Evaluation of aquatic ecosystem health via benthic macroinvertebrates and physicochemical parameters in the northern Sahara, Algeria

Human development and activities are significantly affecting water quality, including the life of organisms such as macrofauna and benthic macroinvertebrates. To meet human needs, the construction of reservoirs and dams is being carried out, which inevitably alters natural conditions and the presence of other organismsth. Therefore, this study aimed to analyze the relationship between water quality parameters and sediment characteristics in river channels affected by the presence of reservoirs and dams on the distribution of benthic macroinvertebrates classified into Functional Feeding Groups (FFG). During the analysis, FFG was used to understand the dynamics of food in aquatic ecosystems and its changes based on the distribution of benthic macroinvertebrates. The investigation was conducted from July to September 2023, in the Central and Lower parts of the Citarum River, located in West Java Province, Indonesia, specifically around Jatiluhur Reservoir in Purwakarta Regency for the Central part and Curug Klari Dam and Walahar Dam in Karawang Regency for the Lower part. Field data collection comprised the sampling of water, sediment, and benthic macroinvertebrates. Data analysis was based on the calculation of benthic macroinvertebrate community structure, pollution indices, BMWP-ASPT (Biological Monitoring Working Party - Average Score per Taxon) biotic index, Pearson correlation, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA). The results showed that FFG distribution was dominated by Gathering-Collectors (72%), Scrapers (22%), Predators (6%), and Filtering-Collectors (0.06%). The pollution index (PI) indicated that the water quality in the central part of the Citarum River was mild, while the lower part was moderately polluted. Based on the biotic index (BMWP-ASPT), the water quality was categorized as poor and heavily to very densely polluted part. The correlation between PI and BMWP-ASPT showed a very strong relationship according to Pearson correlation (r=-0.96). PCA analysis indicated a positive correlation between predators and gatherers in moderately polluted conditions at the Jatiluhur Reservoir location. At the Curug Klari and Walahar dams, characterized by lightly polluted conditions, there was a positive correlation between filtering and scrapers. HCA calculations showed that the conditions in the Central part (Jatiluhur Reservoir) varied from the Lower part (Curug Klari and Walahar dams) of the Citarum River.

The objective of this study was to assess the relationship between river water quality and the distribution of benthic macroinvertebrate communities in the Haraz River in Iran. Using a surber net sampler, benthic macroinvertebrate communities along the stream was sampled in wet and dry seasons of 2015 at nine stations with three replications. The physicochemical water quality parameters were measured in the field by water checker. Hilsenhoff biotic Indices, Shannon Wiener Diversity Indices, Average Score per Taxon (ASPT) Index and Pielou Evenness Index were applied to carry out a biological assessment of water quality. A total of 3781 (spring 769, summer 1092, autumn 1095 and winter 825) benthic macroinvertebrate specimens belonging to 4 orders, 11 classes and 16 families were identified. The lowest number of taxa was recorded in spring while the highest was recorded in autumn. Station 9 had the lowest number of taxa while the highest number of taxa was recorded at station 3. The average values (±SD) of the water quality parameters were temperature 14.75 ± 4.38 °C, pH 7.93 ± 0.62, water flow 14.11 ± 9.04 m3 s−1, electric conductivity 532.75 ± 161.35 μmohs cm−1, total dissolved solids 296.61 ± 76.21 mg L−1, salinity 0.28 ± 0.07 mg L−1, turbidity 580.77 ± 149.92 NTU and dissolved oxygen 8.08 ± 0.75 mg L−1. The assessment of stations 1 to 6 indicated that water quality conditions were suitable. In addition, substantial level of organic pollution was observed in stations 7 and 8. In station 9 water quality was fairly poor, requiring a more favourable management based on the capacity of the self-purification of the Haraz River.

