Journal of Health and Pollution最新文献

Background: Exposure to lead (Pb) has been associated with endocrine, hematological, gastrointestinal, renal and neurological problems in humans. However, effects on the thyroid gland are controversial.

Objectives: The aim of the present study was to assess thyroid function in foundry workers occupationally exposed to Pb and the mechanism of oxidative-antioxidant imbalance.

Methods: Thyroid function parameters and markers of oxidative stress were examined in 59 adult males who had been occupationally exposed to Pb. The results were then compared to those of 28 male subjects who had no history of Pb exposure or thyroid abnormalities and served as a control group.

Results: Mean blood lead levels (16.5±1.74 μg/dl) were significantly higher among the exposed workers compared to those of the control group (12.8±1.16 μg/dl, (p <0.001)). The exposed group had significantly increased free triiodothyronine (FT3), free thyroxine (FT4) and significantly decreased thyroid stimulating hormone (TSH) (1.77±0.44 μIU/ml), whereas the control group had a TSH level of 2.61±0.94 μIU/ml (p< 0.0001). A state of oxidative stress was indicated by the significant increase in mean levels of malondialdehyde (MDA) and significant decrease in glutathione (GSH) (p < 0.0001). There was a significant positive correlation (r=0.358, p <0.05) between blood lead levels (BLL) and duration of employment, while BLL showed a significant negative correlation with TSH (r =-0.486, p <0.001), and GSH (r =-0.336, p <0.05). Of the occupationally exposed workers, 32.76% had elevated thyroid hormones. The results showed a significant positive relationship between GSH and TSH (β coefficient=0.274, p < 0.05), MDA with FT3 (β coefficient=0.355, p < 0.05) and FT4 (β coefficient = 0.491, p < 0.0001) among exposed workers.

Conclusions: Workers exposed to Pb dust proved to be at risk for hyperthyroidism, which was found to have a significant role in oxidative-antioxidant imbalance present among workers with increasing duration of exposure.

Participant consent: Obtained.

Ethics approval: This study was approved by the Ethical Committee of the National Research Centre in Egypt (NRC) under the registration number 15225.

Competing interests: The authors declare no competing financial interests.

Background: In parts of Cambodia and in many other parts of the world, irrigation of rice with groundwater results in arsenic (As) accumulation in soil and rice, leading to health concerns associated with rice consumption. At times, some As is present as relatively nontoxic, non-regulated, dimethylarsinic acid (DMA). Low levels of zinc (Zn) have been found in rice from Bangladesh, Cambodia, and China where As levels in rice are high. Furthermore, there have been claims that Zn deficiency is responsible for stunting the growth of children in Cambodia and elsewhere, however in rural Asia, rice is the major source of Zn. Current data are inadequate for both Zn and DMA in Cambodian rice.

Objectives: The present study aimed to provide a preliminary evaluation of the relationship between the content of Zn and DMA in rice grain in Preak Russey, an area with elevated levels of As in groundwater and to improve the management of Zn deficiency in rice.

Methods: Rice agriculture was evaluated along the Mekong River in Cambodia. Analyses for metals, total As, and As species in rice and water were conducted by inductively coupled plasma mass spectrometry. Analysis of total Zn and As in soils and total Zn in rice were analyzed using X-ray fluorescence (XRF) spectrometry.

Results: Rice in Preak Russey had Zn concentrations less than a third the level recommended by the United Nations World Food Programme. There was a significant (p < 0.05) negative correlation between the Zn content of rice and DMA in rice with the lowest Zn and highest DMA levels occurring near irrigation wells, the source of As.

Conclusions: The highest levels of DMA in rice were associated with Zn deficiency in rice.

Competing interests: The authors declare no competing financial interests.

Background: Artisanal and small-scale gold mining is a human health concern, especially in low-income countries like Uganda due to the use of mercury (Hg) in the mining process.

Objective: The aim of the present study was to assess Hg exposure among artisanal and small-scale gold miners in Uganda through biologic monitoring parameters and Hg-related clinical manifestations.

