Concentrations, sources and human exposure implications of organophosphate esters in indoor dust from South Africa

The concentrations of four organophosphate esters (OPEs) were measured in 50 dust samples from homes (n = 10), offices (n = 9), university computer laboratories (n = 12) and cars (n = 19) in Durban, South Africa. The median concentrations Σn=4 OPEs were 22940, 26930, 19565 and 49010 ng g⁻1 in homes, offices, university computer laboratories and cars respectively. OPEs were detected in all samples with the exception of one car and one computer laboratory sample in which TDCIPP was not detected. Significant association of indoor characteristics with OPE concentrations was observed. OPEs positively correlated (r = 0.22, p value = 0.4862) with electronics and correlated (r = 0.522, p value = 0.0675) with foams and furniture in homes. By employing the median concentrations and an average dust intake rate, the exposure doses (ng d-1) were found to be 169 (TCEP), 74 (TCIPP), 162 (TDCIPP) and 55 (TPHP) for adults; 159 (TCEP), 70 (TCIPP), 108 (TDCIPP) and 57 (TPHP) for teenagers; 317 (TCEP), 152 (TCIPP), 334 (TDCIPP) and 94 (TPHP) for toddlers. The predominance and exposure magnitude of OPEs in the South African environment require further investigations to determine cumulative human health effects arising from mixtures of these compounds through multiple exposure routes.