Health Impacts of Some Persistent Organic Pollutants in Expecting Mothers from Punjab

Abstract

Polychlorinated Biphenyls (PCBs) are persistent, toxic and bio-accumulative organic pollutants present everywhere in the biosphere. PCBs enter the environment mainly as a result of anthropogenic activities and accumulate in mothers through food and respiration. These chemicals transfer from mother body to the fetus inside the womb. Keeping this in view, the present study was conducted to monitor the PCBs and their impacts on expecting mothers from the Punjab Province, Pakistan. In this regard, blood serum, milk and placenta samples were collected from 45 women with the cesarean section from five districts viz; Lahore, Sialkot, Khanewal, Okara and Chakwal. All samples were collected and screened for the quantification of 34 PCB congeners including eight dioxin like PCBs (dl-PCBs) viz: ΣPCB70, 126, 169, 105, 114, 118, 156 and 189) and six indicator PCBs (ΣPCB52, 101, 118, 138, 153 and 180 using Gas Chromatograph Mass Spectrometer (GC/MS). The mean concentrations of Σ34 PCB in blood serum (232.33 ± 110.62 ng/g lip), milk (44.07 ± 27.27 ng/g lip) and placenta (80.26 ± 19.87 ng/g lip) were recorded. The mean concentration of indicator PCBs in blood serum, milk and the placentawas 49.55 ± 42.31 ng/g lip, 10.31 ± 11.70 ng/g lip and 17.69 ± 12.40 ng/g lip respectively. Whereas, the mean concentration (ng/g lw) of dl-PCBs in blood serum, milk and placenta of each study subject were 33.39 ± 40.18, 6.15 ± 8.72 and 9.48 ± 10.92, respectively. The concentration of Σ34PCBs in blood serum on the basis of spatial distribution was recorded highest in women belonging to Chakwal (310.59 ± 119.47 ng/g lip), whereas, the minimum concentration at Okara (251.28 ± 152.61ng/g lip). A similar trend was observed in the case of milk with the highest concentration of Σ34PCBs was recorded from Chakwal (68.33 ± 20.11ng/g lip) and lowest from Okara (30.46 ± 31.07 ng/g lip). In the case of the placenta, the highest concentration was recorded from Chakwal (93.47 ± 29.41 ng/g lip), and lowest from Khanewal (70.46 ± 31.20 ng/g lip). The spatial distribution ii pattern of PCBs homolog concentrations was represented in the maps developed using Arc GIS.The mean Toxic Equivalent Concentration (TEQ) for Σ8dl-PCBs in blood serum was calculated as 0.24 ng TEQ/g lipids. The mean TEQ concentration in human milk and the placenta was calculated as 0.06 ng TEQ/g lipids and 0.08 ng TEQ/g lipids, respectively. The potential risk of dl-PCBs to the health of subject mothers was calculated by Estimated Daily Intake (EDI). The calculated EDI (pg WHO-Teq/ kg body weight) in blood serum (1.94 x 10-3), milk (5.10 x 10-4) and placenta (6.56 x 10-4) were found below the WHO Tolerable Daily Intake (TDI). Among the socio-demographic parameters, dairy products, maternal weight and height showed a positive significant relationship to Σ34PCBs in blood serum and placenta respectively. The concentrations of Σ34PCBs in human milk showed a negative correlation with age of the mothers, parity and lactation. The calculated EDI for dl-PCBs in nursing infants ranged from 400 to 26624.1 pg TEQ kg-1 bw day-1(mean: 8862.6 pg TEQ kg-1 bw day-1) were found to be significantly higher than the tolerable daily intake limits provided by WHO (1–4 pg TEQ kg-1 bw day-1).A negative association was observed in levels of PCBs in human milk and infant anthropometric measures viz; birth weight, head circumference, mid arm circumference and chest circumference and concentrations in human placenta showed a negative relationship with infant‘s birth weight and crown to heel length. These results highlighted that prenatal exposure to PCBs may affect fetal anthropometric development and impair the health of infants. Similarly, the hazard quotient values for Σ8dl-PCBs (range: 40.42 to 2662.41) were far above the benchmark value of 1 at all the sampling sites, indicating the high levels of adverse health risks to infants in the region through breast milk consumption. These results highlighted the need for comprehensive monitoring of PCBs in human and food products to assess and manage the continuous releases of PCB into the environment to prevent future human exposure, particularly of fetuses and infants.