• Environmental Analysis Health and Toxicology
• /
• v.19 no.4
• /
• pp.367-373
• /
• 2004

Mancozeb, a polymeric complex of zinc and manganese salts of ethylene bisthiocarbamate (EBDC), is used widely in agriculture as fungicides, insecticides, and herbicides. Mancozeb can be occupationally and environmentally exposed to human and has been reported to induce estrogenic activity, therein it is considered as an endocrine disrupter. After female ICR mice were treated Mancozeb orally at the doses of 250, 1,000 and 1,500 mg/kg/day for consecutive 30 day, we investigated the effects of Mancozeb on the immunopathological parameters (body-, thymus-, spleen-, liver- and kidny-weight, splenic cellularity, hematological parameters) and mitogen (Con A, LPS)-induced splenocyte proliferation (SP). Liver- and kidney- weight were increased, but body- and thymus-weight, number of splenocytes and WBC were decreased, when compared with control group. When splenocytes isolated from the mice exposed to Mancozeb for 30 days were cultured in presence of mitogens, the SP against Con A was significantly and dose-dependently decreased and the SP against LPS was also slightly decreased. Our present results indicate that subacute exposure of Mancozeb to mice might show immunotoxic effect.

• Korean Journal of Ecology and Environment
• /
• v.50 no.1
• /
• pp.16-28
• /
• 2017

In an aquatic environment, toxicity of metals to organisms depends on external factors (type of metal, exposure concentration and duration, environmental parameters, and water quality) and intracellular processes(metal-binding sites and detoxification). Toxicity of copper(Cu) on the marine microalga Tetraselmis suecica was investigated in this study. Dose-dependent (Cu concentration dependent) inhibition of growth and cell division, as well as, variation of intra- and extra-cellular Cu, Fe and Zn content was observed. T. suecica was sensitive to Cu; the 96 h $EC_{50}$ (concentration to inhibit growth-rate by 50%) of growth rate (${\mu}$) ($21.73{\mu}M\;L^{-1}$), cell division $day^{-1}$ ($18.39{\mu}M\;L^{-1}$), and cells $mL^{-1}$ ($13.25{\mu}M\;L^{-1}$) demonstrate the toxicity of Cu on this microalga. High intra-($19.86Pg\;cell^{-1}$) and extra-cellular($54.73Pg\;cell^{-1}$) Cu concentrations were recorded, on exposure to 24.3 and $72.9{\mu}M\;L^{-1}$ of Cu.

• Corrosion Science and Technology
• /
• v.18 no.3
• /
• pp.86-91
• /
• 2019

Generally, atmospheric corrosion is the electrochemical degradation of metal that can be caused by various corrosion factors of atmospheric components and weather, as well as air pollutants. Specifically, moisture and particles of sea salt and sulfur dioxide are major factors in atmospheric corrosion. Using galvanized steel is one of the most efficient ways to protect iron from corrosion by zinc plating on the surface of the iron. Galvanized steel is widely used in automobiles, building structures, roofing, and other industrial structures due to their high corrosion resistance relative to iron. The atmospheric corrosion of galvanized steel shows complex corrosion behavior, depending on the plating, coating thickness, atmospheric environment, and air pollutants. In addition, corrosion products are produced in different types of environments. The lifespans of galvanized steels may vary depending on the use environment. Therefore, this study investigated the corrosion behavior of galvannealed steel under atmospheric corrosion in two locations in Korea, and the lifespan prediction of galvannealed steel in rural and coastal environments was conducted by means of the potentiostatic dissolution test and the chemical cyclic corrosion test.

