Publications by authors named "Hem Bahadur Katuwal"

4 Publications

  • Page 1 of 1

Occurrence of total mercury and methylmercury in rice: Exposure and health implications in Nepal.

Ecotoxicol Environ Saf 2021 Nov 22;228:113019. Epub 2021 Nov 22.

State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China.

Emerging studies have indicated that the consumption of rice could be the major methylmercury (MeHg) contributor to human mercury (Hg) exposure. Nonetheless, few studies are available on Hg in rice around the world, especially in countries with heavy rice diet. In this study, total Hg (THg) and MeHg levels in rice samples (n = 172) across Nepal were first investigated. The geometric mean THg was 7.05 ± 7.71 µg/kg with a range of 0.622 µg/kg to 158 µg/kg, and the maximum THg level was up to 791% of the Chinese National Standard Limit for THg in rice (20 µg/kg). The geometric mean MeHg was 0.820 ± 0.660 µg/kg with a range of 0.189 µg/kg to 8.59 µg/kg. Overall, the mean MeHg exposure (0.00445 ± 0.00477 µg/kg bw/day) and inorganic Hg (IHg) exposure (0.0360 ± 0.0739 µg/kg bw/day) were lower than the reference dose (RfD) of 0.1 µg/kg bw/day for MeHg and the provisional tolerable weekly intake (PTWI) of 0.571 µg/kg bw/day for IHg, respectively. Concerning different groups of vulnerable populations, the highest MeHg exposure (0.126 µg/kg bw/day) and IHg exposure (1.57 µg/kg bw/day) of preschoolers (37-50 months old) were approximately 126% of the RfD for MeHg and 275% of the PTWI for IHg. When the pregnant mothers eat the rice without awareness of the Hg content in rice, the mean and highest intelligence quotients (IQs) losses were 9554 and 118659 points, respectively, and the corresponding economic costs due to IQ loss could be 15.1 million USD and 188 million USD in Nepal. The results of rice THg and MeHg levels and corresponding exposure in populations highlighted the occurrence of rice THg and MeHg pollution issues in Nepal. More efforts should be made to protect younger groups in Nepal from high rice Hg exposure. CAPSULE: Owing to the high rice consumption rates relative to body mass, preschoolers (37-50 months) may meet the 126% reference dose (0.1 µg/kg bw/day) for MeHg and 275% provisional tolerable weekly intake (0.571 µg/kg bw/day) for IHg exposure in Nepal.
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http://dx.doi.org/10.1016/j.ecoenv.2021.113019DOI Listing
November 2021

Factors affecting the crop raiding behavior of wild rhesus macaques in Nepal: Implications for wildlife management.

J Environ Manage 2021 Nov 21;297:113331. Epub 2021 Jul 21.

Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Chaoyang District, Beijing, 100101, China; Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, 650223, China. Electronic address:

In many areas of South Asia and Southeast Asia, macaques inhabiting agricultural landscapes are considered serious crop pests by local farmers. In Nepal, for example, the expansion of monocultures, increased forest fragmentation, the degradation of natural habitats, and changing agricultural practices have led to a significant increase in the frequency of human-macaque conflict. In order to more fully understand the set of factors that contribute to macaque crop raiding, and the set of preventive measures that can be put in place to avoid human-macaque conflict, we examined patterns of crop raiding by a group of 52 rhesus macaques (Macaca mulatta) in the Kavrepalanchok district, Nepal. We present data on macaque inflicted crop damage in 172 agricultural plots (each plot measuring 380 m) from August to October 2019. Our results indicate that farmland invasions by macaques were principally affected by crop type (maize was preferred over rice), nearness of farmland to both the forest edge and the major travel route used by the macaques, and the mitigation efforts applied by farmers to discourage crop raiding. We found that as the proportion of maize farmland in the most direct path from the macaque's main travel route to nearby crop raiding sites increased, the amount of maize damage decreased. This is likely explained by the fact that macaques traveling across several adjacent maize fields encounter multiple farmers protecting their crops. We estimated that the financial cost to individual farmer households of macaque maize and rice raiding was on average US$ 14.9 or 4.2% of their annual income from cultivating those two crops. As human-macaque conflict is one of the most critical challenges faced by wildlife managers in South Asia and Southeast Asia, studies of macaque crop raiding behavior provide an important starting point for developing effective strategies to manage human-macaque conflict while promoting both primate conservation and the economic well-being of the local community.
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http://dx.doi.org/10.1016/j.jenvman.2021.113331DOI Listing
November 2021

Diet and Activity of Macaca assamensis in Wild and Semi-Provisioned Groups in Shivapuri Nagarjun National Park, Nepal.

Folia Primatol (Basel) 2017 12;88(2):57-74. Epub 2017 Jul 12.

Small Mammals Conservation and Research Foundation, Kathmandu, Nepal.

Studying the behavioural flexibility and adaptability of macaques to different habitats is one approach to designing a conservation plan. To determine the activity budget and feeding behaviour and evaluate the effects of seasonality in wild and human- altered habitats of Assamese macaques (Macaca assamensis), we conducted this study in the Nagarjun forest of Shivapuri-Nagarjun National Park (SNNP) in central Nepal. We also updated the list of plant food items of Assamese macaques in the SNNP. Using scan and all-occurrence sampling, we recorded the diets and activities of Assamese macaques in 2 social groups, a wild-feeding group (WG) and a semi-provisioned group (SPG), throughout the year from August 2013 to July 2014. Both groups spent most of their time in feeding activities and were quite arboreal, but there were significant differences in the activity budgets and diets between the groups. Human food was the main component of the diet for the SPG, whereas it was fruit for the WG, indicating a normally frugivorous diet. Furthermore, the activity budget and diet composition varied in response to the season. These results indicate that provisioning alters the activity and feeding behaviour of macaques, and can also increase human-macaque conflict and disease transmission.
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http://dx.doi.org/10.1159/000477581DOI Listing
November 2017

Seasonal Changes in Bird Species and Feeding Guilds along Elevational Gradients of the Central Himalayas, Nepal.

PLoS One 2016 1;11(7):e0158362. Epub 2016 Jul 1.

Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.

The Himalayas are a global hotspot for bird diversity with a large number of threatened species, but little is known about seasonal changes in bird communities along elevational gradients in this region. We studied the seasonality of bird diversity in six valleys of the Central Himalayas, Nepal. Using 318 plots with a 50 m radius, located from 2200 to 3800 m a.s.l., and repeated sampling during different seasons (mainly pre-monsoon, monsoon, and post-monsoon), we analyzed 3642 occurrences of 178 species. Birds classified in the literature as resident were more species-rich than migratory birds (140 vs. 38 species). In all six valleys and within the studied elevation range, species richness of all birds showed a peak at mid-elevation levels of 2600 or 3000 m a.s.l. Similar patterns were found for the most species-rich feeding guilds of insectivores (96 species) and omnivores (24 species), whereas the species richness of herbivores (37 species including frugivores) increased towards higher elevations. Among these feeding guilds, only species richness of insectivores showed pronounced seasonal changes with higher species numbers during post-monsoon season. Similarly, individual bird species showed distinct spatio-temporal distribution patterns, with transitions from species dominated by elevational differences to those characterized by strong seasonal changes. In an era of climate change, the results demonstrate that individual bird species as well as feeding guilds might greatly differ in their responses to climate warming and changes in the seasonality of the precipitation regime, two aspects of climate change which should not be analyzed independently.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158362PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4930183PMC
August 2017
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