Forensic Science International Volume 292, November 2018, Pages 224-231 Forensic Science International Details of a thallium poisoning case revealed by single hair analysis using laser ablation inductively coupled plasma mass spectrometry 4.3 Pre- and post-poisoning basal levels for thallium and lead The victim’s hair heavy metal levels prior to the poisoning period (1994–1995) was established by analyzing the longest hair, ZL1995H1 (∼30 cm), which should have fallen from the victim in 1994, since she became completely bald at the end of that year and never grew hair of such length in 1995. Thallium and lead concentrations of the first ∼3 cm from the hair root of this hair were 2.8 ng g −1 and 1.4 μg g −1 , respectively, close to the levels (3.7 ng g −1 and 0.8 μg g −1 , respectively) detected near the root of a hair collected in 2015 (ZL2015H100). Analysis of another very long hair, ZL1995H2 (∼26 cm), also showed very similar levels of thallium and lead, respectively ( Table 2 ). Table 2 Averaged Tl and Pb concentrations in each analyzed hair samples. For comparison purpose, only the contents in the last ∼3 cm hair shaft near the root of long hair samples (>3 cm) were averaged. For short hair samples (<3 cm), the contents of the entire length were averaged. Sample ID Collecting time Total length (cm) Tl (ng g −1 ) Pb (μg g −1 ) ZL2015H100 2015 ∼10 3.7 0.8 ZL1995H1 1995 ∼30 2.8 1.4 ZL1995H2 1995 ∼26 2.8 0.6 ZL1995H3 1995 ∼1 165 12 ZL1995H5 1995 ∼0.7 182 43 ZL1995H8 1995 ∼4 15 4 ZL1995H9 1995 ∼7 40 2 4.4 Longitudinal distribution of thallium in Hair ZL1995H9 The entire length of a ∼7 cm long hair (ZL1995H9) was scanned from the tip to the root. The longitudinal distribution profile of thallium was shown by the concentration plotted against the distance from the hair tip and the converted hair growth time, which was estimated based on the mean Asian hair growth rate of 411 (±53) μm/day . Approximately 25 distinguishable peaks, with maximum peak concentrations at or above 50 ng g −1 (∼20-fold above the basal level), were resolved along the entire hair shaft ( Fig. 2 A). The intervals between the sharp maxima of the thallium signal peaks varied between 0.5 and 8.6 mm, corresponding to ∼2–20 days. The distance between the first and the last recognizable thallium peak was ∼55 mm, corresponding to at least ∼4 months of hair growth time. An exceptionally tall peak of ∼530 ng g −1 in the middle of this hair shaft indicated a single exposure to an unusually large dose (∼200-fold above the basal level) of thallium. The duration of each peak was ∼2 days, in agreement with the previously observed rapid clearance of thallium from blood . The thallium concentration baseline escalated near the hair root and was juxtaposed with a cluster of peaks with maximum concentrations of ∼150–220 ng g −1 , suggesting the victim had more frequent exposure to increased doses of thallium (50–80-fold above the basal level) ∼3 weeks before this hair fell out. Fig. 2 (A) The longitudinal Tl profile in Hair ZL1995H9 represented by its concentration against the distance from the hair tip (bottom X axis) and the converted hair growth time (top axis). (B) Alignment of the Tl profiles detected in the 1st and 2nd scan of ZL1995H9. A repeated scan of the entire length of this hair showed identical 205 Tl distribution profile, but at a slightly higher level ( Fig. 2 B), confirming that the thallium had been absorbed internally and incorporated during the formation of the hair shaft via diffusion from blood to the actively growing follicle. This result was in agreement with the conclusion from the previous analysis of the victim’s blood and urine at the time of the diagnosis . 4.5 Longitudinal distribution of thallium in Hair ZL1995H5 In contrast to the smooth surface appearance of hair ZL1995H1, ZL1995H2 and ZL1995H9, a rugged surface and dark gray lateral stripes were observed under the microscope ( Fig. 3 ), on a very short hair, ZL1995H5 (∼0.7 cm). Numerous congested thallium peaks spreading along the entire length of this hair were revealed by the first LA-ICP-MS scan, with concentrations varying between 150–500 ng g −1 (∼50–180 fold above the basal level). Intervals between the sharp maxima of most of the thallium signal peaks were ∼0.1–0.3 mm which corresponded to ∼6–18 h, suggesting consistent daily intakes of thallium. Surprisingly, significantly increased signals of lead ( 206 Pb, 207 Pb and 208 Pb) were also observed in this hair, with several large 208 Pb peaks aligning well with thallium peaks ( Fig. 4 A). The highest 208 Pb peak was ∼100-fold above the Pb baseline detected in ZL1995H1. Fig. 3 Microscopic pictures of hair samples. Before laser ablation, ZL1995H2 (A). After laser ablation ZL1995H2 (B), ZL1995H9 (C), ZL1995H5 (D). The red arrow indicated the laser ablated lines. