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Water supplies in coastal aquifers throughout the world are often threatened by salinization due to seawater intrusion and anthropogenic activities. In the Kalpitiya Peninsula in Sri Lanka, agricultural and domestic water supplies entirely depend on groundwater resources extracted from unconfined Holocene sandy aquifers. To differentiate the effects of seawater intrusion and agriculture on the coastal aquifers of this 160 km 2 peninsula, 43 groundwater samples were collected. These samples were analyzed for major ions, trace elements, and stable isotopes of water (δ 18 O and δ 2 H). The solute compositions were dominated by Cl − , SO 4 2 − , and HCO 3 − , which were mostly balanced by Ca 2+ , Na + , and Mg 2+ . Among the four main water types, Na + -Cl − and Ca 2+ - SO 4 2 − classifications were predominant in the investigated aquifers. Modifications of the groundwater due to evaporation during irrigation activities, but also due to seawater intrusion seem most plausible as indicated by the correlation of δ 18 O with δ 2 H (δ 2 H = 5.51 * δ 18 O-3.08, r  = 0.93) deviating from the local meteoric water line. Particularly in the southern part of the peninsula, Mg 2+ /Ca 2+ ratios and stable isotopes of water attributed salinization of groundwater to agricultural activities. However, especially in the north, seawater intrusions were also evident. Established mass balance calculations revealed that local groundwater had seawater admixtures of up to 12%. Our results indicate that integrated water management is essential and water resources should critically monitor in the Kalpitiya Peninsula in order to avoid over-exploitation and further seawater inflows.

Environmental exposure to trace elements has been widely suspected as an etiological factor for the emergence of chronic kidney disease of undetermined origin (CKDu) that prevails in certain districts of the dry zone areas of Sri Lanka. Contaminated rice can be act as a host for potentially toxic trace elements that ultimately led to health hazards; thus, rice soils were investigated in detail, giving particular attentions to identified CKDu hotspots. A total of 102 rice soil samples were collected from main climatic zones viz. wet and dry zones including CKDu hotspots. In addition to pH, electrical conductivity and cation exchange capacity, acid extracted major and trace element contents in rice soils were determined by using ICP-MS. Significant differences were observed for Mn, Ni, Cu, Zn, and Pb contents between climatic zones. Arsenic and Pb contents in soils were lower than the levels reported in soils from other regions of the world, though significantly higher contents were observed in CKDu regions compared to non-endemic wet zone regions. Calculation of enrichment factor revealed that soils in both dry and wet zones were moderately enriched with As, Cd, and Pb, suggesting an influence of anthropogenic processes. Twenty percent of the wet zone samples showed significant enrichment of Ni, Cu, and Zn. Geo-accumulation index assorted that the studied soil samples were uncontaminated to moderately contaminated, implying that rice soils in both climatic zones are not alarmingly contaminated with toxic trace elements. However, regular and continuous monitoring of rice soil quality is extremely important.

Over the last decade, concern has increased about the deterioration of groundwater quality in coastal aquifers due to salinization processes resulting from uncontrolled abstraction and the impacts of global climate change. This study investigated the groundwater geochemistry of a narrow sandy peninsula bounded by the ocean and brackish water lagoons in northern Sri Lanka. The population of the region has grown rapidly over the last decade with increasing agricultural activities, and therefore, the use of groundwater has increased. To investigate the effects of seawater intrusion and anthropogenic activities, selected water quality parameters and water isotopes (δ2H and δ18O) were measured in 51 groundwater samples. The results showed that selected shallow groundwater wells are vulnerable to contamination from anthropogenic processes and seawater intrusion, mainly indicated by Cl/Br ratios. Iron-rich groundwater (0.11 to 4.2 mg/L) could represent another problem in the studied groundwater. According to Water Quality Index calculations, 41% of shallow wells contained poor and unsuitable water for domestic and irrigation purposes. Most of the groundwater in the region was saturated with Ca and Mg containing mineral phases such as calcite, dolomite, magnesite and gypsum. Water isotopes (δ2H and δ18O) showed that about 50% of the groundwater samples were scattered near the local meteoric water line. This indicates sufficient rainwater infiltration. However, some samples exhibit elevated isotope values due to seawater admixture and secondary evaporation under semi-arid conditions. This study showed the utility of Cl/Br ratios as indicators for distinguishing anthropogenic sources of Cl contributions to groundwater in shallow, permeable aquifer systems.

