The burden of chronic mercury intoxication in artisanal small-scale gold mining in Zimbabwe: data availability and preliminary estimates

Table 4 Sample prevalence and assumed distribution of exposed miners in Zimbabwe around 2004

Column A	B		C		D	E
Subgroups of artisanal small-scale gold (ASG) miners	Sample prevalence of chronic mercury intoxication in ASG miners^*		Main analysis: Numbers and percentages^**of ASG miners assumed for Zimbabwe		Sources of numbers and percentages marked in bold in column C	Scenario analysis: numbers and percentage distribution assumed for Zimbabwe (scenario range)
Subgroups of artisanal small-scale gold (ASG) miners						Min.	Source	Max.	Source
Total (T)	72%	(131/181)	350,000	100%	[8, 9, 50, 51]	No variation		500,000	[54, 55]
Adults (A)’	72%	(118/164)	297,500	85% of T	GMP 2004	No variation		98% of T	[14]
Males (M)	90%	(95/106)	208,250	70% of A	Mid-value of reported data***	50% of A	[8, 9, 50]	89% of A	[52, 53]
15-24	91%	(41/45)	74,350	36% of M	GMP 2004 cross-checked against Mtetwa and Shava [52]	No variation
25-34	88%	(35/40)	86,000	41% of M
35-41	90%	(19/21)	21,450	10% of M
42+	90%	(19/21)	26,450	13% of M
Females (F)	40%	(23/58)	89,250	30% of A	Mid-value of reported data***	11% of A	[52, 53]	50% of A	[8, 9, 50]
15-24	26%	(7/27)	31,860	36% of F	GMP 2004 cross-checked against Mtetwa and Shava [52]	No variation
25-34	52%	(16/31)	36,860	41% of F
35-41			9,190	10% of F
42+			11,340	13% of F
Children”	76%	(13/17)	52,500	15% of T	GMP 2004	2% of T	[14]	No variation
Male (M)			38,500	11% of T
Female (F)			14,000	4% of T

^*The data were taken from the Global Mercury Project (GMP), conducted by UNIDO in Zimbabwe in 2004 [5, 12], and from a health and biomonitoring project focusing on women of child-bearing age and their infants, conducted in Zimbabwe in 2006 by the University of Munich (LMU; Germany) [48]. The sample prevalence of the control group is 0%. The sample prevalence (in %) in every subgroup is determined using Formula 1, Table 1. The number of intoxicated and the subgroup size are shown between parentheses.
^**Numbers and percentages are rounded and include uncertainties because their distribution was derived using the estimates given in the sources in column D.
^***References consulted with estimates for Zimbabwe [8, 9, 50, 52, 53] cross-checked against the GMP 2004.
^‘Adults: individuals 15 years and older.
^”Children: individuals aged 9–14; children aged 0–8 were not assumed to be occupationally exposed.
A: adults; F: females; GMP 2004: own analysis using data from the Global Mercury Project 2004 for Zimbabwe; M: males; Max.: maximum; Min.: minimum; T: total.

ISSN: 1476-069X