The impacts of anthropogenic activities on the physicochemical water quality of Pinyinyi River, Arusha-Tanzania
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Date
2024-01-17
Journal Title
Journal ISSN
Volume Title
Publisher
JWEMPO
Abstract
Rivers are important for aquatic biodiversity. Anthropogenic activities de-
grade rivers and decrease their capacity to offer ecosystem services. This study
used macroinvertebrates to assess the impact of anthropogenic activities on
the Pinyinyi River during dry and wet season. Abundance of macroinverte-
brates, average score per taxon and Shannon Weiner Species Diversity Index
were used to state the ecological status of Pinyinyi River. Because the abun-
dance of macroinvertebrates can be affected by change in water quality, some
of the physicochemical parameters were also measured. A macroinvertebrates
hand net is used to collect the macroinvertebrates per sampling point. DO,
temperature, pH, turbidity and TDS were measured
in-situ using HI-9829
Multiparameter and BOD was measured in the laboratory using Oxydirect le-
vibond method. A total of 164 macroinvertebrates were collected and identi-
fied from Pinyinyi River during dry and wet season. They belong to 13 fami-
lies. The most abundant taxa were mosquito larva, Diptera (41.07%) and aq-
uatic caterpillar, Lepidoptera (23.21%) during dry season representing about
64.28% of the total macroinvertebrates whereas the least abundant taxa were
pouch snail (16.07%) and dragonflies, Odonata (19.64%) during dry season
representing about 35.72% of the total macroinvertebrates. The most abun-
dant taxa collected during wet season were aquatic earthworm, haplotaxida
(19.44%), midges, Diptera (17.59%), black flies, Diptera (15.74%) and creep-
ing water bugs, hemiptera (12.96%) whereas the least abundant were pigmy
back swimmers, hemiptera (2.78%), snail (3.7%), predacious dividing beetle
(4.63%) and coleopteran (4.63%). Average Score per taxon of Pinyinyi River
during dry season was 5.25 and 3.6 during wet season. The Shannon Weiner
Species Diversity Index was 1.318 during dry season and 2.138 during wet season. Based on the score, Pinyinyi River is moderately polluted during dry
season and seriously polluted during wet season. Based on index, Pinyinyi
River has low diversity of macroinvertebrates during dry season and highly in
diversity of macroinvertebrates during wet season. Moreover, it was found
that, agricultural activities, livestock keeping, bathing and washing alter phy-
sicochemical parameters of Pinyinyi River and hence change the abundance
of macroinvertebrates as well as the quality of water. The study, therefore,
recommends that the source of pollutants should be controlled and the river
regularly monitored by the relevant authorities.
Description
Journal of Water Resource and Protection, 2023, 15, 393-412
Keywords
Bioindicators, Ecosystem Services, Macroinvertebrates, Shannon Weiner Diversity Index, Water Pollution, Water Quality
Citation
https://www.scirp.org/journal/jwarp