To explore the correlations among water quality parameters, suspended solids (SS) and total dissolved solids (TDS) with meteorological factors in a shallow reservoir in China, the long-term variations of water quality were considered. A non-parametric regression method, generalized additive models (GAM), was used to analyse the correlations among eleven physicochemical and biological parameters as well as three meteorological factors (wind speed, rainfall and solar radiation) which we collected from 2000 to 2011. The results indicate that the three meteorological factors may have positive effects on SS. Moreover, statistically significant correlations between many water quality parameters and SS or TDS were exhibited seasonally. The correlations between electrical conductivity (EC) and SS were opposite to correlations between EC and TDS. This finding reveals that TDS have a positive impact on EC, while EC negatively affects SS. The results indicated that many parameters, such as total nitrogen, total phosphorus, biological oxygen demand (BOD) and chemical oxygen demand (COD), were related to SS due to the adsorption of SS. Moreover, both positive and negative correlations between COD and TDS were observed in this freshwater reservoir. The positive correlation between chlorophyll a and SS suggested that the change of SS concentration in autumn was caused by the growth of algae. Meanwhile, significant correlations between SS and meteorological factors were also observed, indicating that meteorological factors had effects on SS dynamics. This study provides useful information regarding the correlations among water quality parameters, SS and TDS with meteorological factors in a freshwater reservoir.

Lake Hayq is one of the highland lakes of Ethiopia that furnishes very important ecosystem services, fishing, tourism, transportation, drinking water, livestock watering, and irrigation. However, the lake ecosystem is being degraded by pollution, siltation, and excessive growth of macrophytes, buffer zone degradation, overfishing, and climate variability. Therefore, this study was conducted to assess the physicochemical, heavy metals, and biological water quality parameters of Lake Hayq. Physiochemical (pH, water temperature, conductivity, TDS, total alkalinity, dissolved oxygen, Ca2+, Mg2+, Na+, K+, NH4+, NH3, NO2−, NO3−, CO3−, HCO3−, SO42−, PO43−, SiO2, and total phosphorus), heavy metals (Pb, Fe, Zn, Cr, Cu2+, Mn2+, and Ni), and biological (BOD5 and total coliforms) water quality parameters were analyzed both in situ and ex situ. The physicochemical parameters were measured using portable water quality measuring multimeters, the heavy metal analysis was done using the Atomic Absorption Spectrometer, the BOD5 was measured using a BOD5 meter, and the total coliform analysis was done using the spread plate technique. The collected data were analyzed using multivariate, two-way ANOVA to see the mean difference among sampling sites and seasons through the application of SPSS 16. Most of the water quality parameters of Lake Hayq have met the WHO standards for recreation, aquatic life, and drinking water quality. However, some parameters, such as Pb, BOD5, and total coliforms, were above WHO water quality permissible limits. Therefore, ecohydrological (nature-based) waste treatment methods such as macrophyte restoration in buffer zones and ecofriendly farming activities should be practiced to minimize the contamination of the lake.

Results reported herein include trace element concentrations in sediment and in the clam Macoma petalum (formerly reported as Macoma balthica (Cohen and Carlton 1995)), clam reproductive activity, and benthic macroinvertebrate community structure for a mudflat one kilometer south of the discharge of the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay. This report includes data collected for the period January 2006 to December 2006, and extends a critical long-term biogeochemical record dating back to 1974. These data serve as the basis for the City of Palo Alto's Near-Field Receiving Water Monitoring Program, initiated in 1994. Metal concentrations in both sediments and clam tissue during 2006 were consistent with results observed since 1990. Most notably, copper and silver concentrations in sediment and clam tissue increased in the last year but the values remain well within range of past data. Other metals such as chromium, nickel, vanadium, and zinc remained relatively constant throughout the year except for maximum values generally occurring in winter months (January-March). Mercury levels in sediment and clam tissue were some of the lowest seen on record. Conversely, selenium concentrations reached a maximum level but soon returned to baseline levels. In all, metal concentrations in sediments and tissue remain within past findings. There are no obvious directional trends (increasing or decreasing). Analyses of the benthic-community structure of a mudflat in South San Francisco Bay over a 31-year period show that changes in the community have occurred concurrent with reduced concentrations of metals in the sediment and in the tissues of the biosentinel clam M. petalum from the same area. Analysis of the reproductive activity of M. petalum shows increases in reproductive activity concurrent with the decline in metal concentrations in the tissues of this organism. Reproductive activity is presently stable, with almost all animals initiating reproduction in the fall and spawning the following spring of most years. The community has shifted from being dominated by several opportunistic species to a community where the species are more similar in abundance, a pattern that suggests a more stable community that is subjected to less stress. In addition, two of the opportunistic species (Ampelisca abdita and Streblospio benedicti) that brood their young and live on the surface of the sediment in tubes, have shown a continual decline in dominance coincident with the decline in metals. Heteromastus filiformis, a subsurface polychaete worm that lives in the sediment, consumes sediment and organic particles residing in the sediment, and reproduces by laying their eggs on or in the sediment, has shown a concurrent increase in dominance. These changes in species dominance reflect a change in the community from one dominated by surface dwelling, brooding species to one with species with varying life history characteristics. For the first time since its invasion in 1986, the non-indigenous filter-feeding clam Corbula (Potamocorbula) amurensis has shown up in small, but persistent, numbers in the benthic community.

