Human biomonitoring and wastewater based epidemiology as complementary approaches for early identification of chemical exposure risks at the neighborhood level

Abstract

Human Biomonitoring (HBM) involves the measurement and evaluation of the presence of chemicals, biomarkers, or their metabolites in biological samples from individuals. It is the most commonly used tool to assess human exposure to environmental contaminants and subsequently evaluate potential associations with adverse health effects. However, this approach has significant limitations such as its high cost, logistical complexity, or ethical implications. Therefore, innovative approaches are needed to assess community level exposure to contaminants at a low cost, avoiding HBM campaigns. In this regard, wastewater based epidemiology (WBE) has emerged as an interesting and complementary approach that allows the assessment of lifestyle, health, and well-being of the population through the information obtained from monitoring chemical substances found in wastewater. The first objective of this study aimed to determine if there are differences in exposure to endocrine disrupting compounds (EDCs) among pregnant women residing in different neighborhoods characterized by varying socioeconomic statuses. To achieve this, biomarkers of benzophenones, bisphenols, phthalates, parabens, and flame retardants were measured in the urine of 56 pregnant women living in three Barcelona neighborhoods with different socio-economic levels. We employed a previously developed analytical method based on Captiva and liquid chromatography coupled to high resolution mass spectrometry (HRMS-QTOF-MS/MS). In total, 15 EDCs were detected in the urine samples of pregnant women. Differences in exposure to several of these compound families were observed; for instance, benzophenones used in sun protection products were detected to a lesser extent in the lower socioeconomic status neighborhood, possibly due to these products not being considered primary needs. Flame retardants were detected less in women residing in the high socioeconomic status neighborhood, potentially owing to the purchase of higher quality products with better safety standards and increased environmental awareness. Conversely, residents of this neighborhood exhibited higher concentrations of phthalates (plasticizers), possibly due to a greater consumption of ready-to-eat prepared food. Regarding bisphenols and parabens, no different trends were found in the three neighborhoods.The second objective of the study aimed to compare the presence of detected EDCs in urine samples with those found in influent wastewater at the community level. We analyzed the same analytes in integrated samples collected over seven consecutive days at specific collectors located in the same three neighborhoods. We observed that 12 out of the 15 EDCs detected in urine were also found in wastewater samples. In general, differences were noted in exposures between the profiles determined in urine and wastewater. We observed different trends in flame retardants and parabens, which could be attributed to pregnant women being a conscious but not entirely representative population. Regarding benzophenones, bisphenols, and phthalates, we observed that in the neighborhood with a medium socioeconomic status and the most influenced by tourism, exposure was higher at the community level but lower at the pregnant population level. This discrepancy could be attributed to the presence of a floating population.