A lead isotope perspective on urban development in ancient Naples

Abstract

The influence of a sophisticated water distribution system on urban development in Roman times is tested against the impact of Vesuvius volcanic activity, in particular the great eruption of AD 79, on all of the ancient cities of the Bay of Naples (Neapolis). Written accounts on urbanization outside of Rome are scarce and the archaeological record sketchy, especially during the tumultuous fifth and sixth centuries AD when Neapolis became the dominant city in the region. Here we show that isotopic ratios of lead measured on a well-dated sedimentary sequence from Neapolis' harbor covering the first six centuries CE have recorded how the AD 79 eruption was followed by a complete overhaul of Neapolis' water supply network. The Pb isotopic signatures of the sediments further reveal that the previously steady growth of Neapolis' water distribution system ceased during the collapse of the fifth century AD, although vital repairs to this critical infrastructure were still carried out in the aftermath of invasions and volcanic eruptions.AD 79 Somma-Vesuvius eruption | Pb isotopes | harbor geoarchaeology | Neapolis | paleo-pollution U rban centers have always been critically dependent on a stable water supply, and ancient cities relying on masonry aqueducts were particularly vulnerable to the disruption of their water distribution system by earthquakes and volcanic eruptions (1). The archaeological record of the major eruption of Vesuvius in AD 79 and its effect on the water supply of Naples, then known as Neapolis, and its neighboring cities illustrates well how efficiently the Roman world was able to mitigate the effects of major disasters on the daily life of its population. Neapolis: Water Supply and VolcanismNeapolis and the surrounding region were supplied with water from the Aqua Augusta or Serino aqueduct, built during the reign of Augustus between 27 BC and AD 10 (2, 3). The Augusta was a regional network supplying eight or nine cities, as well as numerous villas, through multiple branches (Fig. 1A): Nola, possibly Pompeii, Acerrae, Atella, Neapolis, Puteoli, Cumae, Baiae, and Misenum (2, 4). The total length of the aqueduct, including its branches, was ∼140 km. The construction of this monumental hydraulic network helped meet a need to secure the water supply for the strategic region of Campania during a critical period: the establishment of the Principate (2). The aim of the Augusta was to provide water to naval harbors (first Portus Iulius and later Misenum) and the commercial harbor of Puteoli, one of the busiest centers of trade in the Roman Empire (5), as well as to cities, coloniae, and villas of influential individuals. At an unknown time between the fifth century BC and the Middle Ages, the Bolla aqueduct (Fig. 1A) was constructed to bring additional water to Neapolis (3).One of the challenges in maintaining the Augusta and, with it, the integrity of the water supply of the heavily settled area around Neapolis, was counteracting the slow movements of the ground associated with the activity of volcanic sy...

Economic resilience of Carthage during the Punic Wars: Insights from sediments of the Medjerda delta around Utica (Tunisia)

“…S4). Recently, such factor analysis has contributed to identifying lead pipes as the Pb pollution source of the ancient harbor sediments of Naples because Pb was clearly separated from other metal trace elements, thus indicating the presence of a pure Pb source (10). Here, the factor analysis shows the opposite, with an impure anthropogenic Pb source containing Pb, Ag, P, Cu, and Zn.…”

“…Our knowledge of ancient mining centers (i) is focused mainly on Roman mining districts (a question of textual sources?) (6,7), (ii) tends to emphasize major centers to the detriment of smaller ones (8), and (iii) concerns Central and Western Europe more than North Africa (5)(6)(7)(9)(10)(11)(12), often without robust chronological timelines (7). This paradox is all the more striking when one observes the spatial distribution of lead-silver mines within the Roman Empire, which is largely devoid of them along its southern and eastern fringes (5)(6)(7).…”

“…At much smaller local scales, such as the area of a city, the Pb paleopollution approach is less ambiguous about the source since the distances traveled by anthropogenic lead pollution are short and the routes well established; they follow the urban hydrographic network. Studies of Pb paleopollution trapped in fluviomarine sediments of ancient harbor basins have thus been able to document unexpected and intriguing facets of urban history in a number of ancient cities around the Mediterranean (10,11,21). These metal paleopollutions trapped in harbor sediments could not have come from aerosols as these contain very low levels of lead, even during episodes of intense atmospheric pollution.…”

Environmental impacts of ancient copper mining and metallurgy: Multi-proxy investigation of human-landscape dynamics in the Faynan valley, southern Jordan

“…This method has proven effective in similar studies elsewhere (Beherec et al, 2016;Delile et al, 2016 Shotyk (1996) lowered EF values by as much as 40% for Pb. Thus, we are confident that the chosen calculation for EF is the most appropriate.…”

Development and decline of the ancient harbor of Neapolis

“…The increase in the high trophic level recorded in the bay until the end of the 3rd century A.D., begins in concurrence with the construction of the Roman baths at the end of the 2nd century A.D. (Figs and C), whose drainage pipe flowed into the harbor probably inducing pollution, such as lead enrichment highlighted by Delile et al. (). During this time interval, more or less similar assemblages (M2a and M2b) are found in both sections (Fig.…”