Urinary profiles of selected metals and arsenic and their exposure pathway analysis in four large floodplains of Pakistan

A multi-environmental source approach to explore associations between metals exposure and olfactory identification among school-age children residing in northern Italy

BACKGROUND

Metal exposures can adversely impact olfactory function. Few studies have examined this association in children. Further, metal exposure occurs as a mixture, yet previous studies of metal-associated olfactory dysfunction only examined individual metals. Preventing olfactory dysfunctions can improve quality of life and prevent neurodegenerative diseases with long-term health implications.

OBJECTIVE

We aimed to test the association between exposure to a mixture of 12 metals measured in environmental sources and olfactory function among children and adolescents residing in the industrialized province of Brescia, Italy.

METHODS

We enrolled 130 children between 6 and 13 years old (51.5% females) and used the "Sniffin' Sticks" test to measure olfactory performance in identifying smells. We used a portable X-ray fluorescence instrument to determine concentrations of metals (arsenic (As), calcium, cadmium (Cd), chromium, copper, iron, manganese, lead (Pb), antimony, titanium, vanadium and zinc) in outdoor and indoor deposited dust and soil samples collected from participants' households. We used an extension of weighted quantile sum (WQS) regression to test the association between exposure to metal mixtures in multiple environmental media and olfactory function adjusting for age, sex, socio-economic status, intelligence quotient and parents' smoking status.

RESULTS

A higher multi-source mixture was significantly associated with a reduced Sniffin' Sticks identification score (β = -0.228; 95% CI -0.433, -0.020). Indoor dust concentrations of Pb, Cd and As provided the strongest contributions to this association (13.8%, 13.3% and 10.1%, respectively). The metal mixture in indoor dust contributed more (for 8 metals out of 12) to the association between metals and olfactory function compared to soil or outdoor dust.

IMPACT STATEMENT

Among a mixture of 12 metals measured in three different environmental sources (soil, outdoor and indoor dust), we identified Pb, Cd and As measured in indoor dust as the main contributors to reduced olfactory function in children and adolescents residing in an industrialized area. Exposure to indoor pollution can be effectively reduced through individual and public health interventions allowing to prevent the deterioration of olfactory functions. Moreover, the identification of the factors that can deteriorate olfactory functions can be a helpful instrument to improve quality of life and prevent neurodegenerative diseases as long-term health implications.

Human biomonitoring of trace metals from different altitudinal settings of Pakistan

Human biomonitoring of toxic trace elements is of critical importance for public health protection. The current study aims to assess the levels of selected trace metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) into paired human nail and hair samples (n = 180 each) from different altitudinal setting along the Indus River, and which were measured by using inductively coupled plasma mass spectrometry (ICP-MS). The human samples (hair and nail) were collected from four different ecological zones of Pakistan which include frozen mountain zone (FMZ), wet mountain zone (WMZ), riverine delta zone (RDZ), and low-lying southern areas (LLZ). Our results showed the following occurrence trends into studied hair samples: higher values (ppm) of Zn (281), Co (0.136), and Mn (5.65) at FMZ; Cr (1.37), Mn (7.83), and Ni (1.22) at WMZ; Co (0.15), Mn (11.89), and Ni (0.99) at RDZ; and Mn (8.99) and Ni (0.90) at LLZ. While in the case of nails, the levels (ppm) of Mn (9.91) at FMZ and Mn (9.38, 24.1, and 12.5), Cr (1.84, 3.87, and 2.33), and Ni (10.69, 8.89, and 12.6) at WMZ, RDZ and LLZ, respectively, showed higher concentration. In general, among the studied trace elements, Mn and Ni in hair/nail samples were consistently higher and exceeded the WHO threshold/published reference values in most of the studied samples (> 50-60%) throughout the Indus basin. Similarly, hair/nail Pb values were also higher in few cases (2-10%) at all studied zones and exceeded the WHO threshold/published reference values. Our area-wise comparisons of studied metals exhibited altitudinal trends for Cd, Cr, Zn, and Mn (p < 0.05), and surprisingly, the values were increasing from south to north (at higher altitudes) and indicative of geogenic sources of the studied toxic elements, except Mn, which was higher at lower floodplain areas. Estimated daily intake (EDI) values showed that food and drinking water had the highest contribution towards Zn, Cu, Mn, and Ni and accumulation at all studied zones. Whereas, dust also acts as the main exposure route for Mn, Co, Cr, and Cd followed by the food, and water.

