Mothball composition: three simple tests for distinguishing paradichlorobenzene from naphthalene

Naphthalene Toxicity in a Three-Year-Old Child Complicated by Severe Hemolytic Anemia and Mild Methemoglobinemia: A Case Report

BACKGROUND

Exposure to naphthalene, which is widely used in mothballs, does not usually produce adverse effects. However, naphthalene can be toxic, especially in individuals with underlying conditions such as glucose-6-phosphate-dehydrogenase (G6PD) deficiency.

CASE REPORT

A 3-year-old boy was brought to our Emergency Department after accidentally ingesting naphthalene mothballs 3 days prior to presentation. Laboratory investigations revealed that he had severe hemolytic anemia and mild methemoglobinemia (6%), which were treated with ascorbic acid and N-acetylcysteine. The patient tested positive for G6PD deficiency after stabilization and completion of his treatment. All provided treatments were administered empirically; test results were available only after the patient was discharged. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Naphthalene exposure is a common pediatric presentation with various complications that can occur in certain high-risk individuals, such as those with G6PD deficiency. Emergency physicians should be aware of this to anticipate and be able to treat worsening toxicity.

Identification of mothball powder composition by float tests and melting point tests

INTRODUCTION

The aim of the study was to identify the composition, as either camphor, naphthalene, or paradichlorobenzene, of mothballs in the form of powder or tiny fragments by float tests and melting point tests.

METHODS

Naphthalene, paradichlorobenzene and camphor mothballs were blended into powder and tiny fragments (with sizes <1/10 of the size of an intact mothball). In the float tests, the mothball powder and tiny fragments were placed in water, saturated salt solution and 50% dextrose solution (D50), and the extent to which they floated or sank in the liquids was observed. In the melting point tests, the mothball powder and tiny fragments were placed in hot water with a temperature between 53 and 80 °C, and the extent to which they melted was observed. Both the float and melting point tests were then repeated using intact mothballs. Three emergency physicians blinded to the identities of samples and solutions visually evaluated each sample.

RESULTS

In the float tests, paradichlorobenzene powder partially floated and partially sank in all three liquids, while naphthalene powder partially floated and partially sank in water. Naphthalene powder did not sink in D50 or saturated salt solution. Camphor powder floated in all three liquids. Float tests identified the compositions of intact mothball accurately. In the melting point tests, paradichlorobenzene powder melted completely in hot water within 1 min while naphthalene powder and camphor powder did not melt. The melted portions of paradichlorobenzene mothballs were sometimes too small to be observed in 1 min but the mothballs either partially or completely melted in 5 min. Both camphor and naphthalene intact mothballs did not melt in hot water.

CONCLUSIONS

For mothball powder, the melting point tests were more accurate than the float tests in differentiating between paradichlorobenzene and non-paradichlorobenzene (naphthalene or camphor). For intact mothballs, float tests performed better than melting point tests. Float tests can identify camphor mothballs but melting point tests cannot. We suggest melting point tests for identifying mothball powder and tiny fragments while float tests are recommended for intact mothball and large fragments.

An algorithm for identifying mothball composition. Clin Toxicol (Phila) 2017;55:919-921. [PMID: 28541143 DOI: 10.1080/15563650.2017.1319954]

INTRODUCTION

Unintentional mothball ingestions may cause serious toxicity in small children. Camphor, naphthalene, and paradichlorobenzene mothballs are difficult to distinguish without packaging. Symptoms and management differ based on the ingested compound. Previous studies have used a variety of antiquated, impractical and potentially dangerous techniques to identify the mothballs. The goal of this study is to discover a simplified identification technique using materials readily available in an emergency department.

METHODS

Mothballs made of naphthalene and paradichlorobenzene along with camphor tablets were tested. Each material was tested both intact and after being fragmented to simulate a partially ingested mothball. Each of these six sample types were then immersed in 40 ml each of 11 fluids: water, 0.45% NaCl, 0.9% NaCl, lactated Ringer's, 5% dextrose in water, 5% dextrose in 0.9% NaCl, 50% dextrose in water, 8.4% NaHCO₃, 3% H₂O₂, 70% isopropanol, and 91% isopropanol. All tests were conducted in standard urinalysis sample cups to replicate available materials. Three toxicologists blinded to the identities of samples and solutions visually evaluated each sample. Observations included assessing response to immersion: sink, float, or dissolve.

RESULTS

All evaluators agreed in their description of 62/66 (94%) of the samples, with all four disagreements being on sinking and dissolving versus sinking only. A two-fluid algorithm utilizing 50% dextrose and water was sufficient to distinguish the sample types. Camphor will float in water while both paradichlorobenzene and naphthalene will sink. In 50% dextrose, both naphthalene and camphor will float while paradichlorobenzene will sink.

CONCLUSION

Mothball materials can be distinguished by immersion in water and 50% dextrose. Limitations of this study include using camphor tablets as a substitute for mothballs given lack of availability.

Hemolytic anemia induced by ingestion of paradichlorobenzene mothballs

Hemolytic anemia and methemoglobinemia are well-known adverse effects that follow ingestion of naphthalene mothballs. They are only rarely reported in association with ingestion of paradichlorobenzene mothballs. An asymptomatic boy presented to our pediatric emergency department after ingesting paradichlorobenzene mothballs. Three daysafter the ingestion, the boy returned with hemolysis and mild methemoglobinemia.