• Korean Journal of Environmental Biology
• /
• v.36 no.3
• /
• pp.392-399
• /
• 2018

Toxicity assessment of antifouling agent, zinc undecylenate (ZU) has been investigated using the rate of survival and population growth in marine rotifer, Brachionus plicatilis. The survival rate of Brachionus plicatilis was determined after 24 h of exposure to ZU and was not affected up to the maximum level of $100.0mg\;L^{-1}$ of ZU. The population growth rate (r) was determined after 72 h of exposure to ZU. It was observed that r in the controls (absence ZU) was greater than 0.5 but exhibited a sudden decrease with an increase in the concentration of ZU. ZU reduced r in a dose-dependent manner and a significant reduction occurred at a concentration greater than $12.5mg\;L^{-1}$. The 50% effective concentration ($EC_{50}$) value of r during ZU exposure was $26.4mg\;L^{-1}$, No-observed-effect-concentration (NOEC) was $6.3mg\;L^{-1}$ and Lowest-observed-effect-concentration (LOEC) was $12.5mg\;L^{-1}$, respectively. Based on the results, it is apparent that ZU concentration greater than $12.5mg\;L^{-1}$ exhibited a toxic effect on the r of zooplankton, B. plicatilis in natural ecosystems.

• Korean Journal of Environmental Biology
• /
• v.37 no.3
• /
• pp.372-379
• /
• 2019

We evaluated the toxic effects of phenanthrene (PHE) and zinc undecylenate (ZU) on the population growth rate (r) of the marine diatom, Skeletonema costatum. The r of S. costatum was determined after 96 hrs of exposure to PHE (0, 25, 50, 100, 200 and 300 mg L^-1) and ZU (0, 5, 10, 15, 20 and 25 mg L^-1). The results showed that r in the control (the absence of PHE and ZU) was greater than 0.04, while r in the treatment groups decreased with increasing PHE and ZU concentrations. PHE and ZU were shown to reduce r in a dose-dependent manner, with significant decreases occurring at concentrations above 50 and 10 mg L^-1, respectively. The EC₅₀ values of r in PHE and ZU exposure were 136.13 and 16.95 mg L^-1, respectively. The no observed effect concentrations (NOEC) were 25 and 5 mg L^-1, and the lowest observed effect concentrations (LOEC) were 50 and 10 mg L^-1. These results indicated that concentrations of greater than 50 mg L^-1 of PHE and 10 mg L^-1 of ZU in marine ecosystems induced a toxic effect on the r of S. costatum. These results can serve as useful baseline data for the establishment of safety concentrations of PHE and ZU in marine ecosystems.

• Journal of Preventive Medicine and Public Health
• /
• v.56 no.5
• /
• pp.422-430
• /
• 2023

Objectives: Prolactin is vital for breastfeeding and milk production, and its secretion is influenced by factors related to the mother, infant, and environment. To date, no study has concurrently investigated the correlation of these factors with serum prolactin levels during lactation. Therefore, the objective of this study was to investigate the correlations among maternal and infant factors, lead exposure, and serum prolactin levels during lactation. Methods: A cross-sectional approach was employed in Surabaya, Indonesia, among 110 exclusively lactating mothers. The mothers' daily diets were determined using multiple 24-hour recalls, while blood lead levels were measured with inductively coupled plasma mass spectrometry. Serum prolactin levels were assessed using the electrochemiluminescence immunoassay. For bivariate analysis, we employed the Spearman correlation, Mann-Whitney, and Kruskal-Wallis tests, while for multivariate analysis, we utilized multiple linear regression. Results: The average serum prolactin level of the lactating mothers was 129.19±88.96 ng/mL. Positive correlations were found between serum prolactin levels and breastfeeding frequency (p<0.001), protein intake (p<0.001), and calcium intake (p=0.011) but had negative correlation with blood lead levels (p<0.001) and vitamin B6 intake (p=0.003). Additionally, prolactin levels were not significantly associated with maternal age; parity; intake of calories, vitamin D, vitamin E, zinc, folic acid, magnesium, or iron; infant age; or infant sex. Conclusions: Breastfeeding frequency had a stronger positive relationship with serum prolactin levels than protein and calcium intake. However, lead exposure was associated with reduced serum prolactin levels during lactation. Consequently, specific interventions from policymakers are necessary to manage breastfeeding in mothers exposed to lead.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.2
• /
• pp.322-328
• /
• 2007