Assessment and Exposure Analysis of Trace Metals in Different Age Groups of the Male Population in Southern Punjab, Pakistan

In developing countries, like Pakistan, the pursuit of urbanization and economic development disrupts the delicate ecosystem, resulting in additional biogeochemical emissions of heavy metals into the human habitat and posing significant health risks. The levels of these trace elements in humans remain unknown in areas at higher risk of pollution in Pakistan. In this investigation, selected trace metals including Copper (Cu), Chromium (Cr), Lead (Pb) Cadmium (Cd), Cobalt (Co), Nickel (Ni), and Arsenic (As) were examined in human hair, urine, and nail samples of different age groups from three major cities (Muzaffargarh, Multan, and Vehari) in Punjab province, Pakistan. The results revealed that the mean concentrations (ppm) of Cr (1.1) and Cu (9.1) in hair was highest in Muzaffargarh. In urine samples, the mean concentrations (μg/L) of Co (93), As (79), Cu (69), Cr (56), Ni (49), Cd (45), and Pb (35) were highest in the Multan region, while As (34) and Cr (26) were highest in Vehari. The mean concentrations (ppm) of Ni (9.2), Cr (5.6), and Pb (2.8), in nail samples were highest in Vehari; however, Multan had the highest Cu (28) concentration (ppm). In urine samples, the concentrations of all the studied metals were within permissible limits except for As (34 µg/L) and Cr (26 µg/L) in Vehari. However, in nail samples, the concentrations of Ni in Multan (8.1 ppm), Muzaffargarh (9 ppm), Vehari (9.2 ppm), and Cd (3.69 ppm) in Muzaffargarh exceeded permissible limits. Overall, the concentrations of metals in urine, nail, and hair samples were higher in adults (39-45 age group). Cr, Cu, and Ni revealed significantly higher concentrations of metals in hair and water in Multan, whereas As in water was significantly (p < 0.001) correlated with urinary As in Multan, indicating that the exposure source was region-specific.

Distribution, Genesis, and Human Health Risks of Groundwater Heavy Metals Impacted by the Typical Setting of Songnen Plain of NE China

Heavy metals pollution in groundwater and the resulting health risks have always been an environmental research hotspot. However, the available information regarding this topic and associated methods is still limited. This study collected 98 groundwater samples from a typical agricultural area of Songnen Plain in different seasons. The pollution status and sources of ten heavy metals (As, Ba, Cd, Co, Cr (VI), Cu, Fe, Mn, Ni, Pb, and Zn) were then analyzed and compared. In addition, the human health risks assessment (HHRA) model was used to calculate human health risks caused by heavy metals in groundwater. The results revealed that heavy metals were mainly distributed in the northwest of the study area and along the upper reaches of the Lalin river and that the concentrations of heavy metals were higher during the wet season than the dry season. Industrial and agricultural activities and natural leaching are the main sources, and each kind of heavy metal may have different sources. Fe and Mn are the primary pollutants, mainly caused by the native environment and agricultural activities. The exceeding standard rates are 71.74% and 61.54%, respectively based on the Class III of Quality Standard for Groundwater of China (GB/T 14848-2017). The maximum exceeding multiple are 91.45 and 32.05, respectively. The health risks of heavy metals borne by different groups of people were as follows: child > elder > young > adult. Carcinogenic heavy metals contribute to the main risks, and the largest risks sources are Cr and As. Therefore, the government should appropriately restrict the use of pesticides and fertilizers, strictly manage the discharge of enterprises, and control man-made heavy metals from the source. In addition, centralized water supply and treatment facilities shall be established to prevent the harm of native heavy metals.