The World Health Organization (WHO) estimates that around ~150 million people in 70 different countries have been consuming water with arsenic levels higher than the recommended limit of 10 μg/L. Here we describe the concentrations of inorganic arsenic in drinking water in homes of pregnant women living in the province of Tacna, near the southern border of Peru. 161 pregnant women were enrolled in their second trimester of pregnancy. A total of 100mL drinking water was collected in each household from the source of most common use. Inorganic arsenic was categorized into 3 levels with a commercial kit. Thirty percent of women had drinking water ≤10 μg/L (the WHO recommended level), 35% had 25 μg/L, and 35% had greater than 50 μg/L. Low arsenic levels were found in the southernmost homes, supplied by groundwater, while high levels were found in the northern and metropolitan homes supplied by river water.

Arsenic exposure during pregnancy might affect foetal development. Arsenic metabolism may modulate the potential damage to the fetus. Tacna has the highest arsenic exposure levels in Peru. However, this region also has the highest birth weight in Peru. It is not known if arsenic exposure is affecting maternal-perinatal health in Tacna. This study aimed to evaluate the association between urinary arsenic metabolism and birth outcomes, specifically birth weight and gestational age at birth in Tacna, Peru. A prospective cohort study was conducted, involving 158 pregnant women in Tacna, Peru, during January-November 2019. Participants were enrolled in their second trimester and followed-up until birth. Urine samples were collected in the second and third trimesters. Urine samples were analysed for total arsenic concentration and its species. Generalised estimating equations analysis was used to evaluate the association of interest. Inter-differences in arsenic toxicokinetics, calculated with principal component analysis was included as an interaction term. Analysis was stratified by pregnancy trimester. The median total urinary arsenic concentration was 33.34 μg/L. Inorganic arsenic and dimethylarsinic acid were higher in the second trimester. Dimethylarsinic acid was the predominant component (84.78% of total urinary arsenic). No significant association was found between urinary arsenic exposure and birth weight or gestational age at birth. The association was not affected by arsenic metabolism. Stratified analyses by pregnancy trimester also showed no significant associations. Urinary arsenic was not associated with birth weight, and this null relationship remained unaffected by arsenic toxicokinetic differences reflected in urine.

Background

Polycyclic aromatic hydrocarbons (PAHs) are abundant and widespread environmental chemicals. They are produced naturally and through man-made processes, and they are common in organic media, including petroleum. Several PAHs are toxic, and a subset exhibit carcinogenic activity. PAHs represent a range of chemical structures based on two or more benzene rings and, depending on their source, can exhibit a variety of side modifications resulting from oxygenation, nitrogenation, and alkylation.

Objectives

Here we discuss the increasing ability of contemporary analytical methods to distinguish not only different chemical structures among PAHs but also their concentrations in environmental media. Using seafood contamination following the Deepwater Horizon accident as an example, we identify issues that are emerging in the PAH risk assessment process because of increasing analytical sensitivity for individual PAHs, and we describe the paucity of toxicological literature for many of these compounds.

Discussion

PAHs, including the large variety of chemically modified or substituted PAHs, are naturally occurring and may constitute health risks if human populations are exposed to hazardous levels. However, toxicity evaluations have not kept pace with modern analytic methods and their increased ability to detect substituted PAHs. Therefore, although it is possible to measure these compounds in seafood and other media, we do not have sufficient information on the potential toxicity of these compounds to incorporate them into human health risk assessments and characterizations.

Conclusions

Future research efforts should strategically attempt to fill this toxicological knowledge gap so human health risk assessments of PAHs in environmental media or food can be better determined. This is especially important in the aftermath of petroleum spills.