Glutathione Peroxidase activity in whole blood is well correlated with the Selenium (Se) levels in cattle hence can be used effectively to assess the supply of Se to farm animals. In this study, Se status of cattle from five different geographic regions of Sri Lanka were assessed based on glutathione peroxidase (GSH-Px) activity. The GSH-Px activity was determined in whole blood samples collected from 80 cattle from 31 different farms in five districts viz. Kandy, Anuradhapura, Batticoloa, Trincomalee and Jaffna using photometric method. Mean GSH-Px activity was found to be 825, 1239, 1039, 849 and 1307 μkat L−1 in above districts, respectively while the reference value was considered as 665.4 μkat L−1. Among the studied animals, insufficient Se levels were detected in 50%, 17%, 9%, 27% and 5%, respectively, from above districts. Kruskal Wallis test indicated a significant variation among the sampled locations with respect to the GSH-Px activity (p = 0.001). Selenium content in pasture and water collected from studied locations varied from 6.0 to 554 μg kg−1 and < 0.03–1.14 μg L−1, respectively. The lower Se levels in feeds recorded from Kandy region infer the lower GSH-Px activity in the animals from the same region. This variability may be due to differences in nutrient supply, age and species of cattle, and lactation stage. Although the assessing method has some limitations, the activity of GSH-Px of the samples indirectly confirms that considerable numbers of cattle from Sri Lanka are with insufficient selenium levels.

Since at least two decades, Chronic Kidney Disease of Uncertain Etiology (CKDu) has become an increasingly discussed health issue in Sri Lanka and as well as in other tropical regions. Areas that are particularly affected with the disease are mostly located in the dry zone of Sri Lanka. The disease is more prominent among communities that consume groundwater as their main source of drinking water. Hydrogeochemical investigations were carried out in the Ginnoruwa area, a known hotspot of CKDu. It revealed possible links between drinking water chemistry and the spreading of the disease. This work compares hydrogeochemical data of drinking water sources of wells whose consumers are affected by CKDu and other nearby wells whose consumers were not affected by the disease. A total of 63 groundwater samples were collected from selected wells. About one-third of these samples (i.e., 19) were collected from wells used by CKDu patients. Significantly higher values of pH, total hardness, electrical conductivity, Ca 2+ , Mg 2+ , F − , Cl − , PO 4 3− , and SO 4 2− were found in wells that were used by CKDu patients. Mean contents of Na + , Ca 2+ , and Mg 2+ in CKDu affected wells were 33.8 mg/L, 30.1 mg/L, and 14.9 mg/L, respectively, compared to 23.1 mg/L, 26.7 mg/L, and 9.65 mg/L in non-CKDu wells. Differences in major ion geochemistry in groundwaters are possibly governed by variable time periods of water storage in fractured hard rock aquifers in this region. Hydrogeochemical parameters were statistically compared by a Mann–Whitney U test and indicated significant differences in total dissolved solids (TDS) ( p  = 0.016), SO 4 2− ( p  = 0.005), PO 4 3− ( p  = 0.030), F − ( p  = 0.048), Na + ( p  = 0.008), and Mg 2+ ( p  = 0.008) between non-CKDu and CKDu wells at p  = 0.050 level. Other suspected solutes such as nephrotoxic trace elements including As, Cd, and Pb were similar in both types of wells. They were also lower than the accepted guideline limits of the World Health Organization (WHO). Results of this study suggest that fluoride in drinking water in combination with water hardness may be one of the responsible factors for kidney damage and progression of the disease. This may be particularly the case when elevated amounts of Mg 2+ are present in hard groundwater.

Fluoride is a beneficial trace element for human health as its deficiency and excess levels can cause detrimental health effects. In Sri Lanka, dry zone regions can have excessive levels of fluoride in drinking water and can cause dental and skeletal fluorosis. In addition to drinking water, traditional habits of tea consumption can cause an additional intake of fluoride in the population. A total number of 39 locally blended black tea samples were collected from a village where chronic kidney disease with undetermined origin (CKDu) is prevalent. In addition, unblended tea samples were obtained from tea-producing factories. The fluoride contents in infusions of 2% weight per volume (w/v) were measured using calibrated ion-selective fluoride electrodes. The mean fluoride content was 2.68±1.03 mg/L in loose tea, 1.87±0.57mg/L in packed tea samples, and 1.14±0.55 mg/L in unblended tea. Repeated brewing of the same tea leaves showed that over 50% of fluoride leached into the solution in the first infusion. An estimate of the daily total average fluoride intake via tea consumption per person is 2.68 mg per day. With groundwater in many dry zone regions in Sri Lanka showing high fluoride levels that exceed 0.5 mg/L, the additional daily intake can rapidly exceed recommended thresholds of 2 mg/day. This can add to adverse health impacts that might also relate to CKDu.

