Enhanced chromium removal from tannery wastewater through electrocoagulation with iron electrodes: Leveraging the Box-Behnken design for optimization.

This study is focused on reducing total chromium level in tannery wastewater through the electrocoagulation process, in order to comply with the maximum permissible limits (MPL) and to determine the effects from its main operating factors. For this purpose, a batch electrocoagulation reactor was manufactured using iron electrodes. Next, the response surface methodology was applied in the experimental design using a Box-Behnken design (BBD) with three factors: current intensity, treatment time, and pH level. In addition, the total chromium removal percentage was taken as a response variable. The corresponding statistical analysis revealed that the treatment time, current intensity, and pH level variables were significant at a confidence level of P-value<0.05. Obtained in this study for a 99% total chromium removal were: current intensity (I)=2.9A, time (t)=18.1min, and pH=5.6. Our results indicated that the electrocoagulation process effectively removes total chromium from tannery effluents up to MPL values.

Cadmium and lead accumulation in important food crops due to wastewater irrigation: Pollution index and health risks assessment.

The contamination of farm soils with heavy metals (HMs) has raised significant concerns due to the increased bioavailability and accumulation of HMs in agricultural food crops. To address this issue, a survey experiment was conducted in the suburbs of Multan and Faisalabad to investigate the spatial distribution, bioaccumulation, translocation, and health risks of cadmium (Cd) and lead (Pb) in agricultural crops. The results show a considerable concentration of Cd and Pb in soils irrigated with wastewater, even though these levels were below the permissible limits in water and soil matrices. The pollution index for Cd was mostly greater than 1 at the selected sites, indicating its accumulation in soil over time due to wastewater irrigation. Conversely, the pollution index for Pb was below 1 at all sites. Among the plants, Zea mays accumulated the highest concentration of Cd and Pb. The translocation factor from soil to root was highest for Brassica olearecea (7.037 for Cd) and Zea mays (6.383 for Pb). The target hazard quotient (THQ) value of Cd exceeded the non-carcinogenic limit for most vegetables. The highest value was found in Allium cepa (5.256) and the lowest in Allium sativum (0.040). In contrast, the THQ level of Pb was below the non-carcinogenic limit for most vegetables, except for Allium cepa (1.479), Solanum lycopersicum (1.367), and Solanum tuberosum (1.326). The study highlights that Allium cepa poses the highest health risk for humans, while Medicago sativa poses the highest risk for animals due to Cd and Pb contamination. These results underscore the urgent need for effective measures to mitigate the health risks associated with HM contamination in crops and soils.

Lead, Cadmium, and Arsenic in Raw Cow's Milk in a Central Andean Area and Risks for the Peruvian Populations.

Milk and its derivatives are basic foods in Peru, especially for children. The Junín region, in the central Andes, is one of the leading dairy basins. However, the safety of milk is affected by mining-metallurgical activities, wastewater dumping, organic residues, and inappropriate use of organophosphate fertilizers in agriculture whose contaminants reach the food chain, putting human health at risk. The purpose of this study was to evaluate the bioaccumulation of lead (Pb), cadmium (Cd), and arsenic (As) in milk produced on a representative farm in central Peru, which uses phosphorous agrochemicals and is adjacent to a small mineral concentrator and a municipal solid waste dump, and to evaluate the potential risk for the Peruvian population of 2-85 years considering three levels of daily intake by age, which constitutes the innovative contribution of the study. These three elements were quantified by flame atomic absorption spectrometry following standardized procedures. The mean contents of Pb (0.062 mg/kg), Cd (0.014 mg/kg), and As (0.030 mg/kg) in milk exceeded the maximum limits allowed by international standards. At all ages, the target quotient hazard followed a descending order of As > Pb > Cd, being > 1 in the case of As. The hazard index was >1 for children under 7, 9, and 11 years of age in the scenarios of low, medium, and high milk intake. The information is valid for formulating policies to prevent adverse health effects and develop standards and awareness programs, monitoring, and control of heavy metals in milk in Peru.

Indoor air quality guidelines from across the world: An appraisal considering energy saving, health, productivity, and comfort.

