Occupational Paraquat and Glyphosate Exposure May Decline Renal Functions among Rural Farming Communities in Sri Lanka

Abstract

Extensive use of herbicides is common among rural agricultural workers in Sri Lanka. Recent studies have postulated their role in the development of chronic kidney disease of unknown etiology (CKDu). Paraquat and glyphosate are leading herbicides used by sugarcane farmers (SF), hence occupational exposure is inevitable. This study examined the expression of urinary paraquat, glyphosate and biomarkers among residential SF in CKDu emerging regions, Warunagama (WA) and Rahathangama (RH), in the Uva Province with non-endemic Matara (MA) in the Southern Province of Sri Lanka. Urinary glyphosate, Paraquat, Kidney injury molecule -1 (KIM-I), Neutrophil gelatinase-associated lipocalin (NGAL) andβ2-microglobulin (B2M) were determined using enzyme-linked immunosorbent assays (ELISA). Urinary creatinine, microalbumin, serum creatinine (SCr), serum cystatin C, estimated glomerular filtration rate (eGFR), and albumin creatinine ratio (ACR) were also assessed. Generally, herbicide residues and kidney injury biomarkers were higher in SF compared to the non-endemic MA. Creatinine-adjusted urinary glyphosate and paraquat levels were significantly higher in WA compared to MA. ACR in RH (median 14.9; IQR 5.4–393.1 mg/g) and WA (23.7; 11.5–64.6) was significantly higher than MA (4.3; 2.2–6.7). This study reports 39 individuals with impaired kidney function among SF in Sri Lanka for the first time. Urinary NGAL levels were significantly higher in both WA (median 2.14; IQR 1.28–6.15 ng/mg Cr) and RH (3.09; 1.15–9.09) compared to MA (1.28; 0.56–2.81). However, urinary KIM-I levels in RH (3.2; 1.29–106.1 ng/g Cr) and WA (3.6; 1.94–115.1) were not significantly higher in MA (1.74; 0.76–116.9). Urinary NGAL (r = 0.493), eGFR (r = −0.147) and ACR (r = 0.171) significantly correlated with urinary glyphosate, but not with urinary paraquat levels. Urinary KIM-1 levels did not correlate with either urinary glyphosate or paraquat, while urinary B2M and serum cystatin C levels showed significant correlation with urinary glyphosate levels. The current study reports higher urinary herbicide levels among sugarcane farmers in WA and RH, and that is potentially linked to the subsequent decline in kidney function, as indicated by ACR, eGFR, and NGAL. We posit that these indicators may serve as markers to detect renal injury among herbicide-exposed SF in Rural Sri Lanka.

An ecological study regarding the association between paraquat exposure and end stage renal disease

“…The authors hypothesize that well water contamination by heavy metals and pesticides contributes to the endemicity of CKDu in the region but that exposure to pesticides such as paraquat and, following its ban in 2010, glyphosphate, partly explain the higher incidence in male farmers. In a related study, Abdul et al assessed urinary glyphosphate and paraquat levels and their association with markers of renal damage among rural farmers in CKDu endemic and non-endemic regions of Sri Lanka [ 36 ]. Urinary glyphosphate and paraquat levels and renal injury biomarkers were higher in CKDu endemic areas; however, associations were observed for glyphosphate but not paraquat.…”

“…Since that time there have been a large number of reports detailing the clinicopathologic features of paraquat associated acute kidney injury [ 28 – 30 ], the mechanism by which this damage occurs has also been widely investigated [ 31 , 32 ]. In contrast, there has been little research regarding the impact of chronic paraquat exposure on renal disease [ 33 – 36 ]. The objective of this study is to investigate the association between county-level measures of paraquat use and the incidence of ESRD.…”

Chronic kidney disease with unknown cause across the global spectrum

“…Glyphosate in abandoned well and groundwater is associated with increased urinary glyphosate in regions with high CKDu rates [3 && ], and groundwater is the primary water source for more than 98% of CKDu patients [21]. Urinary paraquat and glyphosate levels are higher in farmers in CKDu endemic vs. nonendemic regions, and glyphosate levels associate with urinary NGAL (r ¼ 0.49, P ¼ 0.001) and eGFR (r ¼À0.147, P ¼ 0.036) [31].…”

THE CHRONIC KIDNEY DISEASE OF UNKNOWN AETIOLOGY (CKDu) EPIDEMICS IN NORTHERN YOBE STATE

“…However, apart from the identified aetiologies responsible for the disease, environmental factors such as exposure to heavy metals (Kulathunga et al 2019), as well as heat stress (Jayasekara et al 2019) and use of agrochemicals such as residues of glyphosate and Paraguat (Abdul et al, 2021) were all reported as potential risk factors. Similarly, exposure to contaminated drinking water with fluoride (Wasana et al, 2017;Fernando et al 2020) have all been reported in the literature as drivers of CKDu.…”