The Sambaqui shell mounds of Brazil are the largest waste structures from the ancient world, and the most important evidence of the prehistoric populations which lived on the Brazilian coast. The largest of the 2,000 mound sites are found on the coast of Southeastern Brazil, where they reach up to 50m in height and 500m in diameter, looming over the coast like large hills. Sambaquis are made up of up to 64 million kilograms of waste material, including molluscs, fish remains, land mammal bones, ash and plant materials mixed with basalt and various types of sandstone. Handily, they are preserved in layers, called strata, which we can date and thus uncover the period in which they were built. In the coastal plain, the oldest mounds are around 8,720 years old, far older than the Great Pyramids of Giza. The youngest were built around 1,700 years ago. Each mound was layered gradually over centuries or millennia before reaching their maximum size.
Since the 1990’s, archaeological research has pointed toward the fact that these mounds are human constructions, some of the earliest of their size in the world. At first glance, they seem little more than great heaps upon which the ancient Sambaqui cultures of Southeast Brazil cast their litter after feasts.
Despite their appearance, the existence of similarly shaped and sized shell mounds across large areas suggests that they held some common functions. Food refuse, at first, was thought the primary component of the mounds, and before the 1990’s, mounds were mostly considered as evidence for these peoples’ diet, health and physical traits. It is still likely that refuse was important in their construction, but they were much more important than that. In fact, the mounds tell us a lot about the Sambaqui builders’ relationship with their environment, and help us to understand how they lived.
Normally, mounds were built on sites near marine ecosystems, mostly in lagoons, where brackish waters supported an abundance of fish and shellfish. Mounds were constructed near bodies of water as they rose, fell and changed shape, and were highest in number at points where oceans and rivers met. Lagoons and mangroves have great ecological importance as homes to considerable biodiversity and, therefore, readily available food sources for ancient humans. From the sambaquis, we can tell that the builders enjoyed a diet based mostly on fish. They were excellent at exploiting the ocean and rivers; a study of the remains at various shell mounds discovered at least 97 different marine species, far more than we eat today!
The inclusion of large and rare fish such as sharks and rays suggests that they were better at fishing than most other prehistoric cultures. Highly skilled fishing is also shown by the variety of bone tools found, such as lances, hooks, harpoons, needles, nets and pebbles, which functioned as net weights. The sheer amount of fish consumed meant that overfishing of species caused reduction in their body size over millennia. From the mounds we can also tell that the builders foraged and cultivated in the forest. Decorated plates, vessels and grinding stones are found along with seeds, tubers and roots.
Beyond these ancient peoples’ eating habits, the mounds, especially the larger ones, had another crucial function. The huge sizes and the existence of burial chambers within the larger mounds implies that they also existed as important landmarks, like the Spire of Dublin or the Eiffel Tower, but they were also burial chambers, with people (or families) of particular importance buried in chambers inside. The largest mounds have complex clusters of chambers, potentially containing hundreds of burials. Funerary areas were built on surfaces atop previous shell deposits, and would be built over until the next chamber is carved out. Burials were usually in shallow pits, and included offerings and items of importance to the person buried. Typical artefact offerings included shell, bone and stone objects, mostly for use in fishing, foraging or hunting, though there is also jewellery, an indicator of significant members of the community. In ceremonial celebration, fireplaces around the burial pits were lit and feasts would take place. After a while, the building of burials in a particular mound ceased, and they were closed and covered by shells.
The Sambaqui shell mounds show us that there is a lot more to waste than we think. They tell us about the people who lived near them; their habits, their eating patterns, their favourite food, where they choose to live and why they lived there. This ancient waste can even tell us about particular events, when they happened and why. If we can understand this about people that lived thousands of years ago, it is important to think of waste generated by our society in the same way now. The builders of the Sambaqui found a way to organise and give a purpose to their waste, to collect it and make it a crucial part of their lives (and even their afterlife), in this case making huge, impressive structures which represented who they were.
Today, in Brazil, waste is not treated with such care. The production of waste is one of the greatest challenges facing Brazilian municipalities, and their management of waste is still lacking in many aspects. In 2015, only a little over half of the solid waste in Brazilian cities was properly disposed of. Only in 2010 did Brazil establish the National Policy on Solid Waste, with its main goals being the closing of all open dumps and the reduction in the amount of waste disposed of in landfills. However, this policy has had little impact. Disposal in landfills is practically the only waste management approach. The Brazilian population is increasing, with waste produced at around 1kg per person per day, and more and more litter being produced each year. The collection of recyclable material covers less than half of the country, and much of that is inappropriately thrown in landfills anyway. Brazilian cities invest around five times less in waste management compared with cities in other countries. This lack of investment is the main reason most Brazilian cities fail to manage their waste appropriately.
Perhaps lessons should be learned from the Sambaquis, not to pile waste up high in huge mounds (we already do that), but to think about how we can repurpose it, treat it with more care and importance. In Brazil, this might mean improving national recycling programmes, closing the huge open dumps and investing in new technologies to treat the large amounts of organic waste. If this can happen, their streets, and our environment, will benefit.