Thalangama wetland is situated within the Kelani river basin, Colombo District, Sri Lanka. It is one of the most attractive landscapes in Colombo that provides a wide range of ecological, social and economic functions. Wetland water supports aquatic life and is being prominently used for agriculture and bathing and contact recreational activities without knowing if the water quality is appropriate for such uses. This study was therefore conducted to assess the surface water quality of Thalangama wetland using key-physicochemical parameters and to examine the suitability of wetland waters for bathing and contact recreational water, aquatic life, irrigation and other agricultural activities. A total of 10 water quality parameters covering temperature, pH, salinity, TDS, EC, DO, BOD, COD, nitrate, and total phosphate were measured at eight sampling sites of the wetland. The study was conducted in August 2020. The spatial variation of water quality parameters was assessed using one-way ANOVA followed by Tukey’s pairwise comparison. Results were compared with ambient water quality standards of Sri Lanka. The study revealed that the surface water quality parameters including temperature, EC, TDS, DO, BOD, COD, nitrate and total phosphate show a significant spatial variation among the sampling sites. Surface water pH and BOD at all the sampling sites were within the ambient water quality standards for water suitable for bathing and contact recreational water and water suitable for aquatic life, irrigation and agricultural activities. EC at all the sampling sites were within the limits of water suitable for irrigation and agricultural activities. Nitrate and total phosphate concentrations at all the sampling sites were within the limits of water suitable as bathing and contact recreational water and water suitable for aquatic life. DO at six out of eight sampling sites were within the limits of water suitable as bathing and contact recreational waters and water suitable for aquatic life, irrigation and agricultural activities. COD at all the sampling sites were not within the limits of water suitable as bathing and contact recreational water and water suitable for aquatic life. The study identifies agricultural practices, livestock rearing, construction activities and urban discharges as major anthropogenic influences that degrade the surface water quality of the wetland. Hence, the study determines the necessity for effective management of the surface water of Thalangama wetland to prevent pollution and to ensure the water quality of the wetland is within the recommended standards.
 Keywords: Urban wetlands, Surface water quality, Spatial variation, Physicochemical parameters, Ambient water quality standards

This study highlights the importance of managing fishpond effluent to minimize its impact on aquatic environments. Fish effluents are a major concern worldwide in aquatic environments. It also provides information on the impacts of effluents on the water quality index of streams when released into aquatic environments. Streams and fishponds were sampled bimonthly for two annual cycles, covering different sampling stations both upstream and downstream of the fishpond effluents at 50-m intervals. Water quality parameters associated with in situ conditions were determined in the field. In the laboratory, other physicochemical parameters were determined via proper standard protocols. The results of the study revealed that water quality parameters such as turbidity, total suspended solids, total solids, conductivity, total dissolved solids, dissolved oxygen, biological oxygen demand and organic matter recorded in water samples collected from 50 m upstream at the point of effluent discharge were significantly (p < 0.05) different from those recorded at other sampling stations. The WQI value of the discharge point was higher than the WQI recorded in both the upstream and downstream sections of the stream. The findings of this study showed that the point of discharge of fishpond effluents is particularly concerning for the receiving stream compared with other sampling points. This localized area has experienced marked deterioration in water quality, posing significant threats to the health and biodiversity of aquatic ecosystems. The effluent's impact, though slight when dispersed in the receiving waterbody, underscores the necessity for adequate management practices to mitigate its adverse effects. Effective strategies, including regular monitoring, effluent treatment, and sustainable pond management, are imperative to ensure the long-term health and resilience of the aquatic environment.

