Evidence of nickel and other trace elements and their relationship to clinical findings in acute Mesoamerican Nephropathy: A case-control analysis.

BACKGROUND: Although there are several hypothesized etiologies of Mesoamerican Nephropathy (MeN), evidence has not yet pointed to the underlying cause. Exposure to various trace elements can cause the clinical features observed in MeN. METHODS AND FINDINGS: We measured 15 trace elements, including heavy metals, in renal case-patients (n = 18) and healthy controls (n = 36) in a MeN high-risk region of Nicaragua. Toenails clippings from study participants were analyzed using inductively coupled plasma mass spectrometry. A case-control analysis was performed, and concentrations were also analyzed over participant characteristics and clinical parameters. Nickel (Ni) concentrations were significantly higher in toenails from cases (1.554 mg/kg [0.176-42.647]) than controls (0.208 mg/kg [0.055-51.235]; p<0.001). Ni concentrations correlated positively with serum creatinine levels (p = 0.001) and negatively with eGFR (p = 0.001). Greater Ni exposure was also associated with higher leukocyte (p = 0.001) and neutrophil (p = 0.003) counts, fewer lymphocytes (p = 0.003), and lower hemoglobin (p = 0.004) and hematocrit (p = 0.011). CONCLUSIONS: Low-dose, chronic environmental exposure to Ni is a possible health risk in this setting. Ni intoxication and resulting systemic and renal effects could explain the clinical signs observed during early MeN. This study provides compelling evidence for a role of Ni in the acute renal impairment observed in this MeN high-risk population. Additional work to assess exposure levels in a larger and heterogeneous population, identify environmental sources of Ni and exposure pathways, and evaluate the link between Ni and MeN pathogenesis are urgently needed.

Personal air sampling and risks of inhalation exposure during atrazine application in Honduras.

PURPOSE: To assess occupational inhalation exposure to the herbicide atrazine during pesticide application in a developing country. METHODS: Personal air samples were collected during atrazine application using a personal sampling pump equipped with an OSHA Versatile Sampler (OVS-2) sorbent tube. Samples were collected from 24 pesticide applicators in Honduras. Application was observed during sampling, and a survey was completed in the home. RESULTS: Fourteen of the 24 participants used pump backpack sprayers to apply atrazine and 10 used tractor/boom systems. Despite applying about 15 times as much atrazine, the tractor/boom participants (11.5 µg/m(3)) had only slightly higher (not statistically significant) time-weighted averages (TWA) than participants using backpack sprayers (9.6 µg/m(3)). Within the backpack sprayer group, those that used a cone spray nozzle (11.54 µg/m(3)) had nearly double the TWA than applicators using a flat spray nozzle (5.98 µg/m(3); P = 0.04). In the tractor/boom group, the participants that rode on the boom or the back of the tractor monitoring nozzles (15.0 µg/m(3)) had almost double the average TWA than tractor drivers (8.0 µg/m(3); P = 0.097). CONCLUSIONS: Since tractor/boom pesticide application decreases the number of man-hours required to apply pesticides, and does not increase inhalation exposure significantly, it decreases the overall population occupational exposure. Monitoring nozzles on booms from a distance rather than on the back of a tractor or boom may decrease or eliminate inhalation exposure. Use of flat spray nozzles for herbicide application among pump backpack sprayers may reduce their inhalation exposure.