Methods: A cross-sectional study was conducted from June to July 2018 among 183 miners from Ibanda (Western region), Mubende (Central region), Amudat (Karamoja region) and Busia (Eastern region) in Uganda. An interviewer-administered questionnaire and health assessment were used to collect socio-demographic, exposure and self-reported Hg poisoning symptoms. In addition, 41 urine, 41 blood and 26 environment samples were assessed. Descriptive statistics, Kruskal-Wallis test and Wilcoxon signed-rank test for comparison of Hg levels in urine and blood among miners were performed while logistic regression was used to assess associations between exposure and Hg poisoning-related symptoms.

Results: The miners ranged from 15 to 65 years old and were primarily male (72.6%). The majority (73.3%) had worked directly with Hg for an average duration of 5.3 years. Symptoms associated with working directly with Hg included chest pain (odds ratio (OR)=9.0, confidence interval (CI)=3.3 to 24.6), numbness (OR=8.5, CI=2.1 to 34.4), back pain (OR=6.2, CI= 2.2 to 17.5), fatigue and stress (OR=5.4, 2.0 to CI=14.9), headache (OR=4.7, CI=1.9 to 11.3), dizziness (OR=3.8, CI=1.5 to 9.7) joint pain (OR=3.2, CI=1.3 to 8.3) and respiratory problems (3.2, 1.0 to 10.1). Statistically significant differences in Hg levels with p-values less than 0.05 were observed across district, gender and type of work. Mubende had the highest blood and urine levels (136 μg/l and 105.5 μg/l) in comparison with Busia (60 μg/l and 70.6 μg/l) and Ibanda (43 μg/l and 58 μg/l). Females (84.7 μg/l), panners (109 μg/l) and those with knowledge of occupational health and safety measures (95.6 μg/l) reported higher levels of Hg in urine. The average levels of Hg in water and soil samples were 23.79 μg/l and 0.21 μg/l, respectively.

Conclusions: Variation in Hg levels were attributed to varied duration of exposure across geographical sites. There was considerable exposure to Hg as indicated by both clinical manifestations and biologic parameters among miners in Uganda with Hg in urine exceeding the recommended thresholds.

Participant consent: Obtained.

Ethics approval: Ethical approval was obtained from the Makerere University School of Health Science Institutional Review Board (reference number SHSREC REF 2018-2019) and Uganda National Council for Science and Technology (reference number SS 4577).

Competing interests: The authors declare no competing fin

Background: Industries such as electroplating, mining and battery production are major sources of heavy metal-rich waste entering nearby water bodies. Irrigation with heavy metal contaminated water can deteriorate soil quality as well as agricultural produce and have further toxic effects on human health.

Objectives: The objective of the present study was to estimate the concentration of hazardous heavy metals such as chromium (Cr), cadmium (Cd), copper (Cu), nickel (Ni), zinc (Zn) and lead (Pb), as well as physico-chemical variables (pH, electrical conductivity, total dissolved solids, chemical oxygen demand and dissolved oxygen) at sampling locations along the Najafgarh and Loha mandi drains in Delhi, National Capital Region, India.

Methods: The present study evaluated the quality of wastewater from the Najafgarh and Loha mandi drains, which are used for irrigational purposes in the Delhi region. Drain water quality was monitored for a period of 2 years for physico-chemical variables (pH, chemical oxygen demand, electrical conductivity and dissolved oxygen) as well as heavy metal concentrations (Cr, Cu, Cd, Zn, Ni and Pb). The two-year monitoring period (July 2012-March 2014) was chosen to represent three seasons: pre-monsoon, monsoon, and post-monsoon.

Results: Varied concentrations of multiple heavy metals were found due to the extensive discharge of untreated industrial effluents into the drain water. Punjabi Bagh of Najafgarh drain was the most contaminated sampling site with the maximum concentration of Zn (12.040 ± 0.361 mg L^-1), followed by Cr (2.436 ± 0.073mg L^-1) and Cu (2.617 ± 0.078 mg L^-1).

Conclusions: Consumption of heavy metal-contaminated agricultural products can cause deleterious human health effects, leading to further health problems. The presence of multi-heavy metal ions above the Food and Agriculture Organization of the United Nations (FAO) permissible limits indicated that drain water was not suitable for irrigational purposes, and adequate measures are required to remove the heavy metal load from drain water.

Competing interests: The authors declare no competing financial interests.

Background: Mine waste from abandoned mining sites can cause environmental degradation and ecological imbalance to receiving water bodies. Heavy metal pollution affects local communities and may pose health risks to the general public. An abandoned mining facility in Marinduque, Philippines, situated on the of Mogpog River, continuously deposits mine wastes, which may affect the river and the health of local communities.

