Unprecedentedly High Dust Ingestion Estimates for the General Population in a Mining District of DR Congo.

The mining of metals in low income countries is often associated with high exposure to dust that contributes to metal exposure. Here, dust ingestion estimates were made from fecal excretion of inert tracers with corrections for dietary contribution. The study took place in the cobalt mining area of Lubumbashi (DR Congo) and involved 120 nonoccupationally exposed participants in the dry season, with 51 of these being repeated in the rainy season. For each participant, duplicate meals (0-96 h), feces (24-120 h), and indoor/outdoor dust (<250 µm) were collected. The dust ingestion estimates (g day-1) were derived from Nb, Ti, and V as best tracers and were 0.28 (geometric mean), 3.3 (mean), and 13 (P95); these values are almost a factor 10 above currently accepted estimates for the general population in high income countries. Mean dust ingestion in the dry season was twice that of the rainy season, and the P95s were significantly higher in children (3-15 years) than in male adults and toddlers; geophagy (>40 g day-1) was suspected in three individuals. These data explain the previously reported extreme cobalt exposures in children and support the need to manage dust in the metal mining operations.

Agnathia otocephaly: A case from the Katanga Copperbelt.

BACKGROUND: Agnathia otocephaly is a rare craniofacial malformation complex characterised by absent/hypoplastic mandible, abnormally positioned ears meeting at level of neck. Besides mutations in two genes, PRRX1 and OTX2, a teratogenic cause has been suggested. A higher risk of congenital malformations has been associated with paternal work in mining in the Democratic Republic of the Congo's part of the Copperbelt. CASE: We studied a female neonate with a clinical diagnosis of agnathia otocephaly, stillborn in Lubumbashi in 2019. The child's father had been working as an artisanal mineworker at the time of conception. RESULTS: Genetic analysis did not reveal a causal mutation. The concentrations of cobalt, arsenic cadmium, and uranium in cord blood of the infant were much higher than those of normal neonates from a previous study. CONCLUSION: In the absence of identified genetic causes, we hypothesize this case of agnathia otocephaly was related to an exogenous cause, possibly the father's mining-related job.