AIM: Veredas and the aquatic and semi-aquatic communities play a key role in watershed protection in the Cerrado Biome. Information about the effects of physical and chemical variables and habitat integrity on benthic communities has been increased in recent years; however, there is no study evaluating the influence of urbanization on macroinvertebrates of Vereda streams. Thus, improving the knowledge of the relationship between abiotic properties and benthic fauna is very important for understanding the functioning of ecological processes and health of aquatic ecosystems. This study investigated the influence of physical and chemical variables on benthic macroinvertebrate communities along a gradient of anthropogenic disturbance in four Vereda streams in Uberlândia (MG), one in a preserved area and three in the urban area; METHODS: samplings were collected during the dry and rainy seasons; RESULTS: principal component analysis separated the stream in the preserved area from those in the urban area by having lower values of BOD, COD, sediment size, conductivity, detergents, pH, deposited solids and total dissolved solids. Pollution sensitive groups (e.g., Ephemeroptera and Trichoptera) were associated to the stream in the preserved area, and more tolerant groups (e.g., Chironomidae and Oligochaeta) had greater abundance in the streams of the urban area. Canonical Correspondence Analysis indicated that dissolved oxygen, conductivity, BOD, oil and grease, and turbidity explained 56% of the variance in the distribution and abundance of macroinvertebrates; CONCLUSIONS: Benthic communities of Vereda streams in urban areas in the Cerrado Biome seem to be highly affected by human activities that increase water organic pollution and sedimentation.

Abstract. Hertika AMS, Sudaryanti S, Musa M, Amron K, Putra RBDS, Alfarisi MA, Hidayat MR, Pertiwi M, Halimah MF. 2024. Benthic macroinvertebrates as bioindicators to detect the level of water pollution in the upstream segment of Brantas River Watershed in Malang, East Java, Indonesia. Biodiversitas 25: 632-643. The Brantas River is the second longest river on the island of Java after the Bengawan Solo River. The current condition of the Brantas River is facing a worrying decline in water quality due to community activities in the surrounding area. This decline can have a negative impact on both aquatic biota and community welfare. To assess water quality, one method involves the use of biological indicators, specifically benthic macroinvertebrates. The objective of this research is to assess the water quality upstream of the Brantas River by using benthic macroinvertebrate as bioindicators. The assessment is based on the community structure, Biological Monitoring Working Party-Average Score Per Taxon (BMWP-ASPT) method and physico-chemical water parameters. This research was conducted at 10 sampling stations with 5 stations located in Batu City and 5 stations located in Malang City. The benthic macroinvertebrate result consists of 8 classes, 53 families. namely Bivalves (2 families), Clitellata (2 families), Gastropoda (5 families), Hirudinea (1 family), Insecta (35 families), Malacostraca (4 families), Oligochaeta (2 families), Polychaeta (1 family), and Turbellaria (1 family). The abundance of macroinvertebrates ranged from 181-2879 individuals/m2, while the diversity index ranged from 0.563-2.988. The evenness index ranged from 0.208-0.870, while the Simpson dominance index ranged from 0.061-0.799. The ASPT range of the upstream segment of Brantas River was found to be between 2.80-6.19, indicating a variation in water conditions from poor to excellent. The physico-chemical water as supporting parameters is still optimal, except for ammonia, total organic matter, and total dissolved parameters that exceed the quality standard. The results of this research show that based on benthic macroinvertebrates as bioindicators, the BMWP-ASPT index and water quality parameters as support, upstream to downstream the Brantas River watershed in Malang City has poor to very good quality. This is due to anthropogenic activities in land use which can disrupt the quality of aquatic ecosystems. Therefore, local governments need to manage waterfall ecosystems well by controlling human activities around them.

