression (AOR 1.21, 95% CI: 1.07–1.37, p = 0.002), whereas twofold increases in daily vitamin B1, B3 and vitamin A intakes reduced the risk of depression by 17% (0.83, 95% CI: 0.73–0.95, p = 0.005), 20% (0.80, 95% CI: 0.70–0.91, p = 0.001), and 8% (0.92, 95% CI: 0.85–0.99, p = 0.020), respectively. Interactions between heavy metals, vitamin intakes, and sex did not influence the risk of depression. The result shows that increased daily dietary vitamin intake might protect the public against depression. Further studies are needed to reduce the risks posed by heavy metals and to determine more comprehensively the effects of daily dietary vitamin intake on depression.

Biofouling material samples from the Arabian (Persian) Gulf, used as inocula in batch cultures, brought about crude oil and pure-hydrocarbon removal in a mineral medium. Without any added nitrogen fertilizers, the hydrocarbon-removal values were between about 10 and 50 %. Fertilization with NaNO₃alone or together with a mixture of the vitamins thiamine, pyridoxine, vitamin B12, biotin, riboflavin, and folic acid increased the hydrocarbon-removal values, to reach 90 %. Biofouling material samples harbored total bacteria in the magnitude of 10⁷cells g⁻¹, about 25 % of which were hydrocarbonoclastic. These numbers were enhanced by NaNO₃and vitamin amendment. The culture-independent analysis of the total bacterioflora revealed the predominance of the gammaproteobacterial genera Marinobacter, Acinetobacter, and Alcanivorax, the Flavobacteriia, Flavobacterium, Gaetbulibacter, and Owenweeksia, and the Alphaproteobacteria Tistrella, Zavarzinia, and others. Most of those bacteria are hydrocarbonoclastic. Culture-dependent analysis of hydrocarbonoclastic bacteria revealed that Marinobacter hydrocarbonoclasticus, Dietzia maris, and Gordonia bronchialis predominated in the fouling materials. In addition, each material had several more-specific hydrocarbonoclastic species, whose frequencies were enhanced by NaNO₃and vitamin fertilization. The same samples of fouling materials were used in four successive crude-oil-removal cycles without any dramatic loss of their hydrocarbon-removal potential nor of their associated hydrocarbonoclastic bacteria. In the fifth cycle, the oil-removal value was reduced by about 50 % in only one of the studied samples. This highlights how firmly biofouling materials were immobilizing the hydrocarbonoclastic bacteria.

There is no research published sofar on managements that could bioremediate hypersaline soils and water polluted with hydrocarbons. The objective of this study was to assess the effect of vitamin amendment on hydrocarbon removal by microorganisms indigenous to such hypersaline environments. We used in this study ten hydrocarbonoclastic bacterial species and five archaeal species that had been isolated by the conventional plating method on media containing oil as a sole carbon source, from a hypersaline (3–4 M NaCl) coastal area in Kuwait, and characterized by sequencing of their 16S rRNA coding genes. The oil and pure hydrocarbon consumption was measured by gas–liquid chromatography. The oil and pure hydrocarbon consumption potential of all microorganisms in media with hypersalinity was enhanced by vitamin fertilization. This was true for individual microorganisms in pure cultures as well as for microbial consortia in hypersaline soil and water samples used as inocula. Most effective vitamins were thiamin, pyridoxine and vitamin B₁₂. Vitamin fertilization using vitamin rich wastes or byproducts could be an effective practice for enhancing bioremediation of oil contaminated hypersaline environments.