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) Fig. 4 (A) Longitudinal distribution of Tl and Pb over the entire length of ZL1995H5, (B) alignment of the Tl profiles from the 1st and 2nd scan of ZL1995H5, (C) alignment of the Pb profiles from the 1st and 2nd scan of ZL1995H5. The second scan of this hair revealed a similar, but not exactly overlapping, Tl profile ( Fig. 4 B), again slightly higher than the level detected in the first analyses. The misalignment of 205 Tl peaks between the two scans likely resulted from the damaged hair surface structure and disorganized cuticle, which had been observed before on the hair shaft from a victim who died of severe thallium poisoning . In addition, the lead concentration decreased by ∼3-fold, but still ∼10-fold above the basal level ( Fig. 4 C), likely due to the complex reasons discussed below. Nevertheless, with much more frequent and higher thallium peaks and the co-appearance of large amount of lead, Hair ZL1995H5 apparently represented an acute poisoning stage distinguishable from the mainly chronical exposure episode represented by Hair ZL1995H9. Analysis of additional hairs revealed thallium and lead distribution profiles either very similar to ZL1995H9 or similar to ZL1995H5. The averaged concentrations for both metals near the hair root in each analyzed hair sample were shown in Table 2 . Previous studies on the distribution of trace elements in human hair have found that lead and iron appeared to be accumulated near the periphery of the hair regardless of endogenous incorporation or external deposit, presumably due to the preferred binding of these metals by components in the hair cuticle and/or the alternative incorporation route of endogenous elements into hair shaft via secretion from the sebaceous glands after the formation of the hair shaft . We speculated that the significant amount of lead detected in the outer layers of hair ZL1995H5 should not be exclusively ascribed to contamination for at least three reasons. First, the absence of such elevated level of lead in the surface of longer hairs (ZL1995H1, ZL2991H2, ZL1995H9) suggest that the victim was not exposed to an unusual level of environmental lead either in school or at home during this period. Second, it was unlikely that this batch of hair samples have been contaminated by environmental lead during the storage or in the process of our analysis, since higher level of lead was only detected in the very short hairs. Third, exogenously deposited lead would unlikely produce peaks that were correlated with the internally ingested thallium. Nevertheless, an unambiguous determination on whether the victim had ingested large dose of lead during the second thallium poisoning period would require analysis of additional biological specimens that were collected right after the assumed poisoning period.
4.6 Alignment of thallium and lead distribution profiles with the victim’s symptoms The victim had experienced alopecia twice: loss of her long hair at the end of 1994, and then loss of all newly grown short hair in March 1995. Based on the hair length, ZL1995H9 likely fell from the victim during the first occurrence of alopecia, and ZL1995H5 likely fell during the second occurrence. Fig. 5 showed the alignment of the thallium and lead distribution profiles in these two hairs with the victim’s symptoms and life track from late 1994 to early 1995. Fig. 5 Alignment of the Tl and Pb distribution profiles in ZL1995H9 and ZL1995H5 with the victim’s symptoms and life track during 1994–1995. The toxicity of thallium stems from its ability to replace potassium and interfere with various potassium-dependent physiological processes due to similar charge and ionic radius. Thallium ions can be absorbed by human body rapidly and almost completely via virtually any route (ingestion, inhalation, skin contact), causing a wide spectrum of symptoms including gastroenteritis, multi-organ failure and neurologic injuries. The onset of poisoning signs and symptoms varies depending on both dose and exposure route . Alignment of ZL1995H9 with the first episode indicated that the victim had already been exposed to thallium for ∼3 months before the abrupt start of the striking poisoning symptoms. The sporadic intakes of relatively small doses during this prolonged period did not cause any apparent health problems, except a sudden and temporary vision loss occurring sometime in the fall of 1994. This may be attributed to the single high dose of thallium detected in the middle of ZL1995H9. The lack of any gastrointestinal or neurological response upon such a large exposure may suggest that thallium was possibly absorbed through eye contact, which usually only resulted in local irritation instead of systematic effects . It is also noteworthy that the victim used to wear contact lens but had to switch to glasses after this incident. The more frequent and larger thallium peaks near the root of ZL1995H9 correlate with the appearance of the hallmark signs of systematic thallium intoxication starting from early December 1994, including gastrointestinal manifestations (stomach pain, nausea and vomiting) that are characteristics of oral ingestion of thallium, ascending peripheral neuropathy (pins and needles sensation in the hands and feet), and gradual hair loss. Such correlation may indicate a change in exposure route to oral ingestion along with the transition from the chronic to acute poisoning. The victim went home in mid-December and became completely bald in late December 1994, a period of ∼2 weeks during which