3g: Occupational mercury exposure from ASGM and other activities

Mercury resistance in bacteria is strongly correlated with antibiotic resistance. In polluted environments, heavy metal resistance and antibiotic resistance are often spread in bacterial communities by horizontal gene transfer through conjugative plasmids and/or other mobile genetic elements. Therefore, in artisanal and small-scale gold mining (ASGM) where amalgamation continues to play a large role in the gold mining process, mercury pollution may provide an additional driving force for the spread of antibiotic resistance. While this correlation has been widely reported, the specific mechanisms of mutual resistance remain unclear. To better understand this phenomenon, mercury resistant bacteria were isolated from soil samples collected in and around the ASGM community of Tsetsera, Mozambique. Samples were analyzed for total mercury, which ranged from 0.02 to 39.10 ppm. Isolated bacterial colonies were screened for mercury resistance by plating them on agar supplemented to a final concentration of 100 mg/L of HgCl2. Each isolate (regardless or mercury resistance) was also tested for antibiotic resistance to ampicillin (50 μg/ml), kanamycin (10 μg/ml), and chloramphenicol (34 μg/ml). Of the 781 strains analyzed 78% of the 221 mercury resistant colonies showed resistance to at least one antibiotic, while only 51% of the 560 mercury susceptible colonies showed some form of antibiotic resistance. The genome of one of the multi-drug resistant strains, a Pseudomonas species (isolate DRA525) was sequenced and annotated. The 6267580 base pair genome sequence revealed evidence of recent acquisition of several resistance genes suggesting that in areas contaminated with heavy metals, there may be an increased selective pressure resulting in the dissemination of resistance genes to other bacterial species including potential human pathogens. These findings provide a better understanding of how mercury pollution acts as a selective pressure in contaminated environments, which may lead to the spread and maintenance of antibiotic resistance in areas associated with ASGM. Unfortunately, these findings also suggest additional risk factors for the health of communities associated with mercury contamination.

Artisanal and small-scale gold mining (ASGM) in Perus Madre de Dios (MDD) region has grown rapidly since the early 2000s and is a major driver of mercury (Hg) imports to the region. Hg released during ASGM can be transported to aquatic ecosystems, such the MDD river, where it is transformed to monomethylmercury (MeHg), a bioaccumulative neurotoxin. As a result, fish contamination is an issue of concern for individuals living in riverside communities in the MDD region. Not all communities rely on the MDD river for fish, and therefore Hg exposure likely varies depending on geographical region. In this research, we examined total Hg (THg) and MeHg contents in hair samples collected from residents of the MDD region and performed surveys of dietary consumption. This study was part of a larger cohort study to evaluate the health status of communities in MDD, where ASGM and other factors have prompted rapid population growth in the region and large scale alterations to the tropical landscape. Household dietary surveys and proximal 2-cm segments of hair were collected in 2015-2016 from individuals living in communities that were divided into three distinct geographical regions in MDD: within ASGM activity (n=34), near upriver of ASGM (100-120 km; n=31), and far upriver (220 km; n=24). Hair THg was greatest in near upriver communities (average = 5.75 ug/g ; range = 1.86 ug/g to 10.8 ug/g) relative to communities within ASGM (average = 2.00 ug/g ; range = 0.203 ug/g to 11.9 ug/g ) and far upstream of ASGM (average = 3.29 ug/g; range =0.723 ug/g to 6.55 ug/g). In both upriver communities, hair Hg speciation was predominantly MeHg (> 71% in all hair samples), while communities within ASGM had MeHg contents ranging from 8% to 128% of THg. The large variation in the relative MeHg contents for individuals within ASGM likely reflects exposure to multiple Hg sources (i.e. inorganic and organic), whereas the consistently high MeHg percentages in upriver communities suggest that exposure is predominantly through one source, such as fish consumption. These results align with our initial assessment of dietary trends in the region, as individuals within ASGM have been reported to rely on non-fish sources of protein, while those in upstream communities heavily rely on the MDD river for food supply. Ongoing research will examine blood biomarkers for mercury exposure as well as other possible metrics such as polyunsaturated fatty acids for fish consumption.

Mercury is used to extract gold out of the gold-containing crushed ores by forming an amalgam, which is heated, evaporating mercury vapor and leaving a porous sponge gold product. This leads to mercury exposure above the common average of the local population. Uptake, distribution and excretion of mercury in the body are genetically influenced. The differences reported in the manifestation of neurological symptoms of individuals, with a comparable level of exposure to mercury, suggest a genetic component influencing the susceptibility to mercury neurotoxicity.

Genetic variants that have been associated with Hg concentrations in the body have mainly been in glutathione-related genes as glutathione plays a key role in mercury metabolism and elimination, mainly due to formation of a more easily transported glutathione-mercury conjugate. The aim of the present study is to investigate associations between polymorphisms in three SNPs of the potential mercury-transporter ABCC2 gene (rs1885301, rs717620, rs2273697) and severity of mercury-related neurotoxicity.

For the present analysis we included data from former projects addressing exposure and neurotoxicity of inorganic mercury, including 1017 participants from the Philippines, Indonesia, Tanzania and Zimbabwe. To increase the power, we pooled data from Asian and African countries as well as heterozygotes and variant homozygotes of variant genotypes. (GG ref. against GA+AA) The participants were stratified into three exposure subgroups: without mercury exposure from gold mining; living in mercury-contaminated areas; mercury working exposure.

