Assessment of environmental loads of Cu and Zn from intensive inland shrimp aquaculture

Abstract

An experiment was developed to simulate inland shrimp farming using diluted seawater (1.9 g L) containing 75 shrimps (Litopenaeus vannamei) per square meter during a growth cycle of 120 days. In this study, the environmental loads of copper and zinc were estimated and compared to anthropogenic sources and shrimp aquacultures in other locations. Both metals resulted primarily from feeding, which accounted for 91.8% of Cu and 97.0% of Zn. Concentrations of Cu (110.8 ± 11.8 μg g) and Zn (69.0 ± 0.7 μg g) measured in the harvested shrimp had higher Cu and lower Zn concentrations compared to those reported for farmed shrimp from Brazil and Mexico. Clearly, organic sludge was the main route of removal for both metals (Cu 46.2%; Zn 92.6%). The annual environmental loads estimated for inland shrimp aquaculture were 598 ± 74 g Cu ha and 5080 ± 328 g Zn ha.

20-Years Cumulative Impact From Shrimp Farming on Mangroves of Northeast Brazil

“…Emission factors and total annual emission of nutrients (t km −2 year −1 ) and metals (kg km −2 year −1 ) from shrimp aquaculture in Northeast Brazil, afterLacerda et al (2006a,b),Lacerda et al (2011), Sá et al (2013,León-Cañedo et al (2017).…”

Neotropical mangroves: Conservation and sustainable use in a scenario of global climate change

“…Shrimp farming effluents are mostly composed of fine sediments eroded from pond walls by waves provoked by aerators, rich in nonrefractory organic matter, whose oxidation upon reaching estuarine waters rapidly consumes available dissolved oxygen (Lacerda, Vaisman, Maia, Silva, & Cunha, ). Additionally, shrimp aquaculture is responsible for the emission of the greatest quantities of nutrients and some persistent pollutants relative to other sources located in the coastal zone (Table ), contaminating the surrounding environment (León‐Cañedo et al, ; Silva, Rainbow, Smith, & Santos, ).…”

“…Emission factors compiled from Lacerda, Vaisman, et al (), Lacerda, Santos, and Madrid (); Lacerda, Molisani, Sena, and Maia (); Lacerda, Soares, Costa, and Godoy () and León‐Cañedo et al (). Emission figures in bold are maximum values…”

“…However, this picture is also changing. In the Gulf of California, Mexico, which supports over 83,000 ha of shrimp ponds, for example, emits comparable annual loads of 51,469 kg and 77,350 kg of copper from aquaculture and agriculture, respectively (León‐Cañedo et al, ). In addition, contrary to all other anthropogenic sources of nutrients and pollutants to estuaries, only shrimp farming effluents (and sometimes urban wastewaters) are released directly into the estuarine waters (Table ).…”

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“…Some trace elements, such as Cu and Hg, whose emission factors are particularly high relative to other anthropogenic sources (Table 1), are of environmental significance and represent an additional environmental threat. Another trace element of environmental significance is Zn, which has also shown to be affected by shrimp pond effluents (Silva et al, 2001) and seems to present high emission factors (León-Cañedo et al, 2017). Unfortunately, the one study, to our knowledge, that has analyzed Zn in Northeast Brazil mangroves observed an increase in Zn concentrations in oysters and sediments downstream of shrimp farm effluent outfalls (Silva et al, 2001).…”