Buildings are constructed and operated to satisfy human needs and improve quality of life. Good indoor air quality (IAQ) and thermal comfort are prerequisites for human health and well-being. For their provision, buildings often rely on heating, ventilation, and air conditioning (HVAC) systems, which may lead to higher energy consumption. This directly impacts energy efficiency goals and the linked climate change considerations. The balance between energy use, optimum IAQ and thermal comfort calls for scientifically solid and well-established limit values for exposures experienced by building occupants in indoor spaces, including homes, schools, and offices. The present paper aims to appraise limit values for selected indoor pollutants reported in the scientific literature, and to present how they are handled in international and national guidelines and standards. The pollutants include carbon dioxide (CO2), formaldehyde (CH2O), particulate matter (PM), nitrogen dioxide (NO2), carbon monoxide (CO), and radon (Rn). Furthermore, acknowledging the particularly strong impact on energy use from HVAC, ventilation, indoor temperature (T), and relative humidity (RH) are also included, as they relate to both thermal comfort and the possibilities to avoid moisture related problems, such as mould growth and proliferation of house dust mites. Examples of national regulations for these parameters are presented, both in relation to human requirements in buildings and considering aspects related to energy saving. The work is based on the Indoor Environmental Quality (IEQ) guidelines database, which spans across countries and institutions, and aids in taking steps in the direction towards a more uniform guidance for values of indoor parameters. The database is coordinated by the Scientific and Technical Committee (STC) 34, as part of ISIAQ, the International Society of Indoor Air Quality and Climate.

A review on the clean-up technologies for heavy metal ions contaminated soil samples.

The soil contamination with heavy metal ions is one of the grave intricacies faced worldwide over the last few decades by the virtue of rapid industrialization, human negligence and greed. Heavy metal ions are quite toxic even at low concentration a swell as non-biodegradable in nature. Their bioaccumulation in the human body leads to several chronic and persistent diseases such as lung cancer, nervous system break down, respiratory problems and renal damage etc. In addition to this, the increased concentration of these metal ions in soil, beyond the permissible limits, makes the soil unfit for further agricultural use. Hence it is our necessity, to monitor the concentration of these metal ions in the soil and water bodies and adopt some better technologies to eradicate them fully. From the literature survey, it was observed that three main types of techniques viz. physical, chemical, and biological were employed to harness the heavy metal ions from metal-polluted soil samples. The main goal of these techniques was the complete removal of the metal ions or the transformation of them into less hazardous and toxic forms. Further the selection of the remediation technology depends upon different factors such as process feasibility/mechanism of the process applied, nature and type of contaminants, type and content of the soil, etc. In this review article, we have studied in detail all the three technologies viz. physical, chemical and biological with their sub-parts, mechanism, pictures, advantages and disadvantages.

Determination of Heavy Metal Levels and Health Risk Assessment of Raw Cow Milk in Guelma Region, Algeria.

During the recent decades, adverse effects of unexpected contaminants, such as heavy metals on raw cow milk quality, have threatened human health. The objective of this study was to determine heavy metal levels in raw milk collected from autochthonous bovine breeds in the eastern region of Algeria. Eighty-eight pooled milk samples were analyzed using atomic absorption spectrometry for Pb, Cd, Cr, Cu, Ni, Fe, and Zn, and dietary risks were estimated for infants, children, and adults with minimum, average, and maximum milk consumption scenarios. Results revealed that Pb (0.94 ± 0.49 mg/kg), Cd (0.03 ± 0.01 mg/kg), and Cu (0.14 ± 0.08 mg/kg) levels in all analyzed samples were higher than their corresponding maximum residue levels (MRLs). The task hazard quotient (THQ) values suggest potential risk for infants in the three scenarios from Pb, Cd, and Cr; for children in the three scenarios from Pb and in the high scenario from Cr; and for adults in the medium and high scenarios from Pb. The hazard index (HI) values were higher than 1, and the contributions of each metal to the overall HI followed a descending order of Pb, Cr, Cd, Ni, Zn, Cu, and Fe with values of 68.19%, 15.39%, 6.91%, 4.94%, 3.42%, 0.88%, and 0.28%, respectively. Our results indicated that there may be a potential risk of heavy metals, especially Pb, for infants through raw cow milk consumption. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metal effects in future studies.

Quantification of Heavy Metals and Pesticide Residues in Widely Consumed Nigerian Food Crops Using Atomic Absorption Spectroscopy (AAS) and Gas Chromatography (GC).