hair ZL1995H9 likely fell off. After a short remission with hair re-growing, the victim returned to school in late February 1995, only soon suffered another round of acute symptoms that ultimately forced her to go back to home again in early March. She then lost all the newly grown short hair. ZL1995H5 likely fell off during this period, and the short, yet consistent, exposure to the large amount of thallium reflected by this hair shaft would account for these acute intoxication manifestations as well as the clinical signs documented after she was sent to the hospital, including delirium, seizure, convulsion and eventually slipping into a coma for several months. More than a month later, quantitative GF-AAS analysis (measuring only thallium) was conducted and revealed significant amounts of thallium in her urine, blood, cerebrospinal fluid, hair and nails . Continuing monitor of the thallium levels in the victim’s blood and urine during the following medical treatment with thallium-specific antidotes demonstrated the gradual elimination of thallium from her body. The victim was eventually brought back to consciousness ∼4 months later, but suffered permanent memory impairment, another neuropsychological effect which can be caused by thallium intoxication . Computed tomography (CT) scan of her brain revealed both cerebral and cerebellar atrophy . Interestingly, lead could also attack both central and peripheral nervous system and, in the situation of acute exposure of large doses, trigger a set of polyneuropathy clinical signs that are very similar to those resulting from thallium poisoning, including severe pain, muscle weakness, delirium, convulsion and coma. An important mechanism of lead toxicity arises from its ability to replace divalent cations that are necessary for some critical cellular activities. For example, lead can replace calcium ions and pass through the blood-brain barrier, causing neurological abnormalities including memory-related neurotransmitter activities that may lead to memory loss . Therefore, the possible co-ingestion of lead with thallium in the second poisoning episode, as indicated by the co-presence of large amount of thallium and lead in ZL1995H5, would also synchronize with the victim’s symptoms during that period. However, alopecia was a distinct symptom only associated with thallium poisoning , thus the original diagnosis, medical treatment and forensic investigation have only focused on thallium. Thallium is also more acutely toxic than lead , which explains why the victim responded appreciably well to the thallium-specific antidotes, even though more lead than thallium was detected in ZL1995H5. Prior to this work, there had been no suspicion that the victim might have been co-poisoned by another heavy metal, since the amount of thallium detected in her body could adequately explain all the observed symptoms and responses following the medical treatment. This case thus highlighted the importance of assessing multiple elements in different biological specimens to aid in the medico-legal investigation of suspicious heavy metal poisoning upon clinical observations. 5 Conclusions Based primarily on the LA-ICP-MS analysis of two hairs, we have reconstructed the poisoning chronology of an unsolved cold case, which correlated well with the victim’s original symptoms. The results have also exposed a previously unknown chronic poisoning period with sporadic thallium exposures, the potential involvement of another heavy metal (lead), and clues on the possible routes of exposure at different poisoning stages. Future work may include analyzing additional hairs to investigate whether the first thallium peak detected in ZL1995H9 indeed represents the beginning of the first poisoning period. The analysis of other biological specimens collected from the victim around the poisoning period could be carried out to verify whether she had indeed co-ingested lead with thallium during the second poisoning period. Nevertheless, our work has demonstrated the capability of using single hair LA-ICP-MS analysis to retrieve information from meager specimens for the reconstitution of a prolonged and complicated heavy metal poisoning case. We hope this work could also raise the awareness of the importance of assessing multiple elements in different bio specimens due to the overlapping symptoms caused by some heavy metals and the intrinsic limitation of hair analysis to distinguish the internal versus external origins of certain elements. One of the strengths of ICP-MS analysis is the rapid determination of low levels of multiple elements simultaneously. The simple LA-ICP-MS analytical procedure developed in our work could be of considerable medical and forensic importance to resolve complicated heavy metal poisoning incidents. Careful collection and curation of hair samples from poisoning victims would also aid in the establishment of a precise time-line for the ingestions of the heavy metals. Authors’ contributions RDA conducted the LA-ICP-MS experiments and the data analysis, and contributed to the manuscript writing; MH conceived this project, conducted the data analysis and interpretation, and wrote the manuscript.
