Two-Year Responses of Office and Ambulatory Blood Pressure to First Occupational Lead Exposure

Lead exposure causing hypertension is the mechanism commonly assumed to set off premature death and cardiovascular complications. However, at current exposure levels in the developed world, the link between hypertension and lead remains unproven. In the Study for Promotion of Health in Recycling Lead (URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02243904), we recorded the 2-year responses of office blood pressure (average of 5 consecutive readings) and 24-hour ambulatory blood pressure to first occupational lead exposure in workers newly employed at lead recycling plants. Blood lead (BL) was measured by inductively coupled plasma mass spectrometry (detection limit 0.5 µg/dL). Hypertension was defined according to the 2017 American College of Cardiology/American Heart Association guideline. Statistical methods included multivariable-adjusted mixed models with participants modeled as a random effect and interval-censored Cox regression. Office blood pressure was measured in 267 participants (11.6% women, mean age at enrollment, 28.6 years) and ambulatory blood pressure in 137 at 2 follow-up visits. Geometric means were 4.09 µg/dL for baseline BL and 3.30 for the last-follow-up-to-baseline BL ratio. Fully adjusted changes in systolic/diastolic blood pressure associated with a doubling of the BL ratio were 0.36/0.28 mm Hg (95% CI, −0.55 to 1.27/−0.48 to 1.04 mm Hg) for office blood pressure and −0.18/0.11 mm Hg (−2.09 to 1.74/−1.05 to 1.27 mm Hg) for 24-hour ambulatory blood pressure. The adjusted hazard ratios of moving up across hypertension categories for a doubling in BL were 1.13 (0.93–1.38) and 0.84 (0.57–1.22) for office blood pressure and ambulatory blood pressure, respectively. In conclusion, the 2-year blood pressure responses and incident hypertension were not associated with the BL increase on first occupational exposure.

Accumulation of Arsenic and Heavy Metals in Native and Cultivated Plant Species in a Lead Recycling Area in Vietnam

This study was conducted to determine the soil contamination and the accumulation of arsenic (As) and heavy metals including chromium (Cr), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in 15 native and cultivated plant species in a Pb recycling area of Dong Mai village, Hung Yen Province, Vietnam. The analysis of 32 soil samples collected from seven different sites in the study area revealed that the contents of Al, Fe, As, Cr, Cu, Zn, Cd, and Pb in the soils ranged from 6200–32,600, 11,300–55,500, 5.4–26.8, 24.9–290, 66.0–252, 143–455, 0.71–1.67, and 370–47,400 mg/kg, respectively. The contents of As, Cr, Cu, Zn, Cd, and Pb in rice grains and the shoots of 15 plant species ranged from 0.14–10.2, 1.00–10.2, 5.19–23.8, 34.7–165, 0.06–0.99, and 2.83–1160 mg/kg-dry weight (DW), respectively. Hymenachne acutigluma (Steud.) Gilliland, a potential hyperaccumulator of Pb (1160 mg/kg–DW), is considered the best candidate for phytoremediation of Pb-contaminated soil. The cultivation of rice and vegetables, and the use of some native plants for food for humans, pigs, and cattle should be managed with consideration of the accumulation of Pb in their aboveground biomass.

THE CONTRIBUTION OF CURRENT LABORATORY METHODS IN CONDUCTING BIOLOGICAL MONITORING OF LEAD EXPOSURE TO THE WORKERS OF A LEAD RECYCLING PLANT

To assess the informative value of the expansion of the laboratory tests complex in conducting biological monitoring of lead exposure to the organism, in workers of a lead recycling plant there were determined iron and ferritin levels for the analysis of the association of iron metabolism disorders with chronic exposure to lead, polymorphisms of the hemochromatosis gene as a risk factor for increased lead absorption, erythrocytes and reticulocytes parameters for the detection of early signs of toxic effects of lead on erythropoiesis. There was determined an importance of an estimation of an iron metabolism in workers exposed to lead for detecting risk groups of conditions connected with an iron overload. To assess the early signs of the toxic effect of lead on erythropoiesis, it is informative not only to determine the amount of reticulocytes, but also to estimate the ratio of reticulocyte fractions. The determination of the polymorphism of the hemochromatosis gene can be used to assess the individual risk of developing lead poisoning.