Objectives: The aim of the present study was to examine the presence and extent of heavy metal contamination from mine wastes in the aquatic ecosystem of the Mogpog River by determining the level of heavy metal concentration in the water, sediments and biota.

Methods: Four sampling sites were monitored for heavy metals (copper (Cu), arsenic (As), chromium (Cr) and sulfur (S)) pollution. Several analyses were conducted to determine the heavy metals present in the water, sediment and biota. Atomic absorption spectrophotometry was used for the analysis of Cu concentrations in water. X-ray fluorescence was used for the analysis of total heavy metals in the sediments and biota.

Results: An inverse relationship with water and sediment from upstream to downstream of the river were observed. This trend shows deposition of Cu in the sediments as factored by pH. Flora gathered from the riverbanks recorded concentrations of Cu in their leaves and fruits.

Conclusions: It has been difficult for the Mogpog River to regain water quality after years of mine waste deposition. Acid mine drainage occurred upstream of the river which affects the speciation of heavy metals. The potential risk of heavy metal exposure to local communities was observed due to the communities' river utilization.

Participant consent: Obtained.

Ethics approval: The Office of Vice Chancellor for Research and Extension of University of the Philippines Los Baños approved the study.

Competing interests: The authors declare no competing financial interests.

Background: Pollution of the aquatic ecosystem by heavy metals is increasing due to anthropogenic activities. Cadmium (Cd) can accumulate in soil, be taken up by plants, and passed on in the food chain to animals and humans.

Objectives: The present study was conducted to analyze the uptake of Cd in muscles of sampled fish with different feeding habits and to compare levels of Cd in fish from the Ayeyarwady River, Myanmar with international standards.

Methods: The acid digestion procedure was used for sample preparation. Cadmium concentrations in fish samples were determined by flame atomic absorption spectrophotometry (Perkin Elmer AAanalyst 800 and Winlab-32 software).

Results: In herbivorous fish species, Cd content ranged from 0.07 (Catla catla) to 0.086 mg/kg (Osteobrama belangeri). In carnivorous fish species, Cd ranged from 0.060 (Mystus leucophasis) to 0.083 mg/kg (Wallago attu). In omnivorous fish species, Cd ranged from 0.07 (Botia histrionica) to 0.084 mg/kg (Gudusia variegata). Cadmium content did not differ significantly across the three types of feeding habits (p>0.05).

Discussion: The accumulation of Cd in the muscle of studied fish was lower than the permissible limit set down by the European Union in 2001 (0.1 ppm), but above the limits set down by the Food and Agriculture Organization/World Health Organization, European Commission (0.05 ppm) and within the limit of United States Food and Drug Administration (0.01-0.21 ppm). The data obtained in the present study indicate that levels of Cd were not significantly different across fish species with different feeding habits.

Conclusions: The examined fish samples were not fully safe for human consumption due to high levels of Cd.

Competing interests: The authors declare no competing financial interests.

Background: The Meycauayan River is considered one of the most severely polluted rivers in the Philippines due to heavy metal and organic pollution that has caused environmental degradation.

Objectives: The aim of the present study was to provide insight on the current status of the Meycauayan River and outline an appropriate strategy to solve problems of organic and heavy metal contamination.

Methods: The physical, chemical and biological characteristics of the water and sediments were analyzed and evaluated based on available local and international standards. Three sites (upstream, midstream and downstream) of the river were considered for the evaluation of water and sediment quality.

Results: Dissolved oxygen, measured in the morning, was very low at the upstream sampling station (1.87 ppm) and even lower at the downstream site (0.49 ppm). The temperature for the three sites ranged from 28.03°C (upstream) to 30.75°C (downstream). Visual inspection indicated that the color of the water was gray upstream and midstream, and black at the downstream station. Biochemical oxygen demand exceeded the recommended limits of the Department of Environment and Natural Resources (DENR) of 7.0 ppm with values of 13.22 ppm (upstream) and 12.02 ppm (downstream). Chemical oxygen demand exceeded the limit of 20 ppm at the downstream site at 84 ppm. Dissolved oxygen did not reach the recommended limit of 5.0 ppm of the DENR. There was a high coliform count at both the upstream (3.5 × 104 colony-forming unit (cfu)/ml) and downstream (2.5 × 104) sites, which exceeded the limit of the United States Environmental Protection Agency (USEPA) of 126 cfu/100 ml. Heavy metals such lead (Pb), zinc (Zn), copper (Cu), manganese (Mn) and chromium (Cr) exceeded the severe effect level of the National Oceanic and Atmospheric Administration (NOAA), which could be detrimental to humans and aquatic life. The results of one-way analysis of variance showed significant differences (p <0.001) in pH, temperature, dissolved oxygen, conductivity, total dissolved solids, chemical oxygen demand, nitrates and phosphates for water quality and Pb, Zn, Cu, Mn and Cr for sediment quality across the study sites.