More still needs to be learned regards the relative contamination of heavy metals and pesticide residues, particularly those found in widely consumed Nigerian food crops like cereals, vegetables, and tubers. In this current study, the heavy metals and pesticide residues detectable in widely consumed Nigerian food crops were respectively quantified using atomic absorption spectroscopy (AAS) and gas chromatography (GC). Specifically, the widely consumed Nigerian food crops included cereals (rice, millet, and maize), legume (soybean), tubers (yam and cassava), as well as leaf (fluted pumpkin, Amaranthus leaf, waterleaf, and scent leaf) and fruit vegetables (okro, cucumber, carrot, and watermelon). Results showed that the detected heavy metals included arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), iron (Fe), lead (Pb), manganese (Mn), mercury (Hg), and nickel (Ni), whereas the pesticide residues included Aldrin, Carbofuran, g-chlordane, Chlorpyrifos, DichloroBiphenyl, Dichlorodiphenyldichloroethane (DDD), Dichlorodiphenyltrichloroethane (DDT), Dichlorvos, Endosulfan, Heptachlor, Hexachlorobenzene (HCB), Isopropylamine, Lindane, t-nonachlor, and Profenofos. Across the studied food crops, the concentrations of heavy metals and pesticides were varied, with different trends as they largely fell below the established maximum permissible limits, and with some exceptions. Our findings suggest there could be a somewhat gradual decline in the concentration of the heavy metals and pesticide residues of these studied food crops when compared to previously published reports specific to Nigeria. To help substantiate this observation and supplement existing information, further investigations are required into the concentration of these heavy metals and pesticide residues specific to these studied food crops at other parts of the country.

Vermiremediation and comparative exploration of physicochemical, growth parameters, nutrients and heavy metals content of biomedical waste ash via ecosystem engineers Eisenia fetida.

Vermicomposting of Biomedical waste ash (BA) by the earthworm Eisenia fetida was studied with cow dung (CD) as nutrient medium. For 105 days, experiment was carried out in seven vermireactors containing varying ratios of BA and CD. Earthworm activity significantly reduced the pH (8.61-7.24), Electrical conductivity (EC) (4.1-1.62), Total organic carbon (TOC) (38.6-14.92), and Carbon and nitrogen (C/N ratios) (145.4-8.2) of all BA ratios. Levels of Total kjeldahl nitrogen (TKN) (0.26-1.82), Total available phosphorus (TAP) (0.22-0.64), Total potassium (TK) (2.05-12.08), and Total sodium (TNa) (47.53-92.26) were found to be increasing in the postvermicompost mixture. Although heavy metals content decreased from initial to final, it becomes below the permissible limits in the end product. The results showed that earthworm growth and fecundity were best in vermireactors containing 10-25% of BA. The best reproduction and growth of earthworms, demonstrate the vermicomposting's ability to manage hazardous solid wastes like BA. Use of vermitechnology to manage BA has not been performed yet in any kind of the research. Finally, it was determined that vermicomposting can be incorporated into overall plan for BA management. Thus nutrient-rich, detoxified, and physiochemically stable product may be used safely in agricultural processes.

Assessment of heavy metal content of commonly consumed herbal medicines in Sindh, Pakistan.

In Pakistan, herbal medicines are extensively consumed by a major portion of people for the treatment of numerous ailments. Nowadays, the contamination of heavy metals in herbal medicines is a serious concern due to its toxic effects on human health. In the present study, quantitative evaluation of four heavy metals, namely, iron (Fe), cadmium (Cd), nickel (Ni), and copper (Cu), was carried out in forty herbal medicines, frequently sold in the markets of Sukkur and Khairpur, Pakistan, without any quality assurance. Conventional wet acid digestion method was used for the dissolution of samples, and the concentration of heavy metals was determined by using flame atomic absorption spectrometry. Diverse concentration of metals was observed in different herbal medicines. The levels of Fe, Cd, Ni, and Cu were in the range of 30.3-798 mg/kg, 0.002-0.007 mg/kg, 1.52-27.3 mg/kg, and 15.2-194 mg/kg, respectively. The findings of our study were also compared with the WHO maximum permissible limits. It was observed that the concentrations of these heavy metals in most of the analyzed samples were within the permissible limits set by the WHO. Only a few samples of herbal medicines exceeded the recommended levels of Ni and Cu. These medicines should be regularly checked for quality assurance to avoid chronic exposure of metal to human beings.

