Background. Many children in low- and middle-income countries face enhanced risks of exposure to contaminants via the environment, parental occupation, and other routes. While mercury (Hg) is a global pollutant whose transport properties allow it to have an impact even in pristine areas, the presence of significant Hg sources in the developing world can cause localized effects that are more severe than those observed in other areas. Objectives. This paper provides a narrative review of sources of Hg exposure to people in the developing world with a particular focus on children, and presents an overview of key aspects to this important issue. Methods. We searched Web of Knowledge and Google Scholar using keywords including combinations of “mercury” and one or more of the following: “children,” “exposure,” “breast milk,” “artisanal mining,” “prenatal,” “religion,” “medicine,” “dental amalgam,” “chlor-alkali,” “VCM,” “vaccine,” “e-waste,” “industry,” “beauty,” “cosmetics,” “strategies,” “child labor,” “costs,” and “developing countries” to find peer-reviewed articles pertaining to Hg exposure in the developing world. Results. Sources of Hg exposure include mining, consumption, industrial operations, religious practices, traditional medicines, beauty products, vaccines, dental amalgams, and waste scavenging and recycling. Conclusion. Children in the developing world are often subject to higher levels of Hg exposure than those living in developed countries due to the higher prevalence of Hg-intensive industrial processes and consumer products, lack of environmental regulation, and limits in mobility and food choices, among other factors. This issue can be addressed through additional research to fill in data gaps on exposure sources, establish sound and enforceable policies, and increase education and participation in affected communities. Challenges to addressing this problem include limited resources for needed equipment, training, and manpower to implement solutions. Competing Interests. The authors declare no competing financial interests.

Background. E-waste has been identified as the fastest growing waste stream in the world at present. Rapid socio-economic development and technological advancement are the main drivers of this trend. The hazardous chemical components of e-waste have potential adverse impacts on ecosystems and human health if not managed properly. This represents an imminent challenge to achieving sustainable development goals. Although technologically developed countries are the main source of e-product production and e-waste generation, the generated volume has also been increasing in developing countries and those in transition due to transport and transfer from e-waste source countries. Consequently, developing countries are in a vulnerable situation due to their lack of inventory data, waste management policies and advanced technology for environmentally sound management. Objectives. This study aims to demonstrate that the present global e-waste scenarios and health hazards could prolong the achievement of sustainable development targets. This study illustrates scenarios from different perspectives and raises concerns about e-waste, identifies information gaps, and provides a basis for knowledge and awareness building and technological improvement to facilitate global long-term sustainable development. Discussion. Total and per capita global e-waste generation has been increased along with socio-economic development. These products present a significant global challenge due to the hazardous chemicals they contain, their highly technical recycling requirements and the high overhead and costs of environmentally sound management, as well as their adverse impacts to human health. Although high-income countries are the main sources of this waste, low-income countries are experiencing an increase in e-waste due to the shifting process of both recently produced and used electric and electronic equipment (UEEE), as well as cheap management overhead costs. Consequently, they bear the greatest burden of adverse health hazards and ecosystem degradation, prolonging their achievement of sustainable development goals. Conclusions. Sustainability is being prioritized for all development activities by integrating societal, economic, environmental, technological, cultural, and gender perspectives. Considering the adverse potential eco-toxicological impacts and diverse health effects of e-waste, an urgent global multilateral agreement is needed addressing its management (i.e., handling, storage, transportation, recycling, and final disposal), whether by land filling or incineration. Due to the global nature of the issue and the difficulty of establishing sustainable and environmentally sound processing of e-waste in low-income countries, multinational negotiation and collaboration is the only realistic solution. Furthermore, comprehensive global e-waste management and policies could help to off-set the hazards of e-waste and are the best approach for achieving sustainable development.