The first molar is important for mastication and also it plays roles to formation of vertical occlusion and growth of jaw bone after mixed dentition. Impaction of mandibular first molar can result in a short lower facial height, formation of a follicular cyst, pericoronal inflammation, resorption of the roots of neighboring teeth and malocclusion. The options of treatment plans are as follows; observation, surgical exposure, orthodontic traction, surgical relocation and extraction. Surgical exposure could be considered as a basic treatment plan. For surgical exposure it is important to maintain patent channel between the crown and the normal eruptive path into the oral cavity, many techniques including cementation of a celluloid crown, packing with zinc oxide-eugenol surgical pack are used. In these cases, we could observe spontaneous eruption of mandibular first molar using surgical exposure with or without removal of odontoma. Also we could obtain the main patency effectively and conveniently by using surgical pack and translucent retainer.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.4 s.51
• /
• pp.875-884
• /
• 1995

In order to investigate the level of lead exposure of workers in litharge making industry and to evaluate how lead exposure, personal habit such as smoking and drinking affect the prevalence of lead related symptoms and other study variables, we investigate 114 workers(24 office workers and 90 lead exposed workers) in a litharge making industry. Study variables chosen were blood lead(PbB), zinc protoporphyrin in whole blood(ZPP), Hemoglobin(Hb), hematocrit (Hct), SGOT and SGPT symptom questionnaires which had 15 lead exposure related symptoms were provided to all workers and filled up by themselves and reconfirmed by physician. The results obtained were as follows; 1. The mean value of PbB, ZPP and SGOT in lead exposed group were higher than those of non-exposed group, and there were no differences of means in other study variables. 2. The smoking and drinking rate of study subjects were 65.8% and 71.0% as a whole. Smoking rates were lower in non-exposed group than exposed group, but drinking rate were not. 3. There were no differences of mean values of study variables between smoker and non-smoker in non-exposed and exposed group, but there was a difference of mean value of SGOT between drinker and lion-drinker in lead exposed group. 4. While the symptom prevalence of lead exposed group were higher in neuromuscular category than non-exposed group, those of non-exposed group were higher or same with exposed group in gastrointestinal and general symptom category. 5. The symptom prevalence of smoker were higher than non-smoker regardless of exposure. 6. The symptom prevalence of drinker were only higher in gastrointestinal symptom category than non-drinker. 7. In multiple stepwise regression analysis of lead related symptoms as dependent variable and blood lead, smoking habit, drinking habit and work duration as independent variables, drinking habit contributed to the gastrointestinal symptom category, whereas blood lead and smoking contributed to the neuromuscular symptom category. For the total symptoms work duration and smoking habit contributed significantly.

• Journal of Preventive Medicine and Public Health
• /
• v.30 no.4 s.59
• /
• pp.741-751
• /
• 1997