不知道舟子同学的女儿几岁，盲猜是10岁左右，这样回答问题，还是可以理解的
是有一个range的， 可以用来分析。
用生长速度上限和下限，分析结果偏差不大，第一个铊峰出现在八月中旬之前。
171天头发生长期就来自2018年原文。
方田争论的数据，也都来自2018年原文。
本来就很武断啊。下毒的人把从实验室里带出来的铊下在了含铅的食物中就会有这个曲线了。谁告诉你投毒的人必须下毒在纯净水里的？傻x告诉你的？还是你就是那个傻x？
你是男的还是女的？男的寸头，对头发生长速度最敏感了，打个新冠疫苗都可能让头发生长速度延缓一倍，还有不长头发秃头的
上限和下限分别是多少？你定的？
图二
图五
来自2018年文章
Forensic Science International Volume 292, November 2018, Pages 224-231 Forensic Science International Details of a thallium poisoning case revealed by single hair analysis using laser ablation inductively coupled plasma mass spectrometry
4.3 Pre- and post-poisoning basal levels for thallium and lead
The victim’s hair heavy metal levels prior to the poisoning period (1994–1995) was established by analyzing the longest hair, ZL1995H1 (∼30 cm), which should have fallen from the victim in 1994, since she became completely bald at the end of that year and never grew hair of such length in 1995. Thallium and lead concentrations of the first ∼3 cm from the hair root of this hair were 2.8 ng g −1 and 1.4 μg g −1 , respectively, close to the levels (3.7 ng g −1 and 0.8 μg g −1 , respectively) detected near the root of a hair collected in 2015 (ZL2015H100). Analysis of another very long hair, ZL1995H2 (∼26 cm), also showed very similar levels of thallium and lead, respectively ( Table 2 ). Table 2 Averaged Tl and Pb concentrations in each analyzed hair samples. For comparison purpose, only the contents in the last ∼3 cm hair shaft near the root of long hair samples (>3 cm) were averaged. For short hair samples (<3 cm), the contents of the entire length were averaged. Sample ID Collecting time Total length (cm) Tl (ng g −1 ) Pb (μg g −1 ) ZL2015H100 2015 ∼10 3.7 0.8 ZL1995H1 1995 ∼30 2.8 1.4 ZL1995H2 1995 ∼26 2.8 0.6 ZL1995H3 1995 ∼1 165 12 ZL1995H5 1995 ∼0.7 182 43 ZL1995H8 1995 ∼4 15 4 ZL1995H9 1995 ∼7 40 2
4.4 Longitudinal distribution of thallium in Hair ZL1995H9
The entire length of a ∼7 cm long hair (ZL1995H9) was scanned from the tip to the root. The longitudinal distribution profile of thallium was shown by the concentration plotted against the distance from the hair tip and the converted hair growth time, which was estimated based on the mean Asian hair growth rate of 411 (±53) μm/day . Approximately 25 distinguishable peaks, with maximum peak concentrations at or above 50 ng g −1 (∼20-fold above the basal level), were resolved along the entire hair shaft ( Fig. 2 A). The intervals between the sharp maxima of the thallium signal peaks varied between 0.5 and 8.6 mm, corresponding to ∼2–20 days. The distance between the first and the last recognizable thallium peak was ∼55 mm, corresponding to at least ∼4 months of hair growth time. An exceptionally tall peak of ∼530 ng g −1 in the middle of this hair shaft indicated a single exposure to an unusually large dose (∼200-fold above the basal level) of thallium. The duration of each peak was ∼2 days, in agreement with the previously observed rapid clearance of thallium from blood
. The thallium concentration baseline escalated near the hair root and was juxtaposed with a cluster of peaks with maximum concentrations of ∼150–220 ng g −1 , suggesting the victim had more frequent exposure to increased doses of thallium (50–80-fold above the basal level) ∼3 weeks before this hair fell out. Fig. 2 (A) The longitudinal Tl profile in Hair ZL1995H9 represented by its concentration against the distance from the hair tip (bottom X axis) and the converted hair growth time (top axis). (B) Alignment of the Tl profiles detected in the 1st and 2nd scan of ZL1995H9.
A repeated scan of the entire length of this hair showed identical 205 Tl distribution profile, but at a slightly higher level ( Fig. 2 B), confirming that the thallium had been absorbed internally and incorporated during the formation of the hair shaft via diffusion from blood to the actively growing follicle. This result was in agreement with the conclusion from the previous analysis of the victim’s blood and urine at the time of the diagnosis
. 4.5 Longitudinal distribution of thallium in Hair ZL1995H5
In contrast to the smooth surface appearance of hair ZL1995H1, ZL1995H2 and ZL1995H9, a rugged surface and dark gray lateral stripes were observed under the microscope ( Fig. 3 ), on a very short hair, ZL1995H5 (∼0.7 cm). Numerous congested thallium peaks spreading along the entire length of this hair were revealed by the first LA-ICP-MS scan, with concentrations varying between 150–500 ng g −1 (∼50–180 fold above the basal level). Intervals between the sharp maxima of most of the thallium signal peaks were ∼0.1–0.3 mm which corresponded to ∼6–18 h, suggesting consistent daily intakes of thallium. Surprisingly, significantly increased signals of lead ( 206 Pb, 207 Pb and 208 Pb) were also observed in this hair, with several large 208 Pb peaks aligning well with thallium peaks ( Fig. 4 A). The highest 208 Pb peak was ∼100-fold above the Pb baseline detected in ZL1995H1. Fig. 3 Microscopic pictures of hair samples. Before laser ablation, ZL1995H2 (A). After laser ablation ZL1995H2 (B), ZL1995H9 (C), ZL1995H5 (D). The red arrow indicated the laser ablated lines. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) Fig. 4 (A) Longitudinal distribution of Tl and Pb over the entire length of ZL1995H5, (B) alignment of the Tl profiles from the 1st and 2nd scan of ZL1995H5, (C) alignment of the Pb profiles from the 1st and 2nd scan of ZL1995H5.