Conclusions: The results of the present study indicate that the downstream site was more polluted, possibly due to the accumulation of pollutants coming from the upstream site. The deterioration of the Meycauayan River is a result of rapid industrialization, urbanization and population growth. Examination of the water quality of the Meycauayan River indicates that it is very polluted and requires an immediate solution. The results of the present study should be used as a basis for crafting strategies to rehabilitate the Meycauayan River.

Competing interests: The authors declare no competing financial interests. This study was funded by Pure Earth.

Background: In early 2010, outbreaks of lead poisoning due to artisanal gold mining in villages in the northwest Nigerian state of Zamfara have resulted in the death of hundreds of children < 5 years old. There have also been unconfirmed reports of high mortality of geese within these villages.

Objectives: To report a case of lead poisoning in three domestic free-range chickens found in one of the affected communities where illegal small-scale gold mining activities take place.

Methods: Three free-range domestic chickens were presented during a field investigation in one of the villages. The birds were observed to be emaciated, weak, showing nervous manifestations and moribund.

Results: Tissue extracts of liver, spleen and intestines were negative for Newcastle viral antigens, while cultures of liver and spleen biopsy were positive for Escherichia coli. Histopathological lesions were observed in the kidney, proventriculus and brain. Concentrations of lead in the tissues ranged between 7.5 mg/kg and 120.5 mg/kg wet weight, and the potential daily intake of lead in the tissues were estimated at 34.06-200.15 μg/day/kg body weight with an average of 118.37 μg/day/kg body weight.

Conclusions: The results of the present study suggest probable risk to human health due to the consumption of chicken contaminated by lead in the affected villages. Poisoning in animal populations may serve as a sentinel to assess the extent of environmental contamination and human health problems related to lead.

Ethics approval: Protocols were approved and performed in accordance with relevant local guidelines and regulations as set by the Animal Care and Use Committee of the National Veterinary Research Institute, Vom, Nigeria.

Competing interests: The authors declare no competing financial interests.

Background: Gold mining activities in forested areas across Guyana have been a common practice for more than a century. The intensification of artisanal and small-scale gold mining (ASGM) in recent decades caused by global market demand is contributing to the mobilization of mercury into aquatic systems. Indigenous populations who consume high levels of locally sourced fish are greater at risk for methylmercury poisoning from ingestion of contaminated fish.

Objectives: The aim of the present study was to investigate the levels of mercury contamination and identify the risk factors associated with hair mercury levels in four indigenous communities in Guyana.

Methods: Concentrations of total mercury were measured in hair samples from 99 participants from four indigenous communities in the south Rupununi region in Guyana. The findings of this study were compared with those of previous studies to assess the prevalence of mercury contamination in indigenous communities across Guyana.

Results: Hair mercury levels were found to be above the World Health Organization (WHO) reference value for residents who live close to ASGM activities and who consume high quantities of locally sourced fish. Our results are not only consistent with those obtained in previous studies, but also evidence that mercury poisoning has become a generalized problem for indigenous communities in Guyana.

Conclusions: Fish is the main source of protein for many riverine communities and consumption of mercury-contaminated fish poses a serious health hazard for these vulnerable populations. The situation is especially dire for community members of Parabara with 100% of participants showing elevated (>15 μg*g^-1) hair mercury levels. It is therefore crucial that Parabara residents be evaluated by relevant health agencies for clinical symptoms related to mercury toxicity.

Participant consent: Obtained.

Ethics approval: The study protocol was approved by the Institutional Review Board of the Ministry of Public Health, Guyana.

Competing interests: The authors declare no competing financial interests.