Water quality assessment and evaluation of human health risks in the Pusur River, Klaten Regency, Central Java, Indonesia.

This research examines the condition of the water characteristics of the Pusur River to provide data regarding water quality status and risks to human health. In determining the water quality use the NSF-WQI, or National Sanitation Foundation-Water Quality Index based on the main water quality parameters, including temperature, fecal coliform, turbidity, pH, DO, COD, and nitrate. The WQI at the Sudimoro Village location is 37.50, Cokro is 43.54, Wangen is 39.51, Delanggu is 35.45, Juwiring is 38.05, and Taji Village is 34.92. From these six locations, the WQI values are all included in the bad criteria (scores of 26-50). The low WQI values at the six locations were influenced by the low values of the DO, nitrate, temperature, and fecal coliform sub-indices. This low value is related to anthropogenic activities in the region. Furthermore, the data were subjected to applications of the Chronic Daily Index (CDI) Hazard Quotient (HQ), and Hazard Index (HI) to reveal possible non-carcinogenic health risks from nitrate and cadmium contaminants. The hazard quotient through exposure to ingestion from each sampling point includes low risk, namely the value range of 0.1 < HI < 1 for adults and children. Water from rivers must be adequately treated before being used for domestic purposes.


Introduction
The primary source of freshwater essential to ecological, social welfare, and economic development is surface water, particularly that found in rivers [1].In a report published by the United Nations Environment Program (UNEP) [2], in certain countries, surface water provides up to 90% of the population's primary drinking water.Three significant discoveries were presented by UNEP in the same report: first, one-third of rivers in Asia, Africa, and Latin America are impacted by severe disease pollution; second, one-seventh of rivers have severe organic pollution.rivers within the same continent; and thirdly, 10% of the rivers had moderate to severe salinity contamination.As a result, granting access to one of the Sustainable Development Goals (SDGs) is "water and sanitation" (Goal six). of the United Nations (UN) 15-year agenda, acknowledging the gravity of this issue [3].This particular objective is to ensure that everyone on the planet, regardless of their financial situation, has access to safe drinking water and sanitary facilities.All 193 UN members pledged to further this goal.
Rapid economic expansion is common in developing nations, and any development project carries the risk of having unfavorable environmental effects.Additionally, the development draws in more people, which raises the demand for the agricultural sector to produce food.Due to over-nutrient extraction and the requirement for chemical fertilizers, this strains the natural fertility of the soil.Subsequently, the fertilizer seeps into groundwater and rivers, contaminating water supplies and harming ecosystems and human health.To safeguard public health and the environment, thus water quality must be effectively monitored and evaluated.Effective long-term water management is also required [4].
The quality of water frequently determines whether it is suitable for use for various reasons.To determine each water resource's potential for use, evaluating the water quality is essential [5] [6].Numerous factors, including pH levels, dissolved oxygen, total suspended solids, and chemical characteristics, can be employed to keep an eye on the river water quality.By examining trends and patterns in these parameters, it is possible to forecast the quality of the water, enabling responsible authorities to take preventative measures against pollution and to assess the success of restoration efforts [4].
Ecological risk assessment indices are helpful instruments for assessing the consequences of various inorganic and organic pollutants in aquatic environments.They can also give regulatory agencies specific risk assessment data they need to make the decisions that need to be made.When estimating non-carcinogenic hazards that can arise from exposure to specific toxins, the index of health risk assessment is also a helpful tool [7].An analysis that is a quantitative technique for assessing chemicals that are hazardous to the well-being of humans is the method of health risk assessment.Human health is at risk, and organs are harmed when water pollution comes into touch with the body, particularly via the skin and drinking water [8].However, compared to the dermal route, ingestion was found to be a more severe mode of exposure [9] [10].
River water pollution stems from an assortment of sources, comprising human activity, manufacturing, and agriculture, as well as natural elements like soil erosion and rainfall [11].However, one of the primary sources of organic and inorganic pollutants that contribute to the poor quality of the majority of rivers, streams, and dams is anthropogenic processes and inputs, such as industrial wastewater and runoff from homes and farms (livestock and agriculture) [7] [12] [13].The polluter pays principle is one of the laws designed to prevent pollution of surface water bodies, but it is hardly ever enforced [14].Because many people who live along these river basins depend on these bodies of surface water for employment, recreation, and domestic water, increased contamination of these bodies of water results.
The Pusur River is located within the 5,781.87ha Watershed (DAS) area.The water from the sections that are upstream, middle, and downstream of the Pusur Sub Watershed flows into the Bengawan Solo River.The river's upstream region is immediately bordered by tobacco and vegetable farms as well as Mount Merapi National Park (2,911 M).Dairy and beef cattle farming, as well as agroforestry, are the land uses in the central region.In the downstream region, on the other hand, perimeter irrigation is the predominant form of land use.12,000 farmers use the Pusur River to grow crops on an area of about 3000 hectares (CIRAD study data, 2009).As a result, the Pusur River plays a significant role in ensuring food security in the Klaten district.In addition, tubing along the Pusur River has grown in popularity and is now a popular tourist attraction, drawing visitors from all over Indonesia [15].
Water from the Pusur River passes through several communities with differing degrees of human activity, which may have an impact on the water's overall quality.Surface runoff from various agricultural lands along the river flow, in addition to the open disposal of solid waste and the grazing of livestock (ducks), are other possible pollution sources in the Pusur River basin.Therefore, it is essential to report the Pusur River's water purity status because, as far as we are aware, there are no published statistics exist regarding this status.Additionally, the health risk assessment of the research area analysis complements the hefty metals qualitative analysis.To provide information about the state of water quality and health risks to humans, we temporarily evaluated the Pusur River's water quality characteristics for this study.The WQI, or Water Quality Index, a flexible tool for describing the state of a river system's water quality, is used to describe the general condition of the water in rivers.Furthermore, we estimated possible non-carcinogenic health risks related to water consumption based on recorded metal levels because water is utilized for a range of objectives.Management of water quality and the design of water treatment programs benefit from the information gathered from such studies.