The second scan of this hair revealed a similar, but not exactly overlapping, Tl profile ( Fig. 4 B), again slightly higher than the level detected in the first analyses. The misalignment of 205 Tl peaks between the two scans likely resulted from the damaged hair surface structure and disorganized cuticle, which had been observed before on the hair shaft from a victim who died of severe thallium poisoning
. In addition, the lead concentration decreased by ∼3-fold, but still ∼10-fold above the basal level ( Fig. 4 C), likely due to the complex reasons discussed below. Nevertheless, with much more frequent and higher thallium peaks and the co-appearance of large amount of lead, Hair ZL1995H5 apparently represented an acute poisoning stage distinguishable from the mainly chronical exposure episode represented by Hair ZL1995H9. Analysis of additional hairs revealed thallium and lead distribution profiles either very similar to ZL1995H9 or similar to ZL1995H5. The averaged concentrations for both metals near the hair root in each analyzed hair sample were shown in Table 2 .
Previous studies on the distribution of trace elements in human hair have found that lead and iron appeared to be accumulated near the periphery of the hair regardless of endogenous incorporation or external deposit, presumably due to the preferred binding of these metals by components in the hair cuticle and/or the alternative incorporation route of endogenous elements into hair shaft via secretion from the sebaceous glands after the formation of the hair shaft . We speculated that the significant amount of lead detected in the outer layers of hair ZL1995H5 should not be exclusively ascribed to contamination for at least three reasons. First, the absence of such elevated level of lead in the surface of longer hairs (ZL1995H1, ZL2991H2, ZL1995H9) suggest that the victim was not exposed to an unusual level of environmental lead either in school or at home during this period. Second, it was unlikely that this batch of hair samples have been contaminated by environmental lead during the storage or in the process of our analysis, since higher level of lead was only detected in the very short hairs. Third, exogenously deposited lead would unlikely produce peaks that were correlated with the internally ingested thallium. Nevertheless, an unambiguous determination on whether the victim had ingested large dose of lead during the second thallium poisoning period would require analysis of additional biological specimens that were collected right after the assumed poisoning period.
4.6 Alignment of thallium and lead distribution profiles with the victim’s symptoms
The victim had experienced alopecia twice: loss of her long hair at the end of 1994, and then loss of all newly grown short hair in March 1995. Based on the hair length, ZL1995H9 likely fell from the victim during the first occurrence of alopecia, and ZL1995H5 likely fell during the second occurrence. Fig. 5 showed the alignment of the thallium and lead distribution profiles in these two hairs with the victim’s symptoms and life track from late 1994 to early 1995. Fig. 5 Alignment of the Tl and Pb distribution profiles in ZL1995H9 and ZL1995H5 with the victim’s symptoms and life track during 1994–1995.