Investigation of toxic heavy metals content and estimation of potential health risks in Chinese herbal medicine.

The content of toxic heavy metals (THMs), including lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg), was determined in a total of 10,245 samples for 279 types of Chinese herbal medicine (CHM) using a validated inductively coupled plasma mass spectrometry method. The exceeding rate (ER) for the four THMs were calculated based on diverse permissible limits (PLs) established by different organizations and national pharmacopeias. Cluster analysis was used to classify the degree risk of THMs contamination according to the calculated ER. Results revealed that Cibotii rhizome, Selaginellae herba, Morindae officinalis radix, Asprellae ilicis radix, and Toxicodendri resina exhibited high-degree risk of Pb contamination. Eckloniae/Laminariae thallus, Spirodelae herba, and Naturalis indigo possessed high-degree risk of As contamination. Tetrapanacis medulla, Centipedae herba, Cyathulae radix, Linderae radix, Meretricis/Cyclinae concha, and Tabanus displayed high-degree risk of Cd contamination. Toxicodendri resina has high-degree risk of Hg contamination. In addition, six types of CHM, including Asprellae ilicis radix, Toxicodendri resina, Eckloniae/Laminariae thallus, Fossilia Ossis Mastodi, Haematitum, and Hedyotidis diffusae herba, may have non-carcinogenic health risk after consumption of raw materials because the calculated hazard quotient and hazard index were over 1.0. In summary, these data provide useful information about THMs contamination in CHM.

Heavy metals levels in raw cow milk and health risk assessment across the globe: A systematic review.

This systematic review presents the potential toxicity of heavy metals such as lead (Pb), mercury (Hg), cadmium (Cd), iron (Fe), nickel (Ni), aluminum (Al), and copper (Cu) in raw cow milk, focusing on their contamination sources and on the assessment of the related human health risk. Multiple keywords such as "raw cow milk, heavy metals, and human health" were used to search in related databases. A total of 60 original articles published since 2010 reporting the levels of these metals in raw cow's milk across the world were reviewed. Data showed that the highest levels of Ni (833 mg/L), Pb (60 mg/L), Cu (36 mg/L) were noticed in raw cow milk collected in area consists of granites and granite gneisses in India, while the highest level of Cd (12 mg/L) was reported in barite mining area in India. Fe values in raw cow milk samples were above the WHO maximum limit (0.37 mg/L) with highest values (37.02 mg/L) recorded in India. The highest Al level was (22.50 mg/L) reported for raw cow's milk collected close to food producing plants region in Turkey. The Target Hazard Quotients (THQ) values of Hg were below 1 suggesting that milk consumers are not at a non-carcinogenic risk except in Faisalabad province (Pakistan) where THQ values = 7.7. For the other heavy metals, the THQ values were >1 for Pb (10 regions out of 70), for Cd (6 regions out of 59), for Ni (3 out of 29), and for Cu (3 out of 54). Exposure to heavy metals is positively associated with diseases developments. Moreover, data actualization and continuous monitoring are necessary and recommended to evaluate heavy metals effects in future studies.

Toxic Metal Pollution in Pakistan and Its Possible Risks to Public Health.

Environmental pollution has increased many folds in recent years and in some places has reached levels that are toxic to living things. Among pollutant types, toxic heavy metals and metalloids are among the chemicals that pose the highest threat to biological systems (Jjemba 2004). Unlike organic pollutants, which are biodegradable, heavy metals are not degraded into less hazardous end products (Gupta et al. 2001). Low concentrations of some heavy metals are essential for life, but some of them like Hg, As, Pb and Cd are biologically non-essential and very toxic to living organisms. Even the essential metals may become toxic if they are present at a concentration above the permissible level (Puttaiah and Kiran 2008). For example, exposure to Zn and Fe oxides produce gastric disorder and vomiting, irritation of the skin and mucous membranes. Intake of Ni, Cr, Pb, Cd and Cu causes heart problems, leukemia and cancer, while Co and Mg can cause anemia and hypertension (Drasch et al. 2006). Similarly, various studies indicated that overexposure to heavy metals in air can cause cardiovascular disorders (Miller et al. 2007; Schwartz 2001), asthma (Wiwatanadate and Liwsrisakun 2011), bronchitis/emphysema (Pope 2000), and other respiratory diseases (Dominici et al. 2006).