Study Area
Part of the Bengawan Solo Watershed, the Pusur sub-watershed is where this inquiry was carried out.Administratively, it is located in both Boyolali Regency (upstream) and Klaten Regency (central and 3 downstream).Sudimoro, Cokro, and Wangen are the villages situated at the midpoint of the Pusur River where water samples are taken.The villages of Delanggu, Juwiring, and Taji are located along the Pusur River's lower reaches (Figure 1).The upstream section was not sampled because when the river water samples were taken, namely during the dry season in August 2023, the river was dry.To provide representation between regions, comprehend the transition of river changes, identify polluted areas, and determine whether residential density or regional economic activity affects river water quality, three villages were chosen as samples per sub-watershed region.

Data Collection Method
The main source of the quality of the river water data used was the collection of 18 water samples during the dry season in August 2023, upstream from the Pusur River (upstream from Delanggu Village, middle from Juwiring Village, and downstream from Taji Village, three samples each), and downstream from the Pusur River (upstream from Sudimoro Village, middle from Cokro Village, and downstream from Wangen Village, three samples each).The physical characteristics of Pusur River water, specifically temperature, suspended solid (TSS), and turbidity, are the parameters utilized to assess the water's purity.The water in rivers' chemical components include nitrate, pH, DO, and COD.Coliform bacteria, or E. coli, are samples used to measure biological factors in water.Cadmium (Cd) levels in water are tested for heavy metal content.The gathered samples were kept refrigerated until they were taken to the Yogyakarta Center for Environmental Health Engineering and Disease Control's Physics, Chemistry, and Biological Environmental Risk Factors Laboratories for additional analysis.The Water Quality Index (WQI) was then used to assess it and contrasted with the Water Quality Regulation, Government Regulation No. 82 of 2001.To evaluate the quality of the water in river water bodies' middle and downstream areas, a survey and surface water sample collection are the methods utilized in this study.Each area had three water samples taken.The Water Quality Index (WQI) of the National Sanitation Foundation formula is used to determine the condition of the water index.Water managers can easily interpret and utilize the Index of Water Quality, which is a figure that represents the combined impact of multiple criteria for water quality.Equation 1presents the mathematical formula used to calculate WQI [16] [6].
Where Li is the value of the sub-index curve, Wi is each parameter's weight, and n is pollutant variables number.[16] and [6].
Equation ( 1) is used to calculate numerical values for the Index of Water Quality.Table 2 shows how the WQI rates water quality, which goes from very good to unfit for human consumption.

Health risk assessment
Three main pathways exist for humans to become contaminated with pollutants like metals: direct consumption, inhalation through the mouth and nose, and skin absorption through skin exposure.