The toxicity of thallium stems from its ability to replace potassium and interfere with various potassium-dependent physiological processes due to similar charge and ionic radius. Thallium ions can be absorbed by human body rapidly and almost completely via virtually any route (ingestion, inhalation, skin contact), causing a wide spectrum of symptoms including gastroenteritis, multi-organ failure and neurologic injuries. The onset of poisoning signs and symptoms varies depending on both dose and exposure route . Alignment of ZL1995H9 with the first episode indicated that the victim had already been exposed to thallium for ∼3 months before the abrupt start of the striking poisoning symptoms. The sporadic intakes of relatively small doses during this prolonged period did not cause any apparent health problems, except a sudden and temporary vision loss occurring sometime in the fall of 1994. This may be attributed to the single high dose of thallium detected in the middle of ZL1995H9. The lack of any gastrointestinal or neurological response upon such a large exposure may suggest that thallium was possibly absorbed through eye contact, which usually only resulted in local irritation instead of systematic effects . It is also noteworthy that the victim used to wear contact lens but had to switch to glasses after this incident. The more frequent and larger thallium peaks near the root of ZL1995H9 correlate with the appearance of the hallmark signs of systematic thallium intoxication starting from early December 1994, including gastrointestinal manifestations (stomach pain, nausea and vomiting) that are characteristics of oral ingestion of thallium, ascending peripheral neuropathy (pins and needles sensation in the hands and feet), and gradual hair loss. Such correlation may indicate a change in exposure route to oral ingestion along with the transition from the chronic to acute poisoning. The victim went home in mid-December and became completely bald in late December 1994, a period of ∼2 weeks during which hair ZL1995H9 likely fell off. After a short remission with hair re-growing, the victim returned to school in late February 1995, only soon suffered another round of acute symptoms that ultimately forced her to go back to home again in early March. She then lost all the newly grown short hair. ZL1995H5 likely fell off during this period, and the short, yet consistent, exposure to the large amount of thallium reflected by this hair shaft would account for these acute intoxication manifestations as well as the clinical signs documented after she was sent to the hospital, including delirium, seizure, convulsion and eventually slipping into a coma for several months. More than a month later, quantitative GF-AAS analysis (measuring only thallium) was conducted and revealed significant amounts of thallium in her urine, blood, cerebrospinal fluid, hair and nails . Continuing monitor of the thallium levels in the victim’s blood and urine during the following medical treatment with thallium-specific antidotes demonstrated the gradual elimination of thallium from her body. The victim was eventually brought back to consciousness ∼4 months later, but suffered permanent memory impairment, another neuropsychological effect which can be caused by thallium intoxication . Computed tomography (CT) scan of her brain revealed both cerebral and cerebellar atrophy
.
Interestingly, lead could also attack both central and peripheral nervous system and, in the situation of acute exposure of large doses, trigger a set of polyneuropathy clinical signs that are very similar to those resulting from thallium poisoning, including severe pain, muscle weakness, delirium, convulsion and coma. An important mechanism of lead toxicity arises from its ability to replace divalent cations that are necessary for some critical cellular activities. For example, lead can replace calcium ions and pass through the blood-brain barrier, causing neurological abnormalities including memory-related neurotransmitter activities that may lead to memory loss . Therefore, the possible co-ingestion of lead with thallium in the second poisoning episode, as indicated by the co-presence of large amount of thallium and lead in ZL1995H5, would also synchronize with the victim’s symptoms during that period. However, alopecia was a distinct symptom only associated with thallium poisoning , thus the original diagnosis, medical treatment and forensic investigation have only focused on thallium. Thallium is also more acutely toxic than lead
, which explains why the victim responded appreciably well to the thallium-specific antidotes, even though more lead than thallium was detected in ZL1995H5. Prior to this work, there had been no suspicion that the victim might have been co-poisoned by another heavy metal, since the amount of thallium detected in her body could adequately explain all the observed symptoms and responses following the medical treatment. This case thus highlighted the importance of assessing multiple elements in different biological specimens to aid in the medico-legal investigation of suspicious heavy metal poisoning upon clinical observations. 5 Conclusions
Based primarily on the LA-ICP-MS analysis of two hairs, we have reconstructed the poisoning chronology of an unsolved cold case, which correlated well with the victim’s original symptoms. The results have also exposed a previously unknown chronic poisoning period with sporadic thallium exposures, the potential involvement of another heavy metal (lead), and clues on the possible routes of exposure at different poisoning stages. Future work may include analyzing additional hairs to investigate whether the first thallium peak detected in ZL1995H9 indeed represents the beginning of the first poisoning period. The analysis of other biological specimens collected from the victim around the poisoning period could be carried out to verify whether she had indeed co-ingested lead with thallium during the second poisoning period. Nevertheless, our work has demonstrated the capability of using single hair LA-ICP-MS analysis to retrieve information from meager specimens for the reconstitution of a prolonged and complicated heavy metal poisoning case. We hope this work could also raise the awareness of the importance of assessing multiple elements in different bio specimens due to the overlapping symptoms caused by some heavy metals and the intrinsic limitation of hair analysis to distinguish the internal versus external origins of certain elements. One of the strengths of ICP-MS analysis is the rapid determination of low levels of multiple elements simultaneously. The simple LA-ICP-MS analytical procedure developed in our work could be of considerable medical and forensic importance to resolve complicated heavy metal poisoning incidents. Careful collection and curation of hair samples from poisoning victims would also aid in the establishment of a precise time-line for the ingestions of the heavy metals. Authors’ contributions
RDA conducted the LA-ICP-MS experiments and the data analysis, and contributed to the manuscript writing; MH conceived this project, conducted the data analysis and interpretation, and wrote the manuscript.
