Mercury accumulation in bats near hydroelectric reservoirs in Peninsular Malaysia

Abstract

In large man-made reservoirs such as those resulting from hydroelectric dam construction, bacteria transform the relatively harmless inorganic mercury naturally present in soil and the submerged plant matter into toxic methylmercury. Methylmercury then enters food webs and can accumulate in organisms at higher trophic levels. Bats feeding on insects emerging from aquatic systems can show accumulation of mercury consumed through their insect prey. In this study, we investigated whether the concentration of mercury in the fur of insectivorous bat species was significantly higher than that in the fur of frugivorous bat species, sampled near hydroelectric reservoirs in Peninsular Malaysia. Bats were sampled at Temenggor Lake and Kenyir Lake and fur samples from the most abundant genera of the two feeding guilds-insectivorous (Hipposideros and Rhinolophus) and frugivorous (Cynopterus and Megaerops) were collected for mercury analysis. We found significantly higher concentrations of total mercury in the fur of insectivorous bats. Mercury concentrations also differed significantly between insectivorous bats sampled at the two sites, with bats from Kenyir Lake, the younger reservoir, showing higher mercury concentrations, and between the insectivorous genera, with Hipposideros bats showing higher mercury concentrations. Ten bats (H. cf. larvatus) sampled at Kenyir Lake had mercury concentrations approaching or exceeding 10 mg/kg, which is the threshold at which detrimental effects occur in humans, bats and mice.

Bats and Water: Anthropogenic Alterations Threaten Global Bat Populations

“…In Arizona, USA where at least 20 % of bat populations are in decline (King et al 2001), Mexican free-tailed bats (Tadarida brasiliensis) living 8 km from a major copper smelting mine had accumulated significant levels of atmospheric mercury in their tissues (Petit 2007). In another study in Arizona, pallid bats (Antrozous pallidus), western pipistrelles (Parastrellus hesperus), and T. brasiliensis had elevated mercury levels in their liver and muscles that they most likely acquired via drinking from contaminated free-water sources (Reidinger 1972; see also Syaripuddin et al 2014).…”

A checklist of the bats of Peninsular Malaysia and progress towards a DNA barcode reference library

“…Recorded at: Confirmed records of “FOREST” (see above): Selangor : Ulu Gombak [5]; Pahang : Krau Wildlife Reserve [64]; Johor : Endau Rompin [64]; Perlis : Perlis State Park and Kuala Perlis [64]; Kelantan : Gua Musang [64], Perak : Taiping [64], Gunung Stong State Park [67]; Melaka: Unspecified [68]; Terengganu : Tasik Kenyir and Temenggor Lake [69]. …”

“…Recorded at: Pahang : Krau Wildlife Reserve [11, 41], Merapoh [40], Tasik Chini [43], Kuala Atok National Park [44], Cameron Highland, [60, 64], Cherating [64]; Pulau Pinang : Pulau Pinang [23], Fraser Hill Forest Reserve [56]; Selangor : Bukit Lanjan [40], Bangi Forest Reserve [41], Bukit Kutu Wildlife Reserve [51],Ulu Gombak [52–54]; Perak : Bayor River-Rantau Panjang and Selama [49], Taiping [64], Temenggor Lake [69], Temengor Forest Reserve [71]; Perlis: Wang Kelian State Park [50], Perlis State Park [64]; Johor: Endau Kluang Forest Reserve [56]; Kedah : Ulu Muda Forest Reserve [57]; Kelantan : Gua Musang [61, 64], Gunung Reng [62], Gunung Stong State Park [67]; Terengganu : Tasik Kenyir [69]. …”

“…bicolor142: Pahang : Krau Wildlife Reserve [11], Bukit Ibam, Jengka, Klau Besar, and Kenong [100]; Selangor : Semangkok Forest Reserve [101], Ulu Gombak [5, 101]; Terengganu : Pasir Raja, Dungun [15], Tasik Kenyir [69], Gunung Tebu Forest Reserve [101]; Negeri Sembilan : Berembun Forest Reserve [101], Gunung Angsi Forest Reserve [100, 101]; Perak : Temenggor Lake [69], Kledang Saiong Forest Reserve [100]; Kelantan : Gunung Stong State Park [100]; Pulau Pinang : Bukit Panchor [100]; Kedah : Bukit Hijau [100]. Also see records of H .…”

“…Recorded at: Pahang : Krau Wildlife Reserve [11, 41, 42], Tasik Chini [43], Kuala Atok, National Park [44], Bukit Ibam, Kemasul, Jengka, Klau Besar, Kenong and Gunung Aais [100]; Terengganu : Pasir Raja, Dungun [15], Tasik Kenyir [69]; Negeri Sembilan : Pasoh Forest Reserve [45], Gunung Angsi Forest Reserve [100, 101], Berembun Forest Reserve [101]; Perlis: Wang Kelian State Park [50]; Selangor : Ulu Gombak [54, 101], Air Hitam Forest Reserve [55], Semangkok Forest Reserve [101]; Melaka : Lata Bujang Forest Reserve [56], Unspecified [68]; Johor : Endau- Kluang Forest Reserve and Endau-Kota Tinggi Forest Reserve [56], Gunung Panti and Labis Forest Reserve [100]; Kedah: Ulu Muda Forest Reserve [57], Bukit Hijau [100]; Kelantan : Air Panas-Gua Musang, [61]; Perak : Temenggor Lake [69], Kledang Saiong Forest Reserve, [100]; Pulau Pinang : Bukit Panchor [100]. …”