Background. For over a decade, solid tannery waste has been converted into protein concentrate and used as a feed ingredient because of its cheap availability. However, as chromium sulfate is commonly used in the tanning process, the chromium (Cr) content of tanned skin-cut wastes (SCW) may enter the edible parts of poultry through feed. Therefore, there is a chance that Cr and other heavy metals may be present in the edible portion of poultry and consequently transfer to humans upon poultry consumption. Objectives. In this study, skin-cut wastes (SCW)-based poultry feed and the edible parts of chicken fed with this feed were analyzed to understand the potential health risks of their use as poultry feed. Methods. In the present study, the presence of heavy metal content in SCW, poultry feed, and edible portions of different kinds of chicken was determined using atomic absorption spectrophotometer methods and the associated health risk estimation was calculated by comparing the target hazard quotient (THQ) value and reference daily intake value. Results. The results revealed the presence of Cr content ranging from 0.12–3.11 mg/kg and lead (Pb) content ranging from 8.06–22.0 mg/kg in SCW. In addition, Cr and Pb were present in the range of 0.27–0.98 mg/kg and 10.27–10.36 mg/kg, respectively, in poultry feed. However, no cadmium (Cd) was found in SCW, but the presence of Cd ranged from 0.03–0.05 mg/kg in feed. When contaminated poultry feed was fed to live poultry, the presence of Cr, Pb and Cd was observed in the edible portions (i. e. skin, liver, gizzard, and meat). Irrespective of the edible parts and chicken type, Cr values ranged from 0.1–2.440 mg/kg; Pb values ranged from 0.257–1.750 mg/kg; and Cd values ranged from below detection limit (BDL) to 0.037 mg/kg. Conclusions. The estimated daily intake value, THQ, along with the aggregate hazard index value, indicated a potential risk to consumers through consumption of contaminated chicken. Therefore, the study results clearly demonstrate heavy metals accumulation in chicken due to feeding SCW-based feed. The contaminated chicken further transfers these heavy metals to humans through ingestion. Hence, there is a potential human health risk through consumption of contaminated chicken meat.

Background. Soil contamination with heavy metals has severely increased over the last few decades, mainly from industrial wastes and human activities. Soil pollution is a source of danger to the health of people globally. Objectives. To assess the level of soil contamination with heavy metals around steel rolling mills in Jinja municipality, Uganda. Methods. Four composite soil samples were collected from each of the sides of the Jinja steel rolling mills, dried and digested. The digested solution samples were analyzed in triplicates for the levels of lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), copper (Cu), and nickel (Ni), using a flame atomic absorption spectrometer (Savant AA model 2009); the analytical process was monitored using analytical standard solutions. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) software version 19 and Excel. Mean metal concentrations, standard deviations, medians, and skewness were obtained to describe heavy metal concentrations in the soil. Pollution load index and geo-accumulation indices were calculated to determine the level and extent of heavy metal contamination in the soil. Results. The mean concentration loads of the heavy metals in soils around the Jinja steel rolling mills were 43.15 mg/kg for Pb, 28.16 mg/kg for Zn, 0.93 mg/kg for Cd, 0.22 mg/kg for Cr, 80.96 mg/kg for Cu, and 9.40 mg/kg for Ni. The metal load distribution around the industry was in descending order: Left-hand side > Downwind side > Right-hand side > Upwind side. Results for the geo-accumulation index were 1.30 for Pb, −1.31 for Zn, 2.63 for Cd, −7.25 for Cr, 2.99 for Cu, and −1.19 for Ni. The overall pollution load index was 1.08. Conclusions. The concentration levels of heavy metals around the steel rolling mills did not appear to be of serious concern, except for copper and cadmium, which showed moderate pollution and moderate to strong pollution, respectively. All heavy metals were within the limits of the United States Environmental Protection Agency (USEPA) residential soil standards and the Dutch intervention soil standards. Overall, soils around the Jinja steel rolling mills were slightly polluted with heavy metals, and measures therefore need to be taken to prevent further soil contamination with heavy metals.