High levels of mercury in wetland resources from three river basins in Ghana: a concern for public health.

Crustaceans, mollusks, and fish are wetland resources that constitute an important source of protein and foreign exchange for the Ghanaian population, and many species of these are sold in the open market and restaurants, yet studies on their heavy metal contents are generally scarce. This paper evaluates the levels of mercury in five species of crustaceans, two species of mollusks, and ten species of fish inhabiting three river basins with different catchment activities in Ghana. These include the Ankobra Basin, characterized with mining and agriculture, Densu Basin, associated with urban waste discharges and agriculture, and Lower Volta River Basin, associated with agricultural activities. Mercury concentration was highest in Ankobra (2.5 ± 2.59 µg g-1) followed by Densu (1.75 ± 1.35 µg g-1) and Volta (0.74 ± 1.46 µg g-1). The mercury load of the organisms range from <0.1 to 4 µg g-1 with the highest load in Cynoglossus senegalensis at Ankobra. Except for Panaeus notialis from Densu and Ankobra, and three other species from Ankobra (Tympanotonus fuscatus, Cardisoma armatum, Callinectes amnicola) in which mercury was not detected, mercury loads of all the organisms were above the permissible limit of 0.5 mg kg-1 established by Commission Regulation-EC (2006) for fishery products and muscle meat of fish. Weekly quantities of crustaceans and mollusks considered safe for consumption by adults ranged from 88 and 1000 g while that of the fishes were between 70 and 700 g (on a dry weight basis) depending on the species. It was clear that some caution needs to be exercised in the consumption of Ghana's fresh and brackish water fisheries.

Cadmium concentration in liver and muscle of silky shark (Carcharhinus falciformis) in the tip of Baja California south, México.

Cadmium concentrations were determined in the tissues of muscle and liver of Carcharhinus falciformis (silky shark) sampled in Todos Santos, Baja California South, Mexico. This is one of the main shark species for human consumption in Mexico. Results indicate that accumulation of Cd varied in both sexes, based on its metabolism, sex, maturity and other biological characteristics. High Cd values were observed in the liver of adults of male (529.61µgg(-1)) and female (457.43µgg(-1)), whereas, in muscular tissues it was low (0.37µgg(-1)) than the prescribed permissible limits for seafood (0.5µgg(-1)). Substantial correlations were observed between body length and Cd values in adults except young male due to faster growth rate and its metabolism. The study indicated the impact of environmental conditions in the accumulation of Cd and its risk to the food web structure in the marine environment and health hazard for humans.

Heavy metals bioaccumulation in Berseem (Trifolium alexandrinum) cultivated in areas under intensive agriculture, Punjab, India.

Berseem (Trifolium alexandrinum) is one of the main fodder crops of Punjab, India. But due to the heavy metal contamination of agricultural soils by anthropogenic activities, there is rise in metal bioaccumulation in crops like Berseem. In addition to human influence, heavy metal contents in soil are highly dependent on soil characteristics also. Therefore a study was conducted in areas having intensive agricultural practices to analyze physico-chemical characteristics of soils under Berseem cultivation and heavy metal bioaccumulation in Berseem. The studied soils were alkaline, sandy in texture and low in soil organic matter. Among the studied heavy metals (Cr, Cu, Cd, Co and Pb) in soil and Berseem, Cr content in Berseem was found to be above maximum permissible limits. Soil to Berseem metal bioaccmulation factor (BAF) was above 1 for Cr, Cu, Cd and Co in many samples and highest BAF was found for Co (4.625). Hence it can be concluded that Berseem from studied areas was unsafe for animal consumption.

Level of Heavy Metals in Two Highly Consumed Fish Species at District Lower Dir, Khyber Pakhtunkhwa, Pakistan.