The impacts of lead recycling activities to human health and environment in Dong Mai craft village, Hung Yen, Vietnam

Lead (Pb) recycling activities in Dong Mai village, Chi Dao commune, Van Lam district, Hung Yen province have been taking place for more than 30 years. The development of recycling activities contributed to the improvement of the local economics. However, along with economic development, Dong Mai craft village is facing to serious pollution. Soil, air and water polluted by lead (Pb) caused food containing Pb at higher levels than allowed limit from 20 to 40 times. The pollution had the bad effect on human health in this village. The investigation results showed that 100 % of employee who participated on melting lead and 63.5 % of local children were poisoned by Pb. Besides, the local people got diseases relating to skin, eyes, etc. This situation requires the provincial authorities to find immediate solutions to reduce the impacts of Pb recycling activities to environment and human. Hoạt động tái chế chì của thôn Đông Mai, xã Chỉ Đạo, huyện Văn Lâm, tỉnh Hưng Yên đã diễn ra hơn 30 năm nay. Sự phát triển của nghề tái chế đã làm góp phần cải thiện kinh tế của địa phương. Tuy nhiên, cùng với sự phát triển kinh tế, làng nghề Đông Mai đã và đang đối mặt với ô nhiễm môi trường nghiêm trọng. Môi trường đất, nước không khí bị ô nhiễm bởi chì (Pb) dẫn đến thực phẩm nhiễm chì ở hàm lượng cao hơn mức cho phép từ 20- 40 lần. Sự ô nhiễm gây ra những ảnh hưởng xấu tới sức khỏe của người dân làng nghề. Kết quả điều tra cho thấy 100% công nhân tham gia nấu chì và 63.5% trẻ em địa phương bị nhiễm độc chì. Bên cạnh đó, người dân địa phương còn bị mắc của các loại bệnh ngoài da, bệnh về mắt, …. Tình trạng này đòi hỏi chính quyền địa phương phải tìm ra giải pháp khẩn cấp để giảm thiểu tác động của những hoạt động tái chế chì tới môi trường và con người.

Status of heavy metal (Pb, Cd) pollution in agricultural soil in Dong Mai lead recycling craft village in Hung Yen, Vietnam

The newly planned lead recycling zone in Dong Mai village has been operating with primary treatment systems using lime to neutralize acid in wastewater is a good sign for the local environment, yet the real problem that needs further attention and proper solutions is the accumulation of heavy metals typically lead (Pb) and cadmium (Cd) in agricultural land near the old Pb recycling area. In this context, 27 soil samples were collected and analyzed by AAS method to assess the situation and the quality of the agricultural soil. The results showed that the levels of Cd in the soil were still in acceptable level according to National Regulation. However, the lead contents in all of the soil samples exceeded National Regulation. The level of Pb pollution in soil was inversely proportional to the distance with old lead melting zone. The lead content in the soil sample collected at the distance of 50 m radius to the old melting zone reached 7070 ppm, which was 100 times higher than the allowable value of National Regulation. Khu tái chế chì mới tại thôn Đông Mai đã được quy hoạch và đi vào hoạt động cùng hệ thống xử lý sơ bộ với vôi bột là một tín hiệu đáng mừng cho môi trường nơi đây, nhưng vấn đề cần quan tâm và giải quyết triệt để là sự tích lũy một lượng lớn kim loại nặng điển hình là chì (Pb) và cađimi (Cd) trong đất nông nghiệp gần những khu tái chế chì cũ. 27 mẫu đất đã được thu thập và phân tích bằng phương pháp AAS để đánh giá tình trạng, chất lượng đất nông nghiệp tại đây. Kết quả cho thấy hàm lượng Cd trong đất vẫn trong mức độ cho phép theo Quy chuẩn quốc gia. Tuy nhiên, 100% các mẫu đất đều có hàm lượng chì vượt quá mức cho phép theo Quy chuẩn quốc gia. Mức độ ô nhiễm Pb trong đất tỷ lệ nghịch với khoảng cách tới khu lò nấu chì cũ. Mẫu đất cách 50 m so với khu vực lò cũ có hàm lượng chì lên tới 7070 ppm, gấp hơn 100 lần so với Quy chuẩn quốc gia.