Background. The World Health Organization (WHO) global air quality study shows that 27 Indian cities, including New Delhi, are among the one hundred cities with the worst air quality globally. The scope of airway obstruction cases among residents in locations with critical air pollution levels like particulate matter (PM) pollutants PM2.5 and PM1 has not been addressed in the National Capital region, India. Objectives. The present cross-sectional study was undertaken to assess the forced expiratory volume in one second (FEV1) % predicted abnormalities among residents living in the National Capital Region, India with respect to their exposure to particulate matter pollutants (PM1, PM2.5) in ambient air. Methods. Eight hundred and fifty-four residents, including 433 men and 421 women ranging in age from 18–70 years, living in the National Capital Region (NCR) of India participated in the study. Particulate matter concentrations in ambient air (PM2.5 and PM1) were monitored at 10 residential locations in the National Capital Region, India (New Okhla Industrial Development Authority (NOIDA) and Gurgaon). The lung function test (FEV1) was conducted using a spirometer. Results. The Indian Air Quality Index showed either very poor or severe levels for PM2.5 at all study locations. A significant negative linear relationship was found between higher concentrations of PM1 and reduced FEV1% predicted values (r = −0.8, p < 0.05). The prevalence of airway obstruction cases (79.6%, odds ratio 1.96, confidence interval 1.42–2.71) was higher (p<0.001) among female subjects compared to their male counterparts. Even though there was a significant decline in FEV1% predicted among 80% of cases in women, only 19.24% cases were in the moderate category and 6.18% cases in the severe category. The severe category of FEV1% predicted cases showed greater respiratory symptoms than the other two categories, which denotes higher risk among those in the severe category. The present study shows that obstruction cases increased from 1.97 to 7.40% and 2.73 to 14.93% in women, with a corresponding increase in PM1 and PM2.5 from the minimum to maximum concentration. Conclusions. Since the women in this study were non-smokers, the PM in ambient air can be considered to be the major reason for the decline in lung function. The sources of PM pollutants in the study locations are large scale infrastructural development activities such as building and road construction activities. Narrowed lung airways can alter the airway caliber or resistance and flow rates proportional to the airway radius, especially in smaller airways. The present study suggests the need for policy makers and stake holders to take the necessary steps to identify PM sources and reduce the emissions of PM concentrations in ambient air.

In the European registration procedure for pesticides, microcosm and mesocosm studies are the highest aquatic experimental tier to assess their environmental effects. Evaluations of microcosm/mesocosm studies rely heavily on no observed effect concentrations (NOECs) calculated for different population-level endpoints. Ideally, a power analysis should be reported for the concentration–response relationships underlying these NOECs, as well as for measurement endpoints for which significant effects cannot be demonstrated. An indication of this statistical power can be provided a posteriori by calculated minimum detectable differences (MDDs). The MDD defines the difference between the means of a treatment and the control that must exist to detect a statistically significant effect. The aim of this paper is to expand on the Aquatic Guidance Document recently published by the European Food Safety Authority (EFSA) and to propose a procedure to report and evaluate NOECs and related MDDs in a harmonised way. In addition, decision schemes are provided on how MDDs can be used to assess the reliability of microcosm/mesocosm studies and for the derivation of effect classes used to derive regulatory acceptable concentrations. Furthermore, examples are presented to show how MDDs can be reduced by optimising experimental design and sampling techniques.

River plumes are the major source of nutrients, sediments, and other pollutant into the coastal waters. The predictive capability of a 3D hydrodynamic model (POMGL), a version of the common Princeton Ocean Model (POM), adapted for the Great Lakes, is assessed versus field measurements. The model was applied to simulate the nearshore hydrodynamics as the Grand River plume entering Lake Michigan. A nesting technique was adapted to represent the circulation and thermal structure of the surface river plume with a higher resolution. The model was compared with extensive field studies in the vicinity of Grand Haven. The current predictions showed fairly good agreement with observations, although the thermal structure of the flow especially near the river mouth was not very well represented. The model showed a weak stratification and a mild temperature transition from the plume to the lake water and therefore more diffusion. Application of hydrostatic models in exchange flows (e.g., buoyant river plumes) is recommended with reservations and coupling of these models with near field entrainment or empirical models to consider the nonhydrostatic nature of lake-river interface currents.

