Ô nhiễm kim loại nặng trong đất và tiềm năng phục hồi sinh thái của các loài thực vật bản địa tại một khu vực khai thác vàng cũ ở Ghana

Water, Air, and Soil Pollution - Tập 230 - Trang 1-16 - 2019
Joshua Petelka1,2, John Abraham3, Anke Bockreis4, Justus Precious Deikumah3, Stefan Zerbe1
1Faculty of Science and Technology, Free University of Bozen-Bolzano, Bozen, Italy
2Faculty of Biology, Leopold-Franzens University of Innsbruck, Innsbruck, Austria
3Department of Conservation Biology and Entomology, School of Biological Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
4Faculty of Engineering Science, Leopold-Franzens University of Innsbruck, Innsbruck, Austria

Tóm tắt

Nghiên cứu này đã điều tra mức độ ô nhiễm đất và đánh giá tiềm năng phục hồi sinh thái của 25 loài thực vật bản địa tại khu vực bãi thải của một mỏ vàng cũ ở Ghana. Các mẫu cây và mẫu đất liên quan đã được thu thập từ một địa điểm lắng đọng bãi thải và phân tích nồng độ tổng của các nguyên tố As, Hg, Pb và Cu. Nội dung kim loại (loại) trong đất, hệ số tích lũy sinh học (BAFshoots) và ngưỡng hyperaccumulator cũng được xác định để đánh giá mức độ ô nhiễm đất hiện tại và tiềm năng phytoextraction. Nồng độ As và Hg trong đất vượt quá các ngưỡng rủi ro quốc tế, trong khi nồng độ Pb và Cu nằm dưới những ngưỡng đó. Không có loài thực vật nào trong số các loài được nghiên cứu đạt tiêu chuẩn nồng độ hyperaccumulator tuyệt đối. Khả năng sinh khả dụng của các kim loại (loại) trong các mẫu đất nói chung là thấp do pH cao, hàm lượng chất hữu cơ và đất sét cao. Tuy nhiên, đối với Cu, các giá trị tích lũy sinh học tương đối cao (BAFshoots > 1) đã được tìm thấy ở 12 loài thực vật, cho thấy tiềm năng cho việc loại bỏ chọn lọc kim loại nặng thông qua phục hồi sinh thái bởi các cây này. Mức độ cao của As tại khu vực nghiên cứu tạo ra rủi ro về môi trường và sức khỏe, nhưng cũng có tiềm năng cho quá trình phytoextraction đối với Cu (ví dụ: Aspilia africana) và việc phục hồi thông qua trồng lại rừng với Leucaena leucocephala và Senna siamea.

Từ khóa

#ô nhiễm đất #kim loại nặng #phục hồi sinh thái #thực vật bản địa #Ghana

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