To identify chronic inorganic mercury intoxication we developed a neurological score sum including eight binary coded parameters of the anamnestic, clinical and neurophysiological examination. We used multiple logistic regression models to explore genetic factors influencing theoccurrence of mercury intoxication, and multiple linear regression models to explore genetic factors affecting the grade of intoxication. We adjusted for mercury exposure, age and gender. In both analyses we also examined the effect modification of genetic variants on mercury intoxication by including interaction terms between genotype and exposure to mercury.

We found that ABCC2 genotype variety influenced the neurological performance. For rs1885301, the A-allele carriers in African populations showed significantly worse performance at the pencil tapping test. For rs2273697, A-allele carriers in African and Asian populations showed a significant better performance than G-allele carriers at the pencil tapping test. When including an interaction term between genotype and exposure, for rs2273697 the interaction term in Asia showed, at the pencil tapping test and matchbox test, that GA+AA modifies the effect of mercury exposure and leads to a better outcome.

The outcome should ensure us to investigate the associations between mercury and neurotoxic symptoms depending on the ABCC2 transporter more detailed.

Introduction: Mercury is a toxic metal and traditionally used in small scale gold mining. In Portovelo, as the oldest small scale mining area in Ecuador, mercury has been an environmental and health problem for decades and even created an international political conflict. The target of this study was to assess the mercury (Hg) concentration in urine of miners from the Portovelo/Zaruma, Ecuador, to establish a prevalence of high values and to compare it with other ASGM regions.

Methods: Urine samples of 865 gold miners in Ecuador were collected and analyzed for their mercury content, using cold vapor atom absorption spectroscopy. The prevalence of high mercury values (>25µg/ml urine) was estimated.

44 miners with mercury levels >15 µg/l filled in a questionnaire for characteristics and possible confounders and were examined for intoxication symptoms to establish the ten points medical score sum.

Results: The median value was 1.8 µg/l. 78,3% of miners were below the HBM-I threshold (7 µg/l urine) and not at risk of an intoxication. 5,9% of miners exceeded the HBM-II limit (25µg/l urine) and were probable to experience intoxication symptoms. The medical score sum had a range of 2 to 8 points with a median of 6.

Conclusion: The relatively low prevalence of high mercury concentrations shows that the politics and techniques to eliminate the use of mercury are successfully implemented. Further studies are needed to identify factors enabling this process.

Introduction: Mercury is a global pollutant and its effective control in the environment will take scientific study, innovative management strategies, and the cooperation among all nations.

Objectives: The objective of the study was to assess the Knowledge, Attitude and Practice (KAP), awareness and performance towards dental waste including mercury management policy and practices among the dental practitioners in Nepal.

Materials and Methods. An epidemiologic survey was conducted among 130 private dental practitioners. The survey form was composed of 32 self-administered Standard questions frame based on knowledge, attitude, and those regarding the practices of dentists in relation to dental health-care waste management. The resulting data were coded and a statistical analysis was done with EpiInfo, SPSS.

Results and Discussion. About 53.2% of the dentists were not aware of the different categories of biomedical waste generated in their clinics and where is the right place to recycle.

Only 24.9% of the dentists correctly said that outdated and contaminated drugs come under cytotoxic waste. 39.6% said they break the needle and dispose of it and only 17.9% use needle burner to destroy it. 39.0% of the dentists dispose of the developer and fixer solutions by letting them into the sewer, 38.4% of them dilute the solutions and let them into sewer and only 4.6% return them to the supplier. About 38.6% of the dentists dispose of excess silver amalgam by throwing it into common bin. 3.0% of their annual patients have complain of urticarial lesions due to filling and it was completely cure after removal of filling.

Conclusion. It was concluded that not all dentists were aware of the risks they were exposed to and only half of them observe infection control practices. Infection prevention and medical waste management procedure is very important to control and make mercury free society in developing country. In this globalization age, medical tourist is booming in developing country as well, so keep in mind with universal laws, our efforts should be awareness and give the guidance to all medical and dental practitioner. This will ultimately makes developing country mercury pollution Free countries.

Introduction: Heavy metal like mercury was used directly or indirectly since long ago before it was stopped around the world.Since,the value of the metal and its availability in different use in medical appliances is still one of the burdens in developing country like Nepal.The main uses of mercury are in dental amalgam, sphygmomanometers, and thermometers. The mercury once released into the environment can remain for a longer period. Both acute and chronic poisoning can be caused by it. Half of the mercury found in the atmosphere is human generated and health care contributes the substantial part to it. WHO and UNEPissuednew guideline for health care sector to becomemercury free.

Aim and Methods: To find out the Knowledge,attitudeand practice due to hazards of mercury contact among paramedics and patients.

Results and Conclusion: 938 paramedics and 890 patients were asked in-depthstructured questions about mercury hazards and update knowledge. Overall 18% of the paramedics have no knowledge of mercury-free with respect to 69% of the patients. Around 49% of paramedics have broken mercury thermometer in their career and contact with skin. However, 1.2% patient only have a similar history in theirlife time. 4% of the contamination with mercury having SKIN problems. 32% of the patients still have mercury thermometer and sphygmomanometer in their home with respectof0.6% of paramedics.

The above study showed that Healthcare worker has more knowledge of Mercury hazards than patients groups. However, paramedics have broken the mercury instruments than patients party. Similarly, Paramedics have Mercury free device at home thanpatients groups. It meansawareness, literate people having more knowledge towards its practice making mercury free society in a resource poor country like Nepal.