我问的问题那么简单，你贴论文干嘛 最烦的就是问一个简短的问题，砸回来一整篇论文，这是没有概括能力还是啥
你怎么这么固执。原文就一定是100%对的呀？你没有自己写过论文吗？
就是这句话。头发生长速度因人而异，不同人之间差别大了！有的半年不用理发，有的俩月就很长了！
这是正常情况，中毒以后头发生长肯定不正常，毛囊都破坏了
黑体部分。
来自文献的亚洲女性头发生长速度。
你要反驳这个就出数据哈，凭个人“感觉”那是要被理工科的嘲死的。
原文有数据
唯一的朱令案令人信服的数据，为什么不能来讨论
你也拿不出有力的数据和讨论能驳倒这论文啊。
那只有减缓生长速度不是？那更要把初次中毒日期向前推了是不是？
单独贴黑体部分不行吗？ 反驳这个数据只需要用常识就行了，说到理工科，你理解平均两个字是什么意思吗？
当然不是，过快过慢都有可能
平均就是平均，朱令还能偏离平均几个标准差出去？那个几率有多高？
你不考虑她中毒的异常情况吗？
是的，每人体质基因不同，不能一概而论，不是孙干的，为什么清华不发毕业证屁都不放发，你太侮辱北京公交的智力了 ，
中毒以后是减缓头发生长速度几率大还是加速生长几率大？
减缓头发生长会对日期估算发生什么影响？会对初次中毒日期的估算造成什么影响？
你不是理工科专家吗？问我干嘛，真是好笑了
讲概率，不是孙维下毒的高吗？
不读帖么？
头发分析是2018年做的
你让九十年代北京公安怎么看到这些分析？
如果这些分析成立，那孙的概率就低了不是？
孙还没进实验室接触到铊的时候，朱令就已经中毒了
是很好笑啊，你摆不出数据也拿不出逻辑
却以为自己真理在握
问题是头发的长度不能推断具体日期，你要是那么厉害，能推出来，你就给孙维洗白啊，可惜你不能，你没那个本事不是吗？
头发长度至少可以给出一个事件发生时间的range不是？
对厘清案情会没有帮助么？
不精确到日小时秒就没有用处么？
我不需要拿数据，孙维就是很大嫌疑，需要拿出这个数据的是想给孙维洗白的你
你range的可能性不是100％，还叫啥range
当然可以估计到，上面这些就是根据科学技术提供的数据估算出的日期。
你不同意那就拿出数据和逻辑来驳倒。
你拿不出100％孙维不在场的证据，就洗不白孙维，别太急了
411 (±53) ：一共才411，差53啊！
那你算算用 411计算的天数，和用464计算的天数有多大的差别，再说好不好？洗🛀🏻也得用心，用脑。啥都不想用，怎么洗得干净？
态度驳不倒数据
我没能力知道事实真相，只是看到别人的数据和分析，估算初次中毒时间在八月中旬之前我同意而已。
至于这个日期对案件有什么意义，大家自然有判断。
就这还是平均值的一个范围
哈哈哈，
那么孙的嫌疑就是100%？
你不看后句吗？为什么孙不给发毕业证和的出国证明以她的背景不闹上天？这是心里有鬼心虚啊，铊党总是完美身躲开案发时的证据。😖
可惜估算数据没有说服力
她要是100％不是已经被抓了吗？怎么你想连她有嫌疑都不承认了，你有这个本事吗？
我根本没想洗白谁，只是注意到一个案情的关键问题。
是你不愿意接受有可能削弱你立场的数据和分析而已。
用立场和态度来对待数据和逻辑。
是初次中毒是七月中旬到八月中旬的差别。
都可能在朱令返校之前。
https://twitter.com/fangshimin/status/1741607860189204788/photo/1
你觉得孙是清白的，让她回国去重启案子，真正洗清自己，别整天躲得如过街老鼠般，她可以向公安展示这2018年的论文也不晚
我一早就说了头发生长速度差异太大，不能准确估算的，8月中旬和9月只差10来天，这种分析没有意义 是你非要像发现了新大陆一样说这就是有意义的，你的意义无非就是给孙维洗白，怎么还要为这个伟大的发现给你颁发个诺贝尔奖吗？
顶这位妹妹👍
我没觉着谁清白不清白，
只是报告一个新发现
意味着什么大家自有自己的判断
仅此而已
你怎么知道头发哪天掉的，起码应该用中毒峰值找平啊
呵呵呵
我认为有意义，
能帮助确定朱令第一次铊中毒的地点
怎么会没帮助，
任何线索都有助于案情分析和确定凶嫌不是么？