Objective: This study aims to assess the physico-chemical quality of the coastal lagoon waters of Benin in areas dedicated to the farming of Crassostrea tulipa oysters. Methodology and Results: Physico-chemical parameters were measured on a monthly basis over a full annual cycle from January to December 2023, both . in situ (temperature, salinity, dissolved oxygen, pH, and water transparency) and in the laboratory (nitrites, nitrates, ammonium, and orthophosphates), within the oyster farming zones. The results showed that all evaluated parameters varied significantly across months and between farming zones, except for nitrites, ammonium, and dissolved oxygen, which did not show significant spatial variation. The Organic Pollution Index (OPI) calculated for the three oyster farming sites revealed moderate organic pollution levels in all zones (3.33 at Ahouandji and Djondji, and 3.67 at Dégouè on a 5-point scale). Conclusions and Application of results: As the mangrove oyster (C. tulipa) is a highly valuable fishery resource in the Gulf of Guinea region, it is important to regularly monitor the physicochemical quality of the water in oyster production areas. Even slight variations in certain water parameters can greatly affect the reproduction and growth of these bivalve molluscs (oysters), as well as the quality of their flesh, which is consumed by coastal populations. While the values recorded for all physicochemical parameters generally remained within the tolerance ranges for C. tulipa oysters during the study period, indicating that the coastal lagoon offers environmental conditions conducive to oyster farming in Benin, moderate organic pollution shows that these oyster production areas are not pollution-free. In order to ensure sustainable, high-quality oyster production in Benin, it is necessary to implement specific measures for sustainable ecosystem management. These measures include regular monitoring of water quality, regulation of wastewater discharges and the use of organic and chemical fertilisers in the watershed, as well as community awareness programmes.. Keywords: Water quality, Physico-chemistry, Coastal lagoon, Oyster farming, Crassostrea tulipa.

In this article, using the Hawkesbury-Nepean River as a case study, the spatial and temporal trends of water quality variables over three sampling surveys in a peri-urban situation are examined for their effect on benthic macroinvertebrate communities and phytoplankton communities and whether phytoplankton and benthic macroinvertebrate species can be used as indicators for river health assessment. For this, the authors monitored the spatial and temporal difference of 10 water quality parameters: temperature, turbidity, pH, dissolved oxygen, electrical conductivity, oxidation reduction potential, total nitrogen, total phosphorus, manganese, and suspended solids. The variability in water quality parameters clearly indicated a complex pattern, depending on the season (interaction p = 0.001), which highlighted how the river condition is stressed at multiple points as a result of anthropogenic effects. In particular, the downstream locations indicated an accumulation of nutrients, the presence of increased sediments, and phytoplankton related variables such as total counts, bio-volumes, chlorophyll-a, and total phosphorus. The patterns of phytoplankton communities varied in a complex way depending on the season (interaction p = 0.001). Abundances of phytoplankton were also found in low concentrations where the water column is not severely disturbed by flow and tide. However, when the water clarity drops resulting from tidal cycles, inflows from tributaries, and intense boating activities, the phytoplankton abundances also increased considerably. On the other hand, benthic macroinvertebrates compositions were significantly different between locations (p = 0.001) with increased abundances associated with upstream sites. Aphanocapsa holsatica and chironomid larvae appeared as the important indicators for upstream and downstream site differences in water quality. Water temperature influenced the phytoplankton community pattern (ρ(w) = 0.408), whereas pH influenced the benthic macroinvertebrate community pattern (ρ(w) = 0.437). The findings of this study provide valuable insights into the interactions of water quality parameters on biotic assemblages and to the extent that benthic macroinvertebrates and phytoplankton assemblages are suitable as indicators for monitoring and assessing peri-urban river health.