Evaluation of Water Quality
The results of the measurements of nine water quality indicators in the Pusur River conducted in December 2023 during the dry season are shown in Table 4.In Table 4, you can see the results of measurements of Pusur River water samples based on PP No. 82 of 2001 for class II water quality as reported by the intended use of Pusur River water for the surrounding community.The turbidity parameter (100 NTU) measured at all sampling points meets quality standards.Likewise, for the TSS parameter (50 mg/L), the measurement results at all sampling points meet the quality standards.The pH parameter (6-9) at the sampling points in Sudimoro, Cokro, Wangen, Delanggu, and Juwiring is still in the range of quality standard values, namely 7.3-8.6,which meets the quality standards, while those that exceed the quality standards are at the river water sampling points in Taji Village, 5.3 downstream of the Pusur River.The DO parameter (4 mg/L) at sampling points in the villages of Sudimoro, Cokro, Wangen, and Juwiring meets the quality standards, while in Delanggu (10.65 mg/L) and Taji villages (13 mg/L) downstream Pusur River exceeds the quality standards.The COD parameter (25 mg/L) measured at all sampling points meets quality standards.
The stable form of nitrate is derived from fertilizer, waste, animal and human waste, and other sources.The nitrate parameter (10 mg/L), which exceeds the quality standard, is at the sample point in Sudimoro Village (18.30 mg/L) and Cokro Village (17.51 mg/L), located in the middle of the Pusur River.Meanwhile, in Wangen, Delanggu, Juwiring, and Taji villages, the nitrate parameters meet quality standards.The Cd parameter (0.01 mg/L) measured at all sampling points meets the quality standard, namely <0.0066 mg/L.Apart from that, concerning Cd, if the concentration exceeds the water quality standards, it is not suitable for fish cultivation or irrigation of fresh vegetables.Apart from that, it is not appropriate to irrigate fresh vegetables or fish farms if the amount of Cd in the water is higher than the standards for water quality.Cadmium can be harmful to aquatic life and humans, which makes its presence a serious health concern.Cadmium levels can be found in airborne and waterborne emissions from factories and hazardous waste sites.Elevated levels of cadmium have been connected to several illnesses in humans, such as immune system dysfunction, memory loss, cancer, and reproductive abnormalities, among other illnesses that can eventually result in death [6] [18].
The distribution of aquatic species is influenced by temperature because it affects the chemical response and metabolic rate of living forms in water bodies.For the temperature parameters the locations where water is sampled in the villages of Sudimoro, Cokro, Wangen, and Delanggu, the water temperature conditions are still within Number 82 of the Government Regulations of 2001.Quality requirements for Class Two (II) for temperature is deviation 3, This indicates that water T is limited to the range of 22°C-28°C if T is normal at 25°C according to Class II requirements.As a result, the water temperature at this location can still support life in the water.Meanwhile, in Juwiring and Taji Villages, the water temperature is slightly below the quality standard, namely 21°C.For fecal coliform parameters (1000 MPN/100 ml) in all villages, river water samples were taken that exceeded the quality standard in sequence from the largest to the smallest, namely in the villages of Sudimoro > Juwiring > Wangen > Taji > Delanggu > Cokro.Judging from the water pollution class for fecal coliform parameters from all sample points, it is classified as severe pollution.Where the fecal coliform concentration is 2,000-460,000 > 1,000 MPN/100 ml, the water from the river is unfit for contact during irrigation and fishing activities, as well as swimming and bathing [2].In river basins, anthropogenic sources pose a serious risk to the microbial water quality [19].Surface runoff, wastewater discharge, the disposal of animal waste into river bodies, and the disposal of trash and diapers along riverbanks have all been identified as potential sources of pollution [20] [21].Drinking feces-contaminated water has several effects on the spread of diseases like cholera and diarrhea.

Index of Water Quality (WQI)
When calculating the water quality index, use the NSF-WQI based on several key criteria for water quality, such as temperature, turbidity, pH, dissolved oxygen, COD, nitrate, and fecal coliform.Using the ranking data shown in Figure 2, the Index of Water Quality (NSF-WQI) results are applied to jointly evaluate the Pusur River's pollution status in August 2023 in the arid season.Table 5 displays the outcomes of the NSF-WQI calculation for the parameters turbidity, pH, DO, COD, nitrate, temperature, and fecal coliform, from each sampling location.One helpful mathematical technique for predicting the state of surface water quality is the WQI, or Water Quality Index by integrating several factors related to water quality into a single figure [22] [23] [24].For ease of use and interpretation by water managers, the Index of Water Quality (WQI) is an index that shows the combined impact of different criteria for water quality.The WQI is computed in three phases.First, a weight (wi) is allocated to every one of the seven parameters based on how important they are overall in terms of water quality [6].Secondly, use the sub-index curve to find each parameter's Li value.Third, multiply the values of Wi and Li.The total of all (Wi x Li) water quality parameters determines the value of the water quality index.The Pusur Quality of river water index was 37.50 at location A (Sudimoro Village), 43.At every sampling point, the water quality criteria include bad, which falls between 25 and 50 on the score scale (Table 2).The score sequence is Cokro>Wangen>Juwiring>Sudimoro>Delanggu and Taji.

Evaluation of non-carcinogenic health risks
Table 6 and Figure 3 show the outcomes of applying a non-carcinogenic health risk assessment for NO3 and Cd pollutants to Pusur River water during the dry season, specifically in August 2023.The outcomes of the calculation of levels of non-carcinogenic health risks, CDI, HQ, and HI values were calculated from the nitrate and Cd parameters in Pusur River water samples.Each sampling point has a low-risk hazard level (0.1 < HI < 1), with values ranging adults between 0.434 and 0.749 mg/kg/day and children between 0.485 and 0.788 mg/kg/day.It is recommended that before being used for domestic water purposes, river water needs to be treated first.Figure 3 shows that each sampling point's HI value includes low risk, with a value range of 0.1 < HI < 1. Children are more at risk than adults are; comparable studies have documented how susceptible kids are to chemicals in food and water [6] [26].In comparison to cadmium metal, the results of nitrate pollution measurements predominate in non-health hazards.According to research by Lu and An [27], the majority of non-health risks are caused by nitrate contamination, as evidenced by the majority of samples in river tributaries exhibiting unacceptable risks for children.Therefore, to ensure the safety of water use in the river basin, the management of non-point source pollution in agriculture needs to be reinforced in future water environment management plans for the Pusur River area.

Conclusion
The research findings provide initial information regarding the condition of the water of the Pusur River in August 2023, during the dry season.The parameter that exceeds the quality standard is pH at the sampling point in Taji Village, 5.3.The DO parameter in Delanggu Village is 10.65 mg/L, and in Taji, it is 13 mg/L.Nitrate parameters in Sudimoro Village were 18.30 mg/L and in Cokro Village 17.51 mg/L.For fecal coliform parameters in all villages, river water sampling exceeded the respective quality standards from largest to smallest, namely in Sudimoro > Juwiring > Wangen > Taji > Delanggu > Cokro Village.Judging from the water pollution class for the Fecal Coliform parameter, the Pusur River water sample is classified as heavily polluted.WQI shows that the condition of the water of the middle to lower reaches of the Pusur River is in poor condition.The possible non-carcinogenic hazards connected to drinking river water are low for both children and adults.It is recommended to treat river water adequately before using it for domestic and non-domestic needs.
54 at location B (Cokro Village), 39.51 at location C (Wangen Village), 35.45 at location D (Delanggu Village), 38.05 at location E (Juwiring Village), and 34.92 at location F (Taji Village).All six of these locations' WQI values were included in the bad criteria (scores 26-50).The low WQI values at the six sampling locations were influenced by the low values of the DO, nitrate, temperature, and fecal coliform sub-indices.The region's anthropogenic activities are responsible for this low value.Since all wastewater from commercial or farming endeavors is discharged entering bodies of water with little to no treatment, the majority of environmental pollution is caused by human activity and is associated with industrial development [25] [7] [12] [13].

Figure 2 .
Figure 2. Application of the NSF-WQI water quality index results

Figure 3 .
Figure 3. Hazard Index values for Cd and Nitrate parameters at the sampling location.

Table 1 .
Bio-Physical Chemical Parameters and Water Quality Test Methods for Pusur River Water

Table 2 .
Criteria for water quality determined by WQI values

Table 3 .
Rating of health risks

Table 4 :
Data measurement results of water samples.

Table 5 :
Outcomes of Data Calculation August 2023 Index of Water Quality

Table 6 .
Calculation of non-carcinogenic Health Risk Assessment