Mercury levels in common (Actitis hypoleucos) and green (Tringa ochropus) sandpipers from west-central Iran

Protecting water birds of wetlands: Using toxicological tests and ecological risk assessment, based on metal/loid (s) of water, sediment and biota samples

Water, sediment and biota (two fish and one shrimp species) samples were collected from rivers, ponds, mudflat and estuaries within the Mai Po Ramsar site in Hong Kong, China, to determine the concentrations of heavy metals/loid (HMs): cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), zinc (Zn), and arsenic (As). The mutagenicity and toxicity of water and sediment samples were evaluated using Ames test and Microtox® bioassay, respectively. Ecological risk assessments on water birds were also conducted based on HM concentrations in biota, sediment and water samples. In general, results showed that downstream of Shan Pui River and Ng Tung River had relatively higher HM concentrations (e.g. Cu: 0.992-9.49 μg/L; As: 0.342-5.83 μg/L) when compared with estuaries (Cu: 0.400-3.69 μg/L; As: 0.220-0.931 μg/L) and ponds (Cu: 0.0402-2.41 μg/L; As: 0.0501-2.10 μg/L), except Hg and Cd. On the other hand, sediment samples collected from Ng Tung River showed mutagenicity on Salmonella typhimurium tester strain TA100, while the mudflat samples had mutagenicity on tester strain TA98 used in the Ames tests. Microtox® bioassay indicated that only sediment of Ng Tung River showed acute toxicity with a 15 min half maximal effective concentration (EC₅₀) value of 30.5%. Results of ecological risk assessments showed that grey heron (Ardea cinerea), which feeds on fish and shrimps at Shan Pui River and ponds were not at risk. However, common sandpiper (Actitis hypoleucos), which feeds at ponds were subjected to a potential health risk due to its behavior of seeking food from the sediments, especially this bird species has a small body size. This indicates juvenile birds of other species may also be affected. Remediation should be implemented to relief the potential risk of Cu and Pb, to these water birds in the Mai Po Ramsar site.

The complete mitochondrial genome of Tringa ochropus (Charadriiformes, Scolopacidae)

The green sandpiper Tringa ochropus (Charadriiformes, Scolopacidae) is completely migratory with an extremely large distribution range. However, its habitat ecology, and disease spreading are relatively understudied, and the molecular genetics is relatively unclear. In this study, we report the complete mitochondrial genome of T. ochropus, which is a circular molecule of 16,906 bp in length and the A + T content of overall base of the composition of H-strand is 54.88% (A: 31.62%, T: 25.53%, C: 29.47%, G: 13.38%). This study strongly supports the monophyly of Charadriiformes, and division of the order into three major clades, including Lari, Scolopaci, and Charadrii.