为什么这么抗拒？
对你这种无用功我有什么抗拒的，只是看你上蹿下跳而已，你继续
不是八月中旬和九月，如果分析结果是这个，那就没什么意义了。
而是分析结果是首次中毒日期可能在七月中旬到八月中旬
是不是在清华小学期开学前
就算按你的结果，八月中旬和9月就差10来天，你还不知道头发啥时候掉的，你觉得你能说服谁？
是不是无用功你说了没用，
数据和逻辑比态度和立场有用
数据和逻辑要能说明问题，你啥都说明不了，还蹦跶啥
虚张声势
目前所有记录朱令首次完全脱发不晚于94年底，这些分析都是以这个前提为基准的。
你有证据94年底朱令没有完全脱发可以摆出来。
对尊重数据和逻辑的头脑当然有用
你自己都说公开报导的数据有误，这些数据都来自于你的推算（就算按你的推算，也承认八月中旬有可能），事实上头发生长速度并不能确定，只有一个统计平均值，距离9月只有10来天，头发起点怎么算也不好估计，你是怎么自信你的结果是对的呢？
只要真正尊重数据，都不会认为你说的是对的
化妆品 中药里面的铅含量有那么高？ 妈蛋， 那我们是不是都铅中毒了
不是，是汽油添加剂四乙基铅祸害人类。如果1960年代某聪明的人（不记得他的名字了）坚持否定四乙基铅作为汽油抗震添加剂，那么现在的人估计都是低智商的zombie
那厮就是胡说八道，既然说化妆品里铅污染，那就应该给出数据吧，有吗？没有。张嘴就胡诌的汪80，人家一个比如，就是真的了！
方pp连生物都没有搞明白，却窜刑侦里想破案！多荒谬！一外行货反倒能比当年出现场的刑侦人员厉害！可能吗？
一定是宿舍的东西？ 朱令每周末都回家吗，每周去乐团吗？
这智商， 朱爸爸为什么就知道，他也有可能被误导呀。
你才弱智！朱令是回家，难道她爸妈投铊毒她？乐队的人能接触铊吗？问你为什么清华不发毕业证不批孙铊出国她不反抗？如果冤枉她大可回国去告朱家告网友，把那𠆤狗屁论文呈上，不是可以洗清冤枉以后堂堂正正生活了，何必到处被驱逐，过街老鼠一般🙄
演奏会之前要多补补。
大过节的，歇歇吧！一定不是宿舍的东西，是乐团的或者是贝志诚拿来的。薪高粮准的空心菜无心/雪兔子，今晚零点应该给大家发红包吧😄
朱令，现在是无病一身轻，当新年的钟声敲响的时候，别忘记孙铊哈。哎呀，我错了，朱令只能来薛铊家做客啦。其它铊家都是白天。
就是多吃点营养品的意思。 你为啥跳那么高？
你怎么知道孙维当时没有去闹？她去闹了还要告诉你吗？清华只是暂扣了孙维的毕业证，最后还是发了。
你怎么证明清华八月底开学是事实？朱令的同班同学“王一风”(化名)说是9月开学，网上还有一些人说了具体的开学日期是9月6日，你说是8月底，到底哪种说法是事实呢？这个应该不难去证实。
你还把我拉黑了，真可笑。是不是要屏蔽所有和你意见不一样的人？
一般来说，头发中的铅含量的正常范围通常在1到10微克/克（微克/克，即毫克/千克）
什么白宫请愿，颠沛流离，还真以为孙维被美国政府驱逐出境了？美国政府当时都回复了说对请愿的要求不发表评论。
驱逐出境是你说的，你阅读理解不好别出来现。 是是是，没颠沛流离，这回可千万别再跑了，就老老实实待在澳洲，多少人请愿都别跑。 你这根棍子还不如肘子呢，肘子至少敢舔着脸实名硬凹，你披个壳子连露脸的勇气都没有。
“被驱逐出境”也只是我借用你们这些网络侦探的话，我看到很多人说她被美国政府驱逐出境，真是张口就来。还有，从美国搬到澳洲怎么就算是“颠沛流离”了？你想象力真是丰富。
网络暴民实在恐怖，不光是人肉孙维和她室友，还要人肉他们的小孩。还会把不同意见的人都打成铊党，我承认自己怂，不敢实名招惹。我就是个吃瓜网友看不惯这些暴民的所作所为出来说几句。
好像也不是很对。关键词似乎是“有些”。
是反讽吗？ 难道结论不应该是：
“铊的来源几种，有些铊很纯、有些铊不纯吗” 或者是： “定期吃的食物中，有一段时间换口味了，里面有铅”
人家是美国公民，怎么可能被驱逐出境？根本就是胡扯
不管怎样也是在强大的15万人投票下吓尿遁了，不然美国这么舒服跑什么🤔
让孙铊买铊水军吧，让她破破财。
千万别从澳洲又被赶到加拿大。丧家之犬的滋味不好受
让你铊主子晒晒？有这胆儿吗？