The current study was designed to assess heavy metals' concentration in muscle tissues of two Chinese carps, common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix), available to consumers in markets at district Lower Dir, Khyber Pakhtunkhwa, Pakistan. Fish specimens were collected from three main markets in the study area namely; Chakdara, Timergara and Khall. Heavy metals including; manganese (Mn), lead (Pb), iron (Fe), copper (Cu), zinc (Zn), cadmium (Cd) and cobalt (Co) were investigated using atomic absorption spectrophotometer. Cobalt was not detected in any of the fish specimens while the rest of the metals were lying within the permissible limits suggested by FAO/WHO and ITS for food/fish consumption. The results showed a statistically significant (p<0.05) difference between both species with respect to the concentration of the accumulated heavy metals. In common carp, the heavy metal accumulation was in order of Fe>Mn>Zn>Pb>Cu>Cd, while in silver carp the order was Fe>Mn>Zn>Pb>Cd>Cu. Higher concentration of Pb, Mn, Zn, Cu and Cd was recorded in muscle of common carp while the concentration of Fe was higher in silver carp, indicating higher potential of accumulation of heavy metals in common carp. Statistically significant (p<0.05) correlation was observed between Pb and Zn in common carp while between Cu and Cd in silver carp. The concentration of heavy metals was in the suggested permissible limits and poses no threat if consumed. In order to maintain the heavy metals level within permissible limits, proper care should be taken along with regular assessment.

Metal concentrations in demersal fish species from Santa Maria Bay, Baja California Sur, Mexico (Pacific coast).

Concentrations of 11 trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, As, Hg) in 40 fish species from Santa Maria Bay, Baja California Sur, Mexico, the strategically important area for marine mammals and organisms were analyzed. Based on their concentrations the ranking of metals Fe>Zn>Ni>Cr>Mn>Pb>Cu>Co>As>Cd>Hg suggests that organism size, metabolism and feeding habits are correlated with metal concentrations. Local geological formations affect the concentrations of different metals in the aquatic environment and are subsequently transferred to fishes. The correlation analysis suggests that metabolism and nurturing habits impact the concentration of metals. Concentrations of Fe and Mn appear to be influenced by scavenging and absorption processes, which vary by species. The considerable variability in the metal concentrations obtained in different species underscores the importance of regular monitoring.

Hacia un plan nacional para el control de los efectos del mercurio en la salud en Colombia / Toward a national plan to control health effects of mercury in Colombia

Introducción. La problemática del uso del mercurio es global y afecta tanto a los humanos como al ambiente. Los efectos del mercurio en la salud son diversos, por eso es necesario abordar el problema desde una perspectiva amplia, identificando las poblaciones en riesgo de exposición, sus efectos en la salud, los procesos productivos involucrados y las acciones para disminuir la exposición y mitigar el impacto. Objetivo. Diseñar un marco conceptual y operativo para desarrollar estrategias de prevención, control y mitigación de los efectos del mercurio sobre la salud y el ambiente en Colombia. Materiales y métodos. Se hizo un estudio en dos fases: una revisión de la literatura científica siguiendo la metodología Cochrane, y foros con expertos nacionales e internacionales orientados a la planificación integral para identificar las acciones prioritarias y construir la agenda de investigación nacional . Resultados. Los resultados de la revisión se estructuraron en cuatro componentes: efectos del mercurio en la salud, marco legal en Colombia, inventario de emisiones en el país, y planes y programas existentes en el sector de la salud. Se presentaron recomendaciones para diseñar un plan de intervenciones considerando cinco líneas de acción: gestión tecnológica para la prevención de la exposición, fortalecimiento institucional para la prevención y el control de la exposición, fortalecimiento de estrategias de diagnóstico y atención, educación en salud sobre los riesgos del mercurio y generación de conocimiento . Conclusiones. Se visibilizaron vacíos de información, así como debilidades técnicas, administrativas y necesidad de recursos en Colombia, y se propusieron acciones prioritarias para disminuir el impacto económico, social y en salud de la exposición al mercurio.

Introduction: The problem of mercury effects on humans and the environment is global, and it has different impacts on health. It is necessary, therefore, to address this issue from a broad overview to identify populations at risk of exposure, health effects, the production processes involved and the actions aimed at reducing exposure and mitigating the impact. Objective: To design a conceptual and operational framework to develop strategies for prevention, control and mitigation of mercury effects on health and on the environment in Colombia. Materials and methods: We conducted a two-phase study: a literature review following the Cochrane methodology and forums with national and international experts using a comprehensive planning methodology to identify priority actions and establish a national research agenda. Results: The results of the review were structured into four components: mercury effects on health, legal framework in Colombia, emission inventory for the country and health plans and programs. We made recommendations for the design of an intervention plan considering five lines of action: technologies for exposure management, institutional strengthening for exposure prevention and control, strategies for strengthening diagnosis and care, health education on mercury risks, and knowledge generation. Conclusion: We detected information gaps, technical weaknesses, and the need of administrative and other resources in this field in Colombia. We proposed priority actions to reduce the economic, social and health impact from exposure to mercury.