Fresh milk is an important source of essential mineral supplement for humans. However, the levels of trace elements in milk are an important component of its safety and quality. Trace elements also act as a bio-indicator of agricultural pollution. Samples of raw cow milk (n = 68), animal feed [forage (n = 36) and concentrates (n = 14)], and water (n = 35) were collected from different agro-climatic regions of Sri Lanka. The concentrations of 15 trace elements including toxic heavy metals such as Cd, Pb, and As were quantified using inductively coupled plasma mass spectrometry after microwave-assisted digestion. Among the studied trace elements, the mean elemental concentrations of Se, Cd, As, and Cu in cow milk were 18.1, 1.45, 7.35, and 71.7 μg L−1, respectively. The mean concentrations of these elements in forage were 0.216, 0.066, 0.046, and 9.21 mg kg−1, and in concentrate feed were 0.329, 0.202, 0.229, and 2.28 mg kg−1, respectively. The As content of the studied milk was well below the maximum permissible level while 15% of the samples had Pb exceeding the permissible limit of 20 μg L−1. However, As, Cd, and Pb levels in drinking water provided to animals were well below the WHO permissible limits. The results of this study revealed that the trace elements in cow milk depend mainly on the feed, and hence, levels of these contaminants in feed materials should be monitored. Although due to the consumption of milk, the populations have a minor exposure to trace elements and also minimum health risks, a detailed study with a large number of samples is highly recommended.

Background Samples of 226 new improved and 21 indigenous rice ( Oryza sativa L.) varieties were collected from the rice fields in three climatic zones of Sri Lanka and concentrations of 18 trace elements (Li, B, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Ba, Pb and Bi) were measured giving particular emphasis on Se, Cd and As using ICP-MS. The two way multivariate analysis of variance (MANOVA) method was employed to identify the differences in composition among rice from different climatic zones. Results The mean values obtained for both white and red rice were Se (36; 25 µg/kg), As (42; 45 µg/kg) and Cd (70; 123 µg/kg) on dry weight basis. However mean content of Se, As and Cd of native rice varieties were 69, 74 and 33 µg/kg, respectively. Statistical interpretations showed that in the majority of cases, there was a significant difference in Cd content among climatic zones whereas Se and Pb show differences between white and red rice varieties. Arsenic did not indicate any significant difference either between rice types or among climatic regions. Notably Se and As contents in indigenous rice were higher than that of improved rice types. To assess the safety of dietary of intake, daily intake of Se, Cd and As by rice were calculated. Non-gender specific Estimated Daily Intake (EDI) of Se, Cd and As consuming improved rice are 9.31, 24.1 and 12.2 µg day −1 , respectively. Conclusions Since over 50 % of daily meals of people contain rice or rice based products, Se intake is expected to be deficient among the Sri Lankan population.

A chronic Kidney Disease of unknown etiology (CKDu) has emerged with disproportionately high prevalence across dry lowland agricultural communities globally. Here we present the results of a prospective cohort of 293 patients with CKDu in the endemic region of Wilgamuwa, Sri Lanka, in whom we measured baseline kidney function and undertook quarterly follow up over 2 years. Well water was the primary historic drinking water source in the region, although a majority (68%) of participants reported switching to reverse osmosis water during study follow ups. Participants who reported ever drinking from well water had estimated glomerular filtration rates −6.7 (SD: 2.8) ml/min/1.73 m 2 lower than participants who did not drink from well water historically ( p  = 0.0184) during the study period. Geospatial analysis identifies a cluster within the region where CKDu progression is significantly higher than the surrounding area. Samples of household wells ( n  = 262) indicated 68% had detectable agrochemical compounds with concentration above global water quality standards. It is expected that the detected contaminants compounds are indicators of poor water quality and that there is likely additional agrochemical exposure including commercial additives that may contribute to CKDu onset and/or progression. Thus, our study finds that well water exposure during a person’s lifetime in this region is associated with kidney function decline and identifies and quantifies putative nephrotoxic agrochemicals above safe drinking water concentrations in these wells.

Information on the geographic origin of milk is important in determining quality attributes and for economic gain through building brand value associated with origin. Stable isotope signatures and trace element concentrations have been increasingly used in authentication of milk, though information on the power of such technology in verifying agroclimatic origin in small continents with diverse climatic, environmental conditions, and animal management practice is scarce. Therefore, the main objective of this study was to investigate the possibility of using a stable isotope composition of C, N, O, and H and element fingerprints to determine the agroclimatic origin of milk produced in different agroclimatic zones of Sri Lanka. Stable isotopes ratios of C, N, H, and O, and elemental fingerprints of milk samples were determined by IRMS and ICP-MS, respectively. Significant variations were observed in stable isotope ratios, especially δ18O and the mean content of Li, Al, Cr, Mn, and Sr in the bulk milk samples obtained from different agroclimatic zones. A linear discriminant analysis differentiated cow milk produced from four agroclimatic zones based on stable isotope ratios, and the inclusion of elemental ratios enhanced the discriminating ability.