Measurement of blood lead (PbB) and blood zinc protoporphyrin (ZPP) are most common biological indices to identify the individual at risk for excess or the health sequences by lead exposure. Because PbB is known most important and reliable index of lead exposure, PbB is often regarded as a gold standard to detect lead exposure. But in Korea PbB is a secondary test item of detailed health check-up with positive finding of screening test in most occasion. Our lead standard requires all lead workers to take annual heath-check twice a year for investigation of their health effect due to lead exposure. Blood ZPP is one of most important index to detect high lead absorption in lead workers as a screening test. Measurement of blood ZPP is known ,well to correlate with PbB in steady state of exposure in most lead workers and is often used as a primary screening test to detect high lead absorption of lead workers with the advantage of simplicity, easiness, portability and low cost. The current cut-off criteria of blood ZPP for further detailed health check-up is $100{\mu}g/d\ell$ which is supposed to match the level of $40{\mu}g/d\ell$ of PbB according to our standard. Authors tried to investigate the validity of current criteria of cut-off level $(100{\mu}g/d\ell)$ of blood ZPP and possible another better cut-off level of it to detect the lead workers whose PbB level over $40{\mu}g/d\ell$. The subjects in our study were 212 male workers in three small scale storage battery industries. Blood ZPP, PbB and hemoglobin (Hb) were selected as the indices of lead exposure. The results were as follows. 1. The mean of blood ZPP, PbB and Hb in lead workers were $79.5{\pm}46.7{\mu}g/d\ell,\;38.7{\pm}15.1{\mu}g/d\ell,\;and\;14.8{\pm}1.2g/d\ell$, respectively. There were significant differences in blood ZPP, PbB and Hb by industry (P<0.01). 2. The percents of lead workers whose blood ZPP were above $100{\mu}g/d\ell$ in the group of work duration below 1, 1-4, 5-9 and above 10 years were 8.6%, 17.2%, 47.6%, and 50.0%, respectively. The percents of lead workers whose PbB were above $40{\mu}g/d\ell$ in those were 31.4%, 40.4%, 71.4%, and 86.4%, respectively. 3. The percents of lead workers whose PbB were below $40{\mu}g/d\ell$, $40-59{\mu}g/d\ell$ and above $60{\mu}g/d\ell$ were 54.7%, 34.9% and 10.4%, respectively. Those of lead workers whose blood ZPP were below $100{\mu}g/d\ell$, $100-149{\mu}g/d\ell$ and above $150{\mu}g/d\ell$ were 79.2%, 13.7% and 7.1%, respectively. 4. Simple linear regression of PbB on blood ZPP was statistically significant (P<0.01) and as PbB was $40{\mu}g/d\ell$, blood ZPP was $82.1{\mu}g/d\ell$. 5. While the highest sensitivity and specificity of blood ZPP test to detect lead workers with PbB eve. $40{\mu}g/d\ell$ were observed in the cut-off level of $50{\mu}g/d\ell$ and $100{\mu}g/d\ell$ of blood ZPP, respectively, the highest validity (sensitivity+specificity) of blood ZPP to detect lead workers with PbB over $40{\mu}g/d\ell$ was observed in the cut-off level of around $70{\mu}g/d\ell$ of blood ZPP. But even with optimal cut-off level of around $70{\mu}g/d\ell$ of blood ZPP, still 25.0% of false negative and 20.7% false positive lead workers were found. As the result of this study, it was suggested that reconsideration of current blood ZPP cut-off of our lead standard from $100{\mu}g/d\ell$ to somewhat lower level such as around $70{\mu}g/d\ell$ and the inclusion of PbB measurement as a primary screening test for lead workers was highly recommended for the effective prevention of lead workers.

• Journal of Preventive Medicine and Public Health
• /
• v.32 no.4
• /
• pp.499-504
• /
• 1999

Objectives : To evaluate whether a relation between blood lead and zinc proto porphyrin(ZPP) was modified by gender in Korean lead workers. Methods : A cross-sectional study was conducted with 1,304 male and 101 female subjects in 1997. The relation between blood lead and ZPP were evaluated with linear, exponential, and quadratic models. Then, the different effect of gender on the relation was examined by adding the interaction terms in the each model. Results : $Mean{\pm}SD$ of blood lead and ZPP level was different between male$(27.7{\pm}10{\mu}g/dl\;and\;51.3{\pm}23.4{\mu}g/dl)$ and female subjects$(22.5{\pm}9.2{\mu}g/dl\;and\;78.7{\pm}38.6{\mu}g/dl)$. After adjusting for possible confounders, the effect modification by gender was significant in linear$(\beta=1.119,\;p<0.001)$, exponential$(\beta=Exp(0.008),\;p<0.05)$, and quadratic model$(\beta=1.388,\;p<0.001)$. In separate analysis, a quadratic relation between blood lead and ZPP was shown in male lead workers$(\beta=0.036,\;p<0.001)$, but an exponential relation in female lead workers$(\beta=Exp(0.029), p<0.001)$. Conclusion : Our data showed that the increasing rate of ZPP in female were always higher than in male lead workers, suggesting that females were more susceptible to occupational lead exposure than males.