Biochemical performance of native and introduced clam species living in sympatry: The role of elements accumulation and partitioning.

The present study reports metal and arsenic contamination in sediments, as well as element accumulation and partitioning in native (Ruditapes decussatus and Venerupis corrugata) and introduced (Ruditapes philippinarum) clam species living in sympatry at the Óbidos lagoon (Portugal). The biochemical performance and the human health risks derived from the consumption of these species are also discussed. The results obtained showed that R. decussatus was the most abundant species in all the sampling sites, revealing that the introduced clam has not yet supplanted the native species. The concentration of elements was higher in areas with higher Total Organic Matter (TOM) and fines content, being Chromium (Cr), Copper (Cu) and Lead (Pb) the most abundant metals. Clams from these areas showed the highest concentration of elements but the lowest bioaccumulation levels. Furthermore, except for As, higher concentration of elements was found in clams insoluble fraction, the less toxic fraction to the organisms. Due to the low contamination levels and because elements, except As, were mainly allocated to the insoluble fraction, clams presented similar biochemical parameters among distinct areas, with no significant oxidative stress induced. Furthermore, clams from the Óbidos lagoon represent a low health risk to human consumption since, except for As, their contamination levels were below the maximum permissible limits defined by international organizations.

Mudança significativa do limiar auditivo em trabalhadores expostos a diferentes níveis de ruído / Significant auditory threshold shift among workers exposed to different noise levels

OBJETIVO: Avaliar a audição e a ocorrência de mudança significativa do limiar auditivo em trabalhadores de frigoríficos expostos a níveis de ruído abaixo das Normas e Regulamentações nacionais e internacionais e compará-los com trabalhadores expostos a níveis de ruído considerados excessivos. MÉTODOS: Utilizou-se um banco de dados contendo informações longitudinais de 266 trabalhadores. Foram selecionados trabalhadores com um mínimo de três exames audiométricos e os que continham dados de exposição ao ruído. Foram mantidos 63 exames, classificados de acordo com sua exposição ao ruído em três níveis: 79 a 84,9 dB(A), 85 a 89,9 dB(A) e 90 a 98,8 dB(A). Foi avaliada a ocorrência de perdas auditivas e de mudança significativa de limiar auditivo dos participantes de cada subgrupo. RESULTADOS: Verificou-se diferenças em todas as frequências nos testes de comparação entre a média dos limiares auditivos para cada frequência em função do nível de exposição ao ruído. A correlação entre a ocorrência de Perda Auditiva Induzida por Níveis de Pressão Sonora Elevados (PAINPSE) e os anos de exposição ao ruído dentro da empresa atual foi significativa (R=0,373; p=0,079). Foram encontradas mudanças permanentes de limiar auditivo nos três níveis de exposição ao ruído. CONCLUSÃO: Os achados do presente estudo sugerem a existência de uma associação entre mudança significativa do limiar auditivo dos trabalhadores e os anos de exposição ao ruído considerado de baixo risco.

PURPOSE: To assess the hearing status and signs of significant auditory threshold shifts in meat-processing facility workers who are exposed to noise levels below nationally and internationally recommended exposure limits, and to compare these results with data from workers exposed to excessive noise levels. METHODS: Longitudinal audiometric data from 266 workers were evaluated, and only workers with a minimum of three audiometric test results and noise exposure records were selected for this study. The 63 assessments selected were classified according to subjects' noise exposure into three levels: 79 to 84.9 dB(A), 85 to 89.9 dB(A), and 90 to 98.9 dB(A). Occurrences of hearing loss and significant auditory threshold shifts were assessed, in each group. RESULTS: Differences in the mean thresholds were observed in all test frequencies among the different groups. A significant correlation was found between occurrence of noise-induced hearing loss and duration of noise exposure (in years) at the present industrial facility (R=0.373; p=0.079). Significant auditory threshold shifts were found in all three levels of noise exposure. CONCLUSION: The findings of the present study suggest the existence of an association between significant auditory threshold shifts in workers and the years of exposure to low risk noise levels.