Wastewater from textile industry contains a number of pollutants which are hazardous in nature. The direct discharge of the wastewater into the environment affects its ecological status by causing various undesirable changes. As environmental fortification becomes a global anxiety, industries are finding novel solutions for mounting low-cost and environmental-friendly technologies for the dye removal from the waste. The presence of the dyes hinders sunlight penetration and disturbs the ecosystem of water. However, the treatment of wastewater with biodegradable polymer attains a vital importance as they are environmental friendly. The main objective of the work was to make an effort to develop a feasible process for the removal of dyes/color from the textile wastewater by using potato starch, which is a plant-based bio-polymer. A three-level, full-factorial design was selected, and experiments were conducted using a jar test apparatus. The main effects and interactions of dosage, pH, and temperature on the percentage color removal were analyzed. Reduction in color was analyzed using UV-2800 spectrophotometer. A three-way significant interaction was observed. However, dosage is found to be the most important parameter for dye removal using potato starch.

The reaction of Hg²⁺with sulfite is a major identified reduction pathway in the atmosphere. UV absorption spectroscopy was used to study the kinetics of Hg²⁺reduction by sulfite (Na₂SO₃) in the presence of fly ash. Upon the addition of Cumberland and Shawnee fly ash samples, the reduction rates were 0.0071 ± 0.0008 and 0.0009 ± 0.0006 s⁻¹, respectively. This represents c.a. 40 and 90 % decreases in the homogeneous rate, 0.013 ± 0.007 s⁻¹. The reduction reaction was also observed when Cumberland was added without Na₂SO₃. Sulfur elemental analyzer and high-resolution field emission scanning microscopy with energy dispersive X-ray spectroscopy (HR-FE-SEM-EDS) characterization confirmed that Cumberland fly ash particles were rich in sulfur. Nanoparticle Tracking Analysis (NTA) determined the mean particle size in solution to be 246 ± 25 nm for Cumberland fly ash and 198 ± 14 nm for Shawnee. To obtain further insight on observed Hg²⁺homogeneous reduction rates by sulfite, the effects of several environmental variables were investigated. Hg(NO₃)₂and HgO were used as the sources of Hg²⁺. Extended pH (1–7) and temperature (1.0–45.0 °C) ranges were studied for the first time. The enthalpies of activation for the HgO reduction were 94 ± 3 kJ mol⁻¹at pH 1 and 92 ± 4 kJ mol⁻¹at pH 3, while the entropies were 33 ± 9 J mol⁻¹ K⁻¹at pH 1 and 30 ± 10 J mol⁻¹ K⁻¹at pH 3. It was determined that increasing ionic strength, especially with nitrate species, slows down the reaction at pH = 7. Significance of the results on the variability of mercury reduction by sulfite at various environmental conditions, and its implication in modelling are discussed.

A high concentration of dissolved gaseous mercury (DGM) was detected in post-desulfurized waste seawater, which was discharged from a coal-fired power plant equipped with a seawater desulfurization system and which was located in a coastal area. A large amount of DGM was converted from other forms of mercury during transformation processes, such as photo-reduction. The present study targeted the photo-reduction of mercury and the effects of various environmental parameters on DGM production in the post-desulfurized seawater discharged. The results suggested that the photo-reduction of mercury was significantly induced under UV radiation, especially with UVB. The particulate mercury on suspended solids was easily photo-reduced and considered as an important source of DGM. It was confirmed that the suspended solids in post-desulfurized seawater could enhance the reduction process of mercury under UV radiation. The pseudo-first-order rate constants of DGM production, which were determined through the concentration gradient and trial methods, were 1.39 × 10⁻³ min⁻¹and 1.45 × 10⁻³ min⁻¹, respectively. The values showed no significant difference and were both much higher than the reported results, indicating that the photo-reduction of mercury in post-desulfurized seawater deserved more attention. In addition, the initial mercury level was observed when mixing the post-desulfurized seawater with fresh seawater, and this suggested that a significant amount of initial mercury would be produced when the post-desulfurized seawater was discharged into the adjacent sea area and thus becomes another considerable source of DGM.