放养河蚌，提高水体透明度以促进沉水植物生长，是湖泊生态修复中的常用手段之一.而小型杂食性鱼类鳑鲏依赖河蚌繁殖，河蚌放养可能会促进鳑鲏种群的发展；而鳑鲏与河蚌交互作用对水生态系统的影响仍研究较少.于2018年11—12月通过原位受控实验，设置对照组、河蚌组、鳑鲏组和河蚌+鳑鲏组，研究了鳑鲏（大鳍鱊Acheilognathus macropterus）与河蚌（背角无齿蚌Sinanodonta woodiana）对水质、浮游生物和底栖生物的影响.结果表明：鳑鲏显著增加了上覆水总氮、总磷、悬浮质和叶绿素a（Chl.a）浓度；但并未显著影响无机悬浮质的浓度，说明鳑鲏对沉积物的扰动作用较弱.此外，鳑鲏显著增加了浮游植物生物量和蓝藻的比例.浮游动物总生物量并未受鳑鲏的影响，但显著增加了浮游动物的丰度，其中以轮虫为主.鳑鲏组的底栖动物总丰度（主要为水丝蚓）显著高于对照组，说明鳑鲏对水丝蚓的摄食压力较低.鳑鲏与河蚌交互作用对总磷、Chl.a、浮游植物和浮游动物丰度具有显著影响：具体表现为河蚌虽然抵消了部分鳑鲏对水质（如氮、磷和悬浮质浓度，以及Chl.a浓度和浮游植物生物量等）的负面影响，但其对浮游动物和水丝蚓生物量的影响不显著.在湖泊生态修复和管理中，需要关注和重视鳑鲏等此类小型杂食性鱼类对水生态系统可能产生的负面影响，通过物理（网簖等）或生物（放养肉食性鱼类）等方式将其控制在较低密度水平，从而降低这些鱼类对水质、浮游生物和底栖生物群落可能产生的负面影响，维持生态修复效果的长效与稳定运行.;In restoration of shallow eutrophic lakes based on recovery of submerged macrophytes, stocking of the filter-feeding mussels has been commonly used for improving water clarity, thereby enhancing the growth of submerged macrophytes. However, the small omnivorous bitterling fish has to rely on mussels for breeding. Thus, the increased abundance of mussels may enhance the population development of bitterling. Nevertheless, the effects of bitterling (Acheilognathus macropterus) and their host mussels (Sinanodonta woodiana) on the aquatic ecosystems are, so far, not well-studied. We conducted a mesocosm experiment to study the effects of bitterling, mussels, and their interactions on water quality and the community structures of phytoplankton, zooplankton and benthic macroinvertebrates, respectively. Our results showed that bitterling did not substantially affect the concentration of inorganic suspended solids (ISS) indicating weak effects on sediment resuspension. However, the concentrations of total nitrogen and total phosphorus were significantly enhanced by bitterling. Consequently, both the abundance and biomass of phytoplankton were enhanced in the bitterling-only mesocosms, and cyanobacteria dominated the phytoplankton community at the end of the experiment. However, rotifers dominated the zooplankton community leading to a higher abundance of zooplankton in the bitterling-only treatment, while the total biomass of zooplankton did not differ significantly between the control and bitterling-only treatments. Moreover, bitterling significantly increased the total abundance of benthic macroinvertebrates compared with the controls, while the biomass of macroinvertebrates was not pronouncedly affected. The presence of mussels significantly eliminated the negative effects induced by bitterling, such as reducing the concentrations of nutrients, suspended solids and chlorophyll-a and phytoplankton biomass. However, the biomass of zooplankton and benthic macroinvertebrates were not substantially affected by the presence of mussels. Our results suggest that bitterling alone can induce significantly negative effects on water quality though mussels can eliminate part of these impacts under our experimental bitterling-to-mussel biomass ratio. Therefore, in the restoration and management of shallow lakes, more attention should be paid on the effects of small omnivorous fish, like bitterling, on aquatic ecosystems. The biomass of these small omnivores should be controlled at a relatively low level by physical (e.g., trap net) or biological (e.g., stocking of effective piscivorous fish) methods to minimize the negative effects of the fish on lake ecosystems.

The present study is an attempt to apply principal component analysis (PCA) for spatial assessment of water quality parameters that are responsible for water quality deterioration in the Ganga river at four cities of Uttar Pradesh. 48 water samples of the Ganga river from Allahabad, Mirzapur, Shahzadpur and Varanasi in Uttar Pradesh were collected during January to December in 2013. Data were analyzed for assessment of 18 different physicochemical and biological water quality parameters. These variables were examined using PCA to define and standardize the parameters mainly responsible for water quality variance in Ganga river at four selected cities. PCA highlighted anthropogenic effect and industrial effect as two main significant components which explain more than 99.32% of the variance, accounting for 64.47 and 34.85% respectively of the total variance of Ganga water quality at the four cities. Results revealed that total dissolved solids, total alkalinity, total hardness were the important parameters in assessing variations in Ganga water quality during October to April (post-monsoon months) and turbidity, suspended solids are the important parameters in assessing variations in Ganga water quality during June to September (monsoon months). Ca2+, Cl–, $${\text{SO}}_{4}^{{2 - }}$$ , temperature, fluoride, pH, Fe, Cl–, were found to be non-principal water quality parameters. Principal component analysis produced three significant main components explaining more than 82.9% of the variance (anthropogenic and industrial effect) that present 57.1, 13.8 and 12% respectively of the total variance of water quality in Ganga river at the four selected cities. The result reveals that turbidity, dissolved oxygen and biochemical oxygen demand are the parameters that are most important in assessing variations of water quality. Water quality index based on eight parameters (turbidity, DO, BOD, COD, pH, TS, TSS and TDS) calculated for all four cities were found to range from medium to bad. Thus, this study illustrates the usefulness of multivariate statistical techniques for analysis, interpretation of complex data sets and understanding spatial variations in water quality for effective river water quality management.

Biological monitoring of reservoirs is important in assessing aquatic health. This study aimed at assessing the structure of benthic macroinvertebrate communities in relation to physicochemical parameters along Sanyati basin shoreline in Lake Kariba, Zimbabwe. Six sites (S1 to S6) characterized by various human disturbances were sampled for physicochemical parameters and benthic macroinvertebrates from January to March 2018. We computed macroinvertebrate metrics and classified them into functional feeding groups (FFGs). A canonical correspondence analysis (CCA) triplot was constructed to assess species-physicochemical relations. Significant differences across the sampling sites were observed for pH, electrical conductivity, turbidity, nitrate-nitrogen (NO3-N), ammonium nitrogen (NH4-N), total nitrogen (TN), phosphate-phosphorus (PO4-P), total phosphates (TP), and dissolved oxygen (DO). The results from CCA highlighted that S1 was generally associated with high pH, NH4-N, and TN, and Oligochaeta, Syrphidae, and Hydrophilidae families. The highest percentage of EPT taxa (39.83%) was recorded at S6, while the lowest was recorded at S1. The taxa were made up of 50% predators, 26% collector-gatherers, 6% scrappers, 6% shredders, and 3% collector-filters with 3 taxa (Chironomidae, Hydropsychidae, and Leptoceridae) having more than two FFGs. Site S1 had a significantly higher mean abundance of collector-gatherers than the other sites. A high correlation between water parameters and SASS and ASPT scores was observed indicating their ability to detect environmental changes. These findings suggest that macroinvertebrate communities are good candidates for delineating the effects of industrial pollution on water quality.

Use of benthic macroinvertebrates has been in vogue as indicator organisms for water quality monitoring since long. Traditional methods of water quality monitoring incorporate mostly monitoring of physicochemical parameters. However, it is the biomonitoring studies that could help in more accurate water quality monitoring. Due to anthropogenic impact at water sources, integrated water quality monitoring has become a necessity. An integrated study comprising physicochemical parameters and biomonitoring using benthic macroinvertebrates was carried out at six sites along the Mahi river basin, the command area of which has witnessed tremendous economic and cultural progress over a period of time. Diversity Score and Saprobic Score were calculated, and Water Quality Class was determined as per Biological Monitoring Working Party score given by Central Pollution Control Board and results in moderate pollution at all locations, whereas Water Quality Class as per ISI-IS 2296–1982 at M-1, M-4, M-7 and M-12 shows slight pollution. Jaccard’s similarity index compared the biodiversity of benthic macroinvertebrates at all the sites from upstream to downstream locations. It was maximum, i.e., 52.94% between the locations at M-4 and M-7. Species richness (S) has also been monitored at the said locations. The Diversity Score 0.83 is maximum at the Galteshwar (M-12) location of the Mahi river, which indicates that the location was the most ecologically diverse region among all.