Modern strains of Mycobacterium tuberculosis from the Americas are closely related to those from Europe, supporting the assumption that human tuberculosis was introduced post-contact. This notion, however, is incompatible with archaeological evidence of pre-contact tuberculosis in the New World. Comparative genomics of modern isolates suggests that M. tuberculosis attained its worldwide distribution following human dispersals out of Africa during the Pleistocene epoch, although this has yet to be confirmed with ancient calibration points.

Understanding the response of the El Niño-Southern Oscillation (ENSO) to global warming requires quantitative data on ENSO under different climate regimes. Here, we present a reconstruction of ENSO in the eastern tropical Pacific spanning the last 10 thousand years (ka) derived from oxygen isotopes in fossil mollusk shells from Peru. We find that ENSO variance was close to the modern level in the early Holocene and severely damped ~4-5 ka. In addition, ENSO variability was skewed toward cold events along coastal Peru 6.7-7.5 ka owing to a shift of warm anomalies toward the Central Pacific.

The objective of the study was to assess the extent of arsenic contamination of groundwater and surface water in Peru and, to evaluate the accuracy of the Arsenic Econo-Quick™ (EQ) kit for measuring water arsenic concentrations in the field.

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Hydraulic engineering is increasingly relied upon to provide the necessary dry-season discharge for Peru’s hydroelectricity generation. Redirecting stream flow can yield unintended consequences, however, and here we document the wholesale contamination of the Lake Junín National Reserve by acid mine drainage from the Cerro de Pasco mining district. Since construction of the Upamayo Dam in 1932, the Río (river) San Juan, which drains the Cerro de Pasco region